Highly effective degradation of sodium dodecylbenzene sulphonate and synthetic greywater by Fenton-like reaction over zerovalent iron-based catalyst

There is an increasing interest to recycle greywater for meeting non-portable water demand. However, linear alkylbenzene sulphonates (a form of anionic surfactants) that are commonly found in greywater are less biodegradable at moderate to high concentrations. A fenton-like system is a relatively economic advanced oxidation process that can potentially be used for surfactant degradation in greywater treatment. This study investigated the feasibility of zerovalent iron (ZVI)-mediated Fenton's oxidation of sodium dodecylbenzene sulphonate (SDBS) using Fe0/H2O2and Fe2+/Fe0/H2O2systems under a range of operating conditions. For the Fe0/H2O2binary system, the initial pH value and Fe0dosage played important roles in final degradation efficiency. For the Fe2+/Fe0/H2O2ternary systems, a small amount of Fe2+(0.5-1.7mM) contributed a synergistic effect to promote iron recycling and SDBS degradation. Approximately, 90% of SDBS mineralization efficiency was accomplished within 15min at a pH range from 3.0 to 6.5, using 18mM Fe0and 15mM H2O2. However, the removal kinetics was rate-limited by Fe2+dissolution from the ZVI surfaces. The Fenton-like process of the Fe2+/Fe0/H2O2ternary system also presents a promising treatment method for synthetic greywater, in which 90% TOC removal was achieved within the first 10min; 78% COD and 91% BOD5were achieved after 120min of reaction.