Shewanella oneidensis MR-1对Cr(VI)的还原及其影响因素

在实验室纯培养条件下,探讨厌氧体系中Shewanella oneidensis MR-1对Cr（VI）的还原能力,采用扫描电镜（SEM）-能谱（EDS）、X射线光电子能谱（XPS）等方法进行表征.结果表明,S.oneidensis MR-1介导下不同浓度Cr（VI）的生物转化与微生物对铬的耐受特性密切相关,低浓度Cr（VI）对其生长影响不大,高浓度时细菌生长则受到抑制,进而抑制Cr（VI）的还原率;菌株对Cr（VI）的还原作用随着接种菌悬液量的增加而增强;菌株最适生长pH值为中性,弱碱性环境比酸性环境更有利于菌株对Cr（VI）的还原;增加Fe（Ⅲ）的量会加快Cr（VI）完全还原的速率.通过SEM-EDS和XPS分析,在对Cr（VI）进行处理5d后,菌体表面有Cr（VI）和Cr（Ⅲ）两种形态存在,证实S.oneidensis MR-1在对Cr（VI）进行还原的同时也伴有少量的吸附作用.微生物还原为环境中Cr（VI）的去除以及解毒提供了一种有效的方法.     

河北香河亚微米气溶胶组分特性、来源及其演变规律分析

霾的形成发展与细颗粒物化学组分变化紧密相关.本文利用颗粒物化学组分监测仪(ACSM)、黑碳仪等对河北香河夏季亚微米气溶胶(PM1)化学组分、来源及其演变规律进行详细分析.结果表明,PM1平均占到PM2.5的约71%,PM1主要分布在20~80μg·m-3间;观测期间有显著的秸秆燃烧事件,秸秆燃烧时段PM1质量浓度显著升高,其中有机物质量分数迅速升高,平均约占到47%;秸秆燃烧使得大气气溶胶由弱碱性转变为弱酸性;整个观测期间,正交矩阵因子分解法(PMF)共识别出4类有机气溶胶,分别为两种一次有机气溶胶(类烃类有机气溶胶和生物质燃烧有机气溶胶)和两种二次有机气溶胶(低挥发、高氧化性的有机气溶胶和低氧化、半挥发性的有机气溶胶),有机气溶胶氧化程度较高.其中二次有机气溶胶的贡献远大于一次有机气溶胶,平均占到有机物的~69%,而去除秸秆燃烧时段后PMF结果中未解析出生物质燃烧有机气溶胶.     

节杆菌P-1和红球菌J-5降解PVA特性的比较研究

对节杆菌P-1和红球菌J-5降解聚乙烯醇(PVA)的特性进行了比较研究.结果表明,P-1菌在PVA浓度小于1000mgL-1时,PVA降解效率均达到80%以上;J-5菌在PVA浓度为2000mgL-1时,PVA降解效率达到70%.用生产废水进行试验,P-1菌对低浓度PVA废水的处理效率比J-5菌高10%左右;P-1菌受温度的影响小于J-5菌;P-1菌的废水处理效果比J-5菌稳定;分段使用J-5菌与P-1菌处理高浓度的PVA废水具有很好的处理效果,出水能达到国家排放标准.图7表1参9     

Degradation of the herbicide imazapyr by Fenton reactions

The degradation of the herbicide imazapyr has been carried out by three advanced oxidation processes involving iron ions as catalysts: Fentons reagent, photo-Fenton and electro-Fenton. We show that all processes are rapid and efficient. The kinetic rate constant was found to be k=5.4×10⁹ M^–1 s^–1. The mineralization of imazapyr is almost complete using the photo-Fenton and electro-Fenton processes.     

luxAB基因标记甲基对硫磷降解菌DLL-1在土壤和植株根部的生态行为研究

发光酶标记是 1种有效的跟踪微生物在生态环境中动态行为的技术手段。采用luxAB基因标记技术对甲基对硫磷降解菌DLL - 1在土壤中的分布和植株内的定殖情况进行了研究。结果表明 ,DLL - 1可以较长时间的在植株根际定殖 ,3 0d后仍可用X -感光片检测到菌体的存在 ,而根际外未检测到DLL - 1。植株根剖开后在培养基上培养 2 4h后进行X -光片曝光 ,发现DLL - 1能够进入植株根内并定殖。菌株回收后采用测定其农药降解活力和检查质粒图谱 2种方法证实 ,所观测的回收菌株就是接种的DLL - 1菌株     

Ultrastructural and chemical characterization of egg surface of honeybee worker and queen-laid eggs

Summary. Worker policing in honeybees predicts the evolution of a mechanism to discriminate between queenand worker-born eggs. Although it has been postulated that this discrimination is based on an egg recognition pheromone, neither the chemistry nor the glandular source were elucidated. To verify whether egg discrimination might be based on structural differences, we compared the ultrastructure surface of queen-laid diploid and haploid eggs to that of worker-laid eggs using SEM. Only small differences between the different types of eggs were found. Thus, at least based on the fine structure of the egg surface, queen eggs are indistinguishable from worker-laid eggs.To explore the chemosensory hypothesis for egg discrimination, we conducted a detailed comparative chemical analysis of the different egg types. The coating of all egg types was dominated by linear alkanes, but queen eggs, diploid and haploid, differed from those of workers on two accounts: 1. The diversity of compounds found on queenlaid eggs was much greater than found on worker-laid eggs, mainly due to the number of hydrocarbons. 2. Acetates of some fatty alcohols, alkenes and especially monomethylalkanes were characteristic to queen eggs. The origin of the two latter substances and the acetates is still unknown. Whether these compounds constitute the signal that enables police workers to discriminate between queen- and workerborn eggs remains to be investigated.     

正辛醇萃取苯酚稀溶液的特性研究

为探索工业含酚废水处理的适宜萃取剂，进行了正辛醇萃取苯酚稀溶液的实验研究，测定了不同pH值和苯酚初始浓度条件下的萃取平衡数据，萃残液CODCr值，分析了萃残液中CODCr值的来源。综合考虑萃取剂的萃取能力和产生的CODCr值，提出了酸性和中性溶液为正辛醇处理苯酚废水的适宜操作条件。以正辛醇为萃取剂对工业含酚废水进行了错流萃取实验，论证了其应用的可行性。     

大同市空气中多环芳烃与人尿中1-羟基芘的分析

用GC~2/MS和HPLC鉴定出大同市空气中的多环芳烃化合物35种.对大同市不同功能区空气中苯并(a)芘(BaP)和人尿中1-羟基芘同步采样分析.结果表明,不同功能区BaP浓度有显著差别:采暖期浓度急剧增加,城区浓度为对照点的17倍,日均值达330ng/m~3.人尿中1-羟基芘的浓度与空气中BaP的浓度显著相关.采暖期城区尿中1-羟基芘的几何均值为1.86μmol/mol肌酐,非采暖期为1.14μmol/mol肌酐,均较北京市的均值高出五倍多.证明大同市由于直接燃煤,造成空气中多环芳烃的严重污染.     

Studies on reactions of ozone with alkenes

In the last years, a continuous increase of the O3 concentration has been recorded in the lower atmospheric layers. Photochemical reactions with NO(x), CO and organic compounds are the main sources of O3 in the troposphere. In this work, an attempt was made to determine the impact of alkenes on the O3 concentration in the troposphere. A study on the gas-phase reactions of 03 with 1-hexene, 1-heptene and 1-nonene was made. The reactions were carried out at room temperature under atmospheric pressure. Ozone was formed by the ultraviolet radiation emitted by a mercury lamp, in order to simulate the atmospheric conditions. The changes with time in the concentration of O3, 1-alkenes and formed aldehydes were investigated. Qualitative and quantitative analyses were done by means of the gas chromatography and colorimetry. The following products were identified: pentanal from 1-hexene; hexanal from 1-heptene; oktanal from 1-nonene. For each of the reactions, HCHO was also determined as a product. The reaction rate constants were calculated and obtained in units of 10(-17) cm(-3) molecule(-1) s(-1): 1.94-0.99 for 1-hexene, 5.54-4.51 for 1-heptene and 1.54-0.76 for 1-nonene. Based on the results obtained, an explanation of O3 concentration variations in the planetary boundary layer can be given. Last year a considerable increase of O3 concentration on the roads of Western Europe was recorded. This increase could have resulted from the decrease of alkene concentration in the air due to common use of the catalytic converters in cars. The unsaturated hydrocarbons rapidly oxidize on the catalyst. In Eastern Europe, where the amount of cars equipped with catalytic converters is smaller than in Western Europe, the alkene content in the exhaust fumes results in a decrease of the O3 concentration in the troposphere.     

丙烯醛与DNA碱基反应机理的AM1研究

 采用AM1方法计算了在水合质子的参与下，丙烯酸与DNA鸟嘌呤碱基发生烷化加成的可能的反应过程，从得到的能量关联图可以看出，除了其中的一个分子内质子迁移过程外，其余的每一反应过程体系的能量均是降低的,计算得到的各关键步骤的反应活化能均不大，反应易于进行,根据计算的自由能可以看出，整个反应能够自发进行，说明丙烯酸可经过2次烷化加成反应与DNA碱基发生交联作用.