【作者】 席宏波；

【导师】 万力； 杨琦；

【作者基本信息】 中国地质大学（北京） ， 环境工程， 2009， 博士

【摘要】 菲是含三个苯环的典型低分子量多环芳烃(PAHs),是环境中检出率较高的持久性有机污染物(POPs);菲极易从水中分配到生物体、沉积物及有机质中,通过食物链进入人体,危害人类健康。因此研究菲在环境中的迁移转化过程能为菲和其它PAHs污染的修复提供理论依据。本研究从驯化污泥中筛选、分离出六株菲高效降解菌株并对其进行了初步鉴定。论文研究了菲在水环境、污泥及单一菌种悬浊液中的挥发、吸附、降解特性;提出了菲的降解模型并进行了验证;探讨了纯菌种降解菲的酶促动力学和抑制动力学。实验得出如下结论:1、菲在水环境和污泥中的挥发过程符合一级动力学方程;水的流动速度、温度的增加都将显著增大菲的挥发速率;25℃时,实验得出的挥发速率常数ka = 0.0607 h-1,总传质系数k=1.079×10-6 m/s,而理论估算出的总传质系数k = 2.240×10-6 m/s。2、分离出的六株菲高效降解菌株包括:多食鞘氨醇杆菌属(P-1,P-4);芽孢杆菌属(P-2);节杆菌属(P-3);贪噬菌属(P-5);考克氏菌属(P-6),除菌株P-1为革兰氏阴性菌外,其它五种菌株均为革兰氏阳性菌。3、驯化污泥、各菌株菌悬液对菲的吸附均符合Langmuir和Freundlich吸附等温线模式,吸附平衡时间为1 h;吸附符合二级动力学方程;污泥、菌株Sphingobacterium sp. 1、Bacillus sp.菌悬液的吸附活化能分别为6.63 kJ/mol、25.66 kJ/mol和13.38 kJ/mol;吸附过程ΔG < 0,为自发过程;焓变ΔH > 0,为吸热反应。菌株Sphingobacterium sp. 1和Bacillus sp.对萘的吸附能力比菲强,萘、菲竞争吸附符合Langmuir和Freundlich竞争吸附等温线模式。4、驯化污泥及各菌株对菲的降解符合一级动力学方程;15天内,菌株Sphingobacterium sp. 1、Bacillus sp.、Arthrobacter sp.、Sphingobacterium sp. 2、Variovorax sp.、Kocuria sp.对100 mg/L菲的降解率分别为100%、94.0%、68.1%、64.4%、81.3%、14.3%;葡萄糖和酵母粉的加入能促进菲的降解;温度、pH值对菲降解影响较大;菌株Sphingobacterium sp. 1可利用苯酚和萘与菲发生共降解,萘对菌株Bacillus sp.降解菲具有竞争性抑制作用,萘能促进菌株Kocuria sp.对菲的降解;补充氧气能加速菌株对菲的降解。5、萘对菌株Bacillus sp.降解菲存在竞争性抑制作用,抑制常数KI = 0.4240 mg/L;菲浓度对菌株Kocuria sp.降解菲存在底物抑制作用,抑制常数kS = 3.173 mg/L,最佳底物浓度[S]opt = 0.683 mg/L。更多还原

【Abstract】 Phenanthrene, containing three benzene rings, is one of the typical PAHs with low-molecular-weight, persistent organic pollutants (POPs) and high detection rate. Phenanthrene can easily migrate into the the organism, sediment and organic matte, or accumulate in the human body through the food chain, which can endanger human health. So the research on the phenanthrene migration and transformation in the environment can provide reference for the bioremediation of pollution with phenanthrene and other PAHs. This study on selection, isolation and preliminary identification of six phenanthrene degradation strains were conducted. The characteristics of the volatilization, adsorption, biodegradation of phenanthrene by domesticated sludge and the strains were studied. The biodegradation model by strain Bacillus sp. and the enzymatic reaction and inhibition kinetics by strain Sphingobacterium sp. 1, Bacillus sp. and Arthrobacter sp. were discussed. The results of the study are as follows:1. The volatilization of phenanthrene in domesticated and each of the strains could be fit with the first-order kinetics model. The increase of water flow velocity and temperature promoted the volatilization rate. The volatilization rate constant ka and the total mass transfer coefficient k obtained from the experiment data and the calculated total mass transfer coefficient using the empirical formula was 2.240×10-6 m/s.2. The strains isolated from the domesticated sludge conclude: Sphingobacterium sp. (P-1, P-4), Bacillus sp. (P-2), Arthrobacter sp. (P-3), Variovorax sp. (P-5), Kocuria sp. (P-6). All of the six strains are gram-positive bacteria except for the strain P-1.3. The adsorption of phenanthrene on domesticated and each of the strains fitted well with Langmuir adsorption isotherm equation and Freundlich adsorption isotherm equation. The adsorption equilibrium time was 1 h. The adsorption kinetics could be expressed by second-order kinetic equation. The activation energy of the sludge, strain Sphingobacterium sp. 1, strain Bacillus sp. on the phenanthrene adsorption were 6.63 kJ/mol, 25.66 kJ/mol, 13.38 kJ/mol, respectively. The values of gibbs free energy (ΔG < 0) and enthalpy (ΔH > 0) showed that the adsorption reactions of phenanthrene were spontaneous reactions and endothermic reactions. The adsorptions of naphthalene were higher than phenanthrene on the strain Sphingobacterium sp. 1 and strain Bacillus sp.. The competitive adsorption isotherm of naphthalene and phenanthrene on strain Sphingobacterium sp. 1 fitted well with Langmuir and Freundlich competitive isotherm models.4. The experimental outcomes of the degradation of phenanthrene by domesticated sludge and each of the strains could be fit well with the first-order biodegradation kinetics model. The removal efficiency of the phenanthrene degradation by strains Sphingobacterium sp. 1、Bacillus sp.、Arthrobacter sp.、Sphingobacterium sp. 2、Variovorax sp.、Kocuria sp. for 100 mg/L of phenanthrene in 15 d were 100%, 94.0%, 68.1%, 64.4%, 81.3%, 14.3%, respectively. The addition of glucose and yeast powder increased the phenanthrene degradation rates. Temperature and pH value had great impacts on the degradation. Co-metabolism occurred on phenanthrene degradation by strain Sphingobacterium sp. 1 when added in phenol or Naphthalene. Naphthalene promoted the phenanthrene mineralization by strain Kocuria sp. but leaded to competitive inhibition on the phenanthrene degradation by strain Bacillus sp. replenish oxygen accelerated the phenanthrene degradation rates.5. competitive inhibition existed between naphthalene and phenanthrene on the degradation of phenanthrene by strain Bacillus sp. and the value of the competitive inhibition constant KI was 0.4240 mg/L. The high-phenanthrene concentration inhibited the enzymatic reaction of strain Kocuria sp. Substrate inhibition constant kS and the optimum substrate concentration [S]opt were 3.173 mg/L and 0.683 mg/L, respectively.更多还原