TiO₂/porous adsorbents: Recent advances and novel applications

This article reviews two interrelated areas of research: the first is the use of TiO₂-supported adsorbent materials as enhanced heterogeneous photocatalysts and their application to various reactions for organic pollutant removal from air and water; the second is the combination of adsorbent materials with TiO₂ photocatalysts which aims to efficiently regenerate adsorbent materials using illumination. By reviewing both areas of research, the following topics are covered; (i) photocatalytic activation of TiO_2; (ii) related properties of photocatalytic TiO_2; (iii) shortcomings of photocatalytic processes; (iv) preparation methods of composite TiO₂/adsorbent materials and their photocatalytic performance; (v) properties of common adsorbents and their applications for pollutant removal from air and water; (vi) adsorbent regeneration methods and their economic and operational issues; (vii) conclusions and future outlooks. This topic has not been previously reviewed to such an extent, and considerable knowledge can be gained from assembling the large number of studies on adsorption-photocatalysis combinations. As such, this review provides guidance for researchers working in the fields of environmental and chemical engineering focussing on organic pollutant removal and the engineering of new high performance photocatalytic TiO₂-supported porous adsorbent materials.