An optimization and modeling approach for H2O2/UV‐C oxidation of a commercial non‐ionic textile surfactant using central composite design

Abstract

AbstractBACKGROUND: Industrial surfactants are biologically complex organics that are difficult to degrade and may cause ecotoxicological risks in the environment. Until now, many scientific reports have been devoted to the effective treatment of surfactants employing advanced oxidation processes, but there is no available experimental study dealing with the optimization and statistical design of surfactant oxidation with the well‐established H2O2/UV‐C process.RESULTS: Considering the major factors influencing H2O2/UV‐C performance as well as their interactions, the reaction conditions required for the complete oxidation of a commercial non‐ionic textile surfactant, an alkyl ethoxylate, were modeled and optimized using central composite design‐response surface methodology (CCD‐RSM). Experimental results revealed that for an aqueous non‐ionic surfactant solution at an initial chemical oxygen demand (COD) of 450 mg L−1, the most appropriate H2O2/UV‐C treatment conditions to achieve full mineralization at an initial pH of 10.5 were 47 mmol L−1 H2O2 and a reaction time of 86 min (corresponding to a UV dose of 30 kWh m−3).CONCLUSION: CCD allowed the development of empirical polynomial equations (quadratic models) that successfully predicted COD and TOC removal efficiencies under all experimental conditions employed in the present work. The process variable treatment time, followed by the initial COD content of the aqueous surfactant solution were found to be the main parameters affecting treatment performance, whereas the initial H2O2 concentration had the least influence on advanced oxidation efficiencies. The H2O2 concentration and surfactant COD were found to be more important for TOC abatement compared with COD abatement. Copyright © 2009 Society of Chemical Industry