复合微生物絮凝剂的制备及其对水中重金属的去除研究

发布时间：2018-07-24 16:36

【摘要】：水资源是地球上储量最多但又最为宝贵、不可缺少的资源,对于人类社会的发展,以及维持各种动植物生命活动而言都是不可缺少的重要因素。伴随着人口的快速增长、经济社会的发展,人类社会对于水资源的需求日益加大。自然界中存在的金属离子,很多都具有毒性,并且由于生物体的不可代谢原有,导致重金属在生物体中易积累,并通过食物链在各级动物体内产生富集。因此,重金属废水的治理已成为人类社会环境和生态环境治理的一个迫切需要解决和环节的问题。和传统使用的化学絮凝剂相比,微生物絮凝剂因其菌种来源广泛、废水处理效果佳出水水质好、处理过程中没有二次污染等特点,成为现在的研究热点。本文试验研究将对铅和铬分别具有耐受性的菌株复合培养使用,制备出一种高耐受性、高产量、去除效果好、易存储和运输的复合微生物絮凝剂,并对含铅、含铬的重金属模拟废水进行处理效果试验。并进行了实际含铅废水的去除效果试验。该复合絮凝剂采用微生物-微生物复合的模式,一株菌株为本实验室从某受铬严重污染的土壤中分离筛选出来的菌株,经16SrDNA鉴定为芽孢杆菌类菌种,另一株菌株为实验室已筛选出一株编号为KD-1的菌株。为提高微生物絮凝菌的组合效果,本实验通过复合培养发酵的方法,以期通过微生物间的复合作用,提高培养产量和去除效率。将组合发酵培养48h后的复合发酵液移至离心管中,并在4000rpm的离心机中离心30min,舍弃上清液,取离心后微生物菌体经冷冻干燥后制成复合微生物絮凝剂制剂。用复合发酵培养出的复合微生物絮凝剂冻干制品对含铅、含铬的重金属模拟废水进行去除试验,得出如下结果:本实验室制备的复合微生物絮凝剂制剂对废水中的铅具有很好的去除效果,对于一定离子浓度和体积的模拟废水,在溶液初始pH值为6.0,复合微生物絮凝剂投加量为8mg,絮凝振荡时间为50min,絮凝温度为30℃C时,铅离子的去除效果达到最佳,然而对于含铬离子的废水,本实验室制备的复合微生物絮凝剂没有表现出很好的去除效果。通过对复合微生物絮凝剂吸附前后的菌体进行红外光谱、SEM扫描电镜分析和XPS图谱分析,初步探究该复合微生物絮凝剂对含铬、含铅的重金属离子废水的处理过程。对反应前后的复合微生物絮凝剂菌体的SEM图观测分析菌体表面形态结构,结果显示反应前的复合微生物絮凝剂表面有大量短棒状物相互交叠堆积在一起,而且表面存在一定量的孔隙;处理含铅废水后,复合微生物絮凝剂表面的短棒状物有着明显的聚集,交织絮凝成团,并且表面孔隙减少。复合微生物吸附剂其主要成分为多糖,含有少量蛋白质,吸附剂表面基团主要包括羟基、酰胺基及羧基等。XPS光电子能谱分析可以得出,吸附前复合微生物絮凝剂中没有Pb(Ⅱ)和Cr(Ⅵ)的存在,而反应后,样品表面有Pb(Ⅱ)的存在,这说明复合微生物絮凝剂与Pb(Ⅱ)发生了反应,而对于铬离子,SEM扫描电镜显示复合微生物絮凝剂反应前后形态上并没有多大变化。
[Abstract]:Water resources are the most valuable and indispensable resources on the earth. It is an indispensable factor for the development of human society and the maintenance of all kinds of animal and plant life activities. With the rapid growth of the population, the development of the economy and society, the demand for water resources is increasing. Many of the metal ions are toxic, and because of the non metabolism of the organism, the heavy metals are easily accumulated in the organism and are enriched in the animals at all levels through the food chain. Therefore, the treatment of heavy metal wastewater has become an urgent need to solve and link the environmental and ecological environment of human society. Compared with the traditional chemical flocculants, the microbial flocculant has become a hot spot because of its wide range of bacteria, good effluent quality and no two pollution in the process of treatment. A compound microbial flocculant with high yield, high yield, good removal effect, easy storage and transportation, and a test on the treatment effect of heavy metal simulated wastewater containing lead and chromium. The effect test of the removal effect of actual lead containing wastewater was carried out. The strains isolated from the seriously polluted soil were identified as Bacillus species by 16SrDNA, and the other strain was screened out of a strain of KD-1 in the laboratory. In order to improve the combination effect of microbial flocculation bacteria, the experiment was carried out by the method of compound culture fermentation in order to improve the culture through the compound effect of microorganism. The production and removal efficiency. The compound fermentation broth after the combined fermentation of 48h was moved to the centrifuge tube and centrifuged in the centrifuge of 4000rpm, and the supernatant was abandoned. After the centrifuge was centrifuged, the microorganism fungus was made into a compound microbial flocculant preparation after freezing and drying. The results are as follows: the compound microbial flocculant preparation prepared in this laboratory has a good removal effect on the lead in the wastewater. For the simulated wastewater with certain ionic concentration and volume, the initial pH value of the solution is 6, the flocculant dosage of the complex microbial flocculant is 8mg, and the flocculating time is flocculated. For 50min, the removal effect of lead ion is best when the flocculation temperature is 30 C. However, for the wastewater containing chromium ion, the compound microbial flocculant prepared by this laboratory has not shown good removal effect. The infrared spectrum, SEM scanning electron microscope analysis and XPS atlas analysis of the bacteria before and after the adsorption of the compound microbial flocculant are carried out. The treatment process of the compound microbial flocculant for heavy metal ion containing wastewater containing chromium and lead was preliminarily explored. The morphology and structure of the surface of the bacteria were observed and analyzed by the SEM diagram of the compound microbial flocculant before and after the reaction. The results showed that a large number of short rod like objects on the surface of the compound microbial flocculant before the reaction were stacked and stacked together. There is a certain amount of pores on the surface; after the treatment of lead containing wastewater, the short rod on the surface of the compound microbial flocculant has obvious aggregation, interwoven flocculation and flocculation, and the surface pores are reduced. The main components of the composite microbial adsorbent are polysaccharide, containing a small amount of protein, and the surface groups of the adsorbent mainly include hydroxyl, amides and carboxyl groups, and so on.XP S photoelectron spectroscopy analysis showed that there was no Pb (II) and Cr (VI) in the compound microbial flocculants before adsorption, and the presence of Pb (II) on the surface of the sample showed that the compound microbial flocculant reacted with Pb (II), and for chromium ion, SEM scanning electron microscopy showed that the morphology of the compound microbial flocculant was not in shape before and after the reaction. How many changes have been made.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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