碳气凝胶复合TiO_2光催化降解甲苯研究

制备了碳气凝胶复合二氧化钛光催化剂,并利用此复合催化剂对挥发性有机污染物甲苯进行了光催化降解研究,考察了甲苯初始浓度、相对湿度、紫外光能量对降解效率的影响。     

一起由竹夹板着火引起的爆炸事故分析及防范

分析了一起由竹夹板着火引起的空罐爆炸事故,事故原因是竹夹板被点燃后,燃烧产生大量一氧化碳、氢气和甲烷,从而引发了爆炸事故,提出了预防类似事故的措施.     

Simultaneous removal of hydrogen sulfide and toluene in a bioreactor: Performance and characteristics of microbial community

We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment. Operation of the bioreactor was divided into four stages, in which the inlet concentration of toluene and H2S were gradually increased. In Stage I, toluene was the sole target compound with an average removal e ciency of 86.49%. After adding H2S in Stage II, removal e ciency of toluene decreased immediately and recovered gradually to 85.96%. When the inlet concentration of toluene and H2S was increased in Stage III and Stage IV, respectively, the average removal e ciency for toluene increased continuously from 86.31% to 87.24%. The elimination capacities of toluene increased with increasing inlet loading rates of toluene and H2S. Results of the PCR-DGGE analysis showed a turnover growth and decline of the microbial populations in the bioreactor. In Stage I, the dominant toluene-degrading bacteria mainly contained Pseudomonas sp. strain PS+ and Hydrogenophaga sp. In Stage IV, however, the dominant toluene-degrading bacteria was aciduric bacteria (Clostridium populeti). The dominant microbial community in the bioreactor enhanced the elimination capacity of toluene, and adding H2S changed the environment of microbial growth, thus resulted in an evolution of dominant microorganisms. Analyses of microbial community and their activities provides valuable information to e ciently enhance simultaneous removal of toluene and H2S in the bioreactor.     

Co3O4纳米棒的制备及其对气相甲苯的催化氧化

采用低温水热法制备棒状纳米结构的Co3O4,通过加入少量的表面活性剂（聚乙烯吡咯烷酮简称PVP）,在95℃下低温反应,并调控制备过程的老化时间、溶液的pH这2个因素合成了棒状Co3O4纳米结构.X射线衍射（XRD）、透射电镜（TEM）表明制得的是呈立方晶体的Co3O4纳米棒,氢气程序升温还原（H2-TPR）、N2吸附脱附等表征手段表明老化时间和pH会影响Co3 O4纳米棒的尺寸、孔隙结构,进而影响其比表面积大小.采用气相甲苯作为目标物,运用气相色谱（GC）对Co3 O4的催化性能进行研究.结果表明在该实验中,调控老化时间和pH制得的Co3O4纳米棒只影响其低温降解效果,在温度低于260℃,活性最好的是pH=9,老化时间为12 h的催化剂;当温度高于260℃后,其降解曲线基本一致.     

污泥活性炭的制备及对甲苯吸附性能研究

以城市污水厂脱水污泥为原料,采用ZnCl2化学活化法,通过添加适量锯末(SAC-W)或椰壳(SAC-C)制备出不同污泥活性炭,其比表面积分别为450.3 m2/g和539.4 m2/g,比纯污泥活性炭的比表面积增加了31.63%和57.67%。将污泥活性炭和选用的煤质活性炭(CAC)用于甲苯动态吸附实验,研究不同活性炭的吸附性能。结果表明,在相同的甲苯初始浓度下,平衡吸附量大小顺序为SAC-C>CAC>SAC-W,污泥活性炭表现较好的吸附性能。对污泥活性炭进行理化性能分析,发现中孔和化学吸附作用对吸附量增加有一定贡献。污泥活性炭的吸附平衡与Langmuir方程拟合较好,相关系数R2为0.995。     

甲苯二次萃取-直接测汞法快速测定海产品中的甲基汞

建立了甲苯二次萃取-直接测汞的方法对生物样品中的甲基汞进行分析测定.样品经氢溴酸水解、甲苯萃取、L-半胱氨酸反萃取等前处理,应用DMA-80直接测汞仪测定.对甲基汞鱼肉标准物质(GBW 10029)和贻贝标准物质(SRM 2976)的实测结果显示,测定值与标准参考值的相对误差小于4%,测定值的相对标准偏差小于2%,甲基...     

生物滴滤塔同步降解多组分挥发性有机物的实验研究

采用定向驯化活性污泥接种生物滴滤塔(BTF)同时处理甲苯、甲醇、丙烯酸乙酯挥发性有机化合物(VOCs)混合废气,考察BTF的长期稳定运行性能及微生物平均代谢活性.结果表明,混合气进口浓度低于910mg/m3时,BTF对VOCs混合废气总去除率可维持在80%以上,BTF可高效同步净化中低浓度VOCs混合废气;当进气负荷>120g/(m3·h)时,去除负荷趋于稳定,为100g/(m3·h)左右;CO2的生成量与混合废气的去除负荷的比值为1.731,表明BTF对此3种混合废气有较高程度的矿化;BTF对甲苯、甲醇、丙烯酸乙酯的降解行为符合Michaelis-Menten动力学模型,单位体积最大降解速率rmax分别是为90.9,50.5,58.5 g/(m3·h).平均吸光度(AWCD)值分析结果表明塔内微生物具有较高的代谢活性.     

Multistep conversion of cresols by phenol hydroxylase and 2,3-dihydroxy-biphenyl 1,2-dioxygenase

A mulfistep conversion system composed of phenol hydroxylase （PHrND） and 2,3-dihydroxy-biphenyl 1,2-dioxygenase （BphCLA_4） was used to synthesize methylcatechols and semialdehydes from o- and m-cresol for the first time. Docking studies displayed by PyMOL predicted that cresols and methylcatechols could be theoretically transformed by this multistep conversion system~ High performance liquid chromatography mass spectrometry （HPLC-MS） analysis also indicated that the products formed from multistep conversion were the corresponding 3-methylcatechol, 4-methylcatechol, 2- hydroxy-3-methyl-6-oxohexa-2,4-dienoic acid （2- hydroxy-3-methyl-ODA） and 2-hydroxy-5-methyl-6-oxo- hexa-2,4-dienoic acid （2-hydroxy-5-methyl-ODA）. The optimal cell concentrations of the recombinant E. coli strain BL21 （DE3） expressing phenol hydroxylase （PHrND） and 2,3-dihydroxy-biphenyl 1,2-dioxygenase （BphCLA_4） and pH for the multistep conversion of o- and m-cresol were 4.0 （g-L-1 cell dry weight） and pH 8.0, respectively. For the first step conversion, the formation rate of 3- methylcatechol （0.29μmol·L-1·min-1·mg-1cell dry weight） from o-cresol was similarly with that ofmethylca- techols （0.28 μmol·L-1·min-1·mg-1 cell dry weight） from m-cresol by strain PHrND. For the second step conversion, strain BphCLA_4 showed higher formation rate （0.83 μmol·L-1·min-1·mg-1 cell dry weight） for 2-hydroxy-3-methyl- ODA and 2-hydroxy-5-methyl-ODA from m-cresol, which was 1.1-fold higher than that for 2-hydroxy-3-methyl- ODA （0.77 μmol·L-1·min-1·mg-1. mglcell dry weight） from ocresol. The present study suggested the potential application of the multistep conversion system for the production of chemical synthons and high-value products.     

脉冲调制介质阻挡放电和催化联用技术降解甲苯

利用低温等离子体处理挥发性有机化合物(VOCs)废气是目前国内外研究的热点。研究利用脉冲调制介质阻挡放电和催化联用技术降解甲苯,对比分析了连续放电和脉冲调制对去除甲苯的影响;研究了脉冲调制后在有无催化剂的情况下的能量效率,比较了两种情况下的臭氧浓度以及中间产物的不同。结果表明:脉冲调制有效提高了甲苯的降解能效,其能量效率几乎是连续放电时的2倍～3倍;在有催化剂的情况下,能量效率是没催化剂的1.5倍～2倍,臭氧浓度明显降低,结焦产物中含苯环的衍生物的量少于无催化的结焦产物。     

助溶剂甲苯和二甲基亚砜对斑马鱼胚胎发育的复合毒性效应

研究了甲苯和二甲基亚砜(DMSO)对斑马鱼胚胎生长、发育的毒性效应.实验结果表明:低剂量的甲苯(0.05%)单一暴露对斑马鱼胚胎发育有一定毒性,DMSO(0.45%)对斑马鱼胚胎无明显毒性;但甲苯与DMSO具有较强的复合毒性效应,随着DMSO含量的增加,与甲苯单一暴露组相比,斑马鱼胚胎死亡率显著增加、胚胎孵化率下降、胚胎发育迟缓并生成大量畸形;但甲苯以及甲苯和DMSO复合物对人胚肾HEK-293细胞株和人胃癌SGC-7901细胞株的活力均没有明显效应.DMSO可通过提高甲苯在水中的分散性,增加甲苯的神经毒性,但对离体实验模型无显著效应,故在选择不同生物模型评估有机污染物毒性效应时,需考虑不同类型助溶剂所产生的复合效应,以减少实验误差.