Cellulose mineralization with in-situ synthesized amorphous titanium dioxide for enhanced adsorption and auto-accelerating photocatalysis on water pollutant

It is a daunting task to balance the catalyst stability and exposure of active site of highly efficient immobilizing photocatalyst system for wastewater treatment. In this study, an in-situ mineralization method based on homogeneous system was proposed to directly construct amorphous TiO 2 into cellulose hydrogel network as the crosslinker for efficiently and safely processing wastewater. This unique structure not only endowed TiO 2 /cellulose microsphere (TMS) with an adsorption capacity of 91.7 mg/g on methylene blue, which was approximately 14 times to cellulose microsphere containing commercial TiO 2 nanoparticles, but also made TMS reusable due to its pH sensitive adsorption capacity. More interestingly, TMS exhibited an auto-accelerating process in decomposing Rhodamine B where the degradation intermediate could act as the receptor of photo-regenerated holes to improve photocatalytical activity. In further cyclic test, the degradation rate constant of intermediate-adsorbed TMS was up to 0.02 mg −1 min −1 . Moreover, the intermediate-adsorbed TMS obtained visible light responsive property, including a removal ratio of 86.3 % against tetracycline (c 0  = 20 mg/L) in 120 min. This in-situ cellulose mineralization provides a new sight into the design of hydrogel immobilized catalyst system with high dispersion and active site exposure for efficient and safe water treatment.