BiOBr hybrids for organic pollutant removal by the combined treatments of adsorption and photocatalysis.

The x SiO 2 -BiOBr ( x = 0-5) and SN-SiO 2 -BiOBr hybrids were synthesized via a facile one step co-precipitation method. To determine the optimal formula, the photocatalytic degradation of C. I. reactive red 2 (X3B) with x SiO 2 -BiOBr ( x = 0-5) was investigated. Under simulated sunlight irradiation, 4SiO 2 -BiOBr exhibited a better photocatalytic efficiency than other materials; 1.77 and 1.51 times higher than conventional nano TiO 2 and pure BiOBr, respectively. To demonstrate the photocatalytic degradation mechanism, the effect of active species on degradation of X3B was carried out, and a possible degradation pathway was proposed. To realize the combined treatments of adsorption and photocatalysis, an inorganic/organic (I/O) SN-SiO 2 -BiOBr hybrid was further strategized and synthesized. It showed much better adsorption performance than the SiO 2 -BiOBr composite. It could enrich organic pollutants by facile adsorption, and then degrade them to H 2 O and CO 2 under natural sunlight irradiation. Notably, this sunlight-driven photocatalysis can be performed in the slurry resulted from the pollutant adsorption. As a result, the proposed combination of adsorption and photocatalysis will provide a novel strategy to greatly facilitate the treatment of organic wastewater.