▎ 摘　　要

Spongy graphene adsorbents have attracted great research interest recently, because of the high adsorption capacity, easy handling, and low operating cost. Fabrication of graphene sponge with other high-performance adsorbents might combine the merits of both materials, thus deserves more investigations. In this study, TiO2-graphene sponge (TiO2-GS) was prepared by the deposition of amorphous TiO2 on graphene oxide (GO) sheets for the adsorption of tetracycline antibiotics, where lyophilization was adopted to obtain the porous structure. TiO2-GS adsorbed tetracycline with a large adsorption capacity of 1,805 mg/g, larger than that of GO (313 mg/g) and GO-chitosan aerogel (1,470 mg/g). The adsorption kinetics, which finally reached the equilibrium at 48 h, was clearly controlled by the diffusion of tetracycline to TiO2-GS in the initial stage according to intraparticle diffusion model. Thermodynamics investigation indicated that the adsorption process was endothermic and promoted at higher temperature, with a positive Delta H of 35.8 kJ/mol. Generally, higher pH facilitated the adsorption of tetracycline on TiO2-GS, except that the adsorption was also very effective at pH 1. In contrast, ionic strength had insignificant influence. The adsorbed tetracycline could be washed out with acidic ice-cold water to regenerate TiO2-GS. The implication to the applications of TiO2-GS in water treatment is discussed.