Ceramic membrane with double catalytic layer for efficient peroxymonosulfate activation and dissolved organic matter (DOM) membrane fouling control

Abstract

Membrane fouling and low removal of dissolved organic matter (DOM) are the main obstacles for the wide application of ultrafiltration membrane technology in water treatment. Herein, we reported the preparation and application of a novel ceramic membrane, which embedded the cobalt oxide in the membrane support layer, and simultaneously loaded the CoAl composite bimetallic oxide on membrane surface layer. The double catalytic layer membrane (CoAl@AM-Co) enabled more efficient DOM removal and membrane fouling mitigation via in situ peroxymonosulfate (PMS) activation during filtration of actual raw water. Compared to the ceramic membrane with only single catalytic layer, the CoAl@AM-Co/PMS system could achieve much higher normalized membrane flux (0.79 vs. 0.63 and 0.49) and TOC removal (87.47 % vs. 58.35 % and 47.16 %); meanwhile, the molecular weight of DOM in the permeate water would also be significantly decreased. The FT-ICR MS results indicated that the total amount of DOM molecules of the permeate was reduced; the DOM with high H/Cwa and low O/Cwa value could be more easily removed, accompanied with the production of DOM with higher oxidation and unsaturation degree. Singlet oxygen and surface-bound radicals were proved to play a critical role in mitigating the membrane fouling by DOM. The design of ceramic membrane equipped with double catalytic layer and its application in advanced water purification were systematically elucidated for the first time in this work, which provided a new pathway for efficient treatment of surface water containing DOM.