Fang Liping, Wu Baile, Chan Julie K M, Lo Irene M C
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Chemosphere. 2018 Feb;192:209-216. doi: 10.1016/j.chemosphere.2017.10.154. Epub 2017 Oct 30.
Lanthanum-based adsorbents are ideal candidates for phosphate removal because of their excellent affinity to phosphate. However, their application in the removal of trace-levels of phosphate from sewage is still unsatisfactory due to the limited adsorption capacity and inadequate optimization of the operational parameters. To overcome these drawbacks, we have developed a novel lanthanum hydroxide (LH), using a facile precipitation and hydrothermal process that involves a nanorod-like structure with the lengths ranging from 124 to 1700 nm, depending on the La/OH molar ratio. The phosphate adsorption capacity of the developed LH is up to 170.1 mg-P g in synthetic water, while a slightly lower adsorption capacity of 111.1 mg-P g is observed in a sewage sample. A polynominal model consisting of three variables (i.e. dosage, reaction time and initial phosphate concentration) for predicting efficiency of phosphate removal has been successfully developed using a face-centred central composite design (CCD)-based methodology. The results also suggest a strong interactive effect of the dosage with the phosphate concentration, and reaction time, which can significantly affect the optimization of the phosphate removal by LH. Both X-ray photoelectron spectroscopy and X-ray diffraction studies indicate that the inner sphere complexation of phosphate with LH is probably the major mechanism governing phosphate removal.
基于镧的吸附剂因其对磷酸盐具有优异的亲和力而成为去除磷酸盐的理想选择。然而，由于其吸附容量有限以及操作参数优化不足，它们在去除污水中痕量磷酸盐方面的应用仍不尽人意。为了克服这些缺点，我们开发了一种新型氢氧化镧（LH），采用简便的沉淀和水热法，该方法涉及一种纳米棒状结构，其长度根据La/OH摩尔比在124至1700nm范围内变化。所开发的LH在合成水中对磷酸盐的吸附容量高达170.1mg-P/g，而在污水样品中观察到的吸附容量略低，为111.1mg-P/g。使用基于面心中心复合设计（CCD）的方法成功开发了一个由三个变量（即剂量、反应时间和初始磷酸盐浓度）组成的多项式模型，用于预测磷酸盐去除效率。结果还表明剂量与磷酸盐浓度和反应时间之间存在强烈的交互作用，这会显著影响LH去除磷酸盐的优化过程。X射线光电子能谱和X射线衍射研究均表明，磷酸盐与LH的内球络合可能是控制磷酸盐去除的主要机制。
