氧化石墨烯-纤维素复合物的制备及其对钚的吸附性能

Preparation of Composite Adsorbent Graphene Oxide-Cellulose and Its Adsorption Performance for Plutonium

采用NaOH／尿素混合水溶液作为溶剂完全溶解纤维素（FB），再与Hummers法合成的氧化石墨烯（GO）进行复合来制备复合型吸附剂GO-FB，利用红外光谱（FFIR）、扫描电镜（SEM）和拉曼谱图（Raman）对其结构和形貌进行表征。GO—FB的SEM形貌表征可见其表面布满颗粒物的条状物或者团聚体，表明有大量GO附着在FB表面。以钚溶液作为研究对象，考察了溶液pH、吸附刹投加量、吸附时间、钚初始活度以及温度等参数对吸附效果的影响，旨为核工业放射性废水的处理工艺提供理论基础和新的技术途径。结果表明，对于30Bq·L-1的含钚溶液，GO和GO—FB的最佳吸附条件分别为：pH均为8；投加量0．05，0．10g·L-1；吸附时间均为〈1min，最大去钚率分别为98．65％和98．67％。由此可见，GO-FB可以作为优良的吸附剂对放射性含钚废水进行有效净化处理。根据热力学参数吉布斯自由能（AG^0）、焓变（△S^0）和熵变（AS^0）在不同温度下的计算结果可知，GO—FB对溶液中钚的吸附过程为自发的放热反应，低温有利于反应的进行；同时，吸附过程以物理吸附为主。

Cellulose （ FB ） was completely resolved in the mixture solution of NaOH/urea, and then reacted with graphene oxide （GO） synthesized by modified Hummers method. Thus, the composite adsorbent graphene oxide-cellulose （GO-FB） was prepared successfully and characterized by Fourier transform infrared spectroscopy （ FTIR ） , scanning electron microscope （ SEM ） and Haman spectra. It could be seen from the SEM image that there were lots of particles or aggregates on the surface of GO-FB, which indicated that plenty of CO molecular adhered to the surface of GO-FB. The products were used to study the adsorption of plutonium from aque- ous solution. The solution pH, adsorbent dosage, contact time, initial plutonium activity and temperature were investigated to estimate the adsorption properties in order to supply theory basic and new technique method for the treatment of industry radioactive wastewater. The results showed that for the plutonium solution with initial activity of 30 Bq.L-1, the optimum adsorption conditions of GO and GO- FB were pH of 8, the dosages of 0.05 and 0.10 g-L-1, adsorption time of less than 1 rain, and the maximum removal rate of plutoni- um of 98.65% and 98.67%, respectively. Therefore, GO-FB had favorable adsorption property for the efficiency treatment of radioac- tive plutonium wastewater. According to the calculated thermodynamic parameters such as Gibbs free energy （ AGo ） , standard enthalpy change （ AH~ ） and standard entropy change （ AS~ ） at various temperatures the adsorption of uranium onto GO-FB was spontaneous and feasible endothermal reaction. Moreover, the adsorption of uranium on GO-FB was physisorption process and less favorable at higher temperature.