绿茶对水溶液中Pb^2＋和Cd^2＋吸附性能初步研究

Study on adsorption of Pb^(2+) and Cd^(2+) in an aqueous solution containing green tea

研究了绿茶对溶液中Pb2+和Cd2+离子的吸附和解吸性质。考察了pH、温度、吸附时间对绿茶吸附性能的影响,得到吸附动力学曲线和吸附等温线。结果表明,茶叶在pH为4~6的弱酸性范围内对两种金属离子的吸附效果最佳,在30℃时,茶叶对Pb2+和Cd2+的饱和吸附量分别为46.66 mg/g和33.29mg/g,吸附符合Langmuir吸附等温方程,并对吸附机理进行了初步的探讨。对解吸条件研究发现,用0.1 mol/L HCl和EDTA作为解吸剂,对Pb2+和Cd2+的解吸效果较好,解吸率达80%以上,可有效回收重金属Pb2+和Cd2+。

The adsorption and desorption on the green tea in an aqueous solution containing Pb^2＋ and Cd^2＋ were studied. The effects of pH, temperature and adsorption time on adsorption ability of green tea were investigated, and kinetics curves of Pb^2＋ and Cd^2＋ adsorption on green tea and langmuir model were found. The high ability of adsorption on green tea were found at pH 4- 6. At 30 ℃, the maximum enrichment capacities of Pb^2＋ and Cd^2＋ are 44.66 mg/g and 33.29 rag/g, respectively. The experimental biosorption equilibrium data for Pb^2＋and Cd^2＋ were in good agreement with langmuir adsorption isotherm, and initial adsorption mechanism was investigated. Desorption conditions were studied 0.1 mol/L HCl and EDTA were effective as desorbents and desorption efficiencies can reach above 80%. Pb^2＋ and Cd^2＋ were efficiently recovered. The results were satisfactory.