锰印迹半胱氨酸-壳聚糖树脂的制备及其对低浓度Mn2+的选择性吸附

Preparation of Manganese Inprinted Cysteine-chitosan Resin and Its Selective Adsorption of Mn2+ in Dilute Solution

  • 摘要: 以航空煤油为有机分散介质,环氧氯丙烷为交联剂,硝酸锰为印迹分子,采用反相悬浮和溶胶凝胶法结合制备交联壳聚糖微球(Mn-CCTS),并通过与半胱氨酸的羧基官能团接枝合成锰印迹吸附树脂(Cys-Mn-CCTS)。通过SEM扫描、傅里叶红外光谱对Cys-Mn-CCTS的结构进行了表征,并进行了低浓度Mn2+的静态吸附实验。研究表明,Cys-Mn-CCTS较Mn-CCTS吸附性能有显著提高,303 K温度下,Cys-Mn-CCTS对5、10 mg/L的Mn2+的去除率由未接枝前的22.56%、16.26%分别提高至82.87%、82.56%;pH值在4~9范围内,Cys-Mn-CCTS对Mn2+的吸附性能基本不受影响,在pH值为5时吸附性能最佳,吸附容量和去除率分别为7.02 mg/g和96.29%;树脂对Mn2+的去除率在2 h后达到91.9%,吸附过程符合Lagergren准二级动力学方程;在干扰离子Ca2+和Mg2+总浓度达到200 mg/L时,Cys-Mn-CCTS对Mn2+的吸附容量和去除率分别为2.16 mg/g和29.6%,表现出一定的抗干扰能力。

     

    Abstract: Mn2+ inprinted adsorbent grafted by cysteine (Cys-Mn-CCTS) was synthesized via combination of carboxyl groups of cysteine with crosslinked chitosan microspheres (Mn-CCTS) by combining sol-gel method with reverse phase suspension method involving kerosene as dispersant, manganese nitrate as inprinted molecular and epoxy chloropropane as cross-linking agent. Their structures were analyzed utilizing the techniques of SEM and FTIR. Static adsorption experiments for Mn2+ with low concentration indicate that the adsorption performance of Cys-Mn-CCTS is obviously improved. The removal rates of Mn2+ with initial concentrations of 5 mg/L and 10 mg/L are respectively raised from 22.56% and 16.26% to 82.87% and 82.56% at 303 K by Cys-Mn-CCTS. pH values from 4 to 9 have a negligible effect on the adsorption performance of Cys-Mn-CCTS, which reaches the best at pH 5 with the adsorption capacity of 7.02 mg/g and the removal rate of 96.29%. The adsorption kinetics follows the Lagergren pseudo-second-order rate model, and the removal rate of Mn2+ reaches 91.9% after 2 h. However, the adsorption capacity and removal rate of Mn2+ are 2.16 mg/g and 29.6% respectively even when the total concentration of interfering metal ions of Ca2+ and Mg2+ is up to 200 mg/L in dilute solution. Therefore, the Cys-Mn-CCTS to some extend can be considered to have selective adsorption for Mn2+ in dilute solution.

     

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