【作者】 赵静；

【导师】 徐晓军；

【作者基本信息】 昆明理工大学 ， 环境科学， 2014， 硕士

【摘要】 含铅废水不仅对人体产生巨大的伤害,而且对动植物也具有很大的危害。当含铅废水进入到环境中,通过生物体的富集,再由食物链传给人类,这一过程中,铅是在不断富集的,所以,作为食物链的最高端的人类来说,受到铅的危害是极大的。因此,处理含铅废水具有重要的意义。生物吸附法及生物絮凝法是处理含铅废水的一种新方法,具有广阔的发展前景。但微生物吸附及絮凝机理尚未完全被了解,微生物吸附絮凝剂的应用还处于初级阶段。因此,继续深入探索和研究微生物吸附絮凝Pb(Ⅱ)的机理,了解微生物吸附絮凝Pb(Ⅱ)的有效化学成分,从而找出适宜于微生物吸附重金属离子的培养条件,提高微生物对Pb(Ⅱ)的吸附能力；同时,拓宽微生物吸附絮凝剂菌种的资源,从而寻找吸附量大、价格低廉且能吸附絮凝多种重金属离子的微生物,这是现阶段重要的研究工作,其对含铅废水的治理具有重要的经济与社会意义。本文从昆明市呈贡县生活污水处理厂的活性污泥中筛选出一株耐铅、产絮菌株,经16S rDN A鉴定为克雷伯氏菌(Klebsiella sp.)。用其湿菌体作为活性吸附絮凝剂,干燥后的菌体作为非活性吸附絮凝剂,分别研究其对水中Pb(Ⅱ)离子的吸附活性和吸附性能。在处理含铅废水时,研究不同pH值,不同吸附剂用量,不同吸附时间,不同的Pb(Ⅱ)初始浓度及不同转速对克雷伯氏菌(Klebsiella sp.)吸附絮凝Pb(Ⅱ)的影响,确定最佳条件；通过吸附等温模型、吸附动力学、FT-IR、SEM及XPS对其吸附絮凝机理进行探讨,得出如下结果：(1)从污泥中筛选出53株耐铅菌株,其中有10株是耐铅微生物吸附絮凝剂产生菌,絮凝特性最好的耐铅菌株为ZJ-15,对高岭土悬液的絮凝率达到87.93%。ZJ-15耐铅微生物吸附絮凝剂产生菌的最佳培养基成分为：蔗糖15g,KH2PO42g,K2HPO45g,MgSO4.7H2O0.2g,NaCl0.1g,尿素3.3g,蒸馏水1000m1；ZJ-15耐铅微生物吸附絮凝剂产生菌的最佳培养条件为：培养基初始pH=6.0,发酵温度T=28℃,摇床转速为100rpm,金属离子对ZJ-15产絮凝剂的影响：Na+、Cu2+无影响,Fe2+、Fe3+、A13+有抑制作用,Mg2+有促进作用。(2)本文通过革兰氏染色、细菌菌落形态观察及16S rDNA鉴定发现,该株耐铅微生物吸附絮凝剂产生菌ZJ-15被鉴定为克雷伯氏菌(Klebsiella sp.)。(3)活性吸附剂处理含Pb(Ⅱ)废水时：当pH=5,吸附剂用量为8g/L,时间为120min,Pb(Ⅱ)浓度为150mg/L,转速为120rpm时,平衡吸附量为73.3mg/g；非活性吸附剂处理含Pb(Ⅱ)废水时：当p H=4,吸附剂用量为0.5g/L,时间为120min, Pb(Ⅱ)浓度为100mg/L,转速为120rpm时,平衡吸附量为73.7mg/g。(4)吸附剂(活性和非活性)对Pb(Ⅱ)离子的吸附作用能够用Langmuir吸附等温模型更好的拟合,吸附剂对Pb(Ⅱ)离子的吸附主要是单分子层吸附作用；准二级动力学模型能够很好的描述吸附剂对Pb(Ⅱ)离子的吸附动力学过程。(5)吸附剂主要成分为多糖,主要基团包括羟基、酰胺基及羧基等。吸附前后红外光谱图中3467cm-1处、2923cm-1处、1670cm-1处、1421cm-1处和1083cm-1处的吸收峰均有不同程度的移动且强度均明显减弱,说明吸附剂与溶液中Pb(Ⅱ)离子发生了物理吸附及化学吸附作用。(6)将吸附前后的菌体作了SEM对比分析,克雷伯氏菌(Klebsiella sp.)吸附絮凝剂吸附絮凝Pb(Ⅱ)前与后的菌体外貌有明显的不同,说明其与Pb(Ⅱ)发生了某些反应。克雷伯氏菌(Klebsiella sp.)吸附絮凝剂吸附前呈现出大小不同的团块形状,并且有很多的孔隙存在。而吸附后的孔隙变小,且有无定型的晶体存在。(7)将吸附前后的菌体作了XPS对比分析,吸附前没有Pb(Ⅱ)的存在且吸附絮凝剂与Pb(Ⅱ)的结合相对强度较弱,而吸附后有Pb(Ⅱ)的存在且相对强度明显较高并出现了两个峰,这说明活性吸附絮凝剂与非活性吸附絮凝剂均与Pb(Ⅱ)发生了某些反应；对吸附Pb(Ⅱ)后的XPS分解谱图与铅的标准谱图Pb(4f5/2)与Pb (4f7/2)对比发现,其谱峰非常相近,铅的结合能为138.84eV,通过查标准能谱分析得到,吸附后铅的主要存在形态仍为Pb(Ⅱ)。更多还原

【Abstract】 The wastewater containing lead not only has great harm to human, but also have great harm to plants and animals. When the wastewater containing lead enters the environment, the lead of the wastewater is constantly enriched through the enrichment of the organism and the food chain. Therefore, the human being as the top of the food chain are seriously threatened. As a result, lead wastewater treatment has the vital significance.The method of biological adsorption method and the method of biological flocculation are new, which has a broad development prospects. But microbial adsorption and flocculation mechanism are not fully understood, the application of microbial flocculant adsorption is still in its infancy. Therefore, further explore and study of the mechanism of microbial flocculation Pb(Ⅱ) adsorption., the effective chemical components of the microbial flocculation adsorption Pb(Ⅱ) perhaps could help find out the culture conditions suitable for the adsorption of heavy metal ions, improving the ability of microorganism for the adsorption of Pb(Ⅱ). At the same time, researchers must strengthen and broaden the microbial strains of adsorbent resources, and look for the microorganism of big quantity and low price which can adsorb and flocculate more various heavy metal ions at the same time. It will pose important economic and social significance upon the treatment of wastewater containing lead.A lead-resistant and flocculant produced strains was screened from Activated sludge of the sewage treatment plant in Chenggong County, Kunming, which was identified as Klebsiella by16S rDNA. The wet microbial cells were used as active adsorbent, after the drying microbial cells as an non-active adsorbent, we studied adsorption flocculation properties for water Pb(Ⅱ) in water of active and non-active sorbent. In the treatment of the wastewater containing lead, research of Klebsiella adsorption flocculation Pb(Ⅱ) under the different pH, different dosage, different time, different concentration of Pb(Ⅱ) and different speed, in order to determine the best conditions; Explored the adsorption flocculation mechanism through Adsorption isotherm curve, Kinetic models, FT-IR, SEM and XPS, the results are as follows: (1)53Lead-resistant strains were selected from Sludge,10of which can produce lead-resistant microorganisms adsorbed flocculant. And the lead-resistant strains of best flocculation characteristic was ZJ-15, whose flocculation rate on Kaolin suspension was87.93%; Sucrose of15g, KH2PO4of2g, K2HPO4of5g, MgSO4-7H2O of0.2g, NaCl of0.1g, urea of3.3g; distilled water of1000ml, pH of6.0were the best best medium components of ZJ-15lead-resistant strains producing lead-resistant microorganisms adsorbed flocculant; The optimal culture conditions of ZJ-15lead-resistant strains producing lead-resistant microorganisms adsorbed flocculant:initial pH of medium hit6.0, fermentation temperature T reached28℃; and rotation speed was100rpm; The effect that ZJ-15posed upon flocculant produced by ZJ-15:no effect for Na+、Cu2+, inhibition for Fe2+, Fe3+, Al3+, promotion for Mg2+(2) By Gram stain, observation of bacterial colony morphology and16SrDNA identification, it was found that the right ZJ-15lead-resistant strains producing lead-resistant microorganisms adsorbed flocculant was identified as Klebsiella sp.(3) When the active adsorbent treated the waste water with Pb(Ⅱ), the pH was5, the amount of adsorbent was8g/L, the time was120min, the concentration of Pb (Ⅱ) was150mg/L, the speed was120rpm, the equilibrium adsorption amount was73.3mg/g; When the non-active adsorbent treated the waste water with Pb(Ⅱ), the pH was4, the amount of adsorbent was0.5g/L, the time was120min, the concentration of Pb(Ⅱ)was150mg/L, the speed was120rpm, the equilibrium adsorption amount was73.3mg/g.(4) Adsorbent (active and inactive)’s adsorption of Pb(Ⅱ) can better fit Langmuir isotherm model, Adsorbent (active and inactive)’s adsorption of Pb(Ⅱ) mainly monolayer adsorption function; The second order kinetic model can better describe the kinetics process for Pb(Ⅱ) of adsorbent.(5) The FTIR result presented that t the main component of the adsorbent is polysaccharide and the mainly groups including hydroxyl, carboxyl and amide groups.The spectra of the unloaded Klebsiella biological adsorbent indicated strong asymmetrical stretching bands at3467cm-1(-OH groups),2923cm-1(C-H groups),1670cm-1(C=O groups),1421cm-1(COO groups) and1083cm-1C-OH stretching of carboxyl groups). This indicates thatthe physical adsorption and chemisorption occurred between the adsorbent and the Pb (Ⅱ) in the solution.(6) SEM comparative analysis was conducted before and after thallus absorbed the Pb(Ⅱ), the appearance of Klebsiella sp. before and after adsorption Pb(Ⅱ) was quite different, implying that Klebsiella sp. reacted with Pb(Ⅱ). Before absorbing Pb (Ⅱ), the adsorption flocculant were clumps shape with different sizes. But after adsorption Pb (Ⅱ), the pores became smaller, and amorphous crystals existed.(7) XPS comparative analysis was conducted before and after thallus absorbed the Pb2+, before absorbing, the Pb(Ⅱ) was absent, and the combination of the adsorption flocculant and Pb(Ⅱ) was weak, but after adsorption, the Pb(Ⅱ) appeared, and the relative strength of adsorption was obviously higher, and two peak number of the adsorption of lead appeared, showing that both active and non-active adsorption flocculant flocculant reacted with Pb(Ⅱ); After adsorption Pb(Ⅱ), the comparative analysis on the XPS spectra decomposition and the standard spectra of lead of Pb(4f5/2) and Pb(4f7/2) showed that their peaks were very similar,and the binding energy of lead was138.84eV. After analyzing by standard spectrum, it was found that the main form of lead after adsorption is Pb (Ⅱ).更多还原