Fabrication of a reusable polymer-based cerium hydroxide nanocomposite with high stability for preferable phosphate removal

Abstract

Efficient phosphorus removal from municipal or industrial effluents is a valid channel to combat eutrophication. Adsorption has been regarded as an effective approach for enhanced elimination and potential reclamation of phosphorus from wastewater. However, traditional phosphorus adsorbents often suffer from lack of stability and selectivity under complicated solution chemistry. In the current study, a reusable nanocomposite adsorbent HCO@201 of high stability and specific affinity towards phosphate was newly developed and well characterized, where Ce hydroxide (HCO) nanoparticles were encapsulated inside an aminated macroporous polystyrene host D201. The resultant HCO@201 was extremely stable over a wide pH range. Phosphate adsorption by HCO@201 was a pH-dependent process with highest adsorption capacity of 36.4 mg P/g at pH 7.0 ± 0.1. Thanks to the inner-sphere complexation between phosphate and the embedded HCO nanoparticles, HCO@201 could preferentially capture phosphate even coexist with high levels of other competing anions (HCO3−, NO3−, Cl− and SO42−) or dissolved organic matters (humic acid). Fixed-bed adsorption tests demonstrated that HCO@201 could efficiently treat ~1800 bed volumes (BV) of an actual bio-treated sewage (from influent of 1.83 mg P/L to effluent of 0.5 mg P/L), while only ~250 BV for its host D201. The saturated HCO@201 could achieve an efficient in-situ regeneration by a simply desorption method. In conclusion, HCO@201 exhibited an excellent application prospect in efficient phosphate removal from wastewater.