Fe-Mn Bimetallic Oxide-Enabled Facile Cleaning of Microfiltration Ceramic Membranes for Effluent Organic Matter Fouling Mitigation via Activation of Oxone
Guicheng Zhang, Xueying Yang, Zhangxiong Wu, Winston Duo Wu, Xiaoning Wang, Xiao Dong Chen, Sheng-Peng Sun
Abstract
Membrane fouling caused by effluent organic matters (EfOM) remains a major challenge in wastewater reclamation. Herein, we report a promising catalytic microfiltration ceramic membrane (CM) that features with ∼20 μm thickness of Fe-Mn bimetallic oxide (Mn1.5FeO6.35) active layer coating on the α-Al2O3 membrane base (α[email protected] CM), which enables fantastic mitigation of irreversible EfOM fouling via in situ Oxone activation. Modeling results indicated that complete and standard pore blocking dominated an initial fouling mechanism on the α[email protected] CM, followed by a cake mode as the fouling evolution. Critically, the cake fouling layer was effectively removed through a facile on-line cleaning with Oxone aqueous solutions, resulting in rapid flux restoration. The mechanism was dominated by radical cleaning pathways, and hydroxyl radicals (HO·) played a critical role in reducing EfOM fouling over other reactive species (e.g., sulfate radicals (SO4·–) and singlet oxygen (1O2)). A key feature of as-prepared α[email protected] CM is the favorable slightly basic pH cleaning conditions (∼pH 10), restricting Fe and Mn leaching and maximizing the membrane-sustained activity and durability. Hence, this study highlights the robust cleaning capability of α[email protected] CM toward EfOM fouling and proposes a new strategy in developing environmentally friendly catalytic CMs for wastewater reclamation.