Efficient removal of micropollutants from low-conductance surface water using an electrochemical Janus ceramic membrane filtration system

Electrochemical membrane filtration (EMF) technology is effective to remove the micropollutant in the wastewater but its efficacy is drastically compromised in treating the surface water having a typically low conductivity. In this work, a Janus Fe-Pt electrochemical ceramic membrane (ECM) was fabricated by depositing a thin Fe layer on the side of a ceramic membrane facing feed (cathode) and Pt layer on the other side facing permeate (anode). The low Fe-Pt electrode distance (~1 mm) ensured a decent conductance of the EMF system even in the low-salinity surface water and thereby maintained the removal efficiency of the micropollutant. It was identified that hydroxyl radicals (center dot OH) generated via anodic water oxidation and cathodic heterogenous Fenton process on bilateral sides of ECM were the dominant reactive oxygen species. The EMF system not only achieved 74% removal of atrazine (ATZ) from the low-conductance synthetic surface water with a low energy consumption (3.6 Wh per gATZ or 7.2 Wh m - 3), but also realized a stable removal of ATZ from real surface water over a continuous filtration experiment of 168 h. The theoretical computations and experimental analysis identified the degradation pathway, i.e., the dechlorination and dealkylation of ATZ in the EMF system. This study highlights the great potential of the Janus ECM in removing micropollutants from low-conductance surface water and wastewater.

Automated summary

Electrochemical membrane filtration (EMF) technology, using a Janus Fe-Pt electrochemical ceramic membrane (ECM), has been developed for the efficient removal of micropollutants from low-conductivity surface water. The Janus ECM, with thin Fe and Pt layers deposited on each side, ensures decent conductance and maintains removal efficiency. Hydroxyl radicals generated on both sides of ECM are found to be the dominant reactive oxygen species. The system achieves high removal efficiency of atrazine with low energy consumption and stable performance in continuous filtration experiments. The study highlights the potential of Janus ECM in removing micropollutants from low-conductivity surface water and wastewater.