钴/锰印迹半胱氨酸-壳聚糖对低浓度Mn~(2+)和Co~(2+)的选择性吸附

同时以硝酸锰和硝酸钴为印迹分子,采用溶胶凝胶法和反相悬浮法结合制备了交联壳聚糖微球(Co/Mn-CCTS),并通过与半胱氨酸的氨基官能团接枝合成了钴/锰双印迹半胱氨酸-壳聚糖树脂(CysCo/Mn-CCTS)。采用傅里叶红外光谱、扫描电镜对其结构进行了表征,并进行了干扰离子存在下低浓度Co2+和Mn2+静态、动态以及竞争吸附实验。静态实验结果表明,双印迹半胱氨酸-壳聚糖树脂较非印迹树脂的吸附性能有较大提高;干扰离子存在下,树脂对Co2+、Mn2+二元混合溶液中Co2+的吸附性能优于Mn2+,且对Co2+的吸附容量超过Mn2+的16倍。溶液的pH值、温度、吸附时间、干扰离子以及金属离子初始浓度均对树脂的吸附性能有较大影响,树脂对Co2+、Mn2+的吸附过程符合Lagergren准二级动力学和Langmuir模型。动态吸附实验表明,树脂对Co2+、Mn2+的吸附符合Thomas模型,对二者的穿透体积分别为308BV与506BV。

Selective Adsorption of Mn2+ and Co2+ in Dilute Solution by Cobalt/Manganese Imprinted Cysteine-chitosan

The Co²⁺/Mn²⁺ imprinted adsorbent grafted by cysteine (Cys-Co/Mn-CCTS) was synthesized via the combination of amino groups of cysteine with imprinted crosslinked chitosan (Co/Mn-CCTS) by combining sol-gel method with reverse phase suspension method involving both manganese nitrate and cobalt nitrate as imprint molecules. Their structures were analyzed utilizing the techniques of FTIR and SEM. The static and dynamic adsorption and competitive adsorption experiments for Co²⁺ and Mn²⁺ with low concentration were conducted, in presence of other ions. Static adsorption experiments indicate that the performance of Cys-Co/Mn-CCTS is improved and the adsorption of Co²⁺ compared favorably with that of Mn²⁺ in binary solutions, which are 16 times more than that of Mn²⁺ in presence of other cations. The initial pH, temperature, contact time, presence of other cations and initial Co²⁺ and Mn²⁺ concentrations have great effects on the adsorption performance. The adsorption data fit to Lagergren pseudo second order kinetics model and Langmuir model for both Co²⁺ and Mn²⁺. Dynamic adsorption data follow Thomas model and the breakthrough volumes of the adsorbent for Co²⁺ and Mn²⁺ are 308 BV and 506 BV, respectively.