Photocatalytic degradation kinetics and mechanism of pentachlorophenol based on superoxide radicals

Pentachlorophenol could be photocatalytically reduced with superoxide radicals in aqueous solution under simulated sunlight irradiation.     

采油厂硫化氢的安全防护与对策

介绍了油气井中硫化氢的来源、危害,并重点阐述了采油厂含硫化氢油井的分布情况和有关硫化氢的监测和安全防护措施。     

非生物胁迫对盐生杜氏藻DsMPK转录、翻译和磷酸化修饰的影响

促有丝分裂活化蛋白激酶(Mitogen-activated protein kinase,MAPK或MPK)途径是在真核生物中广泛存在的调控多种生理过程的信号途径,在细胞增殖、分化、凋亡、生物和非生物胁迫等生理过程的调控中起着关键的作用.盐生杜氏藻(Dunaliella salina,盐藻)是目前世界上最耐盐的真核光合生物之一.在前期实验中,已发现盐藻MAPK(DsMPK)的表达受到低温和高盐胁迫的抑制.分析DsMPK在高温、低盐、氧化、紫外胁迫中的表达变化,发现DsMPK还受到氧化胁迫的抑制.进而分析DsMPK在高温、低盐、氧化、低温、高盐和紫外胁迫中翻译和磷酸化修饰的变化,发现除低盐胁迫外,在磷酸化修饰水平DsMPK同样受到各种非生物胁迫的抑制.在对不同生长阶段盐藻DsMPK磷酸化变化的分析中还发现,DsMPK的磷酸化水平与生长速率有一致性.各方面DsMPK的变化趋势说明其为一调控生长相关的MAPK.     

烟根腐解物对烟草生长的影响

烟草生产过程中会产生大量烟草残体,为了研究烟草残体对烟草生长的影响,将烟根、水稻土和无菌水按一定比例混合后,在适当条件下培养得到烟根腐解物.将烟根腐解物按不同的施用量设置6个处理组,并以未施用烟根腐解物组作为对照,分别在烟草生长的团棵期、旺长期和成熟期测定烟草的农艺性状、根系活力、硝酸还原酶(nitrate reduc...     

Toxicological assessment of TiO2 nanoparticles by recombinant Escherichia coli bacteria

Rapid and efficient methods to assess nanoparticle toxicity are desired in current research. Here we showed that Escherichia coli labeled by green fluorescent protein can be a good model bacterium for assessing acute toxicity of TiO(2) (about 50% inhibition ratios after 135 min exposure). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that TiO(2) nanoparticles (NPs) can influence certain protein expression in the recombinant bacterium, and the obvious effects in repressed expression and elevated expression were observed in 30/40, 10/20 μg mL(-1) treated cells, respectively. However, the GFP expression (27 kD) was not influenced by introduced TiO(2) NPs. The change of the fluorescence intensity may be caused by the damage in folding and chromophore formation of the GFP post-translational modification due to generated reactive oxygen species. Furthermore, TiO(2) NPs at higher concentrations decreased their toxicity because of aggregation. 20 μg mL(-1) humic acid (HA) introduced to the medium can decrease the fluorescent inhibition owing to the barrier of steric hindrance it provides between NPs and cells.     

Impact of elevated O3 on visible foliar symptom, growth and biomass of Cinnamomum camphora seedlings under different nitrogen loads

The effects of elevated ozone (O(3)) and enhanced nitrogen (N) on the growth and biomass of Cinnamomum camphora, a subtropical evergreen broad-leaved tree species, were investigated. The seedlings, supplied with N (NH(4)NO(3) solution) at 0, 30 and 60 kg ha(-1) year(-1) (simplified as N0, N30, N60, respectively), were exposed to ambient (AA) or elevated O(3) (AA + 60 nmol mol(-1) and AA + 120 nmol mol(-1), designated as AA + 60 and AA + 120, respectively) for the 2009 and 2010 growing seasons. Symptomatic leaf percentages were significantly increased with O(3) concentration. AA + 120 significantly decreased the mean leaf size and chlorophyll content of both 2009- and 2010-emerged leaves, inhibited the growth of stem height and basal diameter, and reduced biomass accumulation of all plant parts except for leaves. By comparison, only the chlorophyll content of 2009-emerged leaves and root dry weight were significantly reduced under AA + 60. Specific leaf area, total leaf area and foliar biomass were not affected even at a higher O(3) level. On the other hand, N loads, especially N60, exerted significantly positive effects on all variables except mean leaf size and shoot/root ratio. No significant interactions between O(3) and N were detected, suggesting that the N supply at ≤60 kg ha(-1) year(-1) did not significantly modify the response of C. camphora to O(3) in terms of seedling growth and biomass accumulation.     

One-pot molten salt method for constructing CdS/C3N4 nanojunctions with highly enhanced photocatalytic performance for hydrogen evolution reaction

The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution. In this study, we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of Cd S and C₃N₄ nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and prot...     

N-doped CoAl oxides from hydrotalcites with enhanced oxygen vacancies for excellent low-temperature propane oxidation

A series of nitrogen-doped CoAlO (N-CoAlO) were constructed by a hydrothermal route combined with a controllable NH₃ treatment strategy. The effects of NH₃ treatment on the physico-chemical properties and oxidation activities of N-CoAlO catalysts were investigated. In comparison to CoAlO, a smallest content decrease in surface Co³⁺ (serving as active sites) while a largest increased amount of surface Co²⁺ (contributing to oxygen species) are obtained over N-CoAlO/4h among the N-CoAlO catalysts. Meanwhile, a maximum N doping is found over N-CoAlO/4h. As a result, N-CoAlO/4h (under NH₃ treatment at 400°C for 4 hr) with rich oxygen vacancies shows optimal catalytic activity, with a T₉₀ (the temperature required to reach a 90% conversion of propane) at 266°C. The more oxygen vacancies are caused by the co-operative effects of N doping and suitable reduction of Co³⁺ for N-CoAlO/4h, leading to an enhanced oxygen mobility, which in turn promotes C₃H₈ total oxidation activity dominated by Langmuir-Hinshelwood mechanism. Moreover, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) analysis shows that N doping facilities the decomposition of intermediate species (propylene and formate) into CO₂ over the catalyst surface of N-CoAlO/4h more easily. Our reported design in this work will provide a promising way to develop abundant oxygen vacancies of Co-based catalysts derived from hydrotalcites by a simple NH₃ treatment.     

铝盐去除浓缩脱水污泥水中悬浮物和磷的效果研究

采用混凝沉淀法处理污泥水中的悬浮固体和磷,考察了聚合氯化铝(PAC)、聚硫氯化铝(PACS)以及PAC和阴离子聚丙烯酰胺(aPAM)复配不同投加量对污泥水沉降性能和磷去除的影响。实验结果表明,PAC和PACS混凝处理污泥水效果基本一致,会恶化污泥水沉降,且随PAC投药量的增加,污泥水SV30越大。PAC与aPAM复配混凝处理污泥水,也难以改善污泥水的沉降性能。结果表明,铝盐混凝剂不适合同步去除污泥水悬浮固体和磷,建议先寻求其它混凝剂改善污泥水沉降再用铝盐除磷。