Maretva Baricot Mendoza Supervisor Dr. Josep Font Capafons Chemical Reaction Engineering and Process...

Maretva Baricot Mendoza

Supervisor Dr. Josep Font Capafons

Chemical Reaction Engineering and Process Intensification Group, Department of Chemical Engineering, Universitat Rovira i Virgili

Tarragona, February 3rd 2005

Experimental design for the functionalization of activated carbon as catalyst in Catalytic wet air oxidation of

phenol

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Content

1. Introduction

2. State of the art

3. Objectives

4. Methodology

5. Expected Results

6. Future work

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Introduction

Environmental problem

AdsorptionMembranes

Filtration UltrafiltrationReverse osmosis

ChemicalOxidation

Biological

Treatments

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Introduction

Activated Carbon

Adsorption, catalyst support but lately…..

As catalyst itself!!!

What is it ?

Growing interest!!!

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Carbonaceous materials, highly crystalline formExtensively developed internal pore structure

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State of the Art

Characterization of carbon surfaceChemical titrations Temperature programmed desorptionsInfrared and X-ray photoelectron spectroscopy

Most common functional groups

PhenolicsCarbonylsCarboxylsQuinonesLactonesAnhydrides

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State of the Art

Carboxylic acid

Lactone

Phenol

Carbonyl

Anhydride

Ether

Quinone

OOH

H

O

CO

OH

O

C O

OH

O

O

O

C

C

O

O

O

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Functional groups

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State of the Art

Baçaoui et alEnviron. Sci. & Technol, 2002.

36(17): p. 3844-3849

Herbicides

Pereira et alAppl. Catal., A, 1999.

184(1): p. 153-160 Activated carbon as catalyst in the oxidative dehydrogenation of ethylbenzene

Modified AC

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State of the Art

CREPI

Phenol oxidation in a Trickle bed reactor (TBR)@ 160ºC and Oxygen partial pressure 0,82 MPa(1)

Conversion up to 99 %

Commercial activated carbon

as Catalyst

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(1) J. Chem. Technol. Biotechnol., 2001. 76(7): p. 743-751

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Objectives

Design an experimental procedure to functionalize activated carbon in order to

obtain a good surface chemistry that improves the catalytic activity of carbon in

the TBR.

Main

Secondary

Superficial functional groupsCarbon textureDefunctionalization-Refunctionalization process

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Methodology

DefunctionalizationHeat treatment under Inert atmosphere

Elimination of surface functional groups

Temperatures ranges

RefunctionalizationHeat treatment under Oxygen and Nitrogen

atmosphere

Formation of specific surface functional groupsVarying T, PO2 and time

Carbon treatment

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Methodology

From Refunctionalization Stage

MAC tests

Adsorption tests

Catalytic activity tests

Batch configuration

TBR, Milder conditions

Set of Modified Activated Carbon MAC

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Methodology

From the set of MAC those that shows better performance as catalyst and adsorptive material…

MAC characterization

Chemical titrationsTGA + TPDInfrared Spectroscopy

Thermogravimetric analysis + Thermal programmed desorptions

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Expected Results

1. Clarification of the influence of the surface chemistry on the AC catalytic performance

2. Determination of better surface chemistry on activated carbon for it to show catalytic activity

3. Obtaining a better catalyst for phenol oxidation than commercial AC

4. Procedure to design tailor made AC active for CWAO, from any source

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Future work

1. Develop an experimental procedure combining oxidizing treatments and characterization techniques to obtain catalyst useful in oxidation of several compounds as halogenated phenols

2. Improve adsorptive performance of AC with chemical surface modification

3. Establish experimental procedures to specifically functionalize AC surface in order to improve its behavior as catalyst, support or adsorptive material

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Questions

Thanks for your attention!!!

Questions ????