College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541004, China; Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin, 541004, China.
College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541004, China.
Chemosphere. 2021 Aug;277:130273. doi: 10.1016/j.chemosphere.2021.130273. Epub 2021 Mar 15.
Biochar prepared by co-pyrolysis of nano-zero-valent iron and sewage sludge (nZVISB) was used to remove As(Ⅴ) from aqueous solution. When the initial pH was 2, the initial As(Ⅴ) concentration was 20 mg L, the dose of nZVISB was 10 g L, the contact time was 24 h, and the adsorption temperature was 298K, the removal efficiency of As(Ⅴ) was greater than 99%. The isothermal removal of As(Ⅴ) followed the Freundlich model better, and the maximum adsorption capacity of As(Ⅴ) was 60.61 mg g. The removal process of As(Ⅴ) could be better described by pseudo-second-order kinetic model, and the rate-controlling step should be liquid film diffusion and chemical reaction. Thermodynamic analysis indicated that the removal of As(Ⅴ) was a spontaneous and endothermic process dominated by chemical adsorption. The characterizations of nZVISB before/after adsorption and the solution after adsorption suggested that the iron-containing substances (Fe, Fe, FeOOH) and organics in the nZVISB had a great effect on the removal of As(Ⅴ), and the As was mainly immobilized on nZVISB by speciation of As-O-Fe.
采用纳米零价铁和污水污泥共热解制备的生物炭（nZVISB）用于从水溶液中去除 As(Ⅴ)。当初始 pH 值为 2 时，初始 As(Ⅴ)浓度为 20mg/L，nZVISB 用量为 10g/L，接触时间为 24h，吸附温度为 298K，As(Ⅴ)的去除率大于 99%。As(Ⅴ)的等温去除更符合 Freundlich 模型，最大 As(Ⅴ)吸附容量为 60.61mg/g。As(Ⅴ)的去除过程更能被准二级动力学模型很好地描述，速率控制步骤应为液膜扩散和化学反应。热力学分析表明，As(Ⅴ)的去除是一个自发的、吸热过程，主要由化学吸附控制。吸附前后 nZVISB 的特性及吸附后溶液的特性表明，nZVISB 中的含铁物质（Fe、Fe 和 FeOOH）和有机物对 As(Ⅴ)的去除有很大的影响，As 主要通过 As-O-Fe 形态固定在 nZVISB 上。
