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891.
Degradation of rhodamine B by Fe(0)-based Fenton process with H2O2 was investigated. The effects of H2O2 dose, Fe(0) dose, initial concentration of rhodamine B and initial pH value on the degradation of rhodamine B were examined. The results showed that the degradation and mineralization of rhodamine B occurred with low dose of H2O2 and Fe(0). The intermediates of rhodamine B were analyzed with UV-Vis spectrophotometry and ion chromatography and the mechanism of oxidative degradation of rhodamine B was also discussed. The reactive oxygen species (·OH) produced in Fe(0)-based Fenton process with H2O2 is the key to the degradation of rhodamine B by ways of N-de-ethylation, chromophore cleavage, ring-opening and mineralization. 相似文献
892.
893.
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895.
不同硅铝比的ZSM-5型沸石分子筛吸附水中Cu2+离子的研究 总被引:3,自引:0,他引:3
考察了3种不同硅铝比的ZSM-5沸石分子筛(25H、38H和50H,25、38和50为硅铝比)对水中Cu2+的吸附过程及其影响因素。结果表明,3种材料均能有效吸附去除水中Cu2+离子,动力学符合假二阶动力学模型,吸附等温线符合Langmuir吸附等温式。3种材料吸附速率及吸附容量顺序为:25H>50H>38H,其中,25H最大吸附容量达到12.83 mg/g。投加量由0.8 g/L增加至2.0 g/L,材料对Cu2+吸附去除率由87.0%增加至97.5%。考察水中常见阳离子对吸附的干扰作用,结果表明,干扰离子的影响顺序为:Pb2+> K+> Na+ > Mg2+;随着干扰离子浓度的增大,材料对Cu2+的去除率显著下降。硅铝比及晶粒形貌均对沸石分子筛吸附Cu2+有较大影响,小的孔径不利于Cu2+的吸附,低硅铝比有利于Cu2+在分子筛上的吸附。 相似文献
896.
Luo SL Chen L Chen JL Xiao X Xu TY Wan Y Rao C Liu CB Liu YT Lai C Zeng GM 《Chemosphere》2011,85(7):1130-1138
This study investigates the heavy metal-resistant bacterial endophytes of Cd-hyperaccumulator Solanum nigrum L. grown on a mine tailing by using cultivation-dependent technique. Thirty Cd-tolerant bacterial endophytes were isolated from roots, stems, and leaves of S. nigrum L. and classified by amplified ribosomal DNA-restriction analysis into 18 different types. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates belonged to four groups: Actinobacteria (43%), Proteobacteria (23%), Bacteroidetes (27%) and Firmicutes (7%). All the isolates were then characterized for their plant growth promoting traits as well as their resistances to different heavy metals; and the actual plant growth promotion and colonization ability were also assessed. Four isolates were re-introduced into S. nigrum L. under Cd stress and resulted in Cd phytotoxicity decrease, as dry weights of roots increased from 55% to 143% and dry weights of above-ground from 64% to 100% compared to the uninoculated ones. The total Cd accumulation of inoculated plants increased from 66% to 135% (roots) and from 22% to 64% (above-ground) compared to the uninoculated ones. Our research suggests that bacterial endophytes are a most promising resource and may be the excellent candidates of bio-inoculants for enhancing the phytoremediation efficiency. 相似文献
897.
W Xi HT Wan YG Zhao MH Wong JP Giesy CK Wong 《Environmental science and pollution research international》2011,19(7):2515-2527
Purpose
In this study, we investigated the effects of maternal transfer of bisphenol A (BPA) and di(2-ethylhexyl) phthalate (DEHP) during gestational and weaning periods on gonadal development of male offspring.Methods
Pregnant CD-1 mice were administered by gavages in corn oil with 0.1, 1, or 10 mg/kg/day of BPA and DEHP from gestational days (GD1?C21) to the weaning period (postnatal days (PND) 1?C21).Results
Our data indicated that the exposure significantly reduced the male-to-female sex ratio and the sizes of the gonads of male pups as recorded at PND15. The testes of the perinatally exposed male pups were developed less and the expression levels of testicular anti-mullerian hormone, androgen receptor, cyclin A, and StAR were significantly lesser than the control male pups. The less developed testes were accompanied with significant reductions in the expression levels of Gnrh and Fsh at the hypothalamic?Cpituitary levels. The negative effects were found to be persistent in the sexually mature pups at PND42.Conclusion
Our data reveal that the maternal transfer of BPA and DEHP may impose negative influence on the development and functions of the reproductive system of male pups. 相似文献898.
Luo ZH Wu YR Pang KL Gu JD Vrijmoed LL 《Environmental science and pollution research international》2011,18(9):1653-1660
Purpose
Dimethyl phthalate esters (DMPEs) are a group of plasticizers commonly detected in the environment with potential adverse human health impact. The degradation of DMPEs by fungal systems has been studied to a limited extent, particularly by yeasts. In this study, a basidiomycetous yeast Trichosporon DMI-5-1 capable of degrading DMPEs was obtained and the degradation pathways were investigated. 相似文献899.
考察了3种不同硅铝比的ZSM-5沸石分子筛(25H、38H和50H,25、38和50为硅铝比)对水中Cu2+的吸附过程及其影响因素。结果表明,3种材料均能有效吸附去除水中Cu2+离子,动力学符合假二阶动力学模型,吸附等温线符合Langmuir吸附等温式。3种材料吸附速率及吸附容量顺序为:25H〉50H〉38H,其中,25H最大吸附容量达到12.83mg/g。投加量由0.8g/L增加至2.0g/L,材料对Cu2+吸附去除率由87.0%增加至97.5%。考察水中常见阳离子对吸附的干扰作用,结果表明,干扰离子的影响顺序为:Pb2+〉K+〉Na+〉Mg2+;随着干扰离子浓度的增大,材料对Cu2+的去除率显著下降。硅铝比及晶粒形貌均对沸石分子筛吸附Cu2+有较大影响,小的孔径不利于Cu2+的吸附,低硅铝比有利于Cu2+在分子筛上的吸附。 相似文献
900.
Particle size distribution (PSD) analysis was used to evaluate the quality of mixed liquors collected from different activated sludge process modifications (i.e., conventional activated sludge, modified Ludzack-Ettinger, high-purity oxygen, step-anoxic, and oxidation ditch). An experiment protocol was developed to define the allowable sample holding time and provide representative and repeatable results. Samples of 26 treatment plants, with a total of 37 samples, were tested. A new indicator, called mean particle size (MPS), was introduced to describe the integrated mean particle size. The results of MPSs of three cut-off sizes (0.5 to 50, 100, and 200 microm) showed that the average size of mixed-liquor biosolids increased with increasing solids retention time (SRT), and the number of particles in the sedimentation supernatant decreased with increasing SRT. Particle deflocculation occurred after excessive sample holding time, and analysis within 12 hours generally eliminated sample holding problems. The results provide a methodology using PSD for characterizing mixed-liquor biosolids. 相似文献