膨化改性稻壳对核素U^(6+)及重金属Cu^(2+),Pb^(2+)离子的吸附特性

The Adsorption Characteristic of U(Ⅵ) and Cu(Ⅱ),Pb(Ⅱ) by Expanded Rice Husk

研究了新型吸附剂膨化改性稻壳对放射性废水中的核素U^(6+)及重金属Cu^(2+),Pb^(2+)的吸附特性,考察了pH值、吸附剂用量、温度、时间和初始浓度等影响吸附的因素,分析了吸附过程中各种离子在溶液中的反应动力学、热力学参数及等温吸附规律。通过实验证明稻壳经膨化改性后对核素U^(6+)及重金属Cu^(2+),Pb^(2+)吸附效果明显,当pH值分别为3,5,5,吸附时间为40 min时,溶液中U^(6+),Cu^(2+),Pb^(2+)的去除率分别可达到89.10%,86.84%,96.58%;通过吸附理论拟合研究证明膨化改性稻壳对Cu^(2+),Pb^(2+)的吸附行为符合Langmuir单分子层吸附模型理论,对U^(6+)的吸附行为符合Freundlich等温多分子层吸附模型理论。

Studies on the materials that remove U （ YI） and heavy metals, Cu （ II ） and Pb （ II ） , have been prevalent at home and abroad. This article aims at applying the expanded rice husk, whose raw material is the natural agricultural waste in grain production in South China, to the treatment of nuclide and heavy metals. Since pH value, sorbent dosage, adsorption temperature, adsorption time and initial concentration have signifi-cant effects on the removal of U（VI） , Cu（II） and Pb（II） in the radioactive waste water, the adsorption characteristic of the target ions on this novel sorbent was investigated. The reaction kinetics, thermodynamics as well as the adsorption isotherm of the adsorption process on the sorbent were also studied. Batch adsorption ex-periments of U（YI） , Cu（II） and Pb（II） to the rice husk which was modified by expanding were peifomied. Results show that the sorbent had good adsorption captivities to those ions, especially to Pb（II）. When the pH value is 3 and the adsorption time is 40 min, the removal efficiency of U（VI） in the simulated solution could achieve 89.10%. For Cu（II） , the removal efficiency is as high as 86.84% at pH 5. Moreover, the removal efficiency of Pb（II） can reach 96.58% , which is higher than the other two ions in the same conditions. Acording to the adsorption theory, the adsorption behavior of Cu（II） and Pb（II） to the sorbent fitted the Lang-muir mono - layer adsorption model theory. However, the the adsorption of U（VI） accorded with the Freundli-ch multi - molecular layer adsorption model theory.