CaCO_3微球吸附重金属的性能机理研究

Study on Adsorption Capacity and Mechanism of Heavy Metals by CaCO_3 Microspheres

为了解碳酸钙去除水溶液中Pb、Cr、Hg、As、Cu、Zn和Ni离子能力的状况,采用聚合物模板法制备的中空微球Ca CO_3为吸附剂,研究其吸附不同金属离子的能力。结果表明,CaCO_3中空微球添加量为1.0 g/20 m L时,母液中Pb、Cu、As、Zn、Hg的去除率分别为98.6%、99.2%、99.5%、88.6%、87.2%;对Cr和Ni而言,去除率较低且波动不大,显著的差异性可能与吸附对象的价态和相对质量相关。低固液比的吸附剂与溶液中Pb、Cu、Hg和As的亲和力较强,反应器中吸附剂添加量0.1 g时,对Pb、Cu、Hg、As吸附量效果为佳;而其吸附机制主要表现为竞争性物理吸附和空隙滞留协同作用,导致元素大量吸附于CaCO_3微球孔隙。

In order to understand the removal ability of calcium carbonate for Pb, Cr, Hg, As, Cu, Zn and Ni ions in aqueous solution, the hollow microspheres CaCO3 were prepared as adsorbent by polymer template method, and the adsorption ability for different metal ion was studied. The results showed that, when CaCO3 hollow microspheres dosage was 1.0 g/20 mL, the removal rate of Pb, Cu, As, Zn and Hg was 98.6%, 99.2%, 99.5%, 88.6%, 87.2%respectively in mother solution. As for Cr and Ni, the removal rate was low with little fluctuation, the significant difference might be related to the valence state and relative mass of the adsorption objects. The adsorbent with low solid to liquid ratio showed strong affinity with Pb, Cu, Hg and As in solution.When adsorbent dosage was 0.1 g in the reactor, the efficiencies of Pb, Cu, Hg and As adsorption capacity was optimal. The adsorption mechanism mainly showed as physical competitive adsorption and void retention synergistically, which resulted large number of elements were trapped in pores of CaCO3 microspheres.