College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, 100083, China.
College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, 100083, China.
Water Res. 2017 Dec 1;126:433-441. doi: 10.1016/j.watres.2017.09.050. Epub 2017 Sep 28.
In this study, La(ion)/La(OH)-W/La(OH)-EW-loaded magnetic cationic hydrogel (MCH) composites were fabricated in situ and characterized to investigate the effects of lanthanum species on phosphate adsorption. The corresponding maximum P adsorption capacities of MCH-loaded La(ion) (MCH-La(ion)), La(OH)-W (MCH-La(OH)-W), and La(OH)-EW (MCH-La(OH)-EW) were 70.5 ± 2.67, 69.2 ± 3.5, and 90.2 ± 2.9 mg P/g, respectively. Furthermore, for MCH-La(OH)-EW, the P adsorption capacity was maintained relatively stable and high at pH 4.5-11 because of the ligand exchange, electrostatic interactions, and Lewis acid-base interactions. The enhanced adsorption of P was achieved over a wide pH range, as well as in the presence of competing anions (including Cl, NO, SO, HCO and SiO). Moreover, the exhausted MCH-La(OH)-EW could be easily regenerated by a NaOH-NaCl desorption agent with above 72% adsorption capacity remained during five recycles. The column adsorption capacity of MCH-La(OH)-EW reached ∼3500 bed volumes (BV) (∼67.7 mg P/g) as the concentration of P decreased from 5 mg/L to 0.1 mg/L. The ATR-IR, Raman, and XPS deconvolution results revealed that both MCH and lanthanum compounds, including La(ion), La(OH)-W and La(OH)-EW, contributed to the phosphate adsorption because of the electrostatic interactions between -N(CH) and phosphate, as well as the formation of LaPO·xHO.
在这项研究中，原位制备了 La(ion)/La(OH)-W/La(OH)-EW 负载磁性阳离子水凝胶 (MCH) 复合材料，并对其进行了表征，以研究镧物种对磷酸盐吸附的影响。相应的 MCH 负载 La(ion) (MCH-La(ion))、MCH-La(OH)-W (MCH-La(OH)-W) 和 MCH-La(OH)-EW (MCH-La(OH)-EW) 的最大 P 吸附容量分别为 70.5 ± 2.67、69.2 ± 3.5 和 90.2 ± 2.9 mg P/g。此外，对于 MCH-La(OH)-EW，由于配体交换、静电相互作用和路易斯酸碱相互作用，在 pH 4.5-11 范围内，P 的吸附容量保持相对稳定和较高。在较宽的 pH 范围内以及存在竞争阴离子（包括 Cl、NO、SO、HCO 和 SiO）的情况下，都实现了 P 的增强吸附。此外，用过的 MCH-La(OH)-EW 可以很容易地用 NaOH-NaCl 解吸剂再生，在五次循环中保留了超过 72%的吸附容量。当 P 的浓度从 5 mg/L 降低到 0.1 mg/L 时，MCH-La(OH)-EW 的柱吸附容量达到约 3500 床体积 (BV)（约 67.7 mg P/g）。ATR-IR、拉曼和 XPS 分解结果表明，由于 -N(CH) 与磷酸盐之间的静电相互作用以及 LaPO·xHO 的形成，MCH 和镧化合物（包括 La(ion)、La(OH)-W 和 La(OH)-EW）都有助于磷酸盐的吸附。
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