Integration of adsorption and advanced oxidation catalysis: Materials, synergistic mechanisms, and applications

Adsorption and advanced oxidation processes are frequently used technologies for the removal of organic pollutants from water. For adsorption there is no transformation of the pollutants and the adsorbent will be eventually saturated, which is the disadvantage of this technology for <i>in situ</i> application. Advanced oxidation processes can cause mineralization of the contaminants, but they are not cost-effective for the degradation of pollutants with low concentrations. Integrated adsorption-advanced oxidation technology based on bifunctional adsorption-catalyzation materials has recently received significant attention, which overcomes the limitations of single use of these two technologies and exhibit synergistic effects in the removal of the pollutants. This article reviews the recent research progress on four types of bifunctional adsorption-catalyzation materials, including carbonaceous materials, clay mineral materials, metal organic framework materials and metal-based materials. Then, the application of these materials in typical integrated adsorption-advanced oxidation technologies was reviewed. The focus is particularly put on the synergistic or antagonistic effects of these two processes from the perspective of surface chemistry of the materials at a molecular level. In addition, the factors that limit the performance of the technology are discussed. One focus of the future study should be the methods to build the materials with specific surface structure that causes the synergistic effects of adsorption and catalysis, as well as the methods for application of these materials.