Contaminant Removal from Source Waters Using Cathodic Electrochemical Membrane Filtration: Mechanisms and Implications.
Removal of recalcitrant anthropogenic contaminants from water calls for the development of cost-effective treatment technologies. In this work, a novel electrochemical membrane filtration (EMF) process using a conducting microfiltration membrane as the cathode has been developed and the degradation of sulphanilic acid (SA) examined. The electrochemical degradation of SA in flow-by mode followed pseudo-first-order kinetics with the degradation rate enhanced with increase in charging voltage. Hydrogen peroxide as well as oxidants such as HO•and Fe(IV)O2+were generated electrochemically with HO•found to be the dominant oxidant responsible for SA degradation. In addition to the anodic splitting of water, HO•was formed via a heterogeneous Fenton process with surface-bound Fe(II) resulting from aerobic corrosion of the steel mesh. In flow-through mode, the removal rate of SA was 13.0% greater than obtained in flow-by mode, presumably due to the better contact of the contaminant with the oxidants generated in the vicinity of the membrane surface. A variety of oxidized products including hydroquinone, p-benzoquinone, oxamic acid, maleic acid, fumaric acid, acetic acid, formic acid, and oxalic acid were identified and an electrochemical degradation pathway proposed. These findings highlight the potential of the cathodic EMF process as an effective technology for water purification.
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , Shanghai 200092, China.
Junjian
J
Zheng
School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia.
Jinxing
0000-0002-5087-3972
J
Ma
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , Shanghai 200092, China.
Zhiwei
0000-0001-6729-2237
Z
Wang
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , Shanghai 200092, China.
Shaoping
S
Xu
School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia.
T David
TD
Waite
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , Shanghai 200092, China.
Zhichao
Z
Wu
D016227:Benzoquinones; D004566:Electrodes; D006861:Hydrogen Peroxide; D007501:Iron; D007700:Kinetics; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical
D016227:Benzoquinones; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D007501:Iron