Sol-gel Synthesis of Fe2O3/CaSO4 Composite Photocatalyst and Photocatalytic Degradation of Rhodamine B Dye

The sol-gel method combined with low temperature calcination technology have been used to synthesized the pure CaSO4, pure Fe2O3, and CaSO4/Fe2O3 composite photocatalyst. The CaSO4/Fe2O3 composite photocatalysts only contains CaSO4 and Fe2O3 phases and without other impurities. The CaSO4/Fe2O3 composite photocatalyst is mainly composed of nano-particles and micron spherical particles. The CaSO4/Fe2O3 composite photocatalyst exhibits high optical absorption coefficient and high visible light photocatalytic activity for degradation of Rhodamine B dye. The optimal dye concentration, catalyst content, illumination time, and pH value were 30 mg/L, 1 g/L, 60 min, and 8, respectively. The high photocatalytic activity of CaSO4/Fe2O3 composite photocatalyst may be due to the synergistic effects of the recombination rate of charge carriers, holes, hydroxyl radicals and superoxide radicals. The total organic carbon (TOC) analyses indicated that almost total mineralization in the photocatalytic experiments. The results provide a technical reference for the synthesis of photocatalysts with multiple heterojunction composites for application in the field of wastewater treatment.