微生物吸附处理低浓度含铀废水的效能

生物吸附是目前处理低浓度含铀废水最有前途的方法之一.本文探讨了不同种类微生物的来源及其对铀的吸附效能.分析了生物吸附过程的影响因素和吸附机理.细菌、放线菌、真菌和藻类对铀的吸附能力依次递减,pH值、菌种预处理、共存离子和金属初始浓度是生物吸附的主要影响因素;微生物的细胞结构在生物吸附过程中发挥了重要的作用,静电吸附、酶促反应、无机微沉淀和氧化还原等是生物吸附的主要机理.最后预测了生物吸附处理低浓度含铀废水的研究方向.

Efficiency of biosorption in treatment of sewage containing uranium of low concentration

This paper is aimed at giving a comprehensive survey over the sources and biosorption capacities of different kinds of microorganisms. Radioactive pollution of sewage containing nuclides has become one of the most serious environmental problems, which has made biosorption one of the most promising technologies in treating sewage with lower concentrated uranium residue. The results of our study shows that the biosorption capacities of uranium by bacteria, actinomycete, fungi, algae were degressive in nature, whose order can be listed as follows: 400-9 000 mg/g (by bacteria)>440 mg/g (by actinomycete)>170-215 mg/g (by fungi)>1.6-560 mg/g (by algae). This paper has also analyzed the influential factors and mechanisms of biosorption, coming to conclude that the pretreatment, pH, interference ions and initial concentration of uranium can be taken as main factors affecting biosorption. Its capacities are likely to be enhanced after pretreatment. Nevertheless, the influences of co-ions are varied from case to case. While there may come an increase in biosorption concomitant with an increase in pH and initial concentration of uranium, the structure of cells, such as active groups on the cell wall and intracellular groups, can play an important role in the biosorption process. In addition, the electrostatic sorption, enzymatic catalysis, abio-micro-precipitation, redox, etc. are also the main mechanisms of the biosorption. Due to the influence of the above factors, the uranium residue is likely to get easily recovered from the metal-loaded biomass by elution with desorption materials, such as 0.01 mol/L hydrochloric acid and so on. And, finally, the paper has made a forecast of the orientation of the development of biosorption of uranium in the time to come.