【作者】 代淑娟；

【导师】 魏德洲； 尹文新；

【作者基本信息】 东北大学 ， 矿物加工工程， 2008， 博士

【摘要】 重金属污染是危害最大的环境污染问题之一。镉是毒性较大的重金属,环保法规定其为一类污染物。电镀是当今全球三大污染工业之一,一般电镀厂的含镉废水在处理前镉的浓度都远高于国家制定的排放标准。因而,电镀废水中镉的去除尤为重要。利用微生物吸附镉等重金属离子具有许多优点,例如：吸附速度快；在低浓度下,金属可以被选择性去除；处理效率高；pH值和温度条件范围宽；投资少,运行费用低；可有效地回收一些贵重金属等。近年来,对于采用生物吸附法去除废水中重金属离子,国内外专家学者开展了较为广泛的研究。本研究以废啤酒酵母、沟戈登氏菌、胶质芽胞杆菌和枯草芽胞杆菌为吸附剂,以电镀厂含镉电镀废水为处理对象,采用沉淀法或浮选法实现固液分离,达到除镉的目的。本文研究了微生物形态与性质,对废啤酒酵母、沟戈登氏菌、胶质芽孢杆菌及枯草芽胞杆菌的染色特征和扫描电子显微镜形貌以及透射电子显微镜结构进行了观察,测试了它们的荷电特性、细胞壁组成及特征官能团。研究发现,它们各自的表面化学特性对其吸附过程产生不同的影响。本文研究了电镀废水的相关物理化学性质及主要成分的存在状态；研究了废水pH值、吸附剂用量、吸附时间、吸附温度、搅拌速度电镀废水中镉吸附效果的影响；研究了废啤酒酵母水洗前后不同沉降时间的沉淀效果；研究了以沟戈登氏菌、胶质芽孢杆菌及枯草芽胞杆菌为吸附剂时,不同pH值及捕收剂用量对微生物吸附-浮选除镉效果的影响。依据动电电位、微生物表面荷电状态、红外光谱、扫描电子显微镜、光电子能谱等测试结果,探索了微生物吸附剂的作用机理。研究结果表明,4种吸附剂对该电镀废水中镉均具有较好的吸附效果。废啤酒酵母经简单水洗处理后,在常规条件下,对电镀废水中镉的吸附率为96.18%,其它三种吸附剂对电镀废水中镉的吸附率均在92%以上。研究所用废啤酒酵母具有较好的沉淀性能,采用吸附-沉淀法去除电镀废水的镉,能获得较好的吸附及固液分离指标。在电镀废水中镉浓度约为26mg/L、水洗废啤酒酵母菌用量为11.4g/L、pH为7、室温(约18℃)、生物吸附时间为30min的条件下,自然沉降3.5h,镉去除率达96%以上。以沟戈登氏菌、胶质芽孢杆菌及枯草芽胞杆菌为吸附剂时,采用浮选法进行固液分离,在电镀废水中镉浓度约为26mg/L、枯草芽胞杆菌用量为10g/L(湿重)、pH为7、室温(约25℃)、生物吸附时间为10min的条件下,以二正丁胺为捕收剂,在用量为4×10-4mol/L时,镉去除率达到76%。以水洗废啤酒酵母为吸附剂,采用吸附-沉淀法对该电镀废水中镉的去除效果明显好于以沟戈登氏菌、胶质芽孢杆菌及枯草芽胞杆菌为吸附剂,采用吸附-浮选法,对该电镀废水中镉的去除效果。加之,废啤酒酵母菌来源广、价格低,比其它三种生物吸附剂具有更大的优势。采用自制装置,以水洗废啤酒酵母为吸附剂,采用吸附-沉淀法进行了扩大试验研究,在电镀废水中镉浓度为26mg/L左右、水洗废啤酒酵母菌用量为40g/L(湿重)、pH为7、室温(约25℃)、生物吸附时间为30min的条件下,自然沉降4h,镉去除率达94%以上；进行的小型连续试验的结果表明,当废水给入速度为10.8mL/min、40mL/min、167mL/min时,水洗废啤酒酵母对电镀废水中镉的吸附率分别为98.43%、96.46%和86.86%。更多还原

【Abstract】 Heavy metals pollution is the one of the biggest environment pollution problems. Cadmium is the most poisonous heavy metal,the enviroment protection law stipulates that cadmium is the first kind of pollution materials.Electroplating is one of three big pollution industry,in general the Cadmium concentration of the Cadmium-containing electroplating wastewater doesn’t meet domestic discharge standard before treatment,so removal of Cadmium in electroplating wastewater is very important. Removing heavy metals by biosorption has many advantages,such as,fast speed, heavy metal can be removed selectively even at its low concentration,high efficiency, a wide range of pH and temperature,less investment and running cost,in addition,some heavy metals can be recovered. Many experts domestic and abroad do a lot of work on biosorption of heavy metals for several years.Waste Saccharomyces cerevisiae,Gordona amarae,Bacillus mucilayinosus and Bacillus subtilis was used as biosorbent,Cadmium-containing electroplating wastewater of an electroplating plant was used to treat objects in studies,separation of solid and liquid was done by precipitation and flotation methods to remove cadmium from wastewater.The shape and characters of micro biology was studied and stain characters,shape appearance and structure of waste saccharomyces cerevisiae,Gordona amarae,Bacillus mucilayinosus and Bacillus subtilis were observed by biology microscope,SEM and TEM, their charge characters and the composition of cell wall and function groups were tested. The research results showed their chemistry characters had different effect on biosorption process, the physics and chemistry naturals and state of main component were studied in the paper.Influence of pH value,dosage of adsorbent,the temperature,the stiring revolution and the contact time on adsorption result were studied. The effect on precipitation result of different precipitation time of waste Saccharomyces cerevisiae before and after water-washing,flotation and removing cadmium influence of different pH value and dasoge of collectors using Gordona amarae,Bacillus mucilayinosus and Bacillus subtilis as adsorbent were studied. The adsorption mechanism to cadmium wasdiscussed by test results of Zeta potential,charge state of cells surface,infrared spectroscopy analysis of the cells, SEM,TEM and XPSThe research results show that adsorption influence of four adsorbents to cadmium in electroplating wastewater are good. The adsorption rate of cadmium in electroplating wastewater is above 96.18% by water-wsahing waste Saccharomyces cerevisiae on the normal condition,adsorption rate of cadmium are all above 92% by the other three adsorbents. Precipitation performance of waste Saccharomyces cerevisiae used in studies is good,the good index of adsorption and solid-liquid separation are got by adsorption-precipitation method by waste Saccharomyces cerevisiae,removal rate of cadmium is over 96% after adsorbing for 30 min with cadmium concentration in cadmium-containing electroplating wastewater about 26mg/L,waste Saccharomyces cerevisiae 11.4 g/L,temperature 18℃,pH 7.0 and static precipitation for 3.5 hours. The flotation method is used in solid-liquid separation when Gordona amarae,Bacillus mucilayinosus and Bacillus subtilis are used adsorbents,removal rate of cadmium was over 76% after adsorbing for 10 min with cadmium concentration in cadmium-containing electroplating wastewater about 26mg/L, Bacillus subtilis 10 g/L(wet weight),at room temperature(about 18℃),pH 6.0 and flotating by collector dibutyamine 4×10-4mol/L for 4min. The effct of removal cadmium adsorption-precipitation by waste Saccharomyces cerevisiae is better than the index of adsorption-flotation by Gordona amarae,Bacillus mucilayinosus and Bacillus subtilis obviously. Additionally, because of abundant waste Saccharomyces cerevisiae and low price,it has more obvious advantages compared with the other three biosorbents.The wide experiments are done with self-made equipment,and the good removal cadmium result is got using adsorption-precipitation by water-wsahing waste saccharomyces cerevisiae,removal rate of cadmium is over 94% after adsorbing for 30 min with cadmium concentration in cadmium-containing electroplating wastewater about 26mg/L,waste saccharomyces cerevisiae 40 g/L(wet weight),at room temperature(about 25℃),pH 7.0 and static precipitation for 4 hours. The continuing adsorption experiments are done with self-made equipment,and the adsorption rate of cadmium is 98.43%,96.46% and 86.86% repectively when the velocity of inflow of wastewater is 10.8 mL/min,40 mL/min and 167mL/min.更多还原