交联壳聚糖吸附处理低浓度含铀废水

Adsorption of Uranium in Low Concentration Uranium-bearing Wastewater onto Cross-linked Chitosan

以天然高分子化合物壳聚糖(CTS)为原料,在碱性条件下用环氧氯丙烷对壳聚糖进行化学改性,制得不溶水的交联壳聚糖(CCTS),用作含铀废水的吸附剂,探讨了pH值、吸附剂用量、铀初始浓度、粒径对吸附的影响及其对铀的吸附动力学规律。结果表明,当废水pH=3～5左右,交联壳聚糖用量为10 mg,铀初始浓度为50 mg/L,经160 min后可达吸附平衡,铀的吸附去除率最高可达98.0%以上,交联壳聚糖对铀的吸附规律较好地符合Langmuir吸附等温式,吸附动力学模型可用准二级速率方程来描述。初始铀浓度为50 mg/L,壳聚糖和交联壳聚糖对铀的吸附去除率分别为87.4%,98.0%,交联壳聚糖对铀的吸附能力得到明显的提高。

Taking the natural polymer compounds of chitosan as raw materials,the insoluble cross-linked chitosan was synthesized by the reaction of chitosan with epichlorohydrin under alkaline conditions as the adsorbent of uranium-bearing wastewater.The influence factors on adsorption of uranium were investigated in details,such as pH value,adsorbent dosage,uranium initial concentration,particle size and equilibrium of adsorption and the adsorption kinetics law of uranium on cross-linked chitosan were described.The results show that under the conditions of pH=3～5,adding 10 mg cross-linked chitosan,the adsorption equilibrium for the 50 mg/L uranium can be obtained after 160min of adsorption,and the adsorption removal efficiency of cross-linked chitosan for uranium was over 98.0%.The adsorption law of uranium on cross-linked chitosan followed the Langmuir model very well and the pseudo second-order kinetics model was used to describe the adsorption process.When the initial concentrations of uranium is 50 mg/L,the adsorption removal efficiency of chitosan and cross-linked chitosan for uranium is 87.4% and 98.0% respectively,and the absorbability of cross-linked chitosan was improved significantly.