摘要：

铬是一种重金属元素，在自然界多以Cr（Ⅲ）或Cr（Ⅵ）的价态存在。而Cr（Ⅵ）的毒性远高于Cr（Ⅲ），对人体健康造成危害。因此，高效去除废水中的Cr（Ⅵ）意义重大。将聚间苯二胺（PmPD）接枝至壳聚糖（CTS）表面，制得聚间苯二胺修饰的壳聚糖吸附剂（CTS-PmPD），研究其最佳合成条件及对水中Cr（Ⅵ）的去除情况。结果表明，CTS-PmPD的最佳合成条件为：m（PmPD）∶m（CTS）=1∶5，反应温度100 ℃。在30 ℃下用0.06 g CTS-PmPD吸附处理pH为3.0、质量浓度为100 mg/L的模拟含Cr（Ⅵ）废水，100 min后Cr（Ⅵ）去除率达到99.7%。CTS-PmPD吸附Cr（Ⅵ）的过程为吸热过程，符合准二级动力学模型与Langmuir吸附等温方程特征。水中的共存阴离子对CTS-PmPD吸附Cr（Ⅵ）的影响程度依次为SO₄^2->NO₃^->Cl^-。CTS-PmPD吸附剂经4次吸附-解吸后，平衡吸附量仍可达到134.1 mg/g，具有较好的重复利用性。

关键词: 聚间苯二胺, 壳聚糖, 六价铬, 吸附, 工业废水

Abstract:

As a heavy metal element, chromium exists in the valence state of Cr(Ⅲ) or Cr(Ⅵ) in nature. The toxicity of Cr(Ⅵ) is much higher than that of Cr(Ⅲ), which is harmful to human health. Therefore, efficient removal of Cr(Ⅵ) from wastewater is of great significance. Poly (m-phenylenediamine) modified chitosan(CTS-PmPD) had been synthesized by grafting poly (m-phenylenediamine) (PmPD) to the surface of chitosan(CTS), and its optimal synthesis conditions and removal of Cr(Ⅵ) from wastewater were researched. The results showed that the optimal synthesis conditions of CTS-PmPD were m(PmPD)∶m(CTS) 1∶5 and reaction temperature 100 ℃. The simulated chromium-containing wastewater at pH 3.0 and mass concentration of 100 mg/L was adsorbed with 0.06 g CTS-PmPD at 30 ℃, and the removal rate of Cr(Ⅵ) reached 99.7% after 100 min. The process of Cr(Ⅵ) adsorption by CTS-PmPD was endothermic process, which complied with the pseudo-second order kinetics model and Langmuir adsorption isotherm. The effect of coexisting anions in water on adsorption of Cr(Ⅵ) by CTS-PmPD was SO₄^2->NO₃^->Cl^- in order. The equilibrium adsorption capacity of CTS-PmPD could still reach 134.1 mg/g after four adsorption-desorptions, which indicated that CTS-PmPD had good reusability.

Key words: poly (m-phenylenediamine), chitosan, chromium(Ⅵ), adsorption, industrial wastewater

中图分类号: 

• X703

• TQ424