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101.
污水厂进水或厌氧单元出水中的硫化物会对污水处理工艺的硝化反应过程产生潜在抑制作用,认识和调控硫化物对活性污泥生化反应过程的影响对污水厂工艺的发展具有重要意义.亚硝化过程对于保障污水工艺氮的去除至关重要,本研究以硫化物对亚硝化过程的影响为研究对象,探讨相关影响过程的特征和发生机制.同时,选择不同典型浓度范围的硫化物和不同存在状态对亚硝化过程的影响开展研究.结果表明,硫化物浓度由10 mg·L~(-1)提高到30 mg·L~(-1),氨氧化抑制率由16.3%提高到40%,但随着硫化物浓度进一步升高,氨氧化抑制率上升并不明显.进一步通过硫化物对羟胺氧化反应的影响实验发现,硫化物导致羟胺氧化速率下降要大于氨氧化阶段.同时系统内硫化物耗尽后,氨氧化反应和羟胺氧化反应均不能完全恢复.铁盐作为常见的硫化物去除剂,铁盐加入后并未能够有效消除硫化物对亚硝化过程的抑制. 相似文献
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ITO/CdS/ZnO interface composite films were successfully prepared by subsequent electrodeposition of CdS and ZnO onto indium tin oxide (ITO) glass substrates. The obtained ITO/CdS/ZnO composite films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy. The photocatalytic activity of ITO/CdS/ZnO composite films were investigated using methyl orange (MO) as a model organic compound under UV light irradiation. The influence of operating parameters on MO degradation including initial concentration of MO, pH value of solution, and inorganic anion species over the composite films were examined. A blue shift of absorption threshold was observed for the ITO/CdS/ZnO film in comparison with ITO/ZnO film. ITO/CdS/ZnO composite films prepared under specific conditions showed a higher photocatalytic activity than that of ITO/ZnO films. It was also found that the photocatalytic degradation of MO on the composite filing followed pseudo-first order kinetics. 相似文献
106.
Effects of silica nanoparticles on growth and photosynthetic pigment contents
of Scenedesmus obliquus 总被引:1,自引:0,他引:1
To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentratio... 相似文献
107.
Quaiser Saqui Mohammad Faisal Abdulrahman A. Alatar Abdulaziz A. Al-Khedhairy Mukhtar Ahme Sabiha M. Ansari Hend A. Alwathnani Mohammad K. Okl Sourabh Dwivedi Javed Musarrat Shelly Praveen Shams T. Khan Rizwan Waha Maqsood A. Siddiqui Javed Ahmad 《环境科学学报(英文版)》2016,28(9):49-62
We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles(Fe_2O_3-NPs) in Raphanus sativus(radish).Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs(1.0 mg/m L) treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species(ROS),mitochondrial membrane potential(ΔΨm),nitric oxide(NO) and Ca2+influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione(GSH),catalase(CAT),superoxide dismutase(SOD) and lipid peroxidation(LPO) has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid(DNA) strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs(2.0 mg/m L) treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles(NPs) and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment. 相似文献
108.
Nitin Shrivastava Devanshu Shrivastava Vipin Shrivastava 《International Journal of Green Energy》2018,15(2):136-143
Biodiesels have come up as a very strong alternative for diesel fuel. Biodiesels such as Jatropha Oil Methyl Ester (JOME) are comparable in performance with that of the diesel engine. The thermal efficiency of engines fuelled with biodiesels was found lower than conventional diesel fuel but due to the bio-origin, the emission characteristics are much better. However, biodiesel increases the NOx emissions as these are rich in oxygen, hence nanoparticles are used in this experiment to curb the high temperatures and reduce the NOx formation. The experiment on naturally aspired diesel engine was conducted with four prepared test fuels other than neat diesel and neat biodiesel. The 50 and 150 of alumina nanoparticles were added separately to the pure diesel and pure Jatropha biodiesel to form the nano emulsions using ultrasonicator. The properties of nanoemulsion were evaluated using dynamic light scattering technique using zetasizer. The performance and emission characteristics of multi-cylinder diesel engine with these nanoemulsions were compared with that of neat fuels. The results showed that using nanoparticles with diesel and biodiesel can contribute in a more efficient, economical, and eco-friendly engine operation. 相似文献
109.
采用过氧化氢在常温常压下对模拟含硫废水进行受控氧化,探讨了受控氧化过程对单质硫收率的影响,并对氧化过程中固相产物的形态特性进行了研究.结果表明,在过氧化氢投加量为9 m L·L-1、初始p H为6、反应时间为10min条件下,将反应体系氧化还原电位(ORP)控制在(30±5)m V时能较好实现含硫废水的受控氧化,此时单质硫收率达76.35%,当体系ORP由(-50±5)m V升高至(50±5)m V时,副产物S2O2-3收率显著下降,由26.54%下降至5.32%.X射线衍射分析表明,氧化过程中的固相产物主要为正交晶系斜方硫;扫描电子显微镜分析表明,液相中的单质硫由多个极小的颗粒聚集而成,其粒径由纳米级逐渐增大至微米级.同时,通过向反应体系中加入分散剂证明了单质硫颗粒增大的主要原因是颗粒间发生了团聚. 相似文献
110.
Sulfate reducing bacteria(SRB) play significant roles in anaerobic environments in oil sands mature fine tailings(MFTs). Hydrogen sulfide(H2S) is produced during the biological sulfate reduction process. The production of toxic H_2S is one of the concerns because it may hinder the landscape remediation efficiency of oil sands tailing ponds. In present study, the in situ activity and the community structure of SRB in MFT and gypsum amended MFT in two settling columns were investigated. Combined techniques of H_2S microsensor and dissimilatory sulfite reductase β-subunit(dsrB) genes-based real time quantitative polymerase chain reaction(qPCR) were applied to detect the in situ H_2S and the abundance of SRB. A higher diversity of SRB and more H_2S were observed in gypsum amended MFT than that in MFT, indicating a higher sulfate reduction activity in gypsum amended MFT; in addition, the activity of SRB varied as depth in both MFT and gypsum amended MFT: the deeper the more H_2S produced. Long-term plans for tailings management can be assessed more wisely with the information provided in this study. 相似文献