Interface-mediated synthesis of monodisperse ZnS nanoparticles with sulfate-reducing bacterium culture

We have created a new method of ZnS nanospheres synthesis. By interface-mediated precipitation method (IMPM), monodisperse ZnS nanoparticles was synthesized on the particle surface of sulfate-reducing bacterium nutritious agar culture. Sulfate-reducing bacterium (SRB) was used as a sulfide producer because of its dissimilatory sulfate reduction capability, meanwhile produced a variety of amino acids acting as templates for nanomaterials synthesis. Then zinc acetate was dispersed into nutritious agar plate. Subsequently agar plate was broken into particles bearing much external surface, which successfully mediated the synthesis of monodisperse ZnS nanoparticles. The morphology of monodisperse ZnS nanospheres and SRB were examined by scanning electron microscopy (SEM), and the microstructure was investigated by X-ray diffraction (XRD). The thermostability of ZnS nanoparticles was determined by thermo gravimetric-differential thermo gravimetric (TG-DTG). The maximum absorption wavelengh was analysed with an ultraviolet-visible spectrophotometer within a range of 199–700 nm. As a result, monodisperse ZnS nanoparticles were successfully synthesized, with an average diameter of 80 nm. Maximum absorption wavelengh was 228 nm, and heat decomposed temperature of monodisperse ZnS nanoparticles was 596°C.     

Numerical simulation of alga growth and control in Dalian Bay

WAHMO model was used to simulate the distribution of pollutants in Dalian Bay, China as to predict well as the growth and control of alga. The observed and predicted values of main pollutants showed a good trend at all study locations and the different between them can be ignored. Simulation results illustrated that phosphate was one of limited factors to control algal growth at the location near the sewage outfall, meanwhile, away from the sewage outfall, the synergy of ammonium nitrogen and phosphate was the limited factor.     

Interface-mediated synthesis of monodisperse ZnS nanoparticles with sulfate-reducing bacterium culture

We have created a new method of ZnS nanospheres synthesis. By interface-mediated precipitation method (IMPM), monodisperse ZnS nanoparticles was synthesized on the particle surface of sulfate-reducing bacterium nutritious agar culture. Sulfate-reducing bacterium (SRB) was used as a sulfide producer because of its dissimilatory sulfate reduction capability, meanwhile produced a variety of amino acids acting as templates for nanomaterials synthesis. Then zinc acetate was dispersed into nutritious agar plate. Subsequently agar plate was broken into particles bearing much external surface, which successfully mediated the synthesis of monodisperse ZnS nanoparticles. The morphology of monodisperse ZnS nanospheres and SRB were examined by scanning electron microscopy (SEM), and the microstructure was investigated by X-ray diffraction (XRD). The thermostability of ZnS nanoparticles was determined by thermo gravimetric-differential thermo gravimetric (TG-DTG). The maximum absorption wavelengh was analysed with an ultravioletvisible spectrophotometer within a range of 199-700 nm. As a result, monodisperse ZnS nanoparticles were successfully synthesized, with an average diameter of 80 nm. Maximum absorption wavelengh was 228 nm, and heat decomposed temperature of monodisperse ZnS nanoparticles was 596℃.     

Identification of key factors governing chemistry in groundwater near the water course recharged by reclaimed water at Miyun County, Northern China

Reclaimed water was successfully used to recover the dry Chaobai River in Northern China, but groundwater may be polluted. To ensure groundwater protection, it is therefore critical to identify the governing factors of groundwater chemistry. Samples of reclaimed water, river and groundwater were collected monthly at Chaobai River from January to September in 2010. Fifteen water parameters were analyzed. Two kinds of reclaimed water were different in type (Na-Ca-Mg-Cl-HCO3 or Na-Ca-Cl-HCO3 ) and concentration of nitrogen. The ionic concentration and type in river were similar to reclaimed water. Some shallow wells near the river bed had the same type (Na-Ca-Mg-Cl-HCO3 ) and high concentration as reclaimed water, but others were consistent with the deep wells (Ca-Mg-HCO3 ). Using cluster analysis, the 9 months were divided into two periods (dry and wet seasons), and all samples were grouped into several spatial clusters, indicating different controlling mechanisms. Principal component analysis and conventional ionic plots showed that calcium, magnesium and bicarbonate were controlled by water-rock interaction in all deep and some shallow wells. This included the dissolution of calcite and carbonate weathering. Sodium, potassium, chloride and sulfate in river and some shallow wells recharged by river were governed by evaporation crystallization and mixing of reclaimed water. But groundwater chemistry was not controlled by precipitation. During the infiltration of reclaimed water, cation exchange took place between (sodium, potassium) and (calcium, magnesium). Nitrification and denitrification both happened in most shallow groundwater, but only denitrification in deep groundwater.     

环境影响评价公众意见调查的真实性评价探讨

公众参与在环境影响评价中扮演着重要的角色,认真做好公众意见调查工作,可以促进环境影响评价工作公正、公开、公平地发展。虽然在建设项目环境影响评价工作中,公众参与起到了一定的积极作用,但是在公众参与的实际过程中,还是遇到了许多具体问题,本文对环境影响评价工作中公众意见调查的结果应如何评估,提出意见和建议。     

ABR反应器中COD/SO_4~(2-)值和硫酸盐负荷对SO_4~(2-)去除影响

利用厌氧折流板反应器,分别考察了反应器启动,及不同COD/SO42-比值和硫酸盐负荷对模拟废水中SO42-去除的影响。实验在(32±0.1)℃,pH为6.0⁶.5的条件下连续运行。结果表明:ABR经过约90 d的启动驯化阶段后,进水硫酸盐及COD浓度分别为1 500 mg/L和3 000 mg/L,水力停留时间为12 h条件下,硫酸盐去除率达到了92%。固定COD/SO42-比值为2.5时,随着进水SO42-浓度的增加(1 5006.5的条件下连续运行。结果表明:ABR经过约90 d的启动驯化阶段后,进水硫酸盐及COD浓度分别为1 500 mg/L和3 000 mg/L,水力停留时间为12 h条件下,硫酸盐去除率达到了92%。固定COD/SO42-比值为2.5时,随着进水SO42-浓度的增加(1 500³ 500 mg/L),SO42-去除率逐渐下降,最低为60%,相反SO42-去除速率随着硫酸盐浓度的增加而增加,最大为7.98 kg(/m3.d);维持恒定的硫酸盐浓度(1 500 mg/L),逐渐缩短水力停留时间以提高反应器中硫酸盐负荷,SO42-去除率呈现先上升后下降的复杂变化趋势,当水力停留时间为6 h时,SO42-去除率达到最大;随着COD/SO42-比值的提高,硫酸盐去除能力增强,且反应体系对硫酸盐负荷的耐受能力也逐渐增强。     

OMS-2负载Pt催化剂的制备及其催化氧化性能研究

采用前掺杂法、沉积-沉淀法和浸渍法制备了氧化锰八面体分子筛(OMS-2)负载Pt催化剂(Pt/OMS-2),对所制催化剂进行了结构和织构表征。并研究了不同制备方法和沉积-沉淀法中不同制备(Pt负载量和溶液的pH值)对Pt/OMS-2催化氧化CO性能的影响。结果表明,沉积-沉淀法制备的Pt/OMS-2-DP催化剂活性最好(T100=100℃)。这与Pt/OMS-2-DP催化剂中Pt颗粒大小及OMS-2载体与Pt之间存在强相互作用有关。Pt负载量明显影响Pt/OMS-2-DP催化剂的催化活性,3Pt/OMS-2-DP催化剂(Pt=3.0 wt%)催化活性最高,这是由于适当Pt负载量,Pt颗粒较小,并与载体OMS-2的相互作用较强,能较好地活化OMS-2晶格氧。pH值对Pt/OMS-2-DP催化剂催化性能影响较大,这与OMS-2的等电点和Pt在不同溶液中存在不同Pt配位体形式有关。     

无锡市大气中类二噁英多氯联苯污染水平

为了了解无锡市大气中类二噁英多氯联苯(Dioxin-like PCBs,DL-PCBs)水平,利用大流量空气采样器在无锡市分别采集了6个气相和6个颗粒相大气样品,气相色谱-质谱(GC-NCI-MS)测定样品中12种类二噁英多氯联苯。结果显示,大气样品中∑_(12)DL-PCBs的总浓度(气相+颗粒相)为1157～2 747 fg/m³,平均浓度为1759 fg/m3,平均浓度为1759 fg/m³。其中,气相的浓度为11 124～2 721 fg/m3。其中,气相的浓度为11 124～2 721 fg/m³,平均值为1 701fg/m3,平均值为1 701fg/m³;颗粒相的浓度为26～143 fg/m3;颗粒相的浓度为26～143 fg/m³,平均值为58fg/m3,平均值为58fg/m³。气相中∑_(12)DL-PCB含量占总量的97%,而颗粒相仅占3%。DL-PCBs的总毒性当量(气相+颗粒相)为2.16～4.47fg TEQ/m3。气相中∑_(12)DL-PCB含量占总量的97%,而颗粒相仅占3%。DL-PCBs的总毒性当量(气相+颗粒相)为2.16～4.47fg TEQ/m³,平均值为3.53fg TEQ/m3,平均值为3.53fg TEQ/m³。DL-PCBs单体中PCB-118的浓度最高,平均占总浓度的54%,其次是PCB-105和PCB-77,PCB+81在所有样品中均未检出。在所有DL-PCBs中,毒性当量浓度的主要贡献者为PCB-126,其平均贡献率为95%,其次为PCB-169,平均贡献率为3%。     

封闭式博物馆室内空气颗粒物离子成分特征

采用气体悬浮物粒子监测仪和NanoMoudi-Ⅱ125A型分级采样器对某封闭式博物馆进行颗粒物数浓度监测和颗粒物采样,测定了不同粒径段颗粒物中的主要离子组分。结果表明,监测期间粗颗粒物(粒径≥2.5μm)、细颗粒物(粒径在0.1~2.5μm之间)和超细颗粒物(粒径≤0.1μm)质量浓度分别为20.50~24.38μg/m3、23.39~24.08μg/m3和16.02~17.48μg/m3。颗粒物数浓度集中在粒径≤0.3μm范围,PM1数浓度占PM10数浓度的97%以上,游客扰动和清洁活动使粗颗粒物数浓度增加了8~172倍。SO42-、NO3-、NH4+峰值出现在0.32~0.56μm粒径段,Na+、Cl-分布较平均,K+峰值出现在0.32~0.56μm和3.2~5.6μm粒径段,Mg2+的峰值出现在3.2~5.6μm粒径段,Ca2+峰值出现在1.8~3.2μm粒径段;总有机酸根离子无明显峰值;乙酸根离子浓度为1.238μg/m3,高于甲酸根和乙二酸根。颗粒物的阳/阴离子比均值为2.83,说明阴离子测定可能有缺失,如碳酸盐等。颗粒物中水溶性离子浓度水平和粒径分布受游客影响不明显,受室外空气输送的影响较大。     

矿区环境影响后评估理论支撑体系构建

介绍了矿区环境影响后评估理论体系研究的重要性,构建了一条主线,一个桥梁,二个基点和二条原则的理论体系框架,并分别对理论体系的主线、系统损伤机制和系统抵御机制进行了具体分析,指出了主线理论和两大机制所涉及的具体生态/经济学原理,最后总结了矿区环境影响后评估的理论支撑体系核心机理.