TiO2/P(AM-co-AMPS) monolith prepared by CO2-in-water HIPEs and its potential application in wastewater treatment

Abstract

Removing dyes and antibiotics from wastewater remains the current requirement for a global health problem. The ionic macroporous adsorbent is an efficient solution to this problem. Herein, a novel sulfonated TiO2/poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) [TiO2/P(AM-co-AMPS)] macroporous composite monolith was first prepared by copolymerization of AM and AMPS in mTiO2-costabilized CO2-in-water Pickering high internal phase emulsions (HIPEs). The composite monoliths were characterized using XRD, SEM, confocal laser scanning microscopy, EDS mapping, FTIR, TGA, and mercury injection methods. The mechanical properties of the TiO2/P(AM-co-AMPS) HIPE were also evaluated. The void diameter could be adjusted by changing the density of carbon dioxide and the amount of mTiO2. The equilibrium swelling ratios of TiO2/P(AM-co-AMPS) with different contents of crosslinking agent of 2, 5, and 10 wt% (AM+AMPS) were 93, 37, and 19 g/g, respectively. TiO2/P(AM-co-AMPS) was used to remove methylene blue (MB) and tetracycline (TC) for evaluating the adsorptive properties of the composite monoliths. Results indicated that the main adsorption driving force was the electrostatic attraction between −SO3− and MB/TC. Adsorption experiments were conducted using a batch technique. The adsorption capacities of TiO2/P(AM-co-AMPS) for MB and TC were 1660 and 1128 mg/g in a wide pH range of 3–10. The equilibrium saturation point could be reached after 90 min for MB and 360 min for TC. Thereafter, the removal of MB and TC by gravity-driven separation was presented. The breakthrough curve and reuse evaluation for the removal of MB/TC were also studied in detail.