Toxicity of TiO2, ZrO2, Fe,Fe2O3, and Mn2O3 nanoparticles to the yeast, Saccharomyces cerevisiae

The growing application of engineered nanomaterials is leading to an increased occurrence of nanoparticles (NPs) in the environment. Thus, there is a need to better understand their potential impact on the environment. This study evaluated the toxicity of nanosized TiO₂, ZrO₂, Fe⁰, Fe₂O₃, and Mn₂O₃ towards the yeast Saccharomyces cerevisiae based on O₂ consumption and cell membrane integrity. In addition, the state of dispersion of the nanoparticles in the bioassay medium was characterized.     

UV/H2O2/Fe-FeOxH2x-3和UV/H2O2工艺降解水中富里酸的研究

采用硼氢化钠还原法制备核-壳结构的Fe-FeO_xH_2x-3复合材料，研究了富里酸在UV/H₂O₂和UV/H₂O₂/Fe-FeO_xH_2x-3两种不同反应体系下的降解情况。结果表明，核-壳结构Fe-FeO_xH_2x-3的存在，提高了UV/H₂O₂降解富里酸的反应速率，TOC去除达到84%。采用XAD树脂吸附法对反应前后的富里酸进行化学分级表征，结果表明，富里酸经反应后憎水酸（HoA）、弱憎水酸（WHoA）和憎水中性物质（HoN）都有所减少，进而转化为亲水性物质（HiM）；用超滤膜法对富里酸进行物理分级表征，考察了富里酸在反应前后分子量分布的变化情况。同时，富里酸经过反应后生成的中间产物降低了三氯甲烷生成趋势。     

微波辐射Bi2O3/沸石-H2O2体系降解废水中的硝基苯

研究了微波辐射下,以负载于沸石上的三氧化二铋为催化剂,以双氧水为氧化剂的催化氧化体系处理硝基苯工艺。通过单因素实验法,从反应催化剂负载量、pH、双氧水用量、微波功率、反应时间、催化剂用量等方面初步考察了硝基苯在该体系中的催化氧化效果。在氧化铋负载量3%（质量比）,pH=2,2 mL 30%双氧水,火力为中火,催化剂投加量为0.7 g,反应2 min,对降解过程所得的中间产物和终产物进行了分析。结果表明,该体系对硝基苯的去除率能够达到99.2%,COD去除率为73.91%。     

O3/H2O2处理嘧啶废水的研究

采用O3/H2O2法对嘧啶废水进行处理,考察了不同反应条件对嘧啶和COD去除率的影响,并对O3/H2O2降解嘧啶的反应机制和动力学进行了初步探讨.实验结果表明,在pH值为11,反应时间为70 min,O3流量为4g/h,H2O2投加量为50 mmol/L的条件下,废水的嘧啶和COD的去除率分别达到86.46%和74.9...     

Fe_3O_4@SiO_2/TiO_2核壳结构纳米颗粒降解TNT溶液

针对TNT炸药废水具有成分复杂、排放量大、有毒等特点,立足于炸药废水在排放前的降解处理,研究开发一种基于核壳结构Fe3O4@SiO2/TiO2纳米颗粒的高效、可控回收、无二次污染且成本低的光催化降解方法。利用高温碳还原法和溶胶凝胶法制备了具有核壳结构的Fe3O4@SiO2/TiO2纳米颗粒。XRD分析表明,内核Fe3O4呈现磁铁矿特征,表面覆盖的纳米TiO2为锐钛矿型。磁滞回线测试结果显示,复合颗粒的饱和磁化强度为46.5 emu/g,N2吸附-解吸分析结果表明,该颗粒具有典型的介孔结构。使用Fe3O4@SiO2/TiO2纳米颗粒在紫外光下对含TNT废水进行降解,降解率达到81.9%,且颗粒的回收率达到88.4%,为实现高效、可控回收、无二次污染光催化-吸附降解TNT奠定了基础。     

纳米Bi2O3/TiO2复合光催化剂的制备及性能研究

以光催化效果为评价标准,采用超声波作用下水解法制备Bi₂O₃/TiO₂复合光催化剂,考察了水解条件和Bi₂O₃掺入量等制备条件对复合光催化剂性能的影响。结果表明,与传统制备方法相比,该方法操作简单、快速;当水和乙醇的比例为4∶1时所得样品的光催化活性最好;Bi₂O₃的掺入拓宽了TiO₂对光的吸收范围,提高了TiO₂的光催化活性,掺入量(Bi₂O₃)为0.25%复合光催化剂催化活性最高;复合光催化剂对多种水溶性染料均具有较好的处理效果。     

Toxicity of nanoparticulate and bulk ZnO, Al2O3 and TiO2 to the nematode Caenorhabditis elegans

Limited information is available on the environmental behavior and associated potential risk of manufactured oxide nanoparticles (NPs). In this research, toxicity of nanoparticulate and bulk ZnO, Al₂O₃ and TiO₂ were examined to the nematode Caenorhabditis elegans with Escherichia coli as a food source. Parallel experiments with dissolved metal ions from NPs were also conducted. The 24-h median lethal concentration (LC₅₀) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic, inhibiting growth and especially the reproductive capability of the nematode. The 24-h LC₅₀ for ZnO NPs (2.3 mg L⁻¹) and bulk ZnO was not significantly different, but significantly different between Al₂O₃ NPs (82 mg L⁻¹) and bulk Al₂O₃ (153 mg L⁻¹), and between TiO₂ NPs (80 mg L⁻¹) and bulk TiO₂ (136 mg L⁻¹). Oxide solubility influenced the toxicity of ZnO and Al₂O₃ NPs, but nanoparticle-dependent toxicity was indeed observed for the investigated NPs.     

UV/H_2O_2/TiO_2联合水解酸化+MBR工艺处理亚砜废水

二甲基亚砜(DMSO)废水因其COD高、可生化性差的特性而较难处理。本实验以采用硫酸二甲酯法生产DMSO的某化工厂废水为研究对象,设计并建立了组合式光催化氧化装置联合水解酸化+MBR工艺的中试系统,探讨了组合式光催化氧化装置、氧化剂投加量、pH、反应时间和水力停留时间对系统处理效果的影响。结果表明,组合式光催化氧化装置可有效提高DMSO废水的可生化性。最优工艺参数为:按H2O2与原水COD质量浓度比为2∶1投加H2O2,在pH值为4、反应时间为6 h、水力停留时间为4 h的条件下,该系统对原水COD(5 000 mg/L)去除率大于98%,出水COD达到《污水综合排放标准》(GB 8978-1996)一级要求。     

Degradation of paracetamol by advance oxidation processes using modified reticulated vitreous carbon electrodes with TiO2 and CuO/TiO2/Al2O3

The degradation of paracetamol in aqueous solutions in the presence of hydrogen peroxide was carried out by photochemistry, electrolysis and photoelectrolysis using modified 100 pores per inch reticulated vitreous carbon electrodes. The electrodes were coated with catalysts such as TiO₂ and CuO/TiO₂/Al₂O₃ by electrophoresis followed by heat treatment. The results of the electrolysis with bare reticulated vitreous carbon electrodes show that 90% paracetamol degradation occurs in 4 h at 1.3 V vs. SCE, forming intermediates such as benzoquinone and carboxylic acids followed by their complete mineralisation. When the electrolysis was carried out with the modified electrodes such as TiO₂/RVC, 90% degradation was achieved in 2 h while with CuO/TiO₂/Al₂O₃/RVC, 98% degradation took only 1 h. The degradation was also carried out in the presence of UV reaching 95% degradation with TiO₂/RVC/UV and 99% with CuO/TiO₂/Al₂O₃/RVC/UV in 1 h. The reactions were followed by spectroscopy UV-Vis, HPLC and total organic carbon analysis. These studies show that the degradation of paracetamol follows a pseudo-first order reaction kinetics.     

纯二氧化碳条件下小球藻固定CO2

微藻固碳已经成为消减温室气体排放的新的研究热点。利用静态吸收方法,考查了通人纯CO2对普通小球藻生长特点、固定CO2效率以及藻液pH值变异的影响。结果表明：通入纯CO2使小球藻生长延滞期显著延长,比普通培养延长10～12d,对其他生长阶段的影响不大;小球藻固定CO2速率可分为2个过程,即物理固碳过程和生物固碳过程,前者在藻细胞延滞期发生,峰值由CO。溶解于培养液造成,后者在藻细胞生长的指数期、稳定期和衰退期发生,峰值由藻细胞指数生长造成,2个过程中,固定CO2速率的变化趋势都是先增大后降低;纯CO2条件下,藻液pH值变化速率高,4d内,藻液即被酸化,随后藻液pH值变化速率逐渐降低,且pH值稳定在适宜水平。因此,采用小球藻固定高浓度CO2时,建议提高接种量并加强培养前期的pH值监测和调控,以保证藻液保持适宜的pH值,并缩短培养时间,提高生物固碳效率。     

柱状V/AC催化剂的再生对脱硫活性的影响

使用常压固定床反应器,考察了吸附SO2的柱状V/AC催化剂的热再生和NH3再生行为.结果表明:柱状V/AC催化剂再生过程中生成的SO2主要沿催化剂轴向由内部向外扩散.催化剂350 ℃NH3再生的效率高于热再生的效率.两次热再生后柱状V/AC催化剂的脱硫活性开始下降,而六次NH3再生后的脱硫活性仍保持不变,甚至还稍高于新鲜柱状V/AC催化剂的脱硫活性.柱状V/AC催化剂孔结构和元素分析结果表明,NH3再生使催化剂表面含N官能团增加,保护了催化剂小于1 nm的微孔.     

Leaf size and surface characteristics of Betula papyrifera exposed to elevated CO2 and O3

Betula papyrifera trees were exposed to elevated concentrations of CO₂ (1.4 × ambient), O₃ (1.2 × ambient) or CO₂ + O₃ at the Aspen Free-air CO₂ Enrichment Experiment. The treatment effects on leaf surface characteristics were studied after nine years of tree exposure. CO₂ and O₃ increased epidermal cell size and reduced epidermal cell density but leaf size was not altered. Stomatal density remained unaffected, but stomatal index increased under elevated CO₂. Cuticular ridges and epicuticular wax crystallites were less evident under CO₂ and CO₂ + O₃. The increase in amorphous deposits, particularly under CO₂ + O_3, was associated with the appearance of elongated plate crystallites in stomatal chambers. Increased proportions of alkyl esters resulted from increased esterification of fatty acids and alcohols under elevated CO₂ + O₃. The combination of elevated CO₂ and O₃ resulted in different responses than expected under exposure to CO₂ or O₃ alone.     

V2O5-TiO2-AlF3/Al2O3催化臭氧化2,4-滴丙酸的氧化效能

为了提高有机物的臭氧化降解效率,工作中利用浸渍法制备了一种新型的三组分催化剂(记为V2O5-TiO2-AlF3/Al2O3)。催化臭氧化降解2,4-滴丙酸的实验结果表明,该催化剂能有效提高臭氧化的效率,体系可能遵循羟基自由基的作用机理。利用相对法计算结果表明,与单独臭氧化相比,V2O5-TiO2-AlF3/Al2O3催化臭氧化体系具有更大的Rct值。重复实验结果表明,该催化剂具有相对较好的稳定性。以上研究结果对推广催化臭氧化技术在实际废水处理中的应用具有重要的实际意义。     

Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment

Rising atmospheric carbon dioxide (CO₂) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O₃) during the present century if higher CO₂ is accompanied by lower stomatal conductance (g_s), as assumed by many models. We investigated how elevated concentrations of CO₂ and O₃, alone and in combination, affected the accumulated stomatal flux of O₃ (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO₂-O₃ enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O₃ was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O₃ deposition. Leaf-level AFst (AFst_l) was not reduced by elevated CO₂. Instead, there was a significant CO₂ × O₃ interaction on AFst_l, as a consequence of lower values of g_s in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst_l than birch leaves, and estimates of AFst_l were not very sensitive to non-stomatal leaf surface O₃ deposition. Our results suggest that model projections of large CO₂-induced reductions in g_s alleviating the adverse effect of rising tropospheric O₃ may not be reasonable for northern hardwood forests.     

铁炭微电解-Fe2+/K2S2O8降解甲基橙

针对偶氮类有机物废水具有色度大,难降解的特点,以对二甲基氨基偶氮苯磺酸钠(甲基橙)为模拟研究对象,对水体系中铁炭微电解-Fe2+/K2S2O8降解甲基橙的方法进行了研究。通过正交实验确定出该方法各因素的影响程度,进一步通过单因素影响实验确定该方法的最佳条件是:铁炭微电解填料、FeSO4和K2S2O8投加量分别为300 g/L、1.3mmol/L和0.7 mmol/L,初始pH值为7.0。在最佳条件下,甲基橙COD和色度去除率分别能达到64.7%和68.2%。     

Vis/Co-TiO_2/KHSO_5体系Fenton-光催化协同降解苯酚

通过溶胶-凝胶法制备了同时具有可见光(Vis)光催化和Fenton催化双重活性的Co-TiO2催化剂。通过对比Vis/Co-TiO2/KHSO5、Co-TiO2/KHSO5和Vis/Co-TiO23种体系对苯酚的降解效果,Vis/Co-TiO2/KHSO5表现出明显的Fenton-光催化协同作用。进一步研究pH值、KHSO5与苯酚摩尔比(nKHSO5∶nC6H6O)和Co-TiO2投加量(mCo-TiO2)对Fenton-光催化协同降解苯酚效果的影响。结果表明,pH=6.9、nKHSO5∶nC6H6O=10∶1、mCo-TiO2=1.0 g/L时,降解率达100%。最后,结合XRD、XPS和UV-DRS等手段和催化活性实验数据分析了Vis/Co-TiO2/KHSO5体系的催化机理。     

Quantifying local traffic contributions to NO2 and NH3 concentrations in natural habitats

NO₂ and NH₃ concentrations were measured across a Special Area for Conservation in southern England, at varying distances from the local road network. Exceedances of the critical levels for these pollutants were recorded at nearly all roadside locations, extending up to 20 m away from roads at some sites. Further, paired measurements of NH₃ and NO₂ concentrations revealed differences between ground and tree canopy levels. At “background” sites, away from the direct influence of roads, concentrations were higher within tree canopies than at ground level; the reverse pattern was, however, seen at roadside locations. Calculations of pollutant deposition rates showed that nitrogen inputs are dominated by NH₃ at roadside sites. This study demonstrates that local traffic emissions contribute substantially to the exceedance of critical levels and critical loads, and suggests that on-site monitoring is needed for sites of nature conservation value which are in close proximity to local transport routes.     

超声波协同H_2O_2处理养殖场污水

为了有效地改善养猪场污水的质量,以H2O2为药剂,对污水进行了水浴加热和超声波辅助的对比实验,考察了超声波发生器输出端电流强度、处理时间、H2O2用量对污水的COD、氨气及颜色的影响,并进行正交实验优化。结果表明,超声波协同H2O2处理养殖污水是一种切实可行的方法,超声波协同H2O2处理污水的最佳工艺条件:电流0.7 A、处理时间2 min、H2O2用量3%,在此条件下降低COD量可达95%以上,氨氮的含量可降至14~15 mg/L,氨臭味大大得到了改善,并将原污水由黑色变为浅黄色。     

Assessment of contribution of SO2 and NO2 from different sources in Jamshedpur region, India

Contribution of pollution from different types of sources in Jamshedpur, the steel city of India, has been estimated in winter 1993 using two approaches in order to delineate and prioritize air quality management strategies for the development of region in an environmental friendly manner. The first approach mainly aims at preparation of a comprehensive emission inventory and estimation of spatial distribution of pollution loads in terms of SO₂ and NO₂ from different types of industrial, domestic and vehicular sources in the region. The results indicate that industrial sources account for 77% and 68% of the total emissions of SO₂ and NO₂, respectively, in the region, whereas vehicular emissions contributed to about 28% of the total NO₂ emissions. In the second approach, contribution of these sources to ambient air quality levels to which the people are exposed to, was assessed through air pollution dispersion modelling. Ambient concentration levels of SO₂ and NO₂ have been predicted in winter season using the ISCST3 model. The analysis indicates that emissions from industrial sources are responsible for more than 50% of the total SO₂ and NO₂ concentration levels. Vehicular activities contributed to about 40% of NO₂ pollution and domestic fuel combustion contributed to about 38% of SO₂ pollution. Predicted 24-h concentrations were compared with measured concentrations at 11 ambient air monitoring stations and good agreement was noted between the two values. In-depth zone-wise analysis of the above indicates that for effective air quality management, industrial source emissions should be given highest priority, followed by vehicular and domestic sources in Jamshedpur region.     

The influence of forest fires on CO, HCN, C2H6, and C2H2 over northern Japan measured by infrared solar spectroscopy

Total column abundances of CO, HCN, C₂H₆, and C₂H₂ have been retrieved from infrared solar spectra observed at Moshiri (44.4°N) and Rikubetsu (43.5°N) in northern Japan from 1997 to 2005. The spectra were recorded with high spectral resolution ground-based Fourier transform infrared (FTIR) spectrometers and total column abundances were calculated by SFIT1 version 1.09e. Deviations of these species relative to their seasonal mean values (ΔCO, ΔHCN, ΔC₂H₆, and ΔC₂H₂) were derived, which showed short-time enhancements in 1998, 2002, and 2003. Good correlations among ΔCO, ΔHCN, ΔC₂H₆, and ΔC₂H₂ in a few months of each year were seen. Since the number of forest fires in Siberia had large enhancements in 1998, 2002, and 2003, trajectory analyses were performed in order to assess the influence of forest fires and it was confirmed that air masses passing over the location of burning points in Siberia reached Moshiri and Rikubetsu. This paper shows that enhancements of these species were driven by biomass burning in Siberia.