Abstract
SiO2-TiO2-C aerogel photocatalysts with different carbon loadings were synthesized by using sol-gel chemistry. The anatase crystal and nonmetal carbon dopant were introduced during the sol preparation and formed by hydrothermal treatment, which can simultaneously enhance the adsorption ability and visible light photo-activity. A high surface area (759 g cm−3) SiO2-TiO2-C aerogel composite can remove up to 80% tetracycline hydrochloride within 180 min under visible light. The characterization of the gel structures shows that the homogeneous dispersion of O, Si, Ti and C in the skeleton, indicating that hydrothermal synthesis could provide a very feasible way for the preparation of composite materials. n(C):n(Ti) molar ratio of 3.5 gives the best catalytic performance of the hybrid aerogel, and the cyclic test still confirms over 60% degradation activity after seven use cycles. All catalysis reaction followed the pseudo-first-order rate reaction with high correlation coefficient. The electrons and holes in the compound could be effectively restrained with doping proper amount of C, and ESR results indicate that the oxidation process was dominated by the hydroxyl radical (•OH) and superoxide radical (•O2−) generated in the system.
Highlights
High recombination rate of photon-generated carrier and low quantum efficiency, which leads to the decrease in photocatalytic activity [12,13]
SiO2-TiO2-C wet gel was taken out after the reaction completed, aged at normal temperatures for 24 h, modified with TMCS/IPA/n-Hexane(volume ratio of TMCS/IPA/n-Hexane = 1:0.3:1) solution which changed once every 24 h until the water was completely replaced, the gel blocks could be observed floating on the modified solution
The SiO2-TiO2-C aerogel was obtained after heat treatment at 50, 80, 150 and 180 ◦C for 2 h, respectively, in the oven
Summary
Tetracycline (TC) is widely used in the medical industry and discharged through human waste to municipal wastewater plants [1]. In a report by a group, the residual S was shown to occupy O sites in TiO2 and the band gap lowering was attributed to the mixing of S 3p and O 2p states [27] Another group has indicated that C-doped TiO2 photocatalyst with high specific surface could be prepared by furfural as carbon source and the main reason for the response of visible light was that the carrier could transfer on both TiO2 and C simultaneously [28]. High surface area charge transfer support material SiO2 aerogel was selected to hybrid with anatase TiO2 with a design target to improve the interactions between the pollutant and the catalyst; in addition, a nonmetal dopant carbon was applied for the enhancement of the system’s visible light response.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
