High phosphate removal using La(OH)loaded chitosan based composites and mechanistic study

• 作者: Shaopeng Zhang Yi Zhang Jie Ding Zepeng Zhang Chao Gao Muslim Halimi Hary Demey Zhen Yang Weiben Yang
• 来源期刊: 环境科学学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: Regular articles
• 页码范围: 105-115
• 页数: 11页
• 语种: 英文

摘要

Our present study was to prepare a biomass-supported adsorbents with high adsorptive ca-pacity and high selectivity to prevent the accelerated eutrophication in water body.To this end,different metal hydroxide (La,Zr and Fe) first was successfully loaded on chitosan mi-crospheres.Then the quatemary ammonium group with different content was introduced into the adsorbent by polymerization.By comparison of adsorption properties,chitosan-La(OH)3-quaternary ammonium-20％ (CS-La-N-20％) has strong adsorption to phosphate(160 mg/g) by immobilizing nano-sized La(OH)3 within a quaternary-aminated chitosan and it maintain high adsorption in the presence of salt ions.The pH results indicated that the CS-La-N-20％ would effectively sequestrate phosphate over a wide pH range between 3 and 7 without significant La3+ leaching.What's more,adsorption capacity on the introduce of pos-itively charged quanternary-aminated groups was significantly higher than that of the un-modified adsorbents at alkaline conditions.The column adsorption capacity reached 1300 bed volumes (BV) when phosphate concentration decreased until 0.5 mg/L at 6 BV/hr.The column adsorption/desorption reveals that no significant capacity loss is observed,indicat-ing excellent stability and repeated use property.Characterizations revealed that phosphate adsorption on CS-La-N-20％ through ligand exchange (impregnated nano-La(OH)3) and elec-trostatic attraction (positively charged quanternary-aminated groups).All the results sug-gested that CS-La-N-20％ can serve as a promising adsorbent for preferable phosphate re-moval in realistic application.