Adsorption of sediment phosphorus by porous ceramic filter media coated with nano-titanium dioxide film

The porous ceramic filter media (PCFM) was applied to reduce the release of P in lake sediment and we wondered if the nano-TiO2 coating could enhance the P adsorption by PCFM alone in lake sediments. The nano-TiO2 film coated on PCFM in this study was prepared by sol–gel process, and the adsorption properties of sediment P in all fractions by the nano-TiO2 film coated PCFM were investigated through a series of stirring and static experiments. P release characteristics and various batch sorption conditions, e.g., adsorbent dosage, stirring time, operation temperature and pH were tested, and the kinetics of sediment P adsorption was discussed. The results showed that the sediment released only a small amount of TP within 8 h. The removal efficiency of sediment P in all fractions could reach maximum in 8 h and 22 d under stirring and static experiments, respectively. The residual concentration of Ca-P, Fe/Al-P, IP, OP and TP in the sediment was 85 mg/kg, 255 mg/kg, 310 mg/kg, 95 mg/kg and 431 mg/kg, respectively, and the corresponding removal rate was 19.04%, 44.81%, 43.04%, 45.09% and 44.10%, respectively, under the optimal conditions: adsorbent dosage 4 g, operation temperature 30 °C and pH 2. The adsorption kinetic models of the sediment P in all fractions could be described well by power function equations (Qt = k·ta, 0 < a < 1). The results suggest that the adsorption of sediment P onto the nano-TiO2 film coated PCFM had the great potential to reduce the pollution of internal phosphorus and regulate the transport of sediment P in the aquatic environment.