Preferable removal of phosphate from water using hydrous zirconium oxide-based nanocomposite of high stability

In this study, we employed a new nanocomposite adsorbent HZO-201, which featured high stability under varying solution chemistry, for preferable removal of phosphate from synthetic solution and a real effluent. An anion exchange resin (D-201) was employed as the host of HZO-201, where nano-hydrous zirconium oxide (HZO) was encapsulated as the active species. D-201 binds phosphate through nonspecific electrostatic affinity, whereas the loaded HZO nanoparticles capture phosphate through formation of the inner-sphere complexes. Quantitative contribution of both species to phosphate adsorption was predicted based on the double-Langmuir model. Preferable removal of phosphate by HZO-201 was observed in the presence of the competing anions at higher levels (CI-, NO3-, SO42-, HCO3-). Fixed-bed adsorption indicated that the effective volume capacity of a synthetic water (2.0 mg P-PO43-/L) by using HZO-201 was,similar to 1600 BV in the first run (<0.5 mg P-PO43-/L), comparable to Fe(III)-based nanocomposite HFO-201 (similar to 1500 BV) and much larger than D-201 (<250 BV). The exhausted HZO-201 can be in situ regenerated by using a binary NaOH-NaCl solution for cyclic runs, whether fed with the synthetic solution or real effluent. In general, HZO-201 is a promising alternative to Fe(III)-based adsorbents for trace phosphate removal from effluent particularly at acidic pH. (C) 2014 Elsevier B.V. All rights reserved.