Department of Chemistry, Jinan University, Guangzhou 510632, PR China.
Analytical & Testing Center, Jinan University, Guangzhou 510632, PR China.
Bioresour Technol. 2018 Sep;263:207-213. doi: 10.1016/j.biortech.2018.04.108. Epub 2018 Apr 30.
A series of La(OH)-modified magnetic pineapple biochar (Lax-MC) with different contents of La(OH) were prepared and used as phosphate adsorbents for the first time. With the increase of La(OH) content, the adsorption capacity for phosphate increased while the magnetic property decreased. La10-MC exhibited excellent magnetic property for easy recovery and high adsorption capacity up to 101.16 mg P/g, which was 27 times that of pineapple biochar and much higher than most phosphate adsorbents. Adsorption isotherm and adsorption kinetics were better fitted by Langmuir model and pseudo second-order model, respectively. The removal efficiency >96.04% in coexisting ions indicated its high selectivity to phosphate. Little decrease in removal efficiency after three adsorption-desorption cycles suggested its excellent stability and cyclic utilization. Leaching study demonstrated the negligible risk of La and Fe leakage during adsorption process. Mechanism study revealed that the adsorption mechanism involved precipitation, electrostatic interaction, ligand exchange and inner-sphere complexation.
一系列不同 La(OH) 含量的 La(OH) 修饰的磁性菠萝生物炭（Lax-MC）首次被用作磷酸盐吸附剂。随着 La(OH) 含量的增加，对磷酸盐的吸附容量增加，而磁性降低。La10-MC 表现出优异的磁性，易于回收，吸附容量高达 101.16mg P/g，是菠萝生物炭的 27 倍，远高于大多数磷酸盐吸附剂。吸附等温线和吸附动力学分别更符合朗缪尔模型和拟二级模型。共存离子的去除效率>96.04%表明其对磷酸盐具有高选择性。三次吸附-解吸循环后去除效率略有下降，表明其具有优异的稳定性和可循环利用性。浸出研究表明，在吸附过程中 La 和 Fe 泄漏的风险可以忽略不计。机理研究表明，吸附机制涉及沉淀、静电相互作用、配体交换和内球络合。
