双有机改性磁性膨润土对Cu(Ⅱ)和Zn(Ⅱ)的吸附

Preparation of dual organic modified magnetic bentonite for Cu(II)and Zn(II) adsorption

为了提高膨润土对Cu(Ⅱ)和Zn(Ⅱ)的吸附性能,采用羧甲基纤维素钠(SCMC)和壳聚糖(CS)通过席夫碱反应形成的复合物(SCMC/CS)对磁性膨润土(MB)进行改性,制备SCMC/CS修饰的磁性膨润土(SC/MB),研究改性膨润土吸附Cu(Ⅱ)和Zn(Ⅱ)的性能并分析吸附机理。结果表明,SC/MB对Cu(Ⅱ)和Zn(Ⅱ)的吸附符合Langmuir模型,吸附容量分别为483和123mg·g^(−1);吸附过程符合准二级动力学模型和孔扩散模型。SCMC/CS中的─COOH、─NH_(2)和─OH提高了材料的磁稳定性和吸附性能,吸附机理包括络合、离子交换、微孔固定和静电吸引作用。总之,SC/MB是一种经济有效的废水重金属吸附材料。

In order to improve adsorption performance of bentonite for Cu(Ⅱ) and Zn(Ⅱ), magnetic bentonite(MB) was organically modified with SCMC/CS complex produced by sodium carboxymethyl cellulose(SCMC)and chitosan(CS) via Schiff-base reaction. Cu(Ⅱ) and Zn(Ⅱ) adsorption performance and mechanism of SC/MB were investigated. The results show that the adsorption of Cu(Ⅱ) and Zn(Ⅱ) on SC/MB follows Langmuir model and the Langmuir adsorption capacities are 483 mg·g^(−1) and 123 mg·g^(−1), respectively.Meanwhile, the dynamic adsorption processes of Cu(Ⅱ) and Zn(Ⅱ) on SC/MB could be fitted by pseudo-second order model and the intra-particle diffusion model. ─COOH, ─NH_(2) and ─OH groups originated from SCMC/CS improved magnetic stability and adsorption performance. The adsorption interactions included complexion, ions exchange, micro-pore fixing and electrostatic attraction. Therefore, SC/MB is an economical and effective adsorbent for heavy metals removal from wastewaters.