DE!%LINATION ELSEVIER Desalination 155 (2003) 49-57 www.elsevier.comllocate/desal Electrochemical oxidation of polyvinyl alcohol using a RuO,/Ti anode Sangyong I&+*, Tak-Hyun Kimqb, Chulhwan Park”, Eung-Bai Shinb ‘Cleaner Production Technology R & D Center, Korea Institute of Industrial Technologv, Chonan 330-825, Korea Tel. +82 (41) 589-8356; Fax +82 (41) 589-8340, email: sykim@kitech.re.kr bDepartment of Civil and Environmental Engineering, Hanyang University, Ansan, 425-791, Korea Received 4 July 2002; accepted 9 October 2002 Abstract Polyvinyl alcohol (PVA), known as the dominant contributor of chemical oxygen demand (COD) in textile wastewater, is very difficult to decompose by conventional treatment technologies. In this study, electrochemical oxidation using a RuO/Ti anode was applied to treat a PVA solution. The mechanisms of PVA degradation and COD destruction were investigated, while the operating parameters affecting the mechanisms were also studied. The parameters investigated included current density, PVA concentration in waste stream, the rate of electrolyte consumption of sodium chloride, and the feed rate of wastewater. The overall mass transport behavior of electrochemical oxidation of PVA was explained by the mathematical relationship of dimensionless numbers such as the Reynolds,Schmidtand Sherwood numbers. Keywords: PVA; Electrochemical oxidation; RuO,/Ti anode;COD;Power consumption 1. Introduction Textile wastewater generally contains a number of different kinds of pollutants such as dyes, salts, oxidizing/reducing agents and sizing agents. The sizing agents include polyvinyl alcohol (PVA), carboxymethyl cellulose, and various surfactants. These sizing agents are removed by hot water after weaving process. PVA concentrations in desizing wastewater *Corresponding author. typically reach as high as 0.5% [1,2]. Unfor- tunately, sizing agents in these wastewaters are very difficult to break down biologically, and they are known as the dominant contributor of COD in the textile wastewater. Conventional treatment technologies do not satisfactorily re- duce PVA concentrations in the wastewaters. Conventional treatments of wastewater con- taining sizing agents include biological oxidation, advanced oxidation and the membrane filtration. The biological treatment of dyeing wastewater [3-51 is cheaper than advanced oxidation and 001 l-9164/03/!$- See front matter Q 2003 Elsevier Science B.V. All rights reserved PII: SO01 l-9164(03)00238-8