负载纳米二氧化钛对好氧颗粒污泥的影响及对磺胺嘧啶的去除研究

发布时间：2018-04-20 15:53

本文选题：好氧颗粒污泥 + 纳米二氧化钛　；参考：《山东大学》2017年硕士论文

【摘要】：磺胺嘧啶(Sulfadiazine,SD)是使用最广的抗生素之一,它是由嘧啶环和苯环共同组成的含有硫和氮两元素的有机物,是在自然界中很难被生物利用降解的有机物,也是最经常使用的磺胺类药物。由于该药的用量逐年增大,环境中经常检测到该物质浓度超标,这严重威胁着水环境生态平衡和人类健康,所以目前针对如何高效降解磺胺类废水的研究越来越多。本论文在序批式污泥反应器中培养得到好氧颗粒污泥并以其为吸附剂负载纳米二氧化钛而制备得到一种新型纳米生物材料,分析其对水中的纳米二氧化钛的吸附机理及二氧化钛负载对颗粒污泥造成的影响。另外,还考察了此纳米生物材料在紫外光条件下对磺胺嘧啶的去除效果及生成的中间产物研究。主要研究内容和结果如下:1.通过提高SBR反应器里的进水负荷和曝气量、加入钙离子作为颗粒内核、不断降低污泥沉降时间等控制条件培养出成熟的颗粒污泥。培养得到的颗粒污泥为黄褐色,具有结构紧凑、快速沉降和生物菌落丰富等特点。形成的颗粒粒径在1-5 mm,SVI大约40 mL/g,反应器对进水COD和氨氮的降解效率高达98%。2.在序批式颗粒污泥反应器中加入一定浓度二氧化钛使其负载到颗粒污泥表面,利用扫描电镜(SEM)、X射线能谱分析(EDS)、激光共聚焦荧光显微镜(CLSM)等方法对生成的纳米生物材料进行表征和生物影响分析。此外,考察了好氧颗粒污泥对溶液中纳米二氧化钛的吸附机理。数据表明,颗粒污泥吸附P25的过程更符合伪二级动力学模型,其相关系数均大于0.999。整个吸附受表面扩散和颗粒内部扩散协同作用影响,但是表面扩散在当中其主要作用。随后的脱附实验发现震荡过程中脱落的P25几乎可以忽略不计,这说明P25和颗粒污泥结合比较牢固。通过对EPS中PN,PS和活死细胞的测定发现,随着二氧化钛浓度的不断增高,颗粒污泥的表面会出现一定量细胞的死亡,从而导致PN,PS的下降。3.紫外光在一定光强和光照时间内,可以促进颗粒污泥中异养菌的活性,并且不会对AOB造成太大影响。紫外线照射促进了 SD的光降解,降解过程中生成了部分中间产物,主要包括:2-AP和4-APS,氨,硫酸根等,其中2-AP和SD 一样容易对生物产生抑制作用,而4-ABS容易被生物所降解。纳米二氧化钛负载后的颗粒污泥对氨氮的降解率并没有下降,这可能是因为SD降解过程中生成部分氨氮;但是其对SD的降解率得到了提高,原因是一方面光降解产生的中间产物4-ABS更利于被生物降解,从而减小了 SD对生物的抑制作用;另一方面二氧化钛在紫外光照下产生的活性自由基促进了 SD的氧化。
[Abstract]:Sulfadiazine SDB is one of the most widely used antibiotics. It is an organic substance consisting of pyrimidine ring and benzene ring containing sulfur and nitrogen, which is difficult to biodegrade in nature. It is also the most frequently used sulfonamides. Because the dosage of the drug increases year by year and the concentration of this substance is often detected in the environment, which seriously threatens the ecological balance of water environment and human health, there are more and more researches on how to efficiently degrade sulfanilamide wastewater. In this paper, aerobic granular sludge was cultured in sequencing batch sludge reactor and loaded with nano-TiO _ 2 as adsorbent to prepare a novel nano-biomaterial. The adsorption mechanism of nano-TiO _ 2 in water and the effect of TIO _ 2 loading on granular sludge were analyzed. In addition, the removal efficiency of sulfadiazine and its intermediate products were investigated under ultraviolet light. The main contents and results are as follows: 1. The mature granular sludge was cultivated by increasing the influent load and aeration rate in the SBR reactor and adding calcium ion as the core of the granules. The cultivated granular sludge is yellowish brown, with compact structure, rapid sedimentation and abundant biological colonies. The particle size is about 40 mL / g, and the degradation efficiency of influent COD and ammonia nitrogen is as high as 98.2. A certain concentration of titanium dioxide was added to the sequencing batch granular sludge reactor to load it onto the surface of the granular sludge. Scanning electron microscopy (SEM) and confocal fluorescence microscopy (CLSM) were used to characterize the nanomaterials and analyze their biological effects. In addition, the adsorption mechanism of aerobic granular sludge to nano-TiO _ 2 in solution was investigated. The data show that the adsorption process of P25 by granular sludge is more in line with the pseudo-second-order kinetic model, and the correlation coefficients are all greater than 0.999. The adsorption is affected by the synergistic effect of surface diffusion and particle diffusion, but surface diffusion plays a major role. The subsequent desorption experiments showed that the P25 falling off during the oscillation process was almost negligible, which indicated that P25 and the granular sludge were relatively strong. It was found that with the increasing concentration of titanium dioxide, a certain number of cells would die on the surface of granular sludge, which would lead to the decrease of PNs. 3. Ultraviolet light could promote the activity of heterotrophic bacteria in granular sludge under certain light intensity and illumination time, and it would not affect AOB significantly. UV irradiation promoted the photodegradation of SD, and some intermediate products were formed during the degradation process, including: 2-AP and 4-APS, ammonia, sulfate, etc. 2-AP and SD can easily inhibit the biodegradation of SD, while 4-ABS is easily biodegradable. The degradation rate of ammonia nitrogen by granular sludge loaded with nano titanium dioxide has not decreased, which may be due to the formation of part of ammonia nitrogen in SD degradation process, but the degradation rate of SD has been improved. The reason is that on the one hand, the intermediate product 4-ABS produced by photodegradation is more favorable to biodegradation, thus reducing the inhibitory effect of SD on biology; on the other hand, the active free radicals produced by titanium dioxide under ultraviolet irradiation promote the oxidation of SD.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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