木钙/壳聚糖复合去污剂去除铀污染特性及机理研究

Decontamination Property and Mechanism Research of CS / CLS Composite Decontaminant for U( VI)

以木质素磺酸钙(木钙)、壳聚糖为原材料,通过改性并与十二烷基苯磺酸钠(SDBS)复配制备了一种用于去除涂漆表面模拟放射性核素U(VI)污染的新型去污剂。研究了木钙与壳聚糖比例对去污剂成膜去污后的自崩解脱落性能的影响及SDBS添加量、环境温度及初始污染量对U(VI)去除率的影响,同时利用扫描电子显微镜(SEM)、X射线能谱(EDX)、X射线光电子能谱(XPS)对去污机理进行了分析。结果表明:当木钙和壳聚糖溶液的体积比为1:2时去污膜的崩解效果及去污率均最好;当初始污染值为50 cps,SDBS添加量为2%(质量分数),环境温度为20℃时,该去污剂对U(VI)的去除率达到最大值99.1%;此外,去污剂对U(VI)的去除是溶解、吸附、黏附和化学吸附共同作用的结果,且去污剂对于U(VI)的化学吸附机理可能为U(VI)与木钙中钙发生离子交换,或与去污剂中的氧发生配位,从而实现对U(VI)的去除。

A new decontaminant was prepared with calcium lignosulphonate(CLS)and chitosan(CS)by modifying and compounding with SDBS and applied to decontaminate U(VI)on the surface of lacquered metal. In this paper,the influence of different raw materials proportion on disintegration situation of deter-gent and the influence of the amount of additive SDBS,environmental temperature and initial pollution a-mount on decontamination for U(VI)were studied. The results show that when CLS and CS ratio is 1:2, the disintegration property and decontamination effect reach to the optimal,when environmental tempera-ture is at room temperature and the initial contaminant level is about 50 cps,the new decontaminant for U (VI)removal efficiency reached a maximum value(99. 1% ). The decontamination mechanism for U (VI)is analyzed using scanning electron microscopy( SEM),energy dispersion X ray fluorescence (EDX),X ray photoelectron spectroscopy(XPS). The results reveal that the U(VI)removal is the re-sults of the dissolution,absorption,conglutination and chemical absorption interaction. Furthermore,The chemical absorpion decontamination mechanism for U(VI)is that U(VI)replaced the calcium in calcium lignosulphonate,or U(VI)coordinated O in the decontaminant.