改性磁性壳聚糖微球对Cu^(2+)、Cd^(2+)和Ni^(2+)的吸附性能

Adsorption Properties of Cu^(2+),Cd^(2+)and Ni^(2+)by Modified Magnetic Chitosan Microspheres

用反相乳液分散-化学交联方法,制备了粒径为50-80μm的Fe3O4/壳聚糖磁性微球,经乙二胺改性,用于吸附重金属离子,考察了改性磁性壳糖微球(EMCS)对Cu2+、Cd2+和Ni2+的吸附性能.结果表明,随着溶液pH值的升高,Cu2+和Ni2+的吸附容量增加,Cd2+吸附容量最佳pH值为3;吸附等温数据符合Langmuir模型,EMCS对Cu2+、Cd2+、Ni2+的饱和吸附容量分别为54.3、20.4、12.4mg·g-1;吸附动力学数据用拟二级反应模型能很好地拟合.经乙二胺改性的Fe3O4/壳聚糖磁性微球在实验pH值范围内对Cu2+的吸附选择性高于Cd2+和Ni2+.

Fe3O4/chitosan magnetic microspheres of 50 to 80 μm were prepared using the inverse phase emulsion dispersion and chemical crosslinking technology, and then modified with ethylenediamine for use in the adsorption of heavy metal ions. The adsorption properties of the modified Fe3O4/chitosan toward Cu^2＋, Cd^2＋ and Ni^2＋ were investigated. It was found that the adsorption capacities of Cu^2＋ and Ni^2＋ increased with pH, and a maximum adsorption for Cd^2＋ occurred at pH=3. The saturated adsorption capacities calculated by Langmuir isotherms were 54.3 mg·g^-1 for Cu^2＋, 20.4 mg·g^-1 for Cd^2＋, and 12.4 mg·g^-1 for Ni^2＋, respectively. The adsorption kinetics were well described by pseudo-secondorder equation models. The experimental results showed that the Fe3O4/chitosan modified with ethylenediamine presented higher adsorption selectivity for Cu^2＋ than for Cd^2＋ and Ni^2＋ in all studied pH ranges.