Song Xiao-Bao, He Shi-Ying, Feng Yan-Fang, Hua Yun, Tang Wan-Ying, Zhu Qiu-Rong, Xue Li-Hong, Yang Lin-Zhang
School of Chemical Engineering, Nanjing Univesity of Science and Technology, Nanjing 210094, China.
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Huan Jing Ke Xue. 2020 Feb 8;41(2):773-783. doi: 10.13227/j.hjkx.201906088.
Lanthanum (La)-based materials have shown great potential for phosphate removal owing to the strong affinity between La and phosphate. In this study, magnetic hydrothermal biochar immobilized La(OH) (La-MHTC) were prepared and used as phosphate adsorbents. Hydrochar was produced by the hydrothermal carbonization process (220℃, 2 h). Magnetic La-MHTC with different La-to-Fe mass ratios were synthesized by the co-precipitation method. Subsequently, La-MHTC was applied to remove phosphate from wastewater. Results indicate that La-MHTC (with a La-to-Fe mass ratio of 2:1) exhibited excellent magnetic properties for easy recovery and high phosphate adsorption capacity up to 100.25 mg·g. Effective phosphate removal was obtained over a wide pH range of 3-10. The absorption isotherm and kinetics were better fitted by the Langmuir model and the pseudo second-order model, respectively, which showed a fast adsorption rate and exhibited superior La utilization efficiency. The La-MHTC has strong selectivity for phosphate in the presence of coexisting ions (Cl, NO, and SO). The adsorption-desorption experiment suggested its excellent stability and cyclic utilization. In addition, La-MHTC was applied to treat real domestic wastewater, efficiently reducing the phosphate concentration (from 0.87 mg·L to 0.05 mg·L). Electrostatic attraction and inner-sphere complexation between La(OH) and P via ligand exchange were the main mechanisms of phosphate adsorption by La-MHTC.
基于镧（La）的材料因La与磷酸盐之间的强亲和力而在去除磷酸盐方面显示出巨大潜力。在本研究中，制备了磁性水热生物炭固定化La(OH)（La-MHTC）并将其用作磷酸盐吸附剂。通过水热碳化过程（220℃，2小时）制备水炭。采用共沉淀法合成了不同La与Fe质量比的磁性La-MHTC。随后，将La-MHTC应用于去除废水中的磷酸盐。结果表明，La-MHTC（La与Fe质量比为2:1）表现出优异的磁性，便于回收，且对磷酸盐的吸附容量高达100.25 mg·g。在3-10的宽pH范围内均能有效去除磷酸盐。吸附等温线和动力学分别较好地符合Langmuir模型和准二级模型，表明吸附速率快且La利用效率高。在共存离子（Cl、NO和SO）存在的情况下，La-MHTC对磷酸盐具有很强的选择性。吸附-解吸实验表明其具有优异的稳定性和循环利用性。此外，La-MHTC应用于处理实际生活污水，有效降低了磷酸盐浓度（从0.87 mg·L降至0.05 mg·L）。La(OH)与P之间通过配体交换的静电吸引和内球络合是La-MHTC吸附磷酸盐的主要机制。
