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.
J Environ Sci (China). 2022 Oct;120:18-29. doi: 10.1016/j.jes.2022.01.003. Epub 2022 Jan 10.
Bimetallic oxides composites have received an increasing attention as promising adsorbents for aqueous phosphate (P) removal in recent years. In this study, a novel magnetic composite MZLCO was prepared by hybridizing amorphous Zr-La (carbonate) oxides (ZLCO) with nano-FeO through a one-pot solvothermal method for efficient phosphate adsorption. Our optimum sample of MZLCO-45 exhibited a high Langmuir maximum adsorption capacity of 96.16 mg P/g and performed well even at low phosphate concentration. The phosphate adsorption kinetics by MZLCO-45 fitted well with the pseudo-second-order model, and the adsorption capacity could reach 79% of the ultimate value within the first 60 min. The phosphate adsorption process was highly pH-dependent, and MZLCO-45 performed well over a wide pH range of 2.0-8.0. Moreover, MZLCO-45 showed a strong selectivity to phosphate in the presence of competing ions (Cl, NO, SO, HCO, Ca, and Mg) and a good reusability using the eluent of NaOH/NaCl mixture, then 64% adsorption capacity remained after ten recycles. The initial 2.0 mg P/L in municipal wastewater and surface water could be efficiently reduced to below 0.1mg P/L by 0.07 g/L MZLCO-45, and the phosphate removal efficiencies were 95.7% and 96.21%, respectively. Phosphate adsorption mechanisms by MZLCO-45 could be attributed to electrostatic attraction and the inner-sphere complexation via ligand exchange forming Zr/La-O-P, -OH and CO groups on MZLCO-45 surface played important roles in the ligand exchange process. The existence of oxygen vacancies could accelerate the phosphate absorption rate of the MZLCO-45 composites.
双金属氧化物复合材料作为一种有前途的吸附剂，近年来在水体磷酸盐（P）去除方面受到越来越多的关注。本研究通过一锅溶剂热法将无定形 Zr-La（碳酸盐）氧化物（ZLCO）与纳米 FeO 杂交，制备了一种新型磁性复合材料 MZLCO，用于高效吸附磷酸盐。我们的最佳样品 MZLCO-45 表现出 96.16mg P/g 的高朗缪尔最大吸附容量，即使在低磷酸盐浓度下也表现良好。MZLCO-45 对磷酸盐的吸附动力学很好地符合准二级模型，在最初的 60min 内，吸附容量可达到最终值的 79%。磷酸盐吸附过程高度依赖于 pH 值，MZLCO-45 在 pH 值为 2.0-8.0 的宽范围内表现良好。此外，MZLCO-45 在存在竞争离子（Cl、NO、SO、HCO、Ca 和 Mg）时对磷酸盐表现出很强的选择性，并且使用 NaOH/NaCl 混合洗脱剂具有良好的可重复使用性，经过十次循环后，仍保留 64%的吸附容量。0.07g/L 的 MZLCO-45 可将城市污水和地表水初始 2.0mg P/L 的磷有效降低至 0.1mg P/L 以下，磷酸盐去除率分别为 95.7%和 96.21%。MZLCO-45 对磷酸盐的吸附机制可归因于静电引力和通过配体交换形成 Zr/La-O-P、-OH 和 CO 基团的内球络合，MZLCO-45 表面上的这些基团在配体交换过程中发挥了重要作用。氧空位的存在可以加速 MZLCO-45 复合材料对磷酸盐的吸收速率。
