SO2-4/TiO2对SO2-C7H16-TiO2复相光化学反应的影响

研究了TiO2与SO2,C7H16复相光化学反应的光催化活性.在SO2-C7H16-O2-TiO2光催化反应过程中,TiO2表面可形成SO2-4/TiO2结构,它的存在可提高庚烷的光催化氧化速率,利用IR和XPS研究了反应过程中TiO2表面形成的SO2-4/TiO2结构.     

Chemical poison and regeneration of SCR catalysts for NOx removal from stationary sources

Selective catalytic reduction (SCR) of NO_x with NH₃ is an effective technique to remove NO_x from stationary sources, such as coal-fired power plant and industrial boilers. Some of elements in the fly ash deactivate the catalyst due to strong chemisorptions on the active sites. The poisons may act by simply blocking active sites or alter the adsorption behaviors of reactants and products by an electronic interaction. This review is mainly focused on the chemical poisoning on V₂O₅-based catalysts, environmental-benign catalysts and low temperature catalysts. Several common poisons including alkali/alkaline earth metals, SO₂ and heavy metals etc. are referred and their poisoning mechanisms on catalysts are discussed. The regeneration methods of poisoned catalysts and the development of poison-resistance catalysts are also compared and analyzed. Finally, future research directions in developing poisoning resistance catalysts and facile efficient regeneration methods for SCR catalysts are proposed.     

Cu/Cr co-stabilization mechanisms in a simulated Al2O3-Fe2O3-Cr2O3-CuO waste system

• Cu and Cr can be mostly incorporated into CuFe_xAl_yCr_2−x−yO₄ with a spinel structure. • Spinel phase is the most crucial structure for Cu and Cr co-stabilization. • Compared to Al, Fe and Cr are easier to be incorporated into the spinel structure. • ‘Waste-to-resource’ by thermal process at attainable temperatures can be achieved. Chromium slag usually contains various heavy metals, making its safe treatment difficult. Glass-ceramic sintering has been applied to resolve this issue and emerged as an effective method for metal immobilization by incorporating heavy metals into stable crystal structures. Currently, there is limited knowledge about the reaction pathways adopted by multiple heavy metals and the co-stabilization functions of the crystal structure. To study the Cu/Cr co-stabilization mechanisms during thermal treatment, a simulated system was prepared using a mixture with a molar ratio of Al₂O₃:Fe₂O₃:Cr₂O₃:CuO= 1:1:1:3. The samples were sintered at temperatures 600–1300°C followed by intensive analysis of phase constitutions and microstructure development. A spinel phase (CuFe_xAl_yCr_2−x−yO₄) started to generate at 700°C and the incorporation of Cu/Cr into the spinel largely complete at 900°C, although the spinel peak intensity continued increasing slightly at temperatures above 900°C. Fe₂O₃/Cr₂O₃ was more easily incorporated into the spinel at lower temperatures, while more Al₂O₃ was gradually incorporated into the spinel at higher temperatures. Additionally, sintered sample microstructures became more condensed and smoother with increased sintering temperature. Cu / Cr leachability substantially decreased after Cu/Cr incorporation into the spinel phase at elevated temperatures. At 600°C, the leached ratios for Cu and Cr were 6.28% and 0.65%, respectively. When sintering temperature was increased to 1300°C, the leached ratios for all metal components in the system were below 0.2%. This study proposes a sustainable method for managing Cu/Cr co-exist slag at reasonable temperatures.     

KMnO4/H2SO4引发制备淀粉改性絮凝剂的研究

以高锰酸钾为引发剂,制备淀粉-丙烯酰胺接枝共聚物.研究酸浓度、引发剂浓度、单体浓度、温度和加料方式对接枝反应的影响.结果表明,少量KMnO4(0.45mmol·l-1)和H2SO4(0.8mmol·l-1)可有效引发淀粉-丙烯酰胺接枝共聚反应,接枝效率达到90%以上,分子量大大提高,对高岭土的絮凝效果较好.     

大气CO2、CH4、CO高精度观测混合标气配制方法

高精度、高准确度的大气CO2、CH4、CO浓度观测需使用以干洁大气为底气的标气.标气中水汽含量及CO2的δ13C对基于光学原理的观测系统有不可忽视的影响.本研究利用自组装的混合标气配制系统,以环境大气为底气,并通过添加高浓度气体或利用吸附剂吸附,调节目标物种浓度.CO2和CO吸附效率分别达99.7%和99.8%,标气水汽含量小于3.7×10-6(物质的量分数,下同),可配制不同浓度范围的CO2、CH4、CO混合标气.在青海瓦里关全球大气本底站配制环境大气浓度范围的标气,CO2、CH4、CO实际配制浓度同目标浓度的偏差小于10×10-6、30×10-9、30×10-9,CO2中δ13C同实际大气接近.本方法配制的标气已应用于我国本底站大气CO2、CH4、CO高精度观测,符合世界气象组织/全球大气观测(WMO/GAW)质量要求.     

Simultaneous removal of NOx and chlorobenzene on V2O5/TiO2 granular catalyst: Kinetic study and performance prediction

• A V₂O₅/TiO₂ granular catalyst for simultaneous removal of NO and chlorobenzene. • Catalyst synthesized by vanadyl acetylacetonate showed good activity and stability. • The kinetic model was established and the synergetic activity was predicted. • Both chlorobenzene oxidation and SCR of NO follow pseudo-first-order kinetics. • The work is of much value to design of multi-pollutants emission control system. The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology, which is still in the initial stage and facing many challenges. We developed a V₂O₅/TiO₂ granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene (i.e., an important precursor of dioxins). The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability. Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited, the reaction order of each reaction was not considerably affected, and the pseudo-first-order reaction kinetics was still followed. The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants (i.e., NO and dioxins) emission control.     

3D flower-like mesoporous Bi4O5I2/MoS2 Z-scheme heterojunction with optimized photothermal-photocatalytic performance

3D flower-like hierarchical mesoporous Bi₄O₅I₂/MoS₂ Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods. The heterojunction with narrow band gap of ～1.95 eV extended the photoresponse to near-infrared region, which showed obvious photothermal effect due to the introduction of MoS₂ with broad spectrum response. MoS₂ nanosheets were anchored onto the surface of flower-like hierarchical m...     

Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst in the catalytic wet air oxidation (CWAO) of cationic red GTL under mild reaction conditions

Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃, an environmental friendly material, was investigated. The catalyst exhibited good catalytic performance in the CWAO of cationic red GTL. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. HO₂· and O₂·⁻ appeared as the main reactive species in the reaction. The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. Hydroperoxy radicals (HO₂·) and superoxide radicals (O₂⁻·) appeared as the main reactive species upon the CWAO of cationic red GTL.     

食蚊鱼(Gambusia afinis)cat、gapdh和gst基因的克隆及其在生态毒理学中的应用

根据Ensembl、Genbank登录的鱼类cat、gapdh和gst基因的CDS序列设计普通PCR扩增引物,寻找食蚊鱼的cat、gapdh和gst基因的c DNA片段,并根据定量引物设计要求设计出相应的SYBR Green I荧光定量RT-q PCR引物,建立了食蚊鱼cat、gapdh和gst基因的SYBR Green I荧光定量RT-q PCR方法。该方法在104~108数量级范围内有良好线性关系(R=0.999~1.000);熔解曲线显示扩增产物特异性良好,均为单一峰值;质粒标准品最高浓度与最低浓度的批内试验变异系数与批间试验变异系数均低于2%。利用该方法监测和评价环境污染物对水生生物的影响,选择了水体中常见典型药物污染物——双氯芬酸,研究其对食蚊鱼抗氧化基因表达的影响。结果表明,雌性食蚊鱼暴露在不同浓度双氯芬酸钠(0.005、0.05、0.5和5 mg·L-1)24 h后,其肝脏cat、gapdh和gst的mRNA呈现显著变化,相对于对照组,在低浓度0.005 mg·L-1时,cat与gst mRNA的表达量均有极显著上升(p0.01),而其它浓度均极显著下降(p0.01)。试验表明该方法具有快速、精确、灵敏度高的优点,可为利用该类小型鱼类的原位污染物的生物监测和生态毒理评价提供有力的技术支持。     

六铝酸盐负载CuO催化还原NO性能

采用共沉淀法制备了LaAl12O19六铝酸盐载体,采用等体积浸渍法制备了不同负载量的CuO/LaAl12O19催化剂,并对其进行了XRD、H2-TPR和BET表征,考察了催化剂对CH4选择催化还原NO的性能.结果表明,CuO的负载并未改变六铝酸盐载体的结构,Cu在载体上以Cu2+的形式存在,活性组分CuO与载体LaAl12O19之间存在协同作用;CuO/LaAl12O19催化剂对CH4选择催化还原NO表现出良好活性,所制备的催化剂均能使NO的转化率达到99%;其中负载量为1.0 wt%的CuO/LaAl12O19催化剂的活性最好,完全反应温度T99%为560℃,且在80 h稳定性试验中表现出了良好的高温活性和热稳定性.     

Separation/degradation behavior and mechanism for cationic/anionic dyes by Ag-functionalized Fe3O4-PDA core-shell adsorbents

● PDA-Fe₃O₄-Ag was made by hydrothermal and oxidation self-polymerization method. ● PDA-Fe₃O₄-Ag had great magnetic separation performance. ● PDA-Fe₃O₄-Ag had good adsorption and degradation performance for ionic dyes. ● PDA-Fe₃O₄-Ag showed NR and MO degradation potential of 91.2% and 87.5%, respectively. High-performance adsorbents have been well-studied for the removal of organic dye pollutants to promote environment remediation. In this study, an Ag nanoparticle-functionalized Fe₃O₄-PDA nanocomposite adsorbent (PDA-Fe₃O₄-Ag) was synthesized, and the adsorption/separation performance of commonly used cationic and anionic organic dyes by the PDA-Fe₃O₄-Ag adsorbent were assessed. Overall, PDA-Fe₃O₄-Ag exhibited a significantly higher adsorption capacity for cationic dyes compared to anionic dyes, the highest of which was more than 110.0 mg/g (methylene blue (MB)), which was much higher than not only the adsorption capacities of the anionic dyes in this study but also other dye adsorption capacities reported in the literature. The dye adsorption kinetics data fitted well to both the pseudo second-order kinetics model and the Langmuir isotherm model, suggesting a monolayer-chemisorption-dominated adsorption mode. Thermodynamics analysis indicated that the adsorption process was both endothermic and spontaneous. Furthermore, the PDA-Fe₃O₄-Ag adsorbent achieved high photodegradation removal rates of the dyes, especially neutral red (NR) and methyl orange (MO), which were 91.2% and 87.5%, respectively. With the addition of PDA-Fe₃O₄-Ag, the degradation rate constants of NR and MO increased from 0.08 × 10⁻² and 0 min⁻¹ to 2.11 × 10⁻² and 1.73 × 10⁻² min⁻¹, respectively. The high adsorption and photocatalytic degradation performance of the PDA-Fe₃O₄-Ag adsorbent make it an excellent candidate for removing cationic and anionic dyes from the industrial effluents.     

Visible-light-driven heterostructured g-C3N4/Bi-TiO2 floating photocatalyst with enhanced charge carrier separation for photocatalytic inactivation of Microcystis aeruginosa

• Bi doping in TiO₂ enhanced the separation of photo-generated electron-hole. • The performance of photocatalytic degradation of MC-LR was improved. • Coexisting substances have no influence on algal removal performance. • The key reactive oxygen species were h⁺ and ^•OH in the photocatalytic process. The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern; moreover, human and animal health is affected by the toxic effects of Microcystin-LR released into the water. In this paper, a floating photocatalyst for the photocatalytic inactivation of the harmful algae Microcystis aeruginosa (M. aeruginosa) was prepared using a simple sol-gel method, i.e., coating g-C₃N₄ coupled with Bi-doped TiO₂ on Al₂O₃-modified expanded perlite (CBTA for short). The impact of different molar ratios of Bi/Ti on CBTA was considered. The results indicated that Bi doping in TiO₂ inhibited photogenerated electron-hole pair recombination. With 6 h of visible light illumination, 75.9% of M. aeruginosa (initial concentration= 2.7 × 10⁶ cells/L) and 83.7% of Microcystin-LR (initial concentration= 100 μg/L) could be removed with the addition of 2 g/L CBTA-1% (i.e., Bi/Ti molar ratio= 1%). The key reactive oxygen species (ROSs) in the photocatalytic inactivation process are h⁺ and ^•OH. The induction of the Bi⁴⁺/Bi³⁺ species by the incorporation of Bi could narrow the bandgap of TiO₂, trap electrons, and enhance the stability of CBTA-1% in the solutions with coexisting environmental substances.     

Self-assembly synthesis of phosphorus-doped tubular g-C3N4/Ti3C2 MXene Schottky junction for boosting photocatalytic hydrogen evolution

Establishing highly effective charge transfer channels in carbon nitride(g-C₃N₄) to enhance its photocatalytic activity is still a challenging issue. Herein, the delaminated 2D Ti₃C₂ MXene nanosheets were employed to decorate the P-doped tubular g-C₃N₄(PTCN)for engineering 1D/2D Schottky heterojunction(PTCN/TC) through electrostatic self-assembly. The optimized PTCN/TC exhibited the highest hydrogen evolution rate(565 μmol h^-...     

One-pot hydrothermal fabrication of BiVO4/Fe3O4/rGO composite photocatalyst for the simulated solar light-driven degradation of Rhodamine B

• BiVO₄/Fe₃O₄/rGO has excellent photocatalytic activity under solar light radiation. • It can be easily separated and collected from water in an external magnetic field. • BiVO₄/Fe₃O₄/0.5% rGO exhibited the highest RhB removal efficiency of over 99%. • Hole (h⁺) and superoxide radical (O₂^•−) dominate RhB photo-decomposition process. • The reusability of this composite was confirmed by five successive recycling runs. Fabrication of easily recyclable photocatalyst with excellent photocatalytic activity for degradation of organic pollutants in wastewater is highly desirable for practical application. In this study, a novel ternary magnetic photocatalyst BiVO₄/Fe₃O₄/reduced graphene oxide (BiVO₄/Fe₃O₄/rGO) was synthesized via a facile hydrothermal strategy. The BiVO₄/Fe₃O₄ with 0.5 wt% of rGO (BiVO₄/Fe₃O₄/0.5% rGO) exhibited superior activity, degrading greater than 99% Rhodamine B (RhB) after 120 min solar light radiation. The surface morphology and chemical composition of BiVO₄/Fe₃O₄/rGO were studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The free radicals scavenging experiments demonstrated that hole (h⁺) and superoxide radical (O₂^•−) were the dominant species for RhB degradation over BiVO₄/Fe₃O₄/rGO under solar light. The reusability of this composite catalyst was also investigated after five successive runs under an external magnetic field. The BiVO₄/Fe₃O₄/rGO composite was easily separated, and the recycled catalyst retained high photocatalytic activity. This study demonstrates that catalyst BiVO₄/Fe₃O₄/rGO possessed high dye removal efficiency in water treatment with excellent recyclability from water after use. The current study provides a possibility for more practical and sustainable photocatalytic process.     

Identification of Illex coindetii, I. illecebrosus and I. argentinus (Cephalopoda: Ommastrephidae) throughout the Atlantic Ocean; by body and beak characters

Shortfinned squid species of the genus Illex support commercial fisheries throughout the Atlantic Ocean and Mediterranean Sea. Previous identification of interspecific and intraspecific populations by morphological and size-at-maturity studies have not provided conclusive results. We analysed morphometric body and beak variables (24 characters) in three species of the genus (I. coindetii, I. illecebrosus and I. argentinus), using a geographic and seasonal series of 33 populations for 1,500 specimens of I. coindetii, I. illecebrosus and I. argentinus. Residuals of the regression between each morphometric body and beak variable and mantle length were used as input in a stepwise discriminant analysis. Species discrimination by body and hectocotylus characters required at least eight variables and resulted in high correct-classification percentages for I. coindetii and I. argentinus (75% and 90%, respectively), whereas the best identification resulted from beak characters (83% correctly classified). Size of the suckerless basal arm, sucker-bearing length and beak lateral wall discriminated best among I. coindetii from northern Iberia, northwest Iberia (year-1996) and Ireland in the Atlantic and western Mediterranean versus middle and eastern Mediterranean samples. Canadian shelf and American samples were discriminated from Canadian slope I. illecebrosus. Winter/shelf and winter/slope samples of I. argentinus seemed to form a single biological group separated from Falkland Island, 46°S/autumn spawners and 46°S/1996 specimens along the Patagonian Shelf. No significant sexual or maturity polymorphism was obtained. Discriminant analysis optimised population diagnosis on a morphometric basis of interest in fisheries strategies. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00227-002-0796-7.     

固定化微生物对养殖水体中NH4^＋—N和NO2^——N转化作用

采用聚乙烯醇（PVA）（ρ＝gL^-1)的方法对沼泽红假单胞菌、诺卡氏菌和假丝酵母3种菌株进行固定化,所得的凝胶颗粒机械强度好,经久耐用,运用这3种菌株的固定化细胞对养殖水体中NH4^ -N和NO2^-－N进行转化,其最适作用温度范围为25－30℃,最适pH范围分别为：6．5－8．5,7．0－7．5及5．5－7．0,且对水质初始氮浓度有很强的适应性,3菌株经固定化后,其对养殖水体中NH4^ -NT和NO2^-－N的转化效率明显优于其游离细胞,若将3菌株按2：1：2组合成复合菌株并固定化,其以养殖水体中的NH4^ -N和NO2^-－N论效果将更佳。     

ZnO-MgO/Al2O3吸附-臭氧催化氧化处理难降解有机废水

以活性氧化铝为载体,采用浸渍法制备催化剂,对甲基橙及草酸模拟废水进行处理.在中性条件下,臭氧催化氧化比单独臭氧氧化能提前30 min使得甲基橙溶液褪色,反应105 min时,臭氧催化氧化对TOC的去除率高达96.53%,比单独使用臭氧氧化对甲基橙TOC去除率提高了47.19%,在处理草酸废水时臭氧催化氧化对TOC去除率高达80.59%,比单独使用臭氧氧化对草酸TOC去除率提高了59.14%.在处理甲基橙及草酸的小试实验中催化剂对有机污染物的吸附作用起到了加快反应进行的作用.在对垃圾渗滤液超滤出水时,O₃与COD质量比为1:1时,臭氧催化氧化对COD去除率为49.09%,比单独使用臭氧氧化提高36.37%,臭氧催化氧化对TOC的去除率是单独使用臭氧氧化的2.54倍,在处理垃圾渗滤液纳滤浓水时,臭氧催化氧化对COD去除率高达88.72%,比单独使用臭氧氧化提高37.60%,并且臭氧催化氧化对TOC的去除率是单独臭氧氧化的1.6倍.臭氧催化氧化反应过程中产生的羟基自由基对有机物更快的反应速率.     

Removal of elemental mercury with Mn/Mo/Ru/Al2O3 membrane catalytic system

In this work, a catalytic membrane using Mn/Mo/Ru/Al₂O₃ as the catalyst was employed to remove elemental mercury (Hg⁰) from flue gas at low temperature. Compared with traditional catalytic oxidation (TCO) mode, Mn/Al₂O₃ membrane catalytic system had much higher removal efficiency of Hg⁰. After the incorporation of Mo and Ru, the production of Cl₂ from the Deacon reaction and the retainability for oxidants over Mn/Al₂O₃ membrane were greatly enhanced. As a result, the oxidization of Hg⁰ over Mn/Al₂O₃ membrane was obviously promoted due to incorporation of Mo and Ru. In the presence of 8 ppmv HCl, the removal efficiency of Hg⁰ by Mn/Mo/Ru/Al₂O₃ membrane reached 95% at 423 K. The influence of NO and SO₂ on Hg⁰ removal were insignificant even if 200 ppmv NO and 1000 ppmv SO₂ were used. Moreover, compared with the TCO mode, the Mn/Mo/Ru/Al₂O₃ membrane catalytic system could remarkably reduce the demanded amount of oxidants for Hg⁰ removal. Therefore, the Mn/Mo/Ru/Al₂O₃ membrane catalytic system may be a promising technology for the control of Hg⁰ emission.     

含氮有机物在Pt／HM,Pd／HM和CuO／HM催化剂上的氧化降解

本文考虑了乙腈、硝基甲烷和乙二胺在Ｐｔ／ＨＭ，Ｐｄ／ＨＭ和ＣｕＯ／ＨＭ催化剂上氧化降解产物随反应温度的变化。在实验温度范围内，含氮产物在Ｎ２，Ｎ２Ｏ和ＮＯ２。随着反应温度的升高，硝基甲烷氧化降解的Ｎ２选择性呈单调下降；而乙腈和乙二胺的Ｎ２选择性出现极小值；高温时Ｎ２选择性升高可能是氧化生成的ＮＯ在高温时更在利于和ＣＮ基或ＮＨ２基相互反应生成Ｎ２的缘故。对于乙腈和乙二胺的催化氧化降解活性为：Ｐｔ／Ｈ