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21.
分别以营养型缓释填料的生物过滤塔(BF)和聚氨酯小球为填料的生物滴滤塔(BTF)去除二氯甲烷(DCM)模拟废气.结果表明,采用"专属菌+综合菌"挂膜方式,BTF和BF分别在25 d和22 d内完成快速挂膜.扫描电镜结果表明,BF填料表面的菌落结构较为疏松、生物膜较薄,BTF填料表面的菌落结构致密、生物膜较厚.在DCM进口浓度100~1 500 mg·m-3、停留时间25~85 s条件下,BTF和BF对DCM均有较好的去除效果,最大去除负荷分别为22.61 g·(m3·h)-1和29.05g·(m3·h)-1.滤塔中CO2生产量与DCM降解量呈线性关系,经拟合得出BTF和BF的矿化率分别为70.4%和66.8%,且BTF矿化程度好于BF,表明滤塔内减少的DCM主要是被微生物利用降解.滤塔内DCM的降解动力学行为符合Michaelis-Menten模型,BTF和BF单位体积最大降解速率r max分别为22.779 0 g·(m3·h)-1和28.571 4 g·(m3·h)-1,气相饱和常数K s分别为0.141 2 g·m-3和0.148 6 g·m-3. 相似文献
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A strain Pandoraea pnomenusa LX-1 that uses dichloromethane(DCM) as sole carbon and energy source has been isolated and identified in our laboratory. The optimum aerobic biodegradation of DCM in batch culture was evaluated by response surface methodology. Maximum biodegradation(5.35 mg/(L·hr)) was achieved under cultivation at 32.8°C, pH 7.3, and 0.66% NaCl. The growth and biodegradation processes were well fitted by Haldane's kinetic model, yielding maximum specific growth and degradation rates of 0.133 hr-1and 0.856 hr-1, respectively. The microorganism efficiently degraded a mixture of DCM and coexisting components(benzene, toluene and chlorobenzene). The carbon recovery(52.80%–94.59%) indicated that the targets were predominantly mineralized and incorporated into cell materials. Electron acceptors increased the DCM biodegradation rate in the following order: mixed oxygen iron sulfate nitrate. The highest dechlorination rate was 0.365 mg Cl-/(hr·mg biomass), obtained in the presence of mixed electron acceptors. Removal was achieved in a continuous biotrickling filter at 56%–85% efficiency, with a mineralization rate of 75.2%. Molecular biology techniques revealed the predominant strain as P. pnomenusa LX-1. These results clearly demonstrated the effectiveness of strain LX-1 in treating DCM-containing industrial effluents. As such, the strain is a strong candidate for remediation of DCM coexisting with other organic compounds. 相似文献
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二氯甲烷和二氯乙烷对蛋白核小球藻的毒性影响研究 总被引:6,自引:2,他引:4
研究了二氯甲烷和1,2-二氯乙烷对蛋白核小球藻(Chlorella pyrenoidosa)生长和生化指标的毒性效应.结果表明,二氯甲烷和1,2-二氯乙烷对蛋白核小球藻生长有影响.随着2种毒物浓度的增大,其对藻生长的抑制越明显,藻细胞密度均呈现下降的趋势.二氯甲烷和1,2-二氯乙烷抑制蛋白核小球藻生长的96 h-EC50分别为550.1 mg/L和276.0 mg/L,1,2-二氯乙烷的毒性要稍强于二氯甲烷.2种毒物联合作用时基本表现为拮抗作用.叶绿素a含量随毒物浓度增加而迅速下降,SOD和CAT的活性随毒物浓度升高呈现先升高后下降的"钟形曲线".MDA的含量随毒物浓度升高而急剧上升,膜脂过氧化加剧.表明毒物通过产生活性氧自由基引起生物大分子的氧化损伤可能是其对蛋白核小球藻产生毒性效应的主要原因. 相似文献
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生物滴滤塔净化氯代烃混合废气的研究 总被引:4,自引:3,他引:1
应用生物滴滤塔进行了二氯甲烷和1,2-二氯乙烷混合废气净化的研究,使用制药厂活性污泥挂膜,35 d后挂膜完成,对二者的去除率可分别维持在80%和75%以上.对二氯甲烷和1,2-二氯乙烷的最大去除负荷分别为13 g·(m3·h)-1和10g·(m3·h)-1.CO2的产生负荷与混合废气的去除负荷呈线性关系,生物滴滤塔对混合废气的矿化率维持在61.2%.对混合废气中二氯甲烷和二氯乙烷相互作用考察发现两者存在一定的抑制作用,同时考察了反应器运行过程中生物量的变化情况. 相似文献
25.
Risk Analysis of Volatile Organic Compounds Through Daily Life Cycle in the Industrial City in Korea
This study analyzed the risk of exposure to volatile organic compounds (VOCs) through a study of activity patterns in the Korean industrial city, Ulsan. The daily life cycle patterns(LCPs) of 331 people in Ulsan were surveyed and the average LCPs in Ulsan were obtained by statistical analysis. Nine to twelve personal air samples of VOC exposure at the breathing zones were collected at each LCP. This included hours for sleeping,cooking and eating, going to and from work, working, participating in field or outdoor activities, reading, watchingTV, and shopping. The components and concentrations of the collected VOCs were identified by a Gas Chromatography-MassDetector (GC-MS). The overall reproducibility of all GC analytical procedures of the simultaneously collected duplicatesample pairs represented a mean of percent differences rangingfrom about 9 to 13%. For the general population of Ulsan, thecarcinogenic and non-carcinogenic risk of exposure to theVOCs during the LCPs was evaluated. The carcinogenic riskwas analyzed using both the chronic daily exposure orlifetime average daily exposure (CDI) and the cancerpotency factor. The non-carcinogenic risk was analyzedusing both the CDI and the chronic reference dose.The major chemical forms of the identified VOCs were oxidized forms (43%), aliphatic alkanes (29%) and aromatics (15%). Even though the highest total exposure strength per unit time of each activity was observed during shopping, the highest totalamount of exposure to VOCs was identified as the exposure duringwork. The total carcinogenic risk of exposure to the carcinogenicVOCs through daily life cycle in Ulsan was 2.0 × 10-4which is substantially exceeding the permissible carcinogenicrisk level, 10-5 10-6. The carcinogenic riskduring most of the life cycle activities, except forreading, mainly performed indoors, was higher than that ofthe activities performed outdoors. The carcinogenic risk bybenzene exposure was about 56% (time weighted average) ofthe total carcinogenic risk by the exposure to thecarcinogenic VOCs. During cooking and eating, shopping andout door activities, however, the carcinogenic risk by theexposure to chlorinated compounds like chloroform exceededthe exposure to benzene. The overall hazard index (non-carcinogenic risk) by a chronic exposure to carcinogenicand non-carcinogenic VOCs through daily life cycle in Ulsanwas evaluated as 3.91 × 10-1, which is much less than1.0 considered as a hazard level to human health, and thusit seems likely not to produce a severe health hazard. 相似文献
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IntroductionDichloromethane (DCM) has been widely usedas an intermediate and solvent in chemical industriesand many other analytical fields. Due to its lowboiling point (40.1℃) and high vapour pressure (47kPa at 20℃), large amounts of dichloromethane enterthe environment via gaseous emissions (Adachi andKomiyama, 2000, 2001; Adachi and Hamamoto,2005). DCM is harmful to human health andhazardous to atmospheric environment. For instance,it is known that DCM is toxic to the central nerves… 相似文献
28.
Response surface methodology (RSM) was employed to evaluate the optimum aerobic biodegradation of dichloromethane (DCM)
in pure culture. The parameters investigated include the initial DCM concentration, glucose as an inducer and hydrogen peroxide
as terminal electron acceptor (TEA). Maximum aerobic biodegradation efficiency was predicted to occur when the initial DCM
concentration was 380 mg/L, glucose 13.72 mg/L, and H2O2 115 mg/L. Under these conditions the aerobic biodegradation rate reached
up to 93.18%, which was significantly higher than that obtained under original conditions. Without addition of glucose, degradation
efficiencies were 6 80% at DCM concentrations < 326 mg/L. When concentrations of DCM were more than 480 mg/L, the addition of
hydrogen peroxide did not help to significantly increase DCM degradation efficiency. When DCM concentrations increased from 240
to 480 mg/L, the overall DCM degradation efficiency decreased from 91% to 60% in the presence of H2O2 for 120 mg/L. 相似文献
29.
对分离筛选到1株能以二氯甲烷(DCM)为唯一碳源和能源生长的菌株Methylobacterium rhodesianum H13进行降解特性研究.在初始菌体浓度0.82 mg.L-1、pH 7.0和温度30℃的条件下,M.rhodesianum H13能够于23 h内将5 mmol.L-1DCM完全降解,细胞得率(细胞/DCM)为0.136 g.g-1.随着DCM的降解,溶液中的Cl-浓度逐渐升高(释放的Cl-浓度约为DCM的2倍),溶液pH值降至6.75,呈弱酸性.通过摇瓶实验考察了温度、pH、DCM浓度、Cl-等因素对菌株H13降解DCM性能的影响,获得其较适宜的生长和降解条件为:温度30℃、pH值7.0.研究还发现M.rhodesianum H13降解DCM的最适浓度为5 mmol.L-1,高浓度的DCM会抑制其降解.研究成果对高效处理环境中的DCM污染具有重要的应用价值. 相似文献
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Mehrnoosh Abtahi Kazem Naddafi Kamyar Yaghmaeian Ramin Nabizadeh Nematollah Jaafarzadeh 《毒物与环境化学》2013,95(5):757-764
The primary data about the role of automotive manufacturing industry in emitting dichloromethane (DCM) to the environment in Iran are provided by a case study of SAIPA Automotive Manufacturing Company in 2012. The average emission rate and emission factor of DCM in the stack exhaust air streams of the solvent-based automotive painting plant were 6.8 kg·d?1 and 19.5 g per car, respectively. The spray booths had the highest portion (about 85%) of DCM emission in the stack exhaust air streams. The average concentration of DCM (± standard deviation) in the generated wastewater of the factory was 64 ± 12 μg·L?1, but in the effluent of the factory wastewater treatment plant, it was reduced to a nondetectable level. DCM was also observed in three groundwater wells out of five monitored water resources. To control DCM emission and prevent pollution, the replacement of solvent-based paints with water-based paints is highly recommended. 相似文献