模拟酸雨对氧化锰吸附砷(Ⅲ)的解吸行为研究

以合成的氧化锰为吸附剂研究了酸雨pH值、酸雨离子强度、解吸时间和解吸次数等因素对模拟酸雨解吸砷(Ⅲ)的影响。实验结果表明:氧化锰对砷(Ⅲ)吸附容量较大,等温平衡吸附量为:48.38 mg/g。模拟酸雨的pH值与离子强度对砷(Ⅲ)的解吸影响不大;解吸反应在90 min后基本达到平衡,平衡解吸量为2.69×10-2mg/g;随解吸次数的增加解吸量变化不大。氧化锰对砷(Ⅲ)的吸附主要是专性的配位吸附,吸附砷(Ⅲ)后难以被模拟酸雨解吸。     

硅烷化改性MCM-41负载戊二酸锌催化CO2与环氧丙烷共聚制备可降解材料

以三甲基氯硅烷(TMCS)为硅烷化试剂,对MCM-41分子筛进行表面改性处理,并以此为载体制备负载型戊二酸锌催化剂(ZnGA/TMCS-MCM-41);采用红外光谱、氮气吸附-脱附和X射线衍射等分析手段对催化剂进行表征,结果表明:三甲基氯硅烷基团被成功接枝到MCM-41分子筛表面,形成比表面积略低的硅烷化MCM-41载体,但其骨架未被破坏,负载活性物质过程中,戊二酸锌能以更小的粒径均匀分散到载体的表面;聚合反应实验表明,与单纯戊二锌催化剂相比,ZnGA/TMCS-MCM-41催化剂对CO2与环氧丙烷(PO)的共聚反应显示出更高的催化效率和更快的反应速度,在反应34 h后催化效率达到86.3 g聚合物/g ZnGA;红外光谱和核磁分析表明所得共聚产物中碳酸酯结构含量大于95.8%。     

Al-MnO2/SBA-15催化剂的制备 及其催化燃烧甲醛的性能

以介孔分子筛SBA - 15为载体,分别浸渍Mn、Al等催化活性组分,制备了MnO2/SBA-15催化剂和Al-MnO2/SBA-15催化剂.采用X射线衍射、N2吸附-脱附对催化剂的结构进行了表征,在微型固定床反应器上对催化剂的低浓度甲醛催化燃烧性能进行了评价.实验结果表明:MnO2/SBA-15系列催化剂均具有SBA...     

ZnO的制备及其光催化性能

分别采用草酸沉淀法和柠檬酸络合法制备了纤锌矿型ZnO,通过X射线粉末衍射仪、扫描电子显微镜和透射电子显微镜对ZnO的结构和形貌进行了表征,并研究了所制备的ZnO对溶液中甲基橙的光催化降解性能.实验结果表明:草酸沉淀法制备的ZnO为小颗粒堆积而成的空心类柱状体,柠檬酸络合法制备的ZnO为小球形颗粒;草酸沉淀法制备的ZnO...     

Dissolution of beryllium in artificial lung alveolar macrophage phagolysosomal fluid

Dissolution of a lung burden of poorly soluble beryllium particles is hypothesized to be necessary for development of chronic beryllium lung disease (CBD) in humans. As such, particle dissolution rate must be sufficient to activate the lung immune response and dissolution lifetime sufficient to maintain chronic inflammation for months to years to support development of disease. The purpose of this research was to investigate the hypothesis that poorly soluble beryllium compounds release ions via dissolution in lung fluid. Dissolution kinetics of 17 poorly soluble particulate beryllium materials that span extraction through ceramics machining (ores, hydroxide, metal, copper-beryllium [CuBe] fume, oxides) and three CuBe alloy reference materials (chips, solid block) were measured over 31 d using artificial lung alveolar macrophage phagolysosomal fluid (pH 4.5). Differences in beryllium-containing particle physicochemical properties translated into differences in dissolution rates and lifetimes in artificial phagolysosomal fluid. Among all materials, dissolution rate constant values ranged from 10⁻⁵ to 10⁻¹⁰ g cm⁻² d⁻¹ and half-times ranged from tens to thousands of days. The presence of magnesium trisilicate in some beryllium oxide materials may have slowed dissolution rates. Materials associated with elevated prevalence of CBD had faster beryllium dissolution rates [10⁻⁷-10⁻⁸ g cm⁻² d⁻¹] than materials not associated with elevated prevalence (p < 0.05).     

Behavioural and biochemical responses of two marine invertebrates Scrobicularia plana and Hediste diversicolor to copper oxide nanoparticles

Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10 μg L⁻¹) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO₃. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves.     

Mechanochemical degradation of chlorinated contaminants in fly ash with a calcium-based degradation reagent

This report presents our results in a low-temperature mechanochemical hydrodechlorination process applied to fly ash coming from a municipal waste incinerator in order to efficiently remove all traces of PCDDs, PCDFs and PCBs. We found that the most suitable degradation agent is a mixture of metallic calcium and calcium oxide. A sample of fly ash presenting a TEQ of 5200 pg g⁻¹ was completely detoxified (no traces of PCDDs, PCDFs and PCBs detected) after ball-milling at 400 rpm over night.     

Anthropogenic N2O production from landfill leachate treatment

The results of a field survey and laboratory study indicated that nitrogenous landfill leachate treatment can be a significant potential source of N2O emission. Nil (raw leachate) to 58.8ngmL(-1)h(-1) (sequential batch reactor) N2O emission was detected at five treatment plants in South China. The production and emission of N2O was especially high soon after the raw leachate was aerated. The emission was positively correlated with the dissolved N2O content in leachate; detected dissolved N2O ranged from 0 to 1309ngmL(-1). All leachate treatment plants studied were effective in NH4+-N removal (>95%); however, the highest N2O emission was estimated to be 0.25g N2Ocapita(-l)year(-1), comparable with the rate of N2O emission in conventional sewage treatment process.     

从粉煤灰中回收氧化铝

简要介绍了国外从粉煤灰中回收氧化铝的几种方法，着重研究了煅烧／稀酸过滤法影响氧化铝回收率的各种因素。     

Involvement of mitochondrial dysfunction in nanosized lead oxide induced cellular damage in human lung alveolar epithelial cells

High levels of industrial lead (Pb) exposure have decreased in the last 10 years as an outcome of removal of the metal from gasoline and paints. However, environmental Pb exposures remain extensive and may be correlated with adverse human health outcomes. The present study was designed to examine molecular mechanisms underlying cytotoxicity of lead oxide nanoparticles (PbONPs) on human lung alveolar epithelial (A549) cells. When A549 cells were incubated with PbONPs, the production of reactive oxygen species was enhanced as observed by 2',7'-dichlorodihydrofluorescein diacetate. PbONPs significantly reduced proliferation of A549 cells and increased caspase3 activity. In addition, exposure of PbONPs decreased levels of glutathione, and increased lipid peroxide levels and activities of superoxide dismutase and catalase. Exposure of PbONPs enhanced DNA damage as evidenced by tail DNA (%) and olive tail moment. Taken together, these finding indicated that PbONPs diminished cell proliferation and increased apoptotic cell death of A549 cells.