Dhaka | Aug-15 | A Study on Electrochemistry of PKL (Pathor Kuchi Leaf) Electrochemical Cell

A Study on Electrochemistry of PKL (Pathor Kuchi Leaf) Electrochemical Cell

Mohammad Al MamunAssistant Professor

Department of Chemistry Jagannath University

Emission of green house gas CO2

• Rising temperature• Shrinking habitat• Food harder to get • Expanding diseases• Competition• Animals at risk

Green House Effect

To Combat

Global Warming

Separation

Capture

Sequesteron

Conversion

Solar Cells

Fuel Cells

Hydrogen Economy

Energy Storage Batteries

Supercapacitors

Carbon ManagementUse of High Strength Materials

Nanocatalysts to improve Fuel Efficiency

Reducing Friction in Engines

Improve Insulation for Buildings

Advanced Lighting Technology

Chemical Electrochemical Photo electrochemical

Reduced Energy

Consumptionand

ImprovingEfficiency

Renewable Energy

andStorage

Technology

Electrochemical Cell

Electrochemical Cell

■ Electrochemical reaction – transfer of electron - Electricity

Zn (s) + Cu2+(aq) = Zn2+(aq) + Cu (s) ■ Anode – Oxidation : Donation of electron-Half cell reaction

Zn(s) – 2e- = Zn 2+ (aq)

■ Cathode - Reduction : Gaining of electron – Half cell reaction Cu 2+ (aq) + 2e- = Cu (s)

■ Electrolytic Medium : Elimination of migration current.

Zn is anode but Cu is cathode - Why?Standard Reduction Potentials in Aqueous Solution at 25° C

Strongly held outerm

ost electron

Zn2+ (aq) + 2e- Zn (s) -0.76

Different types of electrode

Carbon paste electrode

Glassy carbon electrodeModified glassy carbon electrode

Potentiometric Cell

Subs

trat

eTr

ansd

uctio

n la

yer

Bio

reco

gniti

on la

yer

Electrochemical Cell

■ Voltaic Cell Chemical Energy Electrical

Energy

■ Electrolytic cell Electrical Energy

Chemical Energy

Electrolytic Cell

Electrochemical Cell - Current

• Diffusion Current – concentration gradient

• Migration Current – moment of charged particle along an electric field

• Convection Current - physical movement - stirring

Comparision - Schematic

Electrolytic CellVoltaic Cell

2Cl- - e- Cl2 2Na+ + e- 2Na

Comparision - Schematic

H2-O2 fuel cellConcentration cell

Comparision - Schematic

Dry cell Lead storage battery

Alkaloids & Minerals

Organic Acids: ●Palmitic Acid ●Stearic Acid ●Oxalic Acid ●Citric Acid ●Isocitric Acid ●Malic Acid●Succinic Acid●Ascorbic Acid●Amino Acids etc.

▪ Triterpenes, ▪ Glycosides, ▪ Flavonoids, ▪Cardienolides,▪ Steroids, ▪Bufadienolides and ▪ Lipids

Hypothesis -Photosynthesis

PKL Juice Preparation

PKL PKL + Water ( Blending)

Filtration

PKL Solution

Filtration

Without

PKL SuspensionSolid Wastage

Comparision - Schematic

Zn2+

SO42-

Cu2+

SO42-

1 MZnSO4 solution

1 MCuSO4 solution

Zn Anode Cu Cathode

Voltaic Cell (Unit cell)

Digital voltmeter

Zn Anode

40% PKL soln

5% CuSO4

e- e-

PKL Cell

(Unit cell)

Cu Cathode

For electrolytic studies the analyzed PKL Malt/Juice/Sap put in between Zn and Cu flat parallel electrodes with various surface areas separated say a 0.5 ±0.1 cm gaps and discharged using an external load. Using this process we get a unit PKL cell, module, Panel & arrays.

PKL Module

PKL Module Design

Practical Applications•15 kilowatt hr electricity -1 kg of leaves are required.

At a Glancé

Current and Potential Profile

pH Profile

Identification of H2 gas

AAS Analysis

Atomic Absorption Spectrophotometer

AAS Analysis

Ecell = Eoxidation (0.76) + Ereduction (0)° means standard conditions:

1atm, 1M, 25C

How can we determine the Cell EMF ?

Hydrogen ElectrodeVoltaic Cell

Ecathode (0.34 V)Eanode (0.76 V)

How can we determine the Cell EMF ?Ecell

Ecell = E

ox + Ered = 0.76+0.34 = 1.10 V

Theory – Nernst Equation Ecell = E °cell - RT log Q

nF Ecell = E °cell - 0.0592 log Q @ 25°C(298K)

n Ered = E °red - RT log Q

nF Ered = E °red - 0.0592 log Q @ 25°C(298K)

nQ = [Oxidised state]α/[Reduced state]β

α and β are stoichiometric coefficient

Theory – Spontaneity G = - nFEG = - nFE ; ; G = - RTlnK G = - RTlnK

G = Gibbs free energy [Reaction is spontaneous G = Gibbs free energy [Reaction is spontaneous if ΔGif ΔG isis

negative]negative]n = number of moles of electrons. n = number of moles of electrons. F = Faraday constant 9.6485309 x 10F = Faraday constant 9.6485309 x 1044 J/V (1 J/V (1

mol of mol of electrons carries 96,500C )electrons carries 96,500C )E = cell potentialE = cell potentialR = 8.31 J/mol.KR = 8.31 J/mol.KT = Kelvin temperatureT = Kelvin temperatureK = equilibrium constant K = equilibrium constant

[products][products]coeffcoeff/[reactants]/[reactants]coeffcoeff

Probable Electrochemical Reaction in PKL Cell

Anode : Zn → Zn2+ + 2e-, Cathode : 2H+ + 2e- → H2,

Cell : Zn + 2H+ → Zn2+ + H2,

Role of CuSO4 in PKL Cell■ Supporting electrolyte■ Depolarizer■ Secondary Salt (effect)■ Increase the cell EMF

Comparision – life time

• The organic acids are weak acid. These weak Organic acids dissociates in the solution very slowly and that is why longevity of the PKL Sap/Solution for electricity generation is more than the normal Voltaic cell.

• Once a mixture is prepared for producing electricity, it serves the purpose for 6 months continuously

Comparision – Cost

Cost of PKL cell is ~ 4 times less than the conventional Galvanic cell.

Cost of PKL cell is ~ 2.5 times less than the conventional storage battery

Cost of PKL cell is ~ 5 times less than the conventional Solar cell

Recycling Ability

Charging

Discharging

• The conversion efficiency of the PKL electricity can be expressed as:

η = P output / P input where, η =Conversion efficiency P output =Useful PKL electric power P input = Input PKL electric power

• The conversion efficiency lies between 0 & 1.That is 0< η<1. At present we got the maximum conversion efficiency is around 69%.

Efficiency of the PKL Electricity

Equivalent circuit of PKL cell

Conclusion

PKL cell :■ less expensive ■ highly efficient ■ longer shelf-life ■ environmentally friendly■ introduce a sustainable platform to combat the power crisis of this world in future.

Fig. Electrochemical mechanism of PKL cell electricity generation system : (a) pH , short circuit (SC) and open circuit (OP) voltage profile and (b) concentration profile of Zn2+ and Cu2+ ions in PKL electrochemical cell.

Future Work

PKL Wastage

Thanks for your kind attention

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