Investigation of removal of some organic compounds found in waste waters by means of electrosorption from aqueous solutions using activted carbon cloth electrode

In this study, changes in textural, surface chemical and electrochemical properties of high specific surface area activated carbon cloth (ACC) electrode upon polarization with in wide potential range (-1,5 V - 5,0 V) and in different electrolytes (Na2SO4 or KH2PO4/KOH) were systematically investigated. Although the textural properties of ACC do not change appreciably upon polarization, significant changes were observed in surface chemical and electrochemical properties. The results were used in explaining the electrosorptive behaviors of basic dyes. Electrosorption of basic dyes was followed by in-situ UV-VIS spectrophotometric measurements. Kinetic data were treated according to the pseudo first-order model and rate constant were determined. It was seen that complete removal of basic dyes from aqueous solutions can be achieved by electrosorption. A mechanism was proposed for electrosorption of basic blue-7 from Na2SO4 and KH2PO4/KOH solutions considering the solute-solvent interactions and solution pH. In the last part of this study, electrosorption of some aromatic organic acids by cyclic electrosorption (DE) process and 2,4-D pesticides by continuous flow electrosorption process (SAE) onto ACC electrode using a specially designed flow-through cell were carried out and processes were followed by an on-line UV-VIS spectrophotometric method. Electrosorptive behaviors of aromatic organic acids were correlated with their dipole moments and amounts of their ionic species present in solution. The capacity for electrosorption of 2,4-D pesticide onto ACC electrode by SAE process was calculated as 729 mg.g-1. Considerable improvement in the rate and extent of removal of organic molecules from aqueous solutions was achieved using the flow-through cell and this cell was proposed for the practical applications of electrosorption based waste water treatments.