Abstract
Ozonation of 2 commercially important textile biocidal finishing agents (called BI and BII herein) in aqueous solution was studied in a semi-batch bubble column reactor at different ozone feed rates (500, 750, and 900 mg/h) and pH (pH=7 and 12). Ozonation efficiency and kinetics were assessed in terms of COD, TOC and UV absorbance at 280 nm (UV280) and 254 nm (UV254), representing the aromaticity and unsaturated moieties of the studied textile biocides, respectively. Due to its chlorinated aromatic content, the fate of Adsorbable Organic Halogens (AOX) of BI was also followed during the ozonation experiments. At alkaline pH, appreciably higher COD and TOC removals were achieved, speaking for a free radical (•OH) dominated degradation pathway for both tested biocides. AOX, UV280 and TOC abatement rates obtained for BI ozonation at optimized reaction conditions indicated that the degradation of BI followed a sequential path of dechlorination, dearomatization, oxidation and mineralization, respectively.
ACKNOWLEDGMENTS
We are thankful to Dr. Izzet Alaton, Head of the Research & Development Department of Pisa Tekstil for his courtesy of supplying the biocidal finishing agents. The present study was financially supported by TUBITAK (Turkish Scientific and Technical Research Council) under project Nr. ICTAG–C–075 for our participation in COST Action 628 “Pollution Prevention and BAT for Textile Dyeing and Finishing Industry” and the Turkish Academy of Sciences (TUBA).