School of Resources and Environment Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China E-mail:
Water Sci Technol. 2022 Sep;86(5):1017-1033. doi: 10.2166/wst.2022.251.
It is essential to solve the problem of phosphorus pollution in urban landscape water and reduce the degree of eutrophication. In this paper, lanthanum-modified bentonite (La-B) was prepared by high-temperature calcination and liquid-phase precipitation. Then La-B was modified with chitosan to prepare a low-cost environment-friendly functional material: lanthanum/chitosan co-modified bentonite (La-BC). It can reach the adsorption equilibrium within 30 min, and the maximum adsorption capacity is 15.5 mg/g (initial phosphate concentration 50 mg/L); when the target concentration is 2 mg/L, the removal rate can reach 98.5%. La-BC has a stronger anti-interference ability to common coexisting anions SO, HCO, NO and Cl in the urban landscape water body. La-BC has excellent performance in weakly acidic to neutral water, and its pH applicable range has been improved, making it possible to apply in practical water. The fitting results show that the adsorption behavior conforms to the pseudo-second-order kinetic model and the Freundlich model. After 5 regenerations, the removal efficiency remained around 80%. In the actual water test results, the phosphate concentration can be controlled below 0.1 mg/L and the removal rate is above 75%. Due to its low cost and reusability, it has great potential in the practical application of phosphate removal from landscape water.
解决城市景观水富营养化问题，降低磷污染程度至关重要。本文采用高温煅烧和液相沉淀法制备镧改性膨润土（La-B），然后用壳聚糖对 La-B 进行改性，制备出一种低成本、环保的功能材料：镧/壳聚糖共改性膨润土（La-BC）。它可以在 30 分钟内达到吸附平衡，最大吸附容量为 15.5mg/g（初始磷酸盐浓度 50mg/L）；当目标浓度为 2mg/L 时，去除率可达 98.5%。La-BC 对城市景观水体中常见共存阴离子 SO、HCO、NO 和 Cl 具有更强的抗干扰能力。La-BC 在弱酸性至中性水中具有优异的性能，其 pH 适用范围得到了改善，使其有可能在实际用水中应用。拟合结果表明，吸附行为符合准二级动力学模型和 Freundlich 模型。经过 5 次再生，去除效率仍保持在 80%左右。在实际水样测试结果中，可将磷酸盐浓度控制在 0.1mg/L 以下，去除率在 75%以上。由于其成本低、可重复使用，在景观水除磷的实际应用中具有很大的潜力。
