School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China; Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, PR China.
Department of Chemical & Materials Engineering, University of Auckland, New Zealand.
Sci Total Environ. 2020 Apr 20;714:136839. doi: 10.1016/j.scitotenv.2020.136839. Epub 2020 Jan 22.
Phosphate adsorption using metal-modified biochar has awakened much attention and triggered extensive research. In this study, the effect of lanthanum (La)-modified sludge using impregnation-co-precipitation was used for phosphate adsorption. Consequently, La-coated biochar at a pyrolysis temperature of 600 °C had the highest phosphate adsorption and the lowest heavy metal leaching potential. The treatment of virgin biochar with alkali before La loading was found to be beneficial for the increase of phosphate adsorption capacity. The adsorption kinetics was well depicted by the pseudo-second-order model, and indicating that intraparticle diffusion played a crucial role in the adsorption process. The good fitness between adsorption data and the Langmuir isotherm model showed a maximal adsorption capacity of 93.91 mg/g, where phosphate absorption was highly correlated to its concentration in the solution. The La-coated biochar showed high adsorption capacity when the solution pH varied from 3.0 to 6.0, and was insensitive to the coexisting chloride, nitrate, sulfate, bicarbonate and citrate. Moreover, the adsorption mechanism was further explored by using Zeta potential analysis, FTIR and XPS, indicating that the phosphate is adsorbed through electrostatic attraction in the form of the inner-sphere complexation. All the results suggested that the sludge-based biochar, as a support material for La, could serve as a promising adsorbent for phosphate in real applications.
使用金属改性生物炭吸附磷酸盐引起了广泛关注，并引发了大量研究。本研究采用浸渍共沉淀法制备了镧（La）改性污泥，并将其用于吸附磷酸盐。结果表明，在 600°C 下热解的 La 涂覆生物炭具有最高的磷酸盐吸附能力和最低的重金属浸出潜力。研究发现，在负载 La 之前用碱处理原生物炭有利于提高其磷酸盐吸附容量。吸附动力学很好地符合拟二级动力学模型，表明颗粒内扩散在吸附过程中起关键作用。吸附数据与 Langmuir 等温模型拟合良好，表明最大吸附容量为 93.91mg/g，表明磷酸盐的吸收与其在溶液中的浓度高度相关。La 涂覆生物炭在 pH 值为 3.0 至 6.0 的范围内具有较高的吸附容量，对共存的氯离子、硝酸根离子、硫酸根离子、碳酸氢根离子和柠檬酸根离子不敏感。此外，通过 Zeta 电位分析、FTIR 和 XPS 进一步探讨了吸附机制，表明磷酸盐通过内配位形式通过静电引力吸附。所有结果表明，基于污泥的生物炭作为 La 的载体材料，可作为实际应用中去除磷酸盐的一种有前途的吸附剂。
