Magnetic semiconductor nano-photocatalysts for the degradation of organic pollutants

Photocatalytic degradation of organic pollutants using suspended and dispersed semiconductor nano-photocatalysts in wastewater holds unique advantages, including high activity, low cost, solar utilization, and complete mineralization. But the recovery and reuse of photocatalysts are difficult because the fine particles are easily discharged in waters. Immobilization of photocatalysts on supports such as glass and zeolite results in decreased activities due to the low specific area and slow mass transfer. Furthermore, a large amount of the photocatalysts will result in colored contamination. Therefore, it is necessary to develop photocatalysts with a separation function for the reusable and cyclic application. In order to take advantage of the high activity and enable the semiconductor nano-photocatalysts to be reused, the concept of magnetic photocatalysts with separation function was raised. We review the photocatalytic principle, structure, and application of the magnetic semiconductor catalysts.