多粘类芽孢杆菌GA1所产絮凝剂的絮凝性能研究及机理探讨

采用正交絮凝、粒度检测及电镜扫描考察了多粘类芽孢杆菌GA1所产絮凝剂（MBFGA1）对高岭土溶液、土壤悬浊液、洗煤废水及垃圾渗滤液4种废水的絮凝性能,并利用蒽酮试验和红外光谱对絮凝剂成分进行了初步鉴定.在正交絮凝实验获得的最佳絮凝条件下,絮凝剂对高岭土溶液、土壤悬浊液、洗煤废水和垃圾渗滤液的絮凝率分别高达99.53%、99.50%、98.2%和75.60%,絮体沉降速度分别为0.03 m/s、0.025 m/s、0.025 m/s和0.005 m/s;土壤悬浊液中颗粒絮凝后平均粒径增大且大于10　μm,其余３种废水中颗粒平均粒径减小且小于10　μm;电镜扫描结果显示,絮凝前后废水颗粒的形态均从棱角分明转变为包埋的无棱角;EDTA、HCl以及尿素检验发现4种颗粒与絮凝剂分子间靠离子键结合;蒽酮反应及红外光谱结果显示该絮凝剂为含有较多羟基及羧基等官能团的多糖大分子.实验结果表明絮凝剂对高颗粒物浓度废水有很好的处理效果,其絮凝机理主要是吸附架桥作用.

Flocculating Capability and Mechanism of Bioflocculant Produced by Paenibacillus polymyxa GA1

MBFGA1, which was produced by Paenibacillus polymyxa GA1, was used to investigate its flocculating capability in the following waste water, the liquid of kaolin, soil suspended liquid, coal-washing wastewater and the landfill leachate with orthogonal experiments, the inspection of granularity and the scanning electron microanalysis. Meanwhile the anthrone reaction and infrared spectrum are also applied to identify its main component. In the optimal flocculating conditions obtained from the orthogonal experiments, the flocculating rates of the liquid of kaolin, soil suspended liquid, coal-washing wastewater and the landfill leachate were 99.53%, 99.50%, 98.2% and 75.60%, respectively, and the sedimentation velocities of the above four kinds of flocculants were 0.03 m/s, 0.025 m/s, 0.025 m/s and 0.005 m/s, respectively. In addition, the distribution of granularity has changed after flocculation. The size of the average granularity of soil became bigger after flocculation, and reached over 10 microm, but for the other three kinds of granularity just the opposite phenomenon has occurred, and their sizes were all less than 10 microm. From the photos of scan electron microanalysis of four types of granules, it could be drawn that there were no obvious differences in the appearance. It was the same adsorptive mode between MBFGA1 and different flocculating particles, that is the function of electrovalent bond, tested by EDTA, HC1 and urea. The main component of MBFGA1 was polysaccharide, which was determined by anthrone reaction, and it contained a lot of carboxyl and hydroxyl groups examined by infrared spectrum analysis. From the above results, it could be presumed that MBFGA1 can be the best flocculant for the granule-highly-concentrated waste water and the dominative flocculating mechanism of the flocculant was mechanism of adsorption-bridge.