假单胞菌属对染化废水中典型类持久性有机污染物的去除作用机理研究

发布时间：2018-07-14 08:16

【摘要】：染化废水中存在着类持久性有机污染物(类POPs),其成份复杂,类型多样,是导致染化废水难生物降解的主要物质。在现有的研究中,微生物对染化废水中不同类型类POPs的去除机制尚不明确,且缺乏微生物对类POPs去除的强化作用手段。本研究主要以染化废水中典型类POPs微生物强化去除为研究目标,系统地研究了假单胞菌属对不同类POPs的去除作用机制,探讨了强化去除类POPs的技术。首先,对类POPs阳离子染料甲基紫(MV)和非离子污染物苊(ACE)进行了假单胞菌属生化去除,发现类POPs主要以生物吸附去除作用为主。对于甲基紫而言,细胞壁和膜对甲基紫的吸附作用占到80%以上。紧密附着型胞外聚合物(TB-EPS)占到10%左右；而细胞壁和膜对苊的吸附作用占到70%以上,细胞内部物质的吸附作用占到10-25%。该研究表明,对于阳离子型和非离子型类POPs物质,去除作用机理主要是生物吸附作用。生物吸附甲基紫起主要作用的物质是蛋白质,而生物吸附苊起主要作用的物质是脂类物质。其次,对阴离子染料活性蓝13(RB13)和污染物五氯酚(PCP)共存体系进行了研究,发现两者都以生物降解去除为主。研究发现,PCP的存在对生物脱色RB13有抑制作用。通过生物降解RB13的过程分析,研究结果认为,Michaelis-Menten方程中的动力学常数Vmax和Km,在无PCP存在时分别为4.2mg/L·h及90.82 mg/L,而在20 mg/L PCP存在时则分别为0.58 mg/L·h和20.61mg/L。研究表明在多种类POPs污染物共存体系中,存在生物降解的电子竞争作用。对于阴离子型类POPs物质,生物去除的作用机理主要是生物降解作用。最后,针对阴离子型类POPs物质生物降解效率低的问题,研究了强化生物吸附和降解技术的方法。针对吸附去除的强化,制备了假单胞菌干菌,并进行了改性。制备得到的改性干菌,在中性和酸性条件下都能较好地吸附去除阴离子型类POPs。同时探明了在不同pH值条件下,干菌与污染物之间的吸附动力学、等温吸附模型及可能的吸附机理。针对降解去除的强化,通过引入氧化还原介体(AQS)设法提高其生物降解效率。研究考察了AQS对生物降解RB13和PCP的促进作用原理。当AQS最佳投加量为0.3 mmol/L,在有10 mg/L PCP存在的体系中,对于脱色和脱氯分别提高了4倍和2倍。同时对AQS进行了固定化,在序批式反应过程中,连续使用10轮以上,均能取得95%以上的生物脱色效果,表明制备得到的AQS-PVA小球具有较好的抗脱附性及运行稳定性。
[Abstract]:There are persistent organic pollutants (pops) in dyeing wastewater, which are the main substances that lead to the difficult biodegradation of dyeing wastewater. In the existing studies, the removal mechanism of different types of pops in dyeing wastewater by microorganisms is not clear, and there is a lack of means to enhance the removal of pops by microorganisms. In this study, the removal mechanism of different pops by Pseudomonas was systematically studied, and the technology of enhanced removal of pops was discussed. Firstly, pseudomonas was used to remove pops cationic dye methyl violet (MV) and acenaphthene (ACE). For methyl violet, the adsorption of methyl violet by cell wall and membrane accounted for more than 80%. Close adhesion extracellular polymers (TB-EPS) accounted for about 10%, while cell walls and membranes accounted for more than 70% of acenaphthene adsorbed. The results show that the removal mechanism is mainly biosorption for cationic and Nonionic pops-like substances. Protein is the main substance of biosorption of methyl violet, while acenaphthene is mainly adsorbed by acenaphthene. Secondly, the coexistence of reactive blue 13 (RB13) and PCP was studied. It was found that the presence of PCP inhibited biological decolorization of RB13. The kinetic constants Vmax and Km in the Michaelis-Menten equation were found to be 4.2 mg / L and 90.82 mg / L in the absence of PCP, respectively, and 0.58 mg / L and 20.61 mg / L in the presence of 20 mg / L PCP, respectively. It is shown that there is electronic competition in biodegradation in the coexistence system of multiple pops pollutants. For anionic pops-like substances, biodegradation is the main mechanism of bioremoval. Finally, aiming at the low biodegradation efficiency of anionic pops, the methods of enhanced biosorption and degradation were studied. Pseudomonas aeruginosa was prepared and modified to enhance adsorption removal. The prepared modified dry bacteria can effectively adsorb and remove anionic POPslike under neutral and acidic conditions. At the same time, the adsorption kinetics, isothermal adsorption model and possible adsorption mechanism between dry bacteria and pollutants at different pH values were investigated. In order to improve the biodegradation efficiency, the redox medium (AQS) was introduced to enhance the biodegradation efficiency. The effects of AQS on biodegradation of RB13 and PCP were investigated. When the optimal dosage of AQS was 0.3 mmol / L, in the system with 10 mg / L PCP, decolorization and dechlorination were increased by 4 times and 2 times, respectively. At the same time, AQS was immobilized. In the process of sequential batch reaction, more than 95% biological decolorization effect could be obtained by continuous use of more than 10 rounds of batch reaction, which indicated that the prepared AQS-PVA pellets had good desorption resistance and operational stability.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X788;X172

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