磁性生物炭负载Mg-Fe水滑石的制备及其吸附水中Cd（Ⅱ）和Ni（Ⅱ）的性能

合成了一种高吸附容量的磁性生物炭负载Mg-Fe水滑石复合材料（L-BC）,并用于去除水中的Cd²⁺和Ni²⁺。表征结果表明,采用浸渍联合热解法成功制备了磁性生物炭（M-BC）,水热合成法成功地将Mg-Fe水滑石负载在M-BC上。动力学研究结果表明,Cd²⁺和Ni²⁺吸附符合伪二级动力学模型,化学吸附为速率控制步骤。等温吸附研究结果表明,L-BC对Cd²⁺和Ni²⁺的吸附符合Langmuir模型,为单分子层化学吸附,最大吸附量分别为263.156 mg/g和43.291 mg/g。吸附机理主要为Mg-Fe水滑石层间CO₃^2-和表面羟基与Cd²⁺和Ni²⁺产生表面共沉淀。L-BC具有良好的吸附和重复利用性能,是一种很有前景的去除Cd²⁺和Ni²⁺的吸附材料。

Preparation of Mg-Fe hydrotalcite supported on magnetic biochar and its adsorption capacity to Cd（Ⅱ）and Ni（Ⅱ）from water

The composite of magnetic biochar supported Mg-Fe hydrotalcite （L-BC）with high absorbent capacity for removing Cd²⁺ and Ni²⁺ from aqueous solution was synthesized. The characterization results demonstrate that magnetic biochar （M-BC）has prepared by pyrolysis and impregnation method,and Mg-Fe hydrotalcite has loaded on M-BC via hydrothermal synthesis. The kinetic features of Cd²⁺ and Ni²⁺ absorption are modeled by pseudo second-order equations,indicating that chemisorption is the rate controlling step. The study results of isothermal absorption reveal that the Cd²⁺ and Ni²⁺ adsorption on L-BC fits well with the Langmuir model,which is monolayer chemical adsorption and the maximum adsorption capacity is 263.156 mg/g and 43.291 mg/g respectively. The main mechanism of adsorption is the co-precipitation adsorption among Cd²⁺,Ni²⁺,the interlayer anion CO₃^2- as well as surface hydroxyl groups of L-BC. L-BC is a promising absorbent material for Cd²⁺ and Ni²⁺ removal,with the enhanced capability in absorbing as well as recycling.