BTG Mütek GmbH Operation manual - INVEN · Operation manual PCD 03/ PCD 03 pH Particle Charge Detector Mütek WET ® Lab BTG Mütek GmbH

Operation manualPCD 03/ PCD 03 pHParticle Charge Detector

Mütek WET ® Lab

BTG Mütek GmbH

Copyright© 2003 BTG Mütek GmbHAll rights reserved. No part of this manual may be copied, photocopied,

published, reproduced, translated or converted into electronic or machine-readable form without written permission of BTG Mütek GmbH.

Subject to technical modifications

BTG Mütek GmbH, December 2003

Printed in Germany

List of contents

Chapter Paragraph Title Page

List of contents

I. Basic safety instructions

1.1 Manufacturer’s liability . . . . . . . . . . . . . . . . . . . . . . . 51.2 Intended application of the PCD 03/ PCD 03 pH . . 61.3 Non-legitimated usage . . . . . . . . . . . . . . . . . . . . . . 61.4 Qualification of personnel . . . . . . . . . . . . . . . . . . . . 61.5 General safety directions. . . . . . . . . . . . . . . . . . . . . 71.6 Informal safety measures . . . . . . . . . . . . . . . . . . . . 71.7 Expendable and spare parts . . . . . . . . . . . . . . . . . . 71.8 Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.9 Packaging & transport . . . . . . . . . . . . . . . . . . . . . . . 8

II. Product description 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.1 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.2 Measuring principle . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.3 Calculation of charge demand. . . . . . . . . . . . . . . . . 102.1.4 Determination of the isoelectric point . . . . . . . . . . . 102.1.5 Determination of optimum dispersant dosages . . . . 112.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.3 Designation of the PCD 03/ PCD 03 pH . . . . . . . . . 122.4 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.5 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.5.1 PCD 03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.5.2 PCD 03 pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

III. Layout and function 3.1 Description of PCD 03/ PCD 03 pH. . . . . . . . . . . . . 153.1.1 Measuring cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.1.2 pH-Electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

IV. Installation 4.1 Safety rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.2 Personnel requirements . . . . . . . . . . . . . . . . . . . . . 194.3 Preparations on-site . . . . . . . . . . . . . . . . . . . . . . . . 194.4 Installation environment . . . . . . . . . . . . . . . . . . . . . 194.4.1 Installation point . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.4.2 Power connection . . . . . . . . . . . . . . . . . . . . . . . . . . 194.4.3 Sample specification . . . . . . . . . . . . . . . . . . . . . . . . 214.5 Start up procedure. . . . . . . . . . . . . . . . . . . . . . . . . . 234.5.1 Prepare electrical connections . . . . . . . . . . . . . . . . 234.5.2 Automatic titration . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.5.2.1 PCD-Two titrator . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.5.2.2 PCD 03 pH with Metrohm Titrino 702/ 716 . . . . . . . 25

4.5.2.3 Manual operation. . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.5.3 Calibration of pH-electrode of the PCD 03 pH. . . . . 264.5.4 Titrant solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.5.5 Acids/bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.5.6 Cleaning solution. . . . . . . . . . . . . . . . . . . . . . . . . . . 274.5.7 Buffer solutions for pH calibration . . . . . . . . . . . . . . 27

PCD 03/ PCD 03 pH Operation manual 3© BTG Mütek GmbH, December 2003

List of contents

Chapter Paragraph Title Page

V. Operation 5.1 Safety rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.2 Personnel requirements . . . . . . . . . . . . . . . . . . . . . 295.3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.4 Sample preparation . . . . . . . . . . . . . . . . . . . . . . . . 295.4.1 Filtration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.4.2 Centrifugation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.4.3 Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295.4.4 Back titration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.4.4.1 Example of back titration . . . . . . . . . . . . . . . . . . . . 30

5.5 Measuring with the PCD 03/ PCD 03 pH . . . . . . . . 315.6 Titration curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.6.1 Colloidally dissolved particles. . . . . . . . . . . . . . . . . 325.6.2 Solid particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.6.3 Heterogeneous stock systems . . . . . . . . . . . . . . . . 325.6.4 Selection of titration rate. . . . . . . . . . . . . . . . . . . . . 33

VI. Diagnostics and troubleshooting

6.1 Safety rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356.2 Personnel requirements . . . . . . . . . . . . . . . . . . . . . 356.3 Tables of system faults. . . . . . . . . . . . . . . . . . . . . . 35

VII. Maintenance 7.1 Personnel requirements . . . . . . . . . . . . . . . . . . . . . 377.2 Cleaning the measuring cell . . . . . . . . . . . . . . . . . . 377.3 Functional test . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377.3.1 Basic test of PCD without cell. . . . . . . . . . . . . . . . . 377.3.2 Standard titration . . . . . . . . . . . . . . . . . . . . . . . . . . 377.3.3 Check of streaming current . . . . . . . . . . . . . . . . . . 377.3.4 Electrostatic charging of the cell . . . . . . . . . . . . . . . 387.3.5 Functional test of pH-electrode. . . . . . . . . . . . . . . . 38

VIII. Shutting down the system, storage and disposal

8.1 Safety rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398.2 Personnel requirements . . . . . . . . . . . . . . . . . . . . . 398.3 Shutting down the system . . . . . . . . . . . . . . . . . . . 398.4 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398.5 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398.5.1 Official regulations . . . . . . . . . . . . . . . . . . . . . . . . . 39

IX. Part lists 9.1 Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419.2 Consumable goods. . . . . . . . . . . . . . . . . . . . . . . . . 429.3 Work safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4 PCD 03/ PCD 03 pH Operation manual

© BTG Mütek GmbH, December 2003



1.1 Manufacturer’s liability

Notices in the operation manual

- Operators of the PCD 03/ PCD 03 pH have to strictly adhere to the basic safety instructions and the safety rules in order to ensure safe handling and reliable operation of the PCD 03/ PCD 03 pH

- This operation manual contains the basic safety instructions and the safety rules in order to ensure safe handling and reliable operation of the PCD 03/ PCD 03 pH

- All persons operating the PCD 03/ PCD 03 pH must observe this operation manual, and in parti-cular the safety directions

- In addition, all applicable accident prevention regulations have to be met for the specific loca-tion

Obligations of the user

The warranty and service quality pledges are only applicable subject to the following conditions:

- The PCD 03/ PCD 03 pH may be operated only by persons who have to be thoroughly trained and authorized by BTG Mütek GmbH

- All instructions by BTG Mütek GmbH regarding operation and maintenance of the PCD 03/ PCD 03 pH must be observed

- Storage and maintenance of the instrument must be carried out in accordance with BTG Mütek GmbH’s instructions

- Use of any parts other than the original BTG Mütek GmbH replacement and spare parts will cause instant termination of service quality and guarantee claims

- Failures which affect safe operation of the sys-tem have to be repaired immediately

- When the system is obviously damaged or parts in the inside are loose or the system does not work, operation with the PCD 03/ PCD 03 pH has to be stopped

Hazards involved in handling the PCD 03/ PCD 03 pH

The PCD 03/ PCD 03 pH has been built to reflect state-of-the-art techniques and to meet recognized safety rules. However, its operation may entail the risk of accidents for users or third parties or of damage to the PCD 03/ PCD 03 pH or other pro-perty. The PCD 03/ PCD 03 pH shall only be opera-ted

- For the applications outlined in these operation manual

- In a condition meeting all safety rulesUsers are obliged to immediately eliminate without delay any faults that may afffect operational safety.

Warranty and liability

This instrument was built and tested in accordance with EG guidelines EN50081, EN50082 and EN61010 and complied with all safety regulations at the time of leaving our factory. To maintain this con-dition and ensure safe operation, the user must observe the safety instructions and warning notes contained in this operation manual. It is the responsi-bility of the owner and user to make sure that all safety devices and requirements concerning the location of the instrument are adequately provided for. Basically, the General Terms and Conditions of BTG Mütek GmbH will apply and are available to the operator of the PCD 03/ PCD 03 pH at the latest on the day the sales contract is concluded. BTG Mütek GmbH shall not be liable for any warranty or liability claims for personal injury or property damage that may be consequential to one or several of the follo-wing causes:

- Non-legitimated use of the PCD 03/ PCD 03 pH- Opening of the instrument or removing the seal

of the holding down bolt on the rear of the sys-tem

- Inexpert installation/assembly, commissioning, operation and servicing of the PCD 03/ PCD 03 pH

- Operation of the PCD 03/ PCD 03 pH although its safety devices and protection facilities are defective, inexpertly mounted or malfunctioning

- Failure of the user/operator to adhere to the instructions given in this operation manual regar-ding transport, storage, assembly, commissio-ning, operation and maintenance of the PCD 03/ PCD 03 pH



- Modifications made to the PCD 03/ PCD 03 pH without the prior approval of BTG Mütek GmbH

- Inadequate routine checks of PCD 03/ PCD 03 pH parts/assemblies that are subject to wear

- Inexpert repairs- Catastrophes caused by the effects of foreign

objects or by acts of God Trouble-free and safe operation of the instrument is possible only subject to correct transport, correct sto-rage, installation and assembly and to careful hand-ling and maintenance.

If the PCD 03/ PCD 03 pH is sent in for repair the whole system has to be sent in.

The guarantee for the PCD 03/ PCD 03 pH is one year starting with the date of delivery.

For defects included in the guarantee, BTG Mütek GmbH shall not be liable for any damages higher than the cost price.

For defects included in the guarantee, BTG Mütek GmbH has the right to decide whether damaged parts are exchanged or repaired (provided that all parts have been returned to an authorized retailer in time).

This guarantee does not include parts which have been commissioned or altered without prior written permission by an authorized BTG Mütek GmbH-retailer.

Neither does BTG Mütek GmbH take any obligations in connection with the sale of the measuring instru-ment nor has BTG Mütek GmbH instructed any other person to take on such an obligation.

Exclusion of liability

BTG Mütek GmbH has checked the contents of the printed manual for consistency with the hardware described. However, deviations cannot be entirely excluded, so that BTG Mütek GmbH will not accept responsibility for absolute consistency. The contents of this manual are regularly revised, and any correc-tions which may be necessary will be included in later issues.

The right is reserved to make technical alterations.

1.2 Intended application of the PCD 03/ PCD 03 pH

The instrument may only be used for the purposes defined in this operation manual and in the technical description, and only in conjunction with external instruments and components recommended or approved by BTG Mütek GmbH.

The BTG Mütek GmbH Particle Charge Detector PCD 03/ PCD 03 pH is to be solely used for charge identification of aqueous samples and for identifying the isoelectric point.

Any other or further-reaching application is not legiti-mate. BTG Mütek GmbH will not be held liable for damage resulting from such use. An integral part of legitimate use is also:

- To follow all the instructions in this operation manual, and

- To perform the inspection and maintenance work as specified

1.3 Non-legitimated usage

Non-legitimated usage (misuse) is defined as fol-lows:

- Any usage other than the legitimate usage defi-ned above, or extending beyond the designated usage

- Failure to follow the instructions given in this operation manual

- Failure to observe the safety directions- Failure to immediate correction, prior to continu-

ing work with the instrument, any defect which might endanger safety (operation of the instru-ment in a condition which does not meet techni-cal and safety requirements)

- Any unauthorized modification of the instrument

1.4 Qualification of personnel

The instrument may be commissioned and operated only by qualified personnel. Qualified personnel as definded by the safety instructions in these operation manual are persons trained and instructed by BTG Mütek GmbH.




1.5 General safety directions

For all installation, operation, maintenance and repair work performed on the PCD 03/ PCD 03 pH, it is essential that the directions given below be follo-wed:

- Installation and operation has to be performed by trained personnel

- Inspection tasks due on a daily basis must be performed by trained personnel

- Maintenance and repair work not described in this manual should not be performed without first consulting the manufacturer or an authorized service agent

- When working on electrical and electronic parts, the instrument must be switched off at the main switch and the plug disconnected from the power supply

- When replacing defective parts, use only original spare parts

- When handling dangerous materials, please observe the directions for protective equipment, industrial hygiene and proper disposal

1.6 Informal safety measures

Take care to keep this operation manual on the

PCD 03/ PCD 03 pH. In addition, make sure that documentation on general and local accident preven-tion and environmental protection standards is near at hand and strictly adhered to. Keep all safety instructions and warnings on the PCD 03/ PCD 03 pH in a legible condition and renew, if necessary.

1.7 Expendable and spare parts

Use original expandable and spare parts only to ensure operational safety of the PCD 03/ PCD 03 pH and to safeguard your guarantee claims. Spare parts are available from your local authorized representa-tive of BTG Mütek GmbH.

1.8 Symbols

The following symbols and notices are used in this operation manual to designate hazards or to provide special information:

Information

"Information" means tips for operators and useful information.

It helps you make optimum use of all functions of the PCD 03/ PCD 03 pH.

Hint

"Hint" refers to expert handling and operation of the PCD 03/ PCD 03 pH.

Non-adherence to these hints may lead to operatio-nal failures of the PCD 03/ PCD 03 pH or to trouble in its surroundings.

Caution

"Caution" refers to a potentially dangerous situation. Failure to observe this information may result in slight personal injury or in damage to equipment.

Warning

"Warning" refers to potential hazards.

Failure to observe this information may result in severe injury to health.



1.9 Packaging & transport

The BTG Mütek GmbH PCD 03/ PCD 03 pH is a compact and sturdy unit which is easy to transport for onsite measurements.

Hint

The aluminium case does not stand up to rough handling in transit.

Hint

The aluminium case is unsuitable for rail forwarding or postal delivery of the unit.

- To avoid damage in transit to the precision can-tact pins do not keep any small components in the measuring chamber. Before transport, take the measuring cell off the dovetailed guide.

- At outdoor temperatures below +15°C [59°F], it is recommended to let the unit adjust to ambient temperature after transport before putting it into operation.

Hint

If the PCD 03/ PCD 03 pH is exposed to very low temperatures for a protracted period of time, the electronics may be damaged. Take care to remove the device from the trunk of your car in cold weather.



II. Product description


2.1 General

In aqueous systems, such as dispersions or emulsi-ons, the charges play a crucial role, because they are responsible for reaction mechanisms between colloidal particles.

Applying polyelectrolyte titration, the PCD 03/ PCD 03 pH Particle Charge Detector continuously moni-tors the total surface charges of all dissolved and undissolved substances present in an aqueous sample.

2.1.1 Fundamentals

Streaming current

Practically all colloidally dissolved substances and solid particles in water carry electric charges. This leads to a concentration of oppositely charged ions, the so-called counter-ions, on the colloids surfaces. If these counter-ions are separated from, or sheared off, the dissociated macromolecule or particle, a stre-aming current can be measured in mV. A streaming current of zero mV denotes the point of zero charge, i.e. all existing charges in the sample are neutralized.

If the measured potential is unequal to zero, the sign of the measured value merely indicates whether the charge is positive (cationic) or negative (anionic).

The potential itself is a relative parameter that depends on different influential factors, such as

- Electrical conductivity of the sample dispersion- Sample viscosity - Molecular weight and particle sizes of the

sample- Dimensions of the measuring cell- Temperature- Cleaning of the measuring cell- Chemical properties of the sample

2.1.2 Measuring principle

Streaming current measurements with the PCD 03/ PCD 03 pH are based on the following principle (Fig. 2-1 Schematic of test setup): the central element is a plastic measuring cell (4) with a fitted displacement piston (5).

If an aqueous sample is filled into the measuring cell, colloidally dissolved molecules will adsorb at the plastic surface of the piston and on the cell walls under the action of van der Waal forces. The coun-ter-ions remain comparatively free. A defined narrow gap is provided between cell wall and piston.

Driven by a motor (6), the piston (5) oscillates in the measuring cell (4) and creates an intensive liquid flow which entrains the free counter-ions, thus sepa-rating them from the adsorbed sample material.

At the built-in electrodes (3), the counter-ions induce a current which is rectified and amplified electroni-cally (2).

The streaming current is shown on the display (1) with the appropriate sign.

Fig. 2-1 Schematic of test setup

Designations

1 Display 4 Plastic measuring cell

2 Electronics 5 Displacement piston

3 Electrodes 6 Motor

1

2

4

5

6

3


10


2.1.3 Calculation of charge demand

Polyelectrolyte titration

For quantitative charge measurements of the sample, a polyelectrolyte titration has to be conduc-ted which uses the streaming current to identify the point of zero charge (0 mV). To this end, an opposi-tely charged polyelectrolyte of known charge density is added to the sample as a titrant.

The titrant charges neutralize existing charges of the sample. Titration is discontinued as soon as the point of zero charge (0 mV) is reached.

Titrant consumption in ml is the actual measured value which forms the basis for further calculations.

Calculation

The specific charge quantity q [eq/g] is calculated according to the following formula:

V: consumed titrant volume [l]

c: titrant concentration [eq/l]

m: solids of the sample or its active substance [g]

q: specific charge quantity [eq/g]

Example: When measuring an 0.1 % Ti02 suspen-sion, a 10 ml sample contains 0.01 g solids, m = 0.01 g.

Consumption of cationic polyelectrolyte until point of zero charge 2.5 ml.

Titrant concentration was 0.001 N.

By multiplying the specific charge quantity in eq/g by the Faraday’s constant F = 96485 C/eq, the total charge quantity in C/g will be obtained.

If several identical samples are to be compared, the charge quantity q does not have to be calculated pro-vided the samples are titrated under identical conditi-ons, i.e. at the same sample solids and titrant concentrations. In this case, the measured volume of consumed titrant in ml may be directly used and the values obtained are directly comparable. In this con-text, the terms anionic and cationic demand of a sample are in common use.

2.1.4 Determination of the isoelectric point

Acid/base titration

Apart from charge density measurements, the PCD 03/ PCD 03 pH lends itself to identifying the isoelec-tric point (IEP) of dispersions.

The IEP is the pH-dependent point of zero charge of a particle. In this context, existing layers of specifi-cally adsorbed charge carriers are taken into account.

By dropwise addition of a titrant (acid/base), the sample pH’s are shifted until the point of zero charge (streaming current = 0 mV) is reached.

Cationic samples are titrated with a base and anionic samples with an acid up to the point of 0 mV.

The pH value is detected parallel to the streaming potential.

Fig. 2-2 Isoelectric point

V * cq =

m

0.0025 [l] * 0.001 [eq/l]= 250 * 10-6 [eq/g]

0.01 [g]

PCD 03/ PCD 03 pH Operation manual



2.1.5 Determination of optimum dispersant dosages

Optimum dispersant additons are conveniently iden-tified by titrating a particle suspension of a defined solids content with the dispersant solution. For this purpose it will be sufficient to obtain a concentration-dependent potential characteristic without an end-point titration to zero mV being required. Short-chai-ned inorganic dispersants and longer-chained orga-nic additives give clearly different graphs. In both cases, optimum dispersant dosages can be derived from the potential characteristics obtained from the PCD and the results can be readily transferred to the technological process concerned. The PCD 03/ PCD 03 pH thus lends itself very well to an assessment of particle/ additive interactions, overall stability and optimized chemical additions.

Fig. 2-3 Stability maxima

2.2 Applications

Paper making

- Improved machine running through optimized elimination of anionic trash

- Enhanced retention- Increased chemical performance- Good runnability- Chemical savings

Effluent treatment

- Chemical savings by controlled flocculant dosa-ges

- Increased dry content of sludges through impro-ved dewatering

- Precise identification of the demulsification point of emulsions and cooling lubricants

- Optimized selection of flocculants

Filler/pigment processing

- Determination of the optimum dispersed condi-tion and of dispersant amounts.

- Identification of the isoelectric point permits selective particle flocculation.

Dispersant V [ml]

organicdispersant

PC

D-p

ote

ntia

l U

[m

V]

optimumdosage

inorganicdispersant



2.3 Designation of the PCD 03/ PCD 03 pH

In the following, the designationof the PCD 03/ PCD 03 pH is shown.

Hint

The label should be easily visible and legible. Make sure to exchange damaged or illegible plate/label before placing the PCD 03/ PCD 03 pH in service.

Type plate PCD 03/ PCD 03 pH

The following type plate is located on the back of the PCD 03/ PCD 03 pH.

The voltage given on the type plate refers to a power supply of 230VAC or 115 VAC.

Caution

This instrument is only to be operated if the voltage stated on the type plate is identical to the line voltage at the place of operation.

Fig. 2-4 Type plate, PCD 03

Fig. 2-5 Type plate, PCD 03 pH




2.4 Technical data

Measure - Wide: 160 mm [6.3 in.]- Deep: 200 mm [7.9 in.]- High: 340 mm [13.4 in.]

Weight Approximately 10 kg [22 lb.]

Power Supply - Input voltage: 230VAC/ 115VAC- Frequency: 50 Hz/ 60Hz- Consumption: mMaximum 460 W- Fuses of the device: 2 x 315 mA slow-blowat 230 VAC

2 x 630 mA slow-blow at 115 VAC

Conditions of service - Ambient temperature: +5°C to +60°C [41°F - 140°F]; no condensation

- Storage/ transport temperature: -30°C to +60°C [-22°F - 140°F]

Measured variables - Streaming current in mV- Anionic & cationic demand of a sample

Result - Charge level of polyelectrolyte additives in µeq/g, C/g or µeq/l, C/l- pH of the isoelectric point (only for PCD 03 pH)- pH-charge profile (only for PCD 03 pH)

Sample volume - Standard cell type 1: 10 ... 30 ml - Precision cell type 2: 10 ... 60 ml

Measuring values - Streaming current

Output signals - Streaming current display and titrator: +/- 2000 mV- LED showing the charge sign- pH‘s indicated on display, for titrator and recorder

(only for PCD 03 pH)

Operating modes - Manual: hand pipette- Automatic: BTG Mütek GmbH PCD titrator

or any other titration system

Reproducibility Up to a standard deviation of s (x) = 0.01 %

Detection limit Up to 1 ppm depending on sample specification

EU-Specifications - EN 50081- EN 50082- EN 61010

Safety and protection class - Safety class I



2.5 Scope of delivery

2.5.1 PCD 03

Optional

2.5.2 PCD 03 pH

Optional

Pieces Description

1 PCD 03 main unit

1 Standard measuring cell

1 Displacement piston, 0.1 mm

1 Teflon ring

1 Mains cable

1 Piston brush

1 0.001 N PES-Na (100 ml, anionic polye-lectrolyte)

1 0.001 N PolyDadmac (100 ml, cationic polyelectrolyte)

1 Screen for filtrating fiber suspension

1 Application tips for using polyelectrolytes

1 Test printout of standard titration

1 Operation manual

1 Recommended Test Procedure

Pieces Description


1 Precision measuring cell

1 Precision displacement piston

1 Piston-operated pipetter 2 - 10 ml

1 Transportation case

Pieces Description

1 PCD 03 pH main unit

1 Precision measuring cell

1 Precision displacement piston

1 pH-electrode

1 Mains cable

1 Piston brush

1 0.001 N PES-Na (100 ml, anionic polye-lectrolyte)

1 0.001 N PolyDadmac (100 ml, cationic polyelectrolyte)

2 Buffer solution pH = 4.01 (20 ml)

2 Buffer solution pH = 7.00 (20 ml)

1 Screen for filtrating fiber suspension

1 Application tips for using polyelectrolytes

1 Test printout of standard titration

1 Operation manual

1 Recommended Test Procedure

Pieces Description

1 Standard measuring cell



1 Miniature measuring cell

1 Miniature displacement piston

1 Piston-operated pipetter 2 - 10 ml

1 Transportation case



III. Layout and function


3.1 Description of PCD 03/ PCD 03 pH

On its facing side, the front panel (15) features a digi-tal display (14) indicating the potential in mV. A digi-tal pH display (13) is located below (only for PCD 03 pH).

Arranged in the middle are a cationic LED (1) and an anionic LED (3). Vertically arranged are a motor switch (2) for the piston drive. A switch (4) for pH measurement is located below (only for PCD 03 pH).

A power LED (12) is located at bottom right of the panel (15). The measuring chamber (8) accommoda-tes the burette tip holder (5), the measuring cell (9) with contact pins (6) and guide (7) for the measuring cell (9). The displacment piston (10) is mounted in the PCD on suspension (11).

Fig. 3-1 Front view of PCD 03/ PCD 03 pH

Designations

1 LED cationic2 Switch for piston drive3 LED anionic4 Switch for pH measurement (PCD 03 pH)5 Burette tip holder6 Contact pins7 Guide for measuring cell8 Measuring chamber9 Measuring cell10 Displacement piston11 Piston suspension12 Power LED13 pH display (PCD 03 pH)14 Potential mV display15 Front panel

- 1 5 7 9

Mütek PCD 03 pHParticle Charge Detector Power

Motor

Potential (mV)

cationic

anionic

on

off

5 . 6 8pH

on

off

pH

1

23

4

5

15

14

13

12

11

10

9

8

7

6



Arranged on the rear panel of the chassis are the power module connection with a window showing the set voltage (6), a fuse latch (7), the power switch (8) and a power cord socket (9). The output signal jack (12) is located at the right. The BNC connector (12) for the streaming current output optionally serves for connection of the titrator or of a recorder. The CE symbol (11) denotes that the instrument conforms to the CE Directives of the EU.

PCD 03 pH

For PCD 03 pH only, a DIN connector (1) and a BNC connector (2) for the pH-electrode are located on the left side. Both connectors may also be used to con-nect the titrator and to transmit the pH signal. In cases where no BTG Mütek Titrator (including soft-ware) is used, a recorder may be connected to the recorder output (13) to plot pH’s during titration.

Temperature compensation of the built-in pH electro-nics is not automatic but has to be manually adjusted with temperature switch (3). The two adjustment con-trols (4 and 5) serve to set the drift (zero point) ∆pH (5) and the line inclination mV/pH (4) of the pH-elec-trode via buffer solutions.

Fig. 3-2 Back view of PCD 03/ PCD 03 pH

Designations

1 DIN connector for pH-electrode (PCD 03 pH)2 BNC connector for pH-electrode (PCD 03 pH)3 Temperature compensation switch for pH

measuring (PCD 03 pH)4 Inclination of pH line (PCD 03 pH)5 Drift of pH measurement (PCD 03 pH)6 Set voltage/ fuses7 Latch8 Power switch9 Power socket10 Type plate11 CE symbol12 Output signal jack +/- 2000 mV13 Cinch jacks/ recorder output (PCD 03 pH)

Rec. Out Out

D pH mV/pH

In/Out 1

pH Potential (mV)

In/Out 2

C

0

20

40 60

80

100

1

2

3

4

5 6

7

8

9

10

11

12

13




3.1.1 Measuring cells

Fig. 3-3 Standard measuring cell type 1 with piston type 1

Designations

1 Standard measuring cell type 12 Gold electrodes3 Teflon ring4 Piston type 1

The PCD 03 is standard-equipped with a measuring cell type 1 and a piston type 1. A piston with deep grooves providing for a larger clearance is available for highly viscous and shear-sensitive samples.

Alternatively, the precision measuring cell type 2 with precision piston type 2 may be employed. This option is particularly suitable for highly sedimenting particles and larger sample volumes (< 60 ml).

For PCD 03 pH both measuring cells are suitable. Depending on the application the ideal measuring cell according to the above mentioned criteria shall be selected.

The enlarged measuring chamber of the precision measuring cell is rated for commercial pH-electrodes measuring up to 10 mm in diameter.

Fig. 3-4 Precision measuring cell type 2 for highly sedimating samples

Designations

1 Precision measuring cell type 22 Platinum electrodes3 Precision piston type 2 for optimum sample

mixing

4

32

13

1

2



3.1.2 pH-Electrode

The PCD 03 pH is standard-equipped with a pH-mini-electrode which equally goes with the standard measuring cell type 1 and the precision measuring cell type 2.

Fig. 3-5 pH-electrode

Designations

1 Plexiglass shaft2 Ceramic diaphragm3 Support

31

2



IV. Installation

IV. Installation

This chapter covers the installation of the PCD 03/ PCD 03 pH and the necessary preparations. In the course of installation, settings should be made as required.

4.1 Safety rules

Please adhere to the applicable safety rules during preparatory work and when commissioning the sys-tem.

4.2 Personnel requirements

On-site preparations should be made by qualified and skilled personnel. For installation of the PCD 03/ PCD 03 pH, call in a technician of BTG Mütek GmbH or an authorized agent.

4.3 Preparations on-site

Prior to installation of the PCD 03/ PCD 03 pH, all preparations mentioned under chapter 4.4 "Installa-tion environment" must be made and the ambient conditions met.

Allow the PCD 03/ PCD 03 pH to adapt to ambient temperature before commissioning the system.

4.4 Installation environment

4.4.1 Installation point

Hint

In order to guarantee safe handling and reliable ope-ration of the PCD 03/ PCD 03 pH, check the follo-wing requirements before starting to use the device:

❑ Ambient temperature- +15°C to +45 °C [59°F to 113°F]

❑ The device needs to be placed on an even and stable ground

❑ The room where the PCD 03/ PCD 03 pH is used has to be dry and clean

❑ Do not use the device while it is exposed to direct sunlight

❑ Do not use the device when it is or was exposed to water

❑ Do not use the device in explosion prone rooms❑ Do not use the device when it is or was exposed

to aggressive chemical substances❑ If there is condensed water either after storage

or transportation of the device, allow at least two hours before switching on the device

❑ If outdoor temperatures are below +15°C [59°F], wait until the device has adjusted to ambient temperature in the laboratory

4.4.2 Power connection

Hint

Before setting the device to work check whether the voltage shown on the measuring unit is the same as locally used.

❑ Input voltage- 230 VAC- 115 VAC

❑ Frequency- 50 Hz / 60 Hz

❑ The electrical instalation in the room where the PCD 03/ PCD 03 pH is set up must conform to VDE 0107

❑ Do only use the device with shockproof sockets❑ Do not undo any earthing contacts inside or out-

side the device❑ The BTG Mütek GmbH guarantee expires if the

device is used with an inappropriate voltage❑ The PCD 03/ PCD 03 pH is rated for overvoltage

category III to IEC 664


IV. Installation

Voltage selection

The PCD 03/ PCD 03 pH is rated for two different voltages: 230 VAC and 115 VAC Fig. 4-1.

Hint

BTG Mütek GmbH does not assume any guarantee if the voltage is wrongly selected.

Use the voltage selector (3) to set the device to the local power voltage.

• Insert a small screwdriver and depress latch (5) to unlock.

• Remove fuse holder (1).• Remove voltage selector (3), rotate through 180°

and reinsert.• Withdraw fuses (2) from holder (1) and insert the

fuses required for the set voltage:- 230 V: 2 x 315 mA/slow-blow- 115 V: 2 x 630 mA/slow-blow

• Reinsert holder (1) with fuses (2) into enclosure (4) until latch (5) clicks into position.

• Check if the proper voltage appears in the win-dow in fuse holder (1).

Hint

Make sure that only replacement fuses of the speci-fied type and amperage are used. It is not allowed to use repaired fuses or to short-circuit the fuse holder.

Fig. 4-1 Power entry module

Designations

1 Fuse holder2 Fuses3 Voltage selector4 Enclosure 5 Latch

1

2

3

4

5



IV. Installation

4.4.3 Sample specification

General

Basically, nearly every aqueous sample - including original concentrations - can be measured. The measurability of a sample is verified in the PCD itself. To this end, fill the sample into the measuring cell, install the cell together with the piston in the PCD and turn on the motor. If the motor runs smoothly and silently and if the signal is comparatively stable (about 50 mV), the sample can be readily measured.

The limit values indicated in this chapter are not absolute values, but are merely indicative of sample characteristics that might lead to measuring pro-blems.

If there are doubts about whether or not a substance can be measured, a test measurement should be conducted and the sample be suitably prepared, if necessary.

Solvents

Charges can only be measured after functional groups are dissociated. As this dissociation can only take place in aqueous solutions, the substance to be tested must be available in this form or be dispersed in water.

If required, the test substance may also be dissolved in lower alcohols (methanol, ethanol, isopropanol) and then diluted with de-ionized water for subse-quent titration.

The proportion of organic solvents depends on the sample and should be determined in pretests. To begin with, a blank reading should be obtained for the solvent concerned. For this purpose, fill 10 ml of the solvent (de-ionized water or a water/alcohol mix-ture) into the measuring cell and titrate up to the point of zero charge.

Even if the cell is filled with de-ionized water only, the streaming current will not be at 0 mV as might be expected, but shows a comparatively high anionic signal. This signal drops to zero as soon as a mini-mum amount of cationic titrant is added.

If de-ionized water is titrated, approx. 0.02 ml poly-DADMAC is normally required.

The blank value thus obtained is to be deducted from the results of all further titrations.

Particle sizes

If the standard piston or the precision piston are employed, solid particle sizes in the sample should not exceed 300 µm. On the other hand, measure-ments of fibres of a length more than 1 mm are rea-dily possible. For larger particles measuring up to 1 mm, the special piston with deeper grooves should be used.

The lower limit amounts to 10 nm.

Viscosity

The standard piston type 1 is suitable for use with samples of a viscosity below 300 mPa*s.

For samples of higher viscosities up to 6000 mPa*s, the special piston type 1 with deeper grooves has been developed.

Viscosities exceeding the above values impede the oscillating movement of the piston in the cell. Moreo-ver, the flocculation effect typically occurring towards the end of titration will change viscosities, too.

Samples with a viscosity exceeding 6000 mPa*s should be diluted with de-ionized water.

If highly viscous samples are to be titrated, mixing of the titrant with the sample will take longer than with low-viscosity samples. Accordingly, a lower titration rate should be selected.

Molecular weight

The minimum molecular weight of the polyelectroly-tes to be studied should be approximately 300 g/mol. If the molecules are smaller, their adsorption on the cell wall by van der Waal forces cannot be ensured. No ions present in the sample will be measured.

At the upper end of the scale, there is no limiting molecular weight of colloidally dissolved substances.


IV. Installation

Conductivity

The conductivity of the sample decisively impacts the streaming current: the higher the conductivity the lower the electrical resistance in the sample will be and the more the streaming current will decrease wit-hout, however, influencing the titration results.

Fig. 4-2 Conductivity vs. streaming current

In Fig. 4-2, various proportions of NaCl were added to PES-Na 0.001 N and the samples were titrated with poly-DADMAC 0.001 N.

If conductivities are excessively high (20 mS/cm to 50 mS/cm), the streaming current may fluctuate bet-ween anionic and cationic so that an end-point detection and thus titration is no longer possible. In these cases, the conductivity can be reduced by dilu-ting the sample with de-ionized water.

Information

Samples that do not meet the above specifications may be prepared as outlined under chapter 5.4 "Sample preparation", page 29.

0 2 4 6 8 10

0

-1000

-2000

titrant ml

mV

10,80 mS/cm

5.97 mS/cm

3,45 mS/cm

1,86 mS/cm

0,05 mS/cm



IV. Installation

4.5 Start up procedure

4.5.1 Prepare electrical connections

The PCD 03/ PCD 03 pH is rated for automatic or manual titration.

4.5.2 Automatic titration

BTG Mütek GmbH recommends the use of an auto-matic titrator, because it gives results of maximum reproducibility. In addition, the titration curve can be recorded via a printer. Generally, every automatic titrator can be connected to the PCD.

4.5.2.1 PCD-Two titrator

The PCD-Two titrator was specially developed for use in combination with the PCD 03/ PCD 03 pH for polyelectrolyte titrations.

Automatic titration with the PCD 03/ PCD 03 pH is simplest and cheapest with the PCD-Two titrator.

Fig. 4-3 PCD 03/ PCD 03 pH configuration with PCD-Two titrator and printer

PCD 03

Fig. 4-4 Cabling of PCD 03 with PCD-Two titrator and printer

Fig. 4-5 Printout of PCD-Two titrator connected with PCD 03/ PCD 03 pH

PCD 03/ PCD 03 pHPrinter PCD-Two Titrator

RS232 interfaceConnecting cablePCD with titrator

Out

Potential (mV)

RS-232-C

BalanceComputer

Centronics

Printer

IN pH

IN mV

ON/OFFKeyboard Fill StartKeys

Power

PCD 03

PCD-Two Titrator

Titrator/ PrinterCentronic

PCD 03/ PCD-Two-TitratorStreaming potential [mV]


IV. Installation

PCD 03 pH (IEP)

Fig. 4-6 Cabling of PCD 03 pH with PCD-Two titrator and printer

When working with the PCD 03 pH and the PCD-Two titrator the streaming current, the titrant (acid/ base) consumption and the pH value (IEP) is recorded.

After the measurement a three page result will be printed out automatically. It shows the streaming potential mV versus pH, streaming potential mV ver-sus consumption ml and the pH value versus titrant consumption ml.

On the first page the results of consumption at 0 mV and pH value at 0 mV are listed.

Fig. 4-7 Printout of PCD-Two titrator connected with PCD 03 pH

Rec. Out Out

D pH mV/pH

In/Out 1

pH Potential (mV)

In/Out 2

C

0

20

40 60

80

100

RS-232-C

BalanceComputer

Centronics

Printer

IN pH

IN mV

ON/OFFKeyboard Fill StartKeys

Power

PCD 03 pH/ PCD-Two TitratorStreaming current (mV)

PCD 03 pH

Printer

PCD-Two Titratorp

H-e

lect

rod

e

***************** MUETEK PCD Titrator two *****************

Method number: 8

Method name: pH iep >2ml

Titration start: 14:53:40 11.09.02

Sample ident: TI02 1% 2

Titration end: 15:05:08 11.09.02

Active substance: 1.00000 g

Titrant: Conc. Titrant: 1.000000 (mol/l)

Stop pH: pH= 2.000

Stop ml: 20.0 ml

Start value: pH= 7.839 -2005.000mV

End point 0.0 mV IEP: pH= 2.813 0.386 ml

mV/pH

sample ident

mV/ml

pH/ml

sample ident



IV. Installation

4.5.2.2 PCD 03 pH with Metrohm Titrino 702/ 716

This configuration is eminently suitable for determi-ning the isoelectric point and optimum dispersant dosages. Besides, it renders valuable service in the research and development area.

Stability maxima may be derived from the streaming current characteristics optained.The use of BTG

Mütek GmbH titration software which has been spe-cifically tailored to the PCD 03 pH allows a juxta-position of streaming currents and pH’s.

Controlling the Titrino device, this software allows streaming currents, pH’s and consumption levels to be evaluated in parallel.

Fig. 4-8 Configuration of PCD 03 pH/ Titrino 702

Designations

1 Parallel interface2 RS232 interface

3 pH-electrode4 Connecting cable PCD 03 pH/ Titrino

Fig. 4-9 Rear view of configuration PCD 03 pH/ Titrino 702

- 1 5 7 9

Mütek PCD 03 pHParticle Charge Detector Power

Motor

Potential (mV)

cationic

anionic

on

off

1 0 . 6 8pH

on

off

pH

PCD 03 pHTitrinoPCPrinter

1 2 3

4

Rec. Out Out

D pH mV/pH

In/Out 1

pH Potential (mV)

In/Out 2

°C

0

20

40 60

80

100

Mütek Analytic GmbHD-82211 HerrschingFax: (0049) 8152 4374

Made in German y

S-Nr. 42-2001

U: 220/240 V~I: 250 mA

U: 110/117 V~I: 500 mA

f: 50/60 HzS: 30 VA

Muetek Analytic Inc .USA-Marietta, GA 30067Fax: (001) 770 955 2383

Titrino

PC Printer

PCD 03 pH

IND 2 connector

adapter E - F

adapter E - FIND 2 connector

Connecting cablePCD/ Titrino for

mV signal

Connecting cablePCD/ Titrino forpH value

PC/ printer

parallel interface

Titr

ino

/ P

CR

S2

32

fe

ma

le/

RS

23

2 f

em

ale

pH

-ele

ctro

de


IV. Installation

4.5.2.3 Manual operation

To operate the PCD 03/ PCD 03 pH manually, use a measuring pipette to add the titrant dropwise into the measuring cell. The point of zero charge is attained if the streaming current is at 0 mV, which is indicated by the LED. In the majority of cases, titration will be fast at the beginning and slow down towards the end.

Fig. 4-10 Manual operation

Designation

1 Measuring pipette

Titrant consumption can be read off the measuring pipette.

In case of polyelectrolyte titration this information is required to calculate the charge quantity.

If an acid/ base titration is performed with the PCD 03 pH, the pH display indicates the isoelectric point (at 0 mV streaming current).

Manual operation is particularly convenient for quick pretests or onsite measurements.

4.5.3 Calibration of pH-electrode of the PCD 03 pH

Two buffer solutions are needed for calibration: one of about pH 7 and another one in the acid or alkaline range, such as pH 4 or pH 9. The buffers used for calibration should correspond to the pH range of the samples.

• Set temperature compensation switch (3, Fig. 3-2) to the measuring temperature.

• Immerse pH-electrode (Fig. 3-5) in pH 7 buffer.• Wait until signal on pH display (13, Fig. 3-1) sta-

bilizes.• Turn ∆pH control (5, Fig. 3-2) to adjust display to

pH 7.• Rinse pH-electrode (Fig. 3-5) with deionized

water and immerse in pH 4 buffer.• Wait until signal on pH display (13, Fig. 3-2) sta-

bilizes. Turn mV/pH control (4, Fig. 3-2) to adjust to pH 4.

• Check calibration with suitable buffer solutions and repeat the calibration routine, if necessary.

Hint

If the PCD 03 pH is operated with the Titrino plus software (see 4.5.2.2, page 25), both the Titrino and the PCD 03 pH have to be calibrated. (Please refer to the Instruction Manual for the Titrino).

- 1 5 7 9

Mütek PCD 03Particle Charge Detector Power

Motor

Potential (mV)

cationic

anionic

on

off1



IV. Installation

4.5.4 Titrant solutions

Titrants must always carry the opposite charge of the sample. Optimum sample concentration should be selected (dilution) to keep titrant consumption bet-ween 0.2 and 10 ml.

Polyelectrolytes

BTG Mütek GmbH recommends the use of Pes-Na and poly-DADMAC as standard reagents, because their charge densities are practically pH-indepen-dent.

Pes-Na

Pes-Na (polyethene sodium sulfonate) is an anionic polyelectrolyte. It serves as a calibrating substance to determine the content of other titrants.

Poly-Dadmac

Polydimethyl diallyl ammonium chloride is a cationic polyelectrolyte with molecular weight of 107000 g/mol.

For technical reasons, the activity of poly-DADMAC is subject to minor variation between the individual batches. Before using a fresh solution, use Pes-Na to conduct a factor determination. For 10 ml Pes-Na 0.001 N, the poly-DADMAC 0.001 N consumption is usually between 9.5 and 10 ml.

Other polyelectrolytes

The following additional titrants are in frequent use today:

- Cationic: methyl glycol chitosane (MGCH) ‘Hymin’

- Anionic: potassium polyvinyl sulfate (KPVS) dodecyl sulfate sodium salt (SDS)

4.5.5 Acids/bases

For anionic samples, diluted acids are used as a titrant and diluted bases for cationic samples. Hydro-chloric acid, sulfuric acid and sodium hydroxide solu-tion have proven useful in this context and are normally applied in concentrations of 0.1 - 0.01 mol/l.

4.5.6 Cleaning solution

Warning

Acetone and cleaning solution are highly flammable.

Warning

Pay particular attention to the safety rules in chapter 1.5 "General safety directions".

The cleaning solution for manual cleaning is produ-ced from 50 parts sodium bromide (NaBr) and 50 parts acetone plus 125 parts water.

• Prepare the above proportions.• Fill water into a suitable vessel.• Add sodium bromide and dissolve.

Hint

Take care that sodium bromide is dissolved comple-tely.

• Add acetone and mix carefully.

Information

Selection of an optimum detergent depends on the sample concerned.

4.5.7 Buffer solutions for pH calibration

Commercial buffer solutions may be used for pH cali-bration.


IV. Installation



V. Operation

V. Operation

5.1 Safety rules

Make sure to follow the "Basic safety instructions", page 5, before commissioning the PCD 03/ PCD 03 pH.


On-site preparations may be made by qualified and skilled personnel. For installation of the PCD 03/ PCD 03 pH, call in a technician of BTG Mütek GmbH or an authorized agent.

5.3 Preparation

• Setting up the connections in accordance with "Installation environment", page 19

• Clean the measuring cell in accordance with "Cleaning the measuring cell", page 37

5.4 Sample preparation

For stock systems including both colloidally dissolved material and solid particles, different ways of sample preparation will give different data on the charge con-ditions prevailing in a sample Fig. 4-2, page 22.

Generally speaking, results are only directly compa-rable if the samples are prepared in an identical man-ner. Test results obtained for samples of the same kind but which were treated by different methods may yield additional information about, e.g., the charge conditions of solids.

In each case, quantitative sampling must be ensured which gives reproducible values.

5.4.1 Filtration

To separate larger solid particles from the sample, samples are usually filtered with a whiteband filter. This may falsify results because polyelectrolytes tend to be adsorbed at the filter paper. We therefore stron-gly advise against using paper filters.

Ceramic filters do not normally cause any problems.

5.4.2 Centrifugation

It is very important that centrifuging times are identi-cal for all samples.

5.4.3 Screening

In the majority of cases, it will be sufficient to sepa-rate long fibres and larger particles by a coarse nylon screen. However, the formation of a filter cake should be avoided.

Quick and reproducible sampling is achieved in the following way: replace the bottom of a plastic cup by a nylon screen. Immerse the cup into the sample and remove the screened supernatant liquid with a pipette.

Fig. 5-1 Screening of samples

Designations

1 BTG Mütek screen for filtrating fiber suspension (e.g. nylon screen of 300 µm mesh)

2 Original sample e.g. thick stock, coating broke3 Rising measurable sample

12

3


V. Operation

5.4.4 Back titration

This method of sample preparation suggests itself in the following cases:

- Due to their structure, the samples cannot be placed into the cell directly, such as if the charge level of larger chemical pulp fibres is to be quan-titatively determined

- Reaction of test substance with the titrant is too slow so that direct titration would be useless

5.4.4.1 Example of back titration

Type of sample

The total charge of an anionic solid sample contai-ning a large number of long fibres and other solid particles is to be determined. In view of the high solids content or excessive particle sizes, direct measurement in the cell is not feasible. This is where back titration is recommended.

Procedure

Take 20 g of the anionic sample to be measured and fill up to 100 g with poly-DADMAC 0.001 N. Stir this mixture for approx. 2 hours with a magnetic stirrer. During this period, the cationic poly-DADMAC will neutralize all anionic charges of the sample. Since there is an excess amount of poly-DAMAC, a resi-dual cationic charge will remain in the sample. After the reaction period, screen out the solids of the mix-ture. Decant 10 ml of the solution into the measuring cell and titrate up to the point of zero charge with Pes-Na 0.001 N.

Result V1: Consumed Pes-Na 4.83 ml

In addition, titrate 10 ml of fresh poly-DADMAC solu-tion with Pes-Na up to the point of zero charge.

Result V2: Consumed Pes-Na 10.68 ml

Calculation of charge amount q:

V2 - V1: Difference between the charges of the fresh poly-DADMAC and the reacted poly-DADMAC indicates the charge amount neutralized in the sample.

c: Concentration of the titrant, i.e. here 0.001 eq/l.

m: 2 g of the original sample were used for tit-ration. (20 g were filled up to 100 g, of which 10 g were used for titration).

Result: the charge level of the sample under test is 2.925 µeq/g.

Fig. 5-2 Sample preparation methods

(V2 - V1) * c

m

(0.01068 - 0.00483) [l] * 0.001 [eq/l]q =

2 [g]

q = 2.925 * 10-6 [eq/g]

Method SCREENING CENTRIFUGING BACK TITRATION

Sample preparation If possible, the complete sample is measured or the long fibre fraction is separa-ted by screening, e.g

Separation of the solids in the sample by centrifuging

An excessive amount of polyelektrolyte is added to the sample. After a defined period the solids are separa-ted by centrifuging

Sample type Total stock, very fine fibers fillers, long fibers

Colloidally dissolved system Colloidally dissolved system

Result Total charge (fines, fillers colloidally, dissolved matter)

Charge of the colloidallydissolved system(= anionic trash)

Fibre charge and charge ofthe colloidally dissolvedsystem



V. Operation

5.5 Measuring with the PCD 03/ PCD 03 pH

• Fill a sample into the measuring cell (8, Fig. 3-1).

Information

Take care to keep both gold electrodes (2, Fig. 3-3) covered with liquid. The minimum sample volume should be 10 ml. To precisely dose the sample quan-tity for charge quantity calculation, weigh in the sample or use a measuring pipette.

Good reproducibility of results can only be achieved if the sample is appropriately homogenized for quan-titative sampling.

• Position piston ring (3, Fig. 3-3) on the piston (4, Fig. 3-3) of the type 1 standard mesuring cell.

Information

The piston ring prevents spurting of the sample material. Position the ring as far down as possible. A slurping noise during measurement indicates that air enters the narrow gap. This may lead to considerable signal variation and to spurting of sample material. Push the piston ring further down to eliminate the problem.

Should the ring fit too loosely, adjust by bending it slightly.

• Insert piston (4, Fig. 3-3) into the measuring cell (1, Fig. 3-3).

• Displace measuring cell (8, Fig. 3-1) along the guide (6, Fig. 3-1) to the rear up to the stop.- The electrodes should face towards the rear

• Pull piston (9, Fig. 3-1) upward and turn clock-wise to lock it in the bayonet catch (10, Fig. 3-1). - The measuring cell is correctly positioned if

the piston can be hooked in the bayonet catch easily and without canting

Only for PCD 03 pH:

• Insert pH-electrode

Hint

Position the pH-electrode in such a manner that titrant dripping from the burette does not come into direct contact with the electrode.

• Turn on the motor (2, Fig. 3-1). - The streaming current will be indicated in the

display (12, Fig. 3-1)- LEDs (1 and 3, Fig. 3-1) indicate the signs of

the charges• Wait for about 30 seconds until the potential sig-

nal has stabilized. - Precise titration is only possible if the strea-

ming current is stable

• Insert the burette tip into the opening of the tip holder (4, Fig. 3-1) and fasten with the bolt.

Hint

Take care to ensure that every single drop of the titrant reaches the sample. The burette tip may come into contact with the interior wall of the measuring cell, but do not touch the piston or the electrodes with the burette tip, because this may result in strong potential fluctuation.

To exactly position the burette tip, carefully bend the holder into a suitable position.

• Start titration (manual or automatic with titrator system)


V. Operation

5.6 Titration curves

If a titrator with printer is used in PCD 03/ PCD 03 pH measurements, a titration curve may be printed out. This curve gives valuable information on the kind of response of the stock system under test.

Low-concentration solutions are most likely to yield a titration curve that is easily interpreted.

Optionally, three different kinds of sample can be measured:

5.6.1 Colloidally dissolved particles

Titration curve for a colloidally dissolved sample. At the beginning of the titration process, the streaming current remains practically unchanged, because non-adsorbed colloids are neutralized which do not cont-ribute to the streaming current.

Subsequently, the curve shows a sharp drop, which is indicative of adsorbed charge carriers being elimi-nated in the course of titration.

Fig. 5-3 Titration curve of a colloidally dissolved par-ticle

5.6.2 Solid particles

Titration curve for solid particles suspended in water.

The titration curve is nearly straight, because all solid particles make a contribution to the streaming cur-rent.

Fig. 5-4 Titration curve of a solid particle

5.6.3 Heterogeneous stock systems

Titration curve for heterogeneous systems (colloids, dissolved substances, solid particles, fibres, etc.). The curve drops sharply, but flattens out towards the end of titration.

Levelling-off around the point of zero charge may be caused by titrant penetrating into the fibres.

Fig. 5-5 Titration curve of a heterogeneous stock system

0 2 4 6 8 10

-1000

0

1000

2000

titrant ml

mV

0 2 4 6 8 10

-1000

0

1000

2000

titrant ml

mV

0 2 4 6 8 10

-1000

0

1000

2000

titrant ml

mV



V. Operation

5.6.4 Selection of titration rate

The titration rate may influence measuring results and should in each case be selected according to the reaction time between titrant and sample.

If the two substances are very slow to react, the potential will decrease drastically as titrant is added. The observer may gain the impression that the point of zero charge is reached. The potential rises again when reaction actually takes place.

If pure polyelectrolyte solutions are titrated, titrant dosages should not exceed some 300 µl per minute.

If the sample includes layered structures or porous particles (e.g. clay, ion exchangers etc.), the ideal tit-ration rate will be far lower: the usually large molecu-les of the titrant have to penetrate the layers of the sample material before they effect charge neutraliza-tion.

An excessive titration rate is reflected in an irregular curve and a drop in potential after titration is finished. If an end-point titrator is used, dynamic titration can be realized. In this case, the titrator matches additi-ons and addition rates to the changes in potential, thus taking the peculiarities of the sample into account.

If pH-dependent potential characteristics are to be studied, a response time of the pH-electrode has to be taken into account which is at least 10 seconds.

If the results of several titrations are to be compared, it will be indispensable to use an identical titration rate and configuration of the automatic titrator for all tests.

Information

Excessive titration periods may cause changes to fresh production samples.


V. Operation





6.1 Safety rules

In the case of errors not listed in the table below, dis-connect the PCD 03/ PCD 03 pH and mark as "defective". Contact BTG Mütek GmbH to ensure quick remedial action.


Troubleshooting may only be performed by qualified and skilled personnel.

6.3 Tables of system faults

Symptom Probable cause Corrective action

Heavy fluctuations of strea-ming current after sample is filled in

- Excessive electrical conductivity of the sample

• Dilute the sample.

- Sample amount in the cell too small

• Weigh in once again or use pipette.

- High solids in the sample • Dilute the sample or• Centrifuge screen to remove

coarse particles.

- Piston ring incorrectly positioned • Push piston ring further down.

Potential reverses after rea-ching the end point

- Very slow reaction between titrant and sample

• Titrate more slowly or • Perform back titration.• Check sample for homogeneity.

At the start of titration, potential increases instead of decreasing

- Wrong titrant • Select titrant with opposite charge to that of sample.

- Sample concentration too high, titrant concentration too low

• Dilute the sample.

Potential remains essenti-ally unchanged during titra-tion

- Concentration of sample very high • Dilute the sample or • Use a higher strength titrant.

Sign of indicated potential not in conformity with sample specification

- Sample charge depends on pH • Check pH dependence of sample.

- Excessive viscosity • Dilute the sample.

pH-electrode can not be calibrated

- Soiled or defective • Clean or replace pH-electrode.





VII. Maintenance

VII. Maintenance


Maintenance shall exclusively be carried out by qua-lified and skilled personnel.

7.2 Cleaning the measuring cell

The measuring cell has to be always cleaned with water and cleaning solution.

After each measurement, go through the following cleaning routine:

• Empty the measuring cell (9, Fig. 3-1).• Rinse the measuring cell with tap water.• Clean the measuring cell (9, Fig. 3-1) and the

piston (10, Fig. 3-1) with cleaning brush and cleaning solution.

• Rinse both with de-ionized water.• Empty the measuring cell.• Dry with clean paper cloth on the outside of the

measuring cell but not the piston.

Hint

Failure to clean the cell after each measurement will lead to measuring errors and prevent reproducibility of results.

Hint

To avoid deposits in the measuring cell and at the piston, fill the cell with cleaning solution and leave overnight.

Caution

A measuring cell filled with solvent must be removed from the measuring chamber of the PCD, since otherwise the drive might be damaged.

Warning

Before each measurement, clean measuring cell and piston with water as described above, since solvent residues will falsify measured results.

If different samples are measured and maximum measuring precision is required, rinse with cleaning solution first before going through the above cleaning routine.

7.3 Functional test

To avoid measuring errors that are caused by faulty operation of the unit or soiling of the cell, functional testing can be performed by different methods.

7.3.1 Basic test of PCD without cell

• Turn on power switch (8, Fig. 3-2).- LED power (12, Fig. 3-1) will come on

• Switch on piston drive (2, Fig. 3-1).- Digital display (14, Fig. 3-1) streaming current

will indicate 0 mV- Depending on the sign of the streaming cur-

rent signal, LED cationic (1, Fig. 3-1) or LED anionic (3, Fig. 3-1) will come on

7.3.2 Standard titration

Fill 10 ml of the anionic standard Pes-Na into the cell and titrate with poly-DADMAC 0.001 N up to the point of zero charge. If the result obtained deviates from the expected value (9.6 ml - 10.0 ml), clean the cell thoroughly once more (see chapter 7.2, "Clea-ning the measuring cell").

Information

This check should be performed at least once a week. The polyelectrolyte concentration should be continuously monitored.

7.3.3 Check of streaming current

If a freshly cleaned cell is filled with 10 ml of anionic standard Pes-Na 0.001 N repeatedly in succession, the streaming current values measured should be roughly identical. Depending on the equipment, the potential is generally in the range of -1000 to -1600 mV. If the cell is used very frequently, this value will diminish over time due to wear. This does not, howe-ver, affect titration results. If the streaming current is suddenly measured to be some 100 mV below the previous result, the cell is presumably soiled. To avoid measuring errors, clean the cell thoroughly once again (see chapter 7.2, "Cleaning the measu-ring cell").


VII. Maintenance

7.3.4 Electrostatic charging of the cell

If it is doubtful if the PCD receives a signal from the measuring cell, such as when the signal remains stri-kingly stable during the titration process, the function should be verified as follows: switch on the motor and rub your hand quickly up and down on the out-side of the cell. This will cause the signal to bounce. If no such reaction is observed although the motor is running, there is probably an electronics failure. In this case please contact the BTG Mütek GmbH ser-vice or your local BTG Mütek GmbH agency.

7.3.5 Functional test of pH-electrode

Before starting a test series, measure a buffer solu-tion with the pH-electrode.

The electrode should respond within 10 - 30 seconds. If measuring performance is inadequate and cannot be improved by cleaning and repeated calibration, replace the electrode.





8.1 Safety rules

Please adhere to applicable safety rules when put-ting the system out of operation.


The system should only be put out of operation by qualified and skilled personnel.

8.3 Shutting down the system

To shut down the PCD 03/ PCD 03 pH, proceed as follows:

• Switch off the PCD 03/ PCD 03 pH.• Disconnect the PCD 03/ PCD 03 pH from its

main supply.• Disconnect the PCD 03/ PCD 03 pH from PCD-

two titrator.• Clean the measuring cell in accordance with

chapter 7.2, "Cleaning the measuring cell", page 37.

For PCD 03 pH only:

• Clean the pH-electrode with 3 M KCl solution.• The diaphragm of the pH-electrode (2, Fig. 3-5)

must not get dry. Fill the cover of the pH-elec-trode with 3 M KCl solution and keep the pH-electrode in this cover in times of no usage.

8.4 Storage

The PCD 03/ PCD 03 pH should be stored in a pro-tected place inside a building. Do not keep outdoors.

8.5 Disposal

8.5.1 Official regulations

Be sure to meet the local regulations governing the disposal fo the PCD 03/ PCD 03 pH.





IX. Part lists

IX. Part lists

9.1 Components

Pos. Designation Part-No.

1 Aluminium carrying case, suitable for air transport 400 - 09077

2 Standard measuring cell type 1 with gold electrodes for routine measure-ments; sample volume min. 10 ml / max. 30 ml

400 - 10318

3 Standard piston type 1 with 0.1 mm deep grooves for samples of normal vis-cosity

400 - 09120

4 Special piston type 1 with 0.5 mm deep grooves for high-solids and highly vis-cous samples

400 - 09122

5 Teflon ring for piston type 1 400 - 10133

6 Precision measuring cell type 2 with platinum electrodes giving high reprodu-cibility of the mV signal, such as for zeta potential assessments and for critical samples with high conductivity, highly sedimenting particles;

sample volume min. 10 ml / maximum 60 ml

400 - 09119

7 Precision piston type 2 400 - 09121

8 Connecting cable between PCD and titrator (BNC/A2) for transmission of streaming current and pH

570 - 02484

9 Cable BNC and banana plug connecting recorder and PCD 420 - 02485

10 Burette tip holder 410 - 09117

11 Piston brush for cleaning of measuring cells, 20 mm dia. 400 - 10158

12 100 ml plastic bottles with caps 400 - 10161

13 Screen for filtrating fiber suspensions with 300 µm mesh 400 - 18977

14 Precision pipette, 2 - 10 ml 552 - 18772

15 Plastic tips for precision pipette, 2 - 10 ml 552 - 18773

16 pH-electrode, plexiglass shaft, ceramic diaphragm, gel filling, holder 420 - 09115

17 pH-electrode glass shaft, glass section diaphragm, gel filling holder 420 - 09133


IX. Part lists

9.2 Consumable goods

9.3 Work safety

Chapter 9.3 is an excerpt from DIN Safety Sheets.

Cons. Nos. 3, 4, 5, 6, 7, 8 above refer to the con-sumables listed under chapter 9.2 above.

Pos. Designation Remarks Part-No.

1 Polyelectrolyte anionic, 0.001 N, 1000 ml, PES-Na

Standard solution, ready for use 811 - 10216

2 Polyelectrolyte cationic, 0.001 N, 1000 ml, poly-DADMAC

Standard solution, ready for use 811 - 10217

3 Polyelectrolyte anionic, PES-Na, powder

Reagent-grade, approximately 99.5 % dry content, MW 19100 g/mol

812 - 10219

4 Polyelectrolyte concentrated, anio-nic, PES-Na, liquid

Approximately 51 % solids,

MW 21800 g/mol

821 - 10220

5 Polyelectrolyte concentrated, catio-nic, poly-DADMAC, liquid

Approximately 41 % solids,

MW 107000 g/mol

812 - 10218

6 Acetone Commercial quality

7 Sodium bromide (NaBr) Commercial quality

8 3 M KCl-solution Commercial quality

9 Cleaning solution for manual clea-ning

To be prepared (see 4.5.6 "Cleaning solution")

Pos. Designation Disposal Hazard

3/4 Goggles Keep away from open wounds (anticoagulant), rinse thoroughly with water after contact with open wounds

Incineration n.a.

5 Gloves, gog-gles

Rinse thoroughly with water after contact with skin or eyes

Landfilling or incineration

n.a.

6 Gloves, gog-gles

Rinse with water after skin contact. In case of eye contact rinse with water immediately and consult an oculist

Special waste easily flam-mable

7 Gloves, gog-gles

Rinse thoroughly with water after contact with skin or eyes

Special waste n.a.

8 Gloves, gog-gles

Rinse with water after skin contact. In case of eye contact rinse with water immediately and consult an oculist

Special waste easily flam-mable



BTG Mütek GmbHArzbergerstrasse 10D-82211 Herrschingphone +49 8152 9312-0fax +49 8152 4374email [email protected] www.wetendtechnology.com

Documents

BTG Mütek GmbH Operation manual - INVEN · Operation manual PCD 03/ PCD 03 pH Particle Charge Detector Mütek WET ® Lab BTG Mütek GmbH