Advances in design of metal-organic frameworks activating persulfate for water decontamination

Abstract

Metal-organic frameworks (MOFs), a type of extended crystalline porous materials, built from organic linkers and metal ions as centers via coordination interaction, have drawn ever-growing concerns in diversiform fields because of their large surface area, high porosity, and tailorable structure. Taking account of the serious water pollution, persulfate-based advanced oxidation technologies (PS-AOTs), as the essential strategy for wastewater treatments, have attracted more attention in recent years, which allow the transformation of chemical pollutants from different sources into less toxic and more readily biodegradable substances by oxidation and mineralization. The efficiency of the oxidation processes could be crucially improved by using appropriate MOFs. In this review, we summarize the strategies for rationally designing MOF-related materials as very efficient PS activators for the prominent elimination of organic contaminants through (i) tailoring compositions and structures of MOF-related catalysts to increase the number of active sites, enhance the electron transfer capacity and promote the surface properties; (ii) researching effects of environmental factors on catalytic performance and corresponding mechanisms to alleviate the negative influences; and (iii) balancing the contribution of different catalytic pathways (free radical and non-radical pathways) to realize better catalytic performance. Finally, we propose possible future directions for the design of MOF-related catalysts as PS activators based on the degradation mechanism, reusability, and toxicity. Additionally, due to the promising potential of MOFs for the elimination of arsenic compounds from water, the successive As(III) oxidation and by-produced As(V) adsorption in PS-AOTs by MOF-related materials were encouraged. These strategies could advance the future design of MOF-related catalysts as PS activators toward water decontamination.