磁性竹基炭对Pb2+、Cd2+与Cu2+的吸附机理研究

采用微波辐照技术,以枯竹子为碳源制备了磁性竹基炭(BBMC),并将其用于对重金属离子Pb2+、Cd2+与Cu2+的吸附去除.同时,分析了吸附时间、pH值、离子强度及初始金属离子浓度等条件对吸附的影响,讨论了BBMC对3种金属离子的吸附特性与吸附机理.结果表明,金属离子在BBMC上的吸附符合Langmuir等温模式和准二级动力学吸附方程;吸附的机理可归结为金属阳离子与BBMC上的H+之间的离子交换作用,且吸附能力可能与金属离子半径有关,呈现出Pb2+Cd2+Cu2+的趋势,重金属离子Pb2+、Cd2+与Cu2+的最大平衡吸附量分别为16.2、14.0和9.5 mg·g-1.

Adsorption mechanism of Pb2+, Cd2+ and Cu2+ onto bamboo-based magnetic carbon

The adsorption characteristics of three heavy metal ions (Pb²⁺, Cd²⁺ and Cu²⁺) onto Bamboo-based Magnetic Carbon (BBMC) were investigated with respect to the changes in the contact time, the pH of solution, the ionic strength, and the initial metal ion concentrations. BBMC was synthesized from withered bamboo under microwave irradiation. The result indicated that the adsorption processes of these three types of ions followed a pseudo-second order model and Langmuir isotherm model. The ion exchange between metallic ions and H⁺ on the BBMC led to the adsorption of ions onto BBMC, and the adsorption efficiency from high to low was in the following order, Pb²⁺>Cd²⁺>Cu²⁺, which might be attributed to the different ionic radius. The equilibrium adsorbate uptakes of Pb²⁺, Cd²⁺ and Cu²⁺ were 16.2, 14.0 and 9.5 mg·g^-1, respectively.