Removal of total organic carbon from aqueous solution containing polyvinyl alcohol by electrocoagulation technology

The removal of total organic carbon (TOC) from aqueous solution containing polyvinyl alcohol (PVA) using iron electrocoagulation (EC) was investigated. Iron hydroxides generated during EC were used to remove PVA and TOC from the aqueous solution, and the effects of varying current density and solution temperature on PVA and TOC adsorption characteristics were evaluated. The findings indicated that complete PVA removal accompanied by TOC removal of an aqueous PVA solution could be achieved within a reasonable electrolysis time and with relatively low electrical energy consumption. A pseudo-first-order kinetic model provided a good fit to the experimental results at various current densities and solution temperatures. In addition, the experimental data were fitted with several adsorption isotherm models to describe the EC process. The predictions of the Freundlich adsorption isotherm model satisfactorily matched the experimental observations. Thermodynamic parameters, including the Gibbs free energy, enthalpy, and entropy, indicated that the TOC adsorption of the aqueous solution containing PVA on metal hydroxides was feasible, spontaneous and endothermic in the temperature range of 288 K to 318 K. (C) 2010 Elsevier B.V. All rights reserved.