One stone three birds: Simultaneous detection, adsorption and photocatalysis, the novel coordinated treating strategy towards complicated pollution system and the mechanism analysis

Waste water is difficult to treat, mainly because of the co-existence of organic and inorganic contaminants, attracting much attention. Herein, a novel nanohybrid of TiO2/dicarboxylate 1,5-diphenyl-3-thiocarbazone(III) (denoted as TiO2/DAT) was facilely synthesized. TiO2/DAT was used to treat the waste water with the co-existence of tetracycline (TC) and Cd2+. The results indicated that TiO2/DAT can qualitatively/quantitatively detect Cd2+ via colorimetry, and the Cd2+ adsorption can boost the TC degradation by TiO2/DAT. It was found that the co-existence of TC does not affect the detection and adsorption of Cd2+. Furthermore, whether Cd2+ being adsorbed in advance or co-existent with TC, the TC degradation manners over TiO2/DAT were similar. A reasonable deduction for these phenomena is that Cd2+ was adsorbed by TiO2/DAT before TC, which was confirmed by density functional theory (DFT) calculations. So TC and Cd2+ will not compete the surface active sites of TiO2/DAT when treated simultaneously by TiO2/DAT, and that is why TiO2/DAT can effectively treat TC and Cd2+ co-existent waste water. Upon TiO2/DAT, the treating strategies of detection, adsorption and degradation are combined into one functional material. This one stone three birds strategy can simplify the treating process of complex pollution systems, exhibiting highly promising in practical applications.