Mechanisms of phosphorus removal from wastewater by ion exchange resin

This study investigated the mechanisms of phosphorus removal from both synthetic wastewater and effluent of an anaerobic membrane bioreactor (AnMBR) treating sewage by ion exchange resin. The results showed that 88.6% of phosphorous could be removed from the effluent of AnMBR with dosage of 10.0 g/L Amberlite IRA-958 resin, suggesting that ion exchange is a promising method for removing phosphorus from real wastewater. The maximal equilibrium sorption capacity of phosphate (Qe)was obtained at pH 10 for both synthetic wastewater and real wastewater. However, the isothermal sorption model and sorption kinetics of phosphate from synthetic wastewater were different from those of real wastewater due to the complexity of real wastewater. The phosphate sorption capacity and sorption equilibrium time of Amberlite IRA-958 resin in real wastewater were lower than that in synthetic wastewater. Furthermore, the sorption behaviors of synthetic wastewater fitted well with Langmuir isothermal sorption, while those of real wastewater were in agreement with Freundlich isothermal sorption. The results also show that the kinetics of phosphate sorption onto Amberlite IRA-958 resin from both real wastewater and synthetic wastewater corresponded well with the pseudo-first order kinetics model. The regeneration experimental results show that 0.4 mol/L NaCl could be used as the effective regeneration solution to recover the resin.