黑曲霉（Aspergillus niger）对Pb2+的吸附特性研究

以黑曲霉菌丝体作为吸附剂,通过静态吸附实验研究了各种因素对其吸附去除废水中Pb2+的影响。结果表明：当Pb2+初始浓度为50 mg/L,吸附剂用量为1．0 g/L,吸附时间为45 min,pH为5．0时,吸附效果最佳。此时吸附量为44．1 mg/g,去除率为90．86%。使用准二阶动力学方程可较好的拟合黑曲霉对Pb2+的吸附,表明该吸附过程以化学吸附为主。等温吸附过程可用Freundlich方程描述,说明该吸附为多分子层吸附。傅立叶红外光谱分析表明,黑曲霉吸附剂表面的酯羰基(-COO-)、羧基(-COOH )和羟基(-OH )在吸附Pb2+的过程中发挥主要作用。     

哈尔滨市大气主要污染物浓度变化与城市发展因素影响分析研究

采用Daniel趋势检验法对哈尔滨市近年来SO2、NO2和PM10年均浓度变化趋势分析,并对城市总人口与经济、产业结构、民用汽车保有量和能源状况五个城市发展因素进行数据统计分析,用SPSS探究城市发展过程中影响大气污染的因素及相关性.结果表明:浓度变化趋势是SO2明显上升;NO2缓慢上升;PM10整体明显下降,但在2013年点突增至了0.119 mg/m3.SO2与NO2显著相关,相关系数为0.533.经统计,哈尔滨人口经济发展、产业结构调整较为缓慢,全市民用汽车保有量增加并未对NO2浓度影响显著,能源结构依然以煤为主,虽然能源强度提升,但也存在着煤质、散煤的问题.哈尔滨市各城市发展因素与污染物浓度关联度不显著.     

河北省PM2.5污染变化特征及暴露人群健康效应评估研究

PM2.5污染是影响中国城市居民健康和形成雾霾天气的重要原因之一,也是河北省健康发展的一个制约因素.采用环境污染流行病研究为基础的暴露-反应关系估算了2014年和2015年全省因PM2.5污染的居民早逝和罹患相关疾病住院的人数,并利用国家和河北省卫生统计数据,估算出人均人力资源价值和人均住院成本,计算出总经济损失.结果表明,河北省各市的PM2.5年均浓度呈下降趋势,因此,继续坚持有效的大气污染控制和应急健康防护措施,仍然是今后环保工作的重中之重.     

不同浓度草酸对土壤中Cu、Cd形态的影响

用三种不同浓度的草酸(0.5mmol/L、1mmol/L、2mmol/L)处理污染土壤,研究草酸对土壤Cu、Cd形态的影响,结果表明不同浓度的草酸对Cu和Cd的形态均产生一定影响。三种草酸作用下,Cu、Cd的可交换态和碳酸盐结合态均下降,其中0.5mmol/L草酸的作用效果最为显著,Cu分别下降了1.31和3.42个百分点,Cd分别下降了3.37和1.58个百分点。通过比较,可以确定0.5mmol/L的草酸是固定Cu、Cd的最佳浓度。作用于土壤Cu、Cd形态的转变主要是草酸络合溶解和酸性水解综合作用的结果。     

Cf/SiC 复合材料表面 HfO2涂层的制备及其抗热冲击性能研究

目的研究等离子喷涂条件下Cf/SiC复合材料表面HfO_2涂层的物相、显微组织及其抗热冲击性能。方法通过水热合成和喷雾造粒制备出HfO_2粉体,并利用等离子喷涂在Cf/SiC复合材料表面制备HfO_2涂层,研究涂层的物相、显微组织和抗热冲击性能。结果水热合成的纳米HfO_2为单斜相结构,颗粒的平均粒径为10~15nm;等离子喷涂制备的HfO_2涂层组织中存在微裂纹和孔隙,涂层为单斜相结构,且经1350℃热处理后涂层的相结构未发生改变。等离子喷涂的HfO_2涂层与Cf/SiC复合材料基体结合良好,未观察到涂层、基体间界面分离的现象。经1350℃、50周次的空冷热冲击试验后,涂层未发生破坏失效;在1350℃水冷热冲击条件下,热循环20次时涂层表面出现剥落,27次时脱落面积50%。结论通过等离子喷涂制备的HfO_2涂层与Cf/SiC复合材料基体结合良好,涂层能够抵御1350℃空冷、50周次热冲击,且未发生破坏失效,涂层的1350℃水冷热循环寿命达27次。     

Bi2O3-TiO2复合光催化剂协同处理铬-邻苯二甲酸酯复合污染

以硝酸铋和钛酸丁酯为前驱体,采用水热法制备了Bi_2O_3-TiO_2复合半导体材料,并利用X射线衍射(XRD)、紫外-可见吸收光谱(UVVis)、能谱分析(EDS)、X射线光电子能谱(XPS)等手段对复合材料的结构进行了表征.同时,考察了Bi_2O_3-TiO_2复合材料对重金属Cr(Ⅵ)和难降解邻苯二甲酸二丁酯(DBP)复合污染的处理性能,并探讨了复合催化剂协同处理复合污染的作用机制.结果表明:该复合催化剂在可见光下能同时降低重金属Cr(Ⅵ)和有机物DBP的浓度,抑制电子和空穴复合,表现出比对单一Cr(Ⅵ)及DBP污染物更高的处理效率.当Bi_2O_3含量为4%时,复合催化剂表现出最佳的光催化活性.     

Pd/Al2O3粒子电极电催化还原BrO3-的研究

针对常规方法难以去除水中Br_3~-的问题,采用浸渍煅烧法制备了负载型纳米Pd/Al_2O_3粒子电极,研究了该电极电催化还原Br O-3的效果.催化剂的结构表征表明该反应实现了Pd纳米晶的均匀负载,纳米Pd/Al_2O_3具有较高的电催化活性和较低的能耗,其最佳反应条件为3%Pd负载量,0.9 m A·cm-2电流密度和1 g·L催化剂投量,酸性条件可促进Br O-3的直接或间接还原.ESR检测证实了Pd的负载增强了反应体系活性物种[H]的生成,进而促进了Br O-3的间接电催化还原.     

Layered sphere-shaped TiO2 capped with gold nanoparticles on structural defects and their catalysis of formaldehyde oxidation

We describe here a one-step method for the synthesis of Au/TiO₂ nanosphere materials, which were formed by layered deposition of multiple anatase TiO₂ nanosheets. The Au nanoparticles were stabilized by structural defects in each TiO₂ nanosheet, including crystal steps and edges, thereby fixing the Au–TiO₂ perimeter interface. Reactant transfer occurred along the gaps between these TiO₂ nanosheet layers and in contact with catalytically active sites at the Au–TiO₂ interface. The doped Au induced the formation of oxygen vacancies in the Au–TiO₂ interface. Such vacancies are essential for generating active oxygen species (*O⁻) on the TiO₂ surface and Ti^3 + ions in bulk TiO₂. These ions can then form Ti^3 +–O⁻–Ti^4 + species, which are known to enhance the catalytic activity of formaldehyde (HCHO) oxidation. These studies on structural and oxygen vacancy defects in Au/TiO₂ samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.     

Numerical evaluation of the effectiveness of NO2 and N2O5 generation during the NO ozonation process

Wet scrubbing combined with ozone oxidation has become a promising technology for simultaneous removal of SO₂ and NO_x in exhaust gas. In this paper, a new 20-species, 76-step detailed kinetic mechanism was proposed between O₃ and NO_x. The concentration of N₂O₅ was measured using an in-situ IR spectrometer. The numerical evaluation results kept good pace with both the public experiment results and our experiment results. Key reaction parameters for the generation of NO₂ and N₂O₅ during the NO ozonation process were investigated by a numerical simulation method. The effect of temperature on producing NO₂ was found to be negligible. To produce NO₂, the optimal residence time was 1.25 sec and the molar ratio of O₃/NO about 1. For the generation of N₂O₅, the residence time should be about 8 sec while the temperature of the exhaust gas should be strictly controlled and the molar ratio of O₃/NO about 1.75. This study provided detailed investigations on the reaction parameters of ozonation of NO_x by a numerical simulation method, and the results obtained should be helpful for the design and optimization of ozone oxidation combined with the wet flue gas desulfurization methods (WFGD) method for the removal of NO_x.     

In vitro evaluation of inorganic and methyl mercury mediated cytotoxic effect on neural cells derived from different animal species

To extend the current understanding of the mercury-mediated cytotoxic effect,five neural cell lines established from different animal species were comparatively analyzed using three different endpoint bioassays:thiazolyl blue tetrazolium bromide,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay(MTT),neutral red uptake assay(NRU),and Coomassie blue assay(CB).Following a 24-hr exposure to selected concentrations of mercury chloride(HgCl_2) and methylmercury(Ⅱ) chloride(MeHgCl),the cytotoxic effect on test cells was characterized by comparing their 50%inhibition concentration(IC_(50)) values.Experimental results indicated that both these forms of mercury were toxic to all the neural cells,but at very different degrees.The IC_(50)values of MeHgCl among these cell lines ranged from 1.15±0.22 to 10.31 ± 0.70 μmol/L while the IC_(50) values for HgCl_2 were much higher,ranging from 6.44 ± 0.36 to 160.97±19.63 μmol/L,indicating the more toxic nature of MeHgCl.The IC_(50) ratio between HgCl_2and MeHgCl ranged from 1.75 to 96.0,which confirms that organic mercury is much more toxic to these neural cells than inorganic mercury.Among these cell lines,HGST-BR and TriG44 derived from marine sea turtles showed a significantly high tolerance to HgCl_2 as compared to the three mammalian neural cells.Among these neural cells,SK-N-SH represented the most sensitive cells to both chemical forms of mercury.