海藻酸钙@Fe3O4/生物碳磁性复合材料的制备及其对Co(Ⅱ)的吸附性能和机制

摘要

A magnetic microspheres(Calcium Alginate@Fe3O4/Biochar)was prepared using calcium alginate(CA) encapsulated biochar(BC)and Fe3O4as the green adsorbent for Co(Ⅱ)removal from aqueous solution.The effects of the initial Co(NO3)2concentration,initial pH value of Co(Ⅱ)solution and equilibrium contact time were investi-gated on CA@Fe3O4/BC.The isothermal thermodynamic datas of the CA@Fe3O4/BC conformed to the Langmuir model.The maximum adsorption capacity of the CA@Fe3O4/BC from the Langmuir equation is 16.23 mg·g-1at pH=6.It appears a synergistic effect between biochar and Fe3O4in CA,which enhances the maximum adsorption capacity of Co(Ⅱ)ion.The presence of the magnetic particles in magnetic microsphere allows easy isolation of the material from aqueous solutions by using a magnet.The adsorptions of Co(Ⅱ)by the CA@Fe3O4/BC are in good agreement with pseudo-second-order kinetic.The mechanism studies for Co(Ⅱ)removal by the CA@Fe3O4/BC show that the nature of Co(Ⅱ)abstraction takes place through the ion exchange between Ca(Ⅱ)and Co(Ⅱ)as well as the formation of coordination complex.%利用海藻酸钙(CA)包覆生物碳(BC)、Fe3O4制备了一种新型磁性微球(CA@Fe3O4/BC),用以吸附水溶液中的Co(Ⅱ).系统的研究了Co(NO3)2溶液浓度、pH 和时间对吸附的影响.CA@Fe3O4/BC 吸附 Co(Ⅱ)等温热力学数据符合 Langmuir 模型,在 pH=6 的条件下对 Co(Ⅱ)的最大吸附量为 16.23 mg/g.研究显示, CA@Fe3O4/BC存在显著的协同效应,对Co(Ⅱ)具有更好的吸附性能.由于磁性颗粒的存在,CA@Fe3O4/BC吸附Co(Ⅱ)后可以用磁铁吸附快速分离.CA@Fe3O4/BC 吸附 Co(Ⅱ)动力学数据符合准二级动力学模型,研究表明,CA@Fe3O4/BC吸附Co(Ⅱ)的机制主要包括形成配合物及Ca(Ⅱ)与Co(Ⅱ)发生离子交换.