改性生物凝胶对重金属离子的吸附性能研究

以桔子汁加工残渣为原料,制备钙型和氢型生物凝胶作为吸附剂,用于去除水溶液中的重金属离子.结果表明,上述凝胶在水溶液中稳定性较好,对重金属离子的吸附性能优良.钙型凝胶的吸附选择性顺序为:Fe3 ＞Pb2 ＞Cd2 ＞Zn2 ,饱和吸附容量分别为:Pb2 、Cd2 、Zn2 均为约1.1mmol/g、Fe3 为1.5mmol/g;氢型凝胶的吸附选择性顺序为:Pb2 ＞Zn2 ＞Cd2 .钙型凝胶对Fe3 的吸附行为明显不同于氢型凝胶,钙型凝胶以离子交换机理以及Fe3 与Ca2 之间的共沉淀作用为主;而氢型凝胶对Fe3 的吸附则以离子交换机理为主.

STUDY ON ADSORPTION BEHAVIORS OF MODIFIED BIO-GEL TOWARD HEAVY METAL IONS

In this study,preparation of Ca-form and H-form adsorption bio-gel from orange juice residue was investigated,for removing heavy metal ions from aqueous solution.The results indicated that both gels were stable in aquatic solution and very effective in adsorbing heavy metal ions.The selectivity order for metal ions uptake by Ca-form gel was Fe3 >Pb2 >Cd2 >Zn2 .The maximum adsorption capacity was,1.1mmol/g for Pb2 ,Cd2 and Zn2 ,while that was 1.5mol/g for Fe3 .The adsorption selectivity order of H-form gel toward metal ions was Pb2 >Zn2 >Cd2 .The adsorption behavior of Ca-form gels for Fe3 was different from the H-form gels.The higher adsorption of Fe3 on the Ca-form gel at pH>3.0 may be attributable to co-precipitation of adsorbed Fe3 with Ca2 together with the cation exchange mechanism.However,in the case of H-form gels,the adsorption of metal cations takes place mainly according to a cation exchange mechanism.