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Title: Modification and characterisation of carbon fibre ion exchange media
Authors: Harry, I.D.
Keywords: Viscose rayon based activated carbon cloth
Sorption isotherms
Electrochemical oxidation
Electrochemical reduction
Lead
Copper
Chromium(VI)
Competitive and noncompetitive sorption
Characterisation
Issue Date: 2008
Publisher: © Ibiba Dateinm Harry
Abstract: This thesis examines the use of electrochemically treated viscose rayon based activated carbon cloth (ACC) for the removal of metal ions from aqueous effluent streams. Two types of treatment were performed: (i) electrochemical oxidation and (ii) electrochemical reduction to enhance cation and anion sorption capacities of the ACC, respectively. Electrochemical oxidation resulted in a loss of 61% BET surface area due to blockage of pores through formation of carboxylic acidic groups but its cation exchange capacity and oxygen content increased by 365% and 121%, respectively. The optimum constant current at which a combination of applied current and oxidation time at any extent of oxidation to produce ACC of maximum cation exchange capacity was found to be 1.1 A, with voltage of 4.2 V and current density of 0.8 mA/m2. Batch sorption experiments showed that the maximum copper and lead sorption capacities for electrochemically oxidised ACC increased 17 and 4 times, respectively, for noncompetitive sorption and 8.8 and 8.6 times, respectively for competitive sorption. Therefore, electrochemically oxidised ACC is an effective adsorbent for treating aqueous solution contaminated with copper/lead in both single component and multi-component systems. Industrial wastewaters are multicomponent systems, therefore, electrochemical oxidation of ACC is an efficient way of enhancing lead and copper ions sorptive capacity for industrial wastewater treatment. Electrochemical reduction resulted in a loss of 28% BET surface area due to formation of ether groups but its anion exchange capacity increased by 292%. The optimum constant current at which a combination of applied current and reduction time at any extent of reduction to produce ACC of maximum anion exchange capacity was found to be 5.5 A, with voltage of 9.8 V and current density of 6.4 mA/m2. Batch sorption experiments showed that the maximum chromium(VI) sorption capacity for electrochemically reduced ACC increased 2.12 times, with highest maximum chromium(VI) sorption capacity of 3.8 mmol/g at solution pH 4. Most industrial wastewaters contaminated with chromium(VI) are highly acidic, therefore, electrochemical reduction of ACC is an efficient way of enhancing chromium(VI) sorptive capacity for industrial wastewater treatment.
Description: A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.
URI: https://dspace.lboro.ac.uk/2134/14123
Appears in Collections:PhD Theses (Chemical Engineering)

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