Department of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000, China.
School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, China.
J Environ Sci (China). 2021 Aug;106:105-115. doi: 10.1016/j.jes.2021.01.009. Epub 2021 Jan 30.
Our present study was to prepare a biomass-supported adsorbents with high adsorptive capacity 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 microspheres. Then the quaternary ammonium group with different content was introduced into the adsorbent by polymerization. By comparison of adsorption properties, chitosan-La(OH)-quaternary ammonium-20% (CS-La-N-20%) has strong adsorption to phosphate (160 mg/g) by immobilizing nano-sized La(OH) 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 La leaching. What's more, adsorption capacity on the introduce of positively charged quanternary-aminated groups was significantly higher than that of the unmodified 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, indicating excellent stability and repeated use property. Characterizations revealed that phosphate adsorption on CS-La-N-20% through ligand exchange (impregnated nano-La(OH)) and electrostatic attraction (positively charged quanternary-aminated groups). All the results suggested that CS-La-N-20% can serve as a promising adsorbent for preferable phosphate removal in realistic application.
本研究旨在制备具有高吸附容量和高选择性的生物质负载吸附剂，以防止水体富营养化加速。为此，首先成功地将不同的金属氢氧化物（镧、锆和铁）负载到壳聚糖微球上。然后，通过聚合将不同含量的季铵基团引入到吸附剂中。通过吸附性能比较，壳聚糖-镧（OH）-季铵-20%（CS-La-N-20%）通过将纳米级 La(OH) 固定在季铵化壳聚糖内，对磷酸盐具有很强的吸附能力（160mg/g），并且在盐离子存在下仍保持高吸附能力。pH 值结果表明，CS-La-N-20% 在 3 到 7 之间的宽 pH 范围内可以有效地螯合磷酸盐，而不会有显著的 La 浸出。此外，在碱性条件下，引入正电荷的季铵化基团的吸附能力明显高于未改性的吸附剂。当磷酸盐浓度降低到 0.5mg/L 时，在 6BV/hr 的流速下，柱吸附容量达到 1300 床体积（BV）。柱吸附/解吸表明，没有观察到容量明显损失，表明具有优异的稳定性和可重复使用性。表征结果表明，CS-La-N-20% 通过配体交换（浸渍纳米 La(OH)) 和静电吸引（带正电荷的季铵化基团）吸附磷酸盐。所有结果表明，CS-La-N-20% 可以作为一种有前途的吸附剂，用于实际应用中优先去除磷酸盐。
