Efficient phosphate removal and recovery from wastewater with Zn(OH)2@DETA-aminated polyacrylonitrile fibre

The current eutrophication from excess phosphorus (P) discharge and the potential shortage crisis from explosive P demand, have attracted extensive attention from researchers. To solve this dilemma, adsorption technology is a promising method to simultaneously achieve phosphate removal and recovery. However, the difficulty in separation and high cost of adsorbents limit their application in wastewater treatment. Thus, an inexpensive Zn(OH)2 @DETA-aminated polyacrylonitrile (PAN) fibre was prepared to remove and recover phosphate from wastewater. The maximum adsorption capacity reached 108.0 ± 2.8 mg/g with the adsorption equilibrium time of 20 min. The inner sphere complex forming the ZnOP bond was confirmed to be the dominant force, resulting in over 70% anti-interference performance even at a coexisting molar ratio of NO3−, Cl−, SO42−, CO32−, and humic acid (HA) to phosphate of 100:1. Using the Zn(OH)2@DETA-aminated PAN filter column to continuously treat real wastewater, the effluent of phosphate concentration below 0.1 mg/L was obtained with approximately 100% of P-removal. In addition, phosphate in the desorption solution was recovered as P-rich Zn2(PO4)(OH) products. In brief, this study recommends Zn(OH)2@DETA-aminated PAN as a phosphate adsorbent, along with positive prospects for P recovery.