Coupled infrared extinction spectra and size distribution measurements for several non-clay components of mineral dust aerosol (quartz, calcite, and dolomite)

Simultaneous size distributions and Fourier transform infrared (FTIR) extinction spectra have been measured for several representative components of mineral dust aerosol (quartz, calcite, and dolomite) in the fine particle size mode (D=0.1–1 μm). Optical constants drawn from the published literature have been used in combination with the experimentally determined size distributions to simulate the extinction spectra. In general, Mie theory does not accurately reproduce the peak position or band shape for the prominent IR resonance features in the 800–1600 cm⁻¹ spectral range. The resonance peaks in the Mie simulation are consistently blue shifted relative to the experimental spectra by 20–50 cm⁻¹. Spectral simulations, derived from a simple Rayleigh-based analytic theory for a “continuous distribution of ellipsoids” particle shape model, better reproduce the experimental spectra, despite the fact that the Rayleigh approximation is not strictly satisfied in these experiments. These results differ from our previous studies of particle shape effects in silicate clay mineral dust aerosols where a disk-shaped model for the particles was found to be more appropriate.     

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.     

Comparative study of the oxidation of atrazine and acetone by H2O2/UV, Fe(III)/UV, Fe(iii)/H2O2/UV and Fe(II) or Fe(III)/H2O2

In this study, the rates of degradation of organic compounds by several AOPs (H₂O₂/UV, Fe(III)/UV, Fe(III)/H₂O₂/UV, Fe(II)/H₂O₂ and Fe(III)/H₂O₂) have been compared. Experiments were carried out at pH ≈ 3 (perchloric acid / sodium perchlorate solutions) and with UV reactors equipped with a low-pressure mercury vapour lamp (emission at 253.7 run). The data obtained with atrazine ([Atrazine]_o = 100 μg/L) showed that the rate of degradation of atrazine in very dilute aqueous solution is much more rapid with Fe(III)/UV than with H₂O₂/UV. Photo-Fenton process (Fe(III)/H₂O₂/UV) was found to be more efficient than H₂O₂/UV and Fe(II)/H₂O₂ for the mineralization of acetone ([Acetone]_o = 1 mM).     

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。     

一台气相色谱仪同时测定陆地生态系统CO2、CH4和N2O排放

通过对气相色谱仪进样、分析气路和阀驱动系统的改造,同一台色谱仪可以同时检测空气样品中的CO2、CH4和N2O.测试结果表明,仪器的灵敏度、分辨率和精密度均很高,线性范围符合要求;仪器系统能够在野外实验室长期稳定运转,可方便用于测定陆地生态系统CO2、CH4和N2O排放,能快速、准确、可靠地获取观测数据.     

负载V2O5-WO3/TiO2掺炭纤维脱除烟气中Hg0

通过固定床实验系统研究烟气脱除零价汞的实验,首先研究了滤袋常用的聚苯硫醚（polyphenylene sulfide,PPS）以及活性炭纤维（activated carbon fiber,ACF）在不同温度、不同气体组分下负载V₂O₅-WO₃/TiO₂催化剂,对模拟燃煤烟气中零价汞（Hg⁰）的脱除效果。然后对比研究了活性炭纤维协同滤袋常用纤维负载催化剂后,对模拟燃煤烟气中Hg⁰的脱除性能。结果表明,在汞蒸气入口浓度为50 μg/m³,纯N₂气氛下,当温度为25℃时,两者脱除率均能达到99%,当温度为200℃,负载催化剂的活性炭纤维脱除率在30%左右,PPS纤维仅为10%左右。在200℃情况下,模拟烟气的组分为N₂+O₂时,2种纤维的Hg⁰脱除率提高了10%~20%,当在混合气体中添加0.01‰后,负载催化剂的PPS纤维Hg⁰脱除率能达到80%,活性炭纤维Hg⁰脱除率能达到98%。当温度为200℃,模拟烟气的组分为N₂+O₂+HCl时,不同性能掺炭纤维负载催化剂后Hg⁰脱除率在69%~95%范围之间变化,其中PPS掺炭纤维对Hg⁰脱除效率最高达到95%,因此,负载V₂O₅-WO₃/TiO₂催化剂的PPS掺炭纤维能在高温烟气中保持较高的Hg⁰脱除率。     

烟气成分对负载V_2O_5-WO_3/TiO_2聚苯硫醚纤维脱除烟气中Hg~0的影响

通过固定床实验系统模拟烟气脱除Hg0的实验,研究了O2、HCl、NO、SO2、H2O和NH3对滤袋常用的聚苯硫醚(PPS)纤维负载V2O5-WO3/TiO2新型催化剂后脱除烟气中Hg0的影响,并分析其影响机理。结果表明,在温度为200℃、高纯N2气氛下,Hg0的脱除率很低,加入4%O2后,脱除率有所增加;0.05‰HCl条件下Hg0的脱除率仅为5%,而0.01‰HCl与4%O2并存的条件下,脱除率明显提高;NO对Hg0的催化氧化促进作用不是很显著;SO2对Hg0氧化具有毒害作用;H2O和NH3可抑制Hg0的脱除,O2的存在可抵消NH3的部分抑制作用。     

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.     

La_(1-x)Ce_xCu_yMn_(1-y)O_3/HZSM-5催化剂低温去除柴油机碳烟和NO_x

为实现对柴油机碳烟和NOx的低温同步去除,采用柠檬酸络合法制备分子筛负载钙钛矿型金属复合氧化物催化剂,应用X衍射分析仪(XRD)和电镜扫描仪(SEM)对催化剂性能进行表征,并在微型固定床反应器中对催化剂低温去除碳烟和NOx进行活性评价。利用程序升温反应(TPR)技术,进行催化剂活性评价、柴油机负荷和排放等特性实验。结果表明,A位用适量Ce部分取代La,B位用适量Cu部分取代Mn,可使碳颗粒燃烧温度降低,CO2选择性好,NOx转化率升高。La0.4Ce0.6Cu0.2Mn0.8O3/HZSM-5催化剂的最大NOx转化率为81.0%,Ti、Tm和Tf分别为250、350和475℃,表明该催化剂具有较好的催化活性,能在低温条件下去除碳烟和NOx。     

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.     

微气泡曝气 O3/ H2O2处理 RO 浓水的效能及影响因素简

采用O₃/H₂O₂高级氧化工艺处理炼油厂反渗透（RO）浓水,用溶气泵加压溶气并产生微气泡强化传质,确定装置运行条件,考察气体中臭氧浓度、H₂O₂/O₃初始摩尔比、pH和温度对O₃/H₂O₂处理RO浓水效果的影响,并对RO浓水处理效能进行研究。结果表明,随着气体中臭氧浓度的增加,COD的去除率基本呈线性增加;加入适当量H₂O₂能提高臭氧氧化RO浓水的效果,H₂O₂/O₃初始摩尔比在0~0.8范围内,COD的去除率先增加后下降,H₂O₂/O₃初始摩尔比为0.5时COD去除率最大;pH从6.84增加到9.01,COD去除率逐渐增大,pH为10.03时COD去除率反而降低;在14~28℃范围内,温度低时,升高温度COD去除率增加较大,温度较高时,升高温度对COD去除率的影响较小。为考察该工艺的稳定性,在H₂O₂/O₃初始摩尔比为0.5、溶液pH为8~9、臭氧浓度为80~100 mg/L、温度为10~28℃条件下,对COD为90~140 mg/L的RO浓水氧化处理4~10 h,出水COD维持在39.9~49.9 mg/L,达到《城镇污水处理厂污染物排放标准（GB 18918-2002）》中的一级A标准;去除1 g COD消耗O₃ 1.4~3.3 g,消耗O₃与H₂O₂的总氧量为2.2~4.4 g。     

负载铁分子筛催化H2O2对活性艳蓝的脱色

以13X分子筛为载体制备负载铁催化剂,比较了经稀硫酸和氢氧化钠2种不同预处理液处理后催化剂的催化效果。利用制备的负载铁分子筛催化剂协同H2O2对活性艳蓝进行脱色研究,得出当pH=2.03,Ⅱ型催化剂投加量为4.0 g/L,过氧化氢投加量为1.1 g/L,反应时间为4 h时,脱色率最佳可达92%。     

Analysis of the relationship between ambient levels of O3, NO2 and NO as a function of NOx in the UK

Monitoring data from the UK Automatic Urban and Rural Network are used to investigate the relationships between ambient levels of ozone (O₃), nitric oxide (NO) and nitrogen dioxide (NO₂) as a function of NO_x, for levels ranging from those typical of UK rural sites to those observed at polluted urban kerbside sites. Particular emphasis is placed on establishing how the level of ‘oxidant’, OX (taken to be the sum of O₃ and NO₂) varies with the level of NO_x, and therefore to gain some insight into the atmospheric sources of OX, particularly at polluted urban locations. The analyses indicate that the level of OX at a given location is made up of NO_x-independent and NO_x-dependent contributions. The former is effectively a regional contribution which equates to the regional background O₃ level, whereas the latter is effectively a local contribution which correlates with the level of primary pollution. The local oxidant source has probable contributions from (i) direct NO₂ emissions, (ii) the thermal reaction of NO with O₂ at high NO_x, and (iii) common-source emission of species which promote NO to NO₂ conversion. The final category may include nitrous acid (HONO), which appears to be emitted directly in vehicle exhaust, and is potentially photolysed to generate HO_x radicals on a short timescale throughout the year at southern UK latitudes. The analyses also show that the local oxidant source has significant site-to-site variations, and possible reasons for these variations are discussed. Relationships between OX and NO_x, based on annual mean data, and fitted functions describing the relative contributions to OX made by NO₂ and O₃, are used to define expressions which describe the likely variation of annual mean NO₂ as a function of NO_x at 14 urban and suburban sites, and which can take account of possible changes in the regional background of O₃.     

The influence of engineered Fe2O3 nanoparticles and soluble (FeCl3) iron on the developmental toxicity caused by CO2-induced seawater acidification

An embryo development assay using a common test organism, the edible mussel (Mytilus galloprovincialis), exposed to both Fe₂O₃ nanoparticles and soluble FeCl₃ at 3 acidic pHs, has provided evidence for the following: (1) CO₂ enriched seawater adjusted to pH projections for carbon capture leakage scenarios (CCS) significantly impaired embryo development; (2) under natural pH conditions, no significant effect was detected following exposure of embryos to Fe, no matter if in nano- or soluble form; (3) at pH of natural seawater nano-Fe particles aggregate into large, polydisperse and porous particles, with no biological impact detected; (4) at pH 6 and 7, such aggregates may moderate the damage associated with CO₂ enrichment as indicated by an increased prevalence of normal D-shell larvae when nano-Fe was present in the seawater at pH 7, while soluble iron benefited embryo development at pH 6, and (5) the observed effects of iron on pH-induced development toxicity were concentration dependent.     

Application of the EPR spin-trapping technique for the investigation of the reactions of carbonate, bicarbonate, and phosphate anions with hydroxyl radicals generated by the photolysis of H2O2

The spin trapping technique with electron paramagnetic resonance (EPR) detection of spin adducts was applied for the investigation of the reaction of hydroxyl radicals, generated by the photolysis of hydrogen peroxide, with bicarbonate and carbonate anions. The results have been compared with those obtained for aqueous solutions of hydrogen peroxide as well as solutions containing phosphate buffers at pH values identical with those of the carbonate, and bicarbonate solutions. Both the carbonate, and bicarbonate anions quenched the hydroxyl radicals more efficiently than phosphate buffers. The effect depended on the anion concentrations, and it was most pronounced in the presence of carbonate. Rate constants for the reaction of OH with the investigated anions have been calculated. They are very close to values reported in the literature, obtained using optical detection of the carbonate and phosphate radicals.     

硅藻土酸洗液-H2O2(Fenton)去除垃圾渗滤液色度及COD

垃圾渗滤液由于色度高、可生化性差,有时候需采用高级氧化技术（如Fenton法）处理。利用硅藻土酸洗改性产生的酸洗废水与30%H2O2制成Fenton试剂处理初始色度为800倍,COD浓度为810.4 mg/L的垃圾渗滤液。结果表明,当酸洗液与30%H2O2的体积比为6∶4,pH值为3.0,有紫外光照和搅拌的条件下,色度和COD的去除效率最好,分别达到了96.25%和74.14%;且产生的污泥量（干重）最少。     

Al2O3含量对提铁后的钢渣及粉煤灰微晶玻璃结构与性能的影响

为了实现熔融态钢渣的“渣”和“热”高附加值双利用,提出了将熔融提铁后钢渣制备成高附加值微晶玻璃的研究思路。采用DTA、XRD、SEM和EDS等手段研究了Al2O3含量对提铁后钢渣微晶玻璃的影响,结果显示随Al2O3含量的增大微晶玻璃析晶温度逐渐升高,并且主晶相由假硅灰石转变为铝黄长石,最终转变为钙长石。Al2O3含量为15％时微晶玻璃的力学性能较好,其抗弯强度、显微硬度、抗压强度分别达到了49．85MPa、3．52GPa和181．47MPa,同时钢渣和粉煤灰的利用率分别高达56％和36％。     

Synergistic increase in cell lethality by dieldrin and H2O2 in rat thymocytes: Effect of dieldrin on the cells exposed to oxidative stress

Dieldrin, one of persistent pesticides, is highly resistant to biotic and abiotic degradation. It is accumulated in organisms. Recent studies suggest that dieldrin exerts a potent cytotoxic action on cells exposed to oxidative stress. In this study, the effect of dieldrin on rat thymocytes exposed to hydrogen peroxide (H₂O₂)-induced oxidative stress was examined. Dieldrin at 5 μM and H₂O₂ at 300 μM slightly increased cell lethality from a control value of 5.4 ± 0.5% (mean ± standard deviation of four experiments) to 7.8 ± 1.3% and 9.0 ± 0.3%, respectively. Simultaneous application of dieldrin and H₂O₂ significantly increased cell lethality to 46.2 ± 1.8%. The synergistic increase in cell lethality was dependent on dieldrin concentration (0.3–5 μM) but not on H₂O₂ concentration (30–300 μM). Dieldrin accelerated H₂O₂-induced cell death, which was estimated with the help of annexin V-FITC and propidium iodide. Presence of either dieldrin or H₂O₂ decreased the cellular content of nonprotein thiol and increased intracellular Zn²⁺ concentration. The combination of dieldrin and H₂O₂ further pronounced these effects. TPEN, a chelator of intracellular Zn²⁺, significantly attenuated the synergistic increase in cell lethality induced by dieldrin and H₂O₂. It is, therefore, suggested that dieldrin augments the cytotoxicity of H₂O₂ in a Zn²⁺-dependent manner.     

B,N和Ce共掺杂TiO_2催化剂光催化活性研究

采用溶胶-凝胶法制备出B,N和Ce共掺杂TiO2光催化剂,并用XRD、SEM等表征了其结构特征。以酸性大红染料溶液的光催化降解为探针反应,考察了制备条件对共掺杂TiO2催化剂活性的影响。结果表明,在400℃,当B,N和Ce的原子比为1∶2∶0.1,焙烧3 h时,光催化剂活性最大,大红染料的降解率达到98%。     

A new approach to quantify the degradation kinetics of linuron with UV, ozonation and UV/O3 processes

The degradation of linuron, one of phenylurea herbicides, was investigated for its reaction kinetics by different treatment processes including ultraviolet irradiation (UV), ozonation (O₃), and UV/O₃. The decay rate of linuron by UV/O₃ process was found to be around 3.5 times and 2.5 times faster than sole-UV and ozone-alone, respectively. Experimental results also indicate overall rate constants increased exponentially with pH above 9.0 while the increase of rate constants with pH below 9 is insignificant in O₃ system. All dominant parameters involved in the three processes were determined in the assistant of proposed linear models in this study. The approach was found useful in predicting the process performances through the quantification of quantum yield (rate constant for the formation of free radical HOO⁻ from ozone decomposition at high pH), rate constant of linuron with ozone (k_O3,LNR), rate constant of linuron with hydroxyl radical (k_OH,LNR), and α (the ratio of the production rate of OH and the decay rate of ozone in UV/O₃ system).