好氧微生物在硝基苯污染河水原位修复中的应用

在好氧条件下,从长期受硝基苯污染的化工厂排污口底泥和河道底质中分离得到3株对硝基苯有明显降解作用的优势微生物.为了比较这些优势菌的降解效果,作了硝基苯初始质量浓度分别为50 mg/L、25 mg/L、12.5 mg/L、6.25 mg/L、3.13 mg/L等不同梯度下的模拟修复实验,并且检验了单一菌与混合菌的降解能力.实验结果表明:当硝基苯初始质量浓度为50 mg/L时,优势菌作用不明显,硝基苯的去除主要依靠自然挥发作用;当硝基苯初始质量浓度为3.13 mg/L时,混合菌对硝基苯的降解能力较强,72 h的去除率达到99%,而此时空白对照(CK)的去除率仅为60%.分析实验结果得到,混合菌可能存在协同作用;由于产物中未检出NO2-,所以硝基苯降解途径中可能存在部分还原历程.     

水体中苯胺光降解的实验研究

为了更好地了解苯胺类物质在环境中的化学行为,在自行设计的光化学反应器上进行模拟天然水体的苯胺光降解实验,用气相色谱法测定苯胺的残余质量浓度,考察了水体pH值、光强、反应时间、光敏化剂、水质等条件影响下苯胺的光降解效果和规律.3h内苯胺在3个不同体系中的降解效果从大到小依次是:去离子水模拟天然水体、加入光敏化物质的灭菌河水、未加光敏化物质的灭菌河水.pH值为5.0,Fe2 、过氧化氢、腐殖质存在时苯胺的光降解效果较好.     

电转化法将luxAB基因导入毒死蜱降解茵β菌株的研究

采用电转化法将带发光酶基因luxAB的质粒pTR102导人毒死蜱降解菌β菌株,研究了细胞生长状态、电压强度、电击时间和质粒浓度对转化效率的影响,并对转化子的生理特性进行研究.实验结果表明,以处于对数生长早期的菌液制备感受态细胞,在质粒浓度16.5μg·mL-1、电压2.5kV,电击时间3ms条件下的转化率最高,可达2....     

怕死是因为渴望生存

近几年,自然灾难的频频侵扰,造成了巨大的人员伤亡。受此激刺,一个新群体正在悄悄地倔起——怕死客。怕死客的中文拼音缩写是PSK,而PSK同时也是英语personal survival kits的首字母缩写,意即幸存者私人的成套工具,     

有机磷农药降解方法及应用研究新进展

现代农业的发展和有机磷农药的使用密切相关,所造成的严重的农产品和环境污染是农业发展有待解决的关键问题之一。介绍了超声波技术、吸附、洗涤和辐照等物理方法,微生物、降解酶和工程菌等生物方法,水解、氧化分解和光化学降解等化学方法对有机磷农药的降解作用及其相关的应用研究。     

Effect of platinum on the photocatalytic degradation of chlorinated organic compound

TiO2 nanoparticles, doped with di erent Pt contents, were prepared by a modified photodeposition method using Degussa P-25 TiO2, H2PtCl6 6H2O and methanol as the solvents. The physicochemical properties of Pt/TiO2 were investigated by the nitrogen adsorption and desorption isotherm measurement technique, X-ray di raction analysis and photoluminescence spectra, respectively. Reaction rates from photocatalytic removal of dichloromethane over Degussa P-25 TiO2 and Pt/TiO2 were evaluated. The average diameter and BET surface area of the TiO2 catalyst particles were 300 nm and 50 m2/g, respectively. The degradation e ciency was 99.0%, 82.7%, 55.2%, and 57.9% with TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. And the degradation e ciency was 99.3%, 79.7%, 76.5%, and 73.4% with a 0.005 wt.% Pt/TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. In addition, we found that the photoluminescence emission peak intensities decreased with increases in the doping amount of Pt, which indicates that the irradiative recombination was weakened. Furthermore, the results showed that the UV/0.005 wt.% Pt/TiO2 process was capable of e ciently decomposing gaseous DCM in air.     

Potential particulate pollution derived from UV-induced degradation of odorous dimethyl sulfide

UV-induced degradation of odorous dimethyl sulfide (DMS) was carried out in a static White cell chamber with UV irradiation. The combination of in situ Fourier transform infrared (FT-IR) spectrometer, gas chromatograph-mass spectrometer (GC-MS), wide-range particle spectrometer (WPS) technique, filter sampling and ion chromatographic (IC) analysis was used to monitor the gaseous and potential particulate products. During 240 min of UV irradiation, the degradation e ciency of DMS attained 20.9%, and partially oxidized sulfur-containing gaseous products, such as sulfur dioxide (SO2), carbonyl sulfide (OCS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2) and dimethyl disulfide (DMDS) were identified by in situ FT-IR and GC-MS analysis, respectively. Accompanying with the oxidation of DMS, suspended particles were directly detected to be formed by WPS techniques. These particles were measured mainly in the size range of accumulation mode, and increased their count median diameter throughout the whole removal process. IC analysis of the filter samples revealed that methanesulfonic acid (MSA), sulfuric acid (H2SO4) and other unidentified chemicals accounted for the major non-refractory compositions of these particles. Based on products analysis and possible intermediates formed, the degradation pathways of DMS were proposed as the combination of the O(1D)- and the OH- initiated oxidation mechanisms. A plausible formation mechanism of the suspended particles was also analyzed. It is concluded that UV-induced degradation of odorous DMS is potentially a source of particulate pollutants in the atmosphere.     

读《生命的未来》

多年前,他在位于落基山脉亚高山地带的露营场采访时,看到路边的标牌上写着:"请把花留给别人欣赏。"后来这块木牌的标志被腐蚀,一片一片地剥落,于是新的标志代替了这些旧的标志,上面写着:"让花儿继续活下去。"——《生命的未来》尽管和梭罗(Henry DavidThoreau,1817-1862)相隔112岁之遥,声名卓著的生物学家爱德华·威尔逊(Edward Osborne Wilson,1929-)博士还是坚持给业已作古的梭罗写了一封永远无法寄达的长信,放在其2002年出版的著作《生命的未来》(The Future of Life)一书的卷首,     

中心组合设计优化S-Cr-TiO2催化剂光降解工艺条件

在确定的温度和光照条件下,采用中心组合设计法研究了固相反应法合成的硫与铬共掺杂二氧化钛(S-Cr-TiO2)光催化剂与水溶苯胺蓝(ANB)可见光降解过程中的三个作用因子:催化剂的浓度、水溶苯胺蓝水溶液的pH值及其初始浓度之间的相互作用关系,得到了影响因子与降解速率之间的回归方程及因素之间相互作用的响应面图.结果表明,S...     

气候变化导致了2000年英国洪灾

气候科学研究人员首次成功量化了人类活动引发气候变化与洪水频发的关系。牛津大学的科学家认定,2000年全球变暖使得洪水在英国的发生次数增加了两到三倍。另一项发表于《自然》杂志的加拿大研究也表示,首次证实暴雨、大雪、冰雹等极端天气的增加是气候变化的结果。