固定化啤酒废酵母对Cr(Ⅵ)的吸附

用2%海藻酸钠与1%明胶混合作为包埋剂固定啤酒废酵母,研究固定化啤酒废酵母对Cr(Ⅵ)的吸附特性。结果表明,固定化啤酒废酵母吸附Cr(Ⅵ)受吸附时间、起始pH、固定化菌体浓度、Cr(Ⅵ)起始浓度及共存离子等因素的影响。确定固定化啤酒废酵母对Cr(Ⅵ)最佳吸附条件为:pH2,Cr(Ⅵ)起始浓度100 mg/L,固定化菌体浓度2 g/L,吸附90 min。此条件下Cr(Ⅵ)的吸附率可达96.8%。Pd2+等并存离子可抑制固定化啤酒废酵母对Cr(Ⅵ)的吸附。用1 mol/L盐酸洗脱固定化啤酒废酵母所吸附的Cr(Ⅵ)3 h,解吸率为93.6%。

Adsorption of Chromium （Ⅵ） from Aqueous Solution Using Zeolite/Chitosan Hybrid Composite

This study investigated the adsorption ability of ZCHC （zeolite/chitosan hybrid composite） as adsorbent for chromium （Cr（Ⅵ））, ZCHC was prepared with sol-gel method by mixing zeolite and chitosan. Adsorption experiment from aqueous solutions containing known amount of Cr（Ⅵ） using zeolite, chitosan and ZCHC was explored to evaluate the efficiency of ZCHC as adsorbent for Cr in a batch system. The amount of Cr（Ⅵ） adsorbed at different pH values, initial concentrations, adsorbent dosages, and contact times were determined by ICP-AES （inductively coupled plasma-atomic emission spectrometry） in order to determine the optimum conditions for Cr（Ⅵ） adsorption. Furthermore, the adsorption mechanism of Cr（Ⅵ） by zeolite, chitosan and ZCHC was investigated by applying Langmuir and Freundlich isotherm equations to the data obtained. In addition, the rates of adsorption were found to conform to pseudo-second order kinetics.