Efficient absorptive removal of Cd(II) in aqueous solution by biochar derived from sewage sludge and calcium sulfate
Efficient absorptive removal of Cd(II) in aqueous solution by biochar derived from sewage sludge and calcium sulfate
复制标题
污水污泥生物炭和硫酸钙高效吸附去除水溶液中的 Cd(II)
DOI：
10.1016/j.biortech.2021.125333
复制
发表时间：
2021-05-31
影响因子：
11.4
通讯作者：
Li, Baoxiang
中科院分区：
文献类型：
--
作者：
Liu, Liheng;Yue, Tiantian;Li, Baoxiang
污水污泥和硫酸钙共热解产生的生物炭用于去除水溶液中的 Cd(II)。结果表明，Cd(II)吸附较好地遵循Freundlich模型，最大吸附容量分别为109.0 mg/g (288 K)、127.9 mg/g (298 K)和145.4 mg/g (308 K)。 Cd(II)的去除是一个以化学吸附为主的多层吸附过程，也是一个自发的吸热过程。随着Cd(II)初始浓度的增加，物理吸附的贡献逐渐增加。 Cd(II)的去除过程更好地遵循准二级动力学模型，分为三个阶段。第一阶段（0-0.3 h）和第二阶段（0.3-2 h）分别由液膜扩散/颗粒内扩散/化学反应和液膜扩散/化学反应控制，而第三阶段（0.3-24 h）为动态平衡过程。生物炭表面Cd的形态分布主要为CdCO3/CdOOC和CdO/CdSiO3，表明共沉淀、离子交换和络合对Cd(II)的去除贡献更大。
Biochar derived from co-pyrolysis of sewage sludge and calcium sulfate was used to remove Cd(II) from aqueous solution. The results showed that the Cd(II) adsorption better followed Freundlich model, and the maximum adsorption capacities were 109.0 mg/g (288 K), 127.9 mg/g (298 K) and 145.4 mg/g (308 K). The Cd(II) removal was a multi-layer adsorption process dominated by chemisorption, which was also a spontaneous and endothermic process. The contribution of physisorption gradually increased as the Cd(II) initial concentration. The Cd (II) removal process which better followed pseudo-second-order kinetic model, was divided into three stages. The first (0-0.3 h) and second stages (0.3-2 h) were separately controlled by liquid film diffusion/intraparticle diffusion/chemical reaction and liquid film diffusion/chemical reaction, while the third stage (0.3-24 h) was the dynamic equilibrium process. The speciation distribution of Cd on biochar surface was mainly CdCO3/CdOOC and CdO/CdSiO3, indicating coprecipitation, ion exchange and complexation contributed more to the Cd(II) removal.