Effect of sodium dodecyl benzene sulfonate on the process of Fenton degradation of 4-chlorophenol

Abstract

The Fenton process has been shown to be very successful in removing highly toxic chlorinated phenols from water. However, the influence of other constituents in industrial wastewater, such as sodium dodecyl benzene sulfonate (SDBS) surfactants should be intensively researched. In this study, the effects of SDBS on the kinetics of 4-chlorophenol (4-CP) degradation undergoing Fenton process have been studied. Results showed that 4-CP degradation ratio decreased as SDBS concentration increased. The 4-CP degradation ratio declined from 98.3 to 84.5% when the SDBS concentration increased from 0 to 2.0 mmol L−1 after 10 min reaction. This experimental result was attributed to the hydration between 4-CP and SDBS and the consumption of hydroxyl radicals (⋅OH) by surfactants. The SDBS had amphiphilic structure in water environment with hydrophilic and hydrophobic entities. It could interact with 4-CP functional groups via hydrophilic groups (benzene sulfonate) by hydration in the aqueous phase. The kinetics modeling indicates that the 4-CP degradation reaction followed the pseudo-first-order reaction for 4-CP concentration. The SDBS also had affirmative effects on the hydrophilic and organic acid intermediate organic matter mineralization. The SDBS existence could reduce the maximum concentrations of intermediate products. For example, the organic acids intermediate maleic acid concentration was descend from 2.59 to 0.21 mmol L−1 when the SDBS concentration increased from 0 to 2.0 mmol L−1. In a word, the surfactants SDBS can reduce the 4-CP degradation ratio and encourage the intermediate products mineralization.