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.     

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℃.     

发挥城市基层组织作用,有效进行公众参与工作

根据作者从事环境评价工作的经验,结合北京市的城市建设项目的案例,说明在公众参与工作中结合中国城市基层组织特点,发挥基层组织作用,能够有效使公众参与环境保护、体现公众环境知情权、制止群体事件的发生,进一步做好公众参与工作。     

黄河入河沙漠颗粒物对磷酸盐的吸附特征

研究了黄河入河沙漠颗粒物在天然水(河水和海水)中对磷酸盐的吸附行为,用改进的Langmuir和Freundlich等温吸附模型对实验数据进行了拟合.结果表明,①改进的Langmuir等温吸附模型更适用于描述黄河入河沙漠颗粒物对磷酸盐的吸附特征,其物理意义更明确,得到的拟合参数更合理;②颗粒物对磷的最大吸附容量Qmax变化范围为41.322～357.143mg.kg-1,其中居延海颗粒物Y2的Qmax最大.Qmax与颗粒物(Y1～Y5)的有机质有着极显著的正相关关系;③除巴丹吉林沙漠颗粒物Y1外,颗粒物的临界磷平衡浓度EPC0值均大于其相应水体的磷浓度.Y1在黄河水中吸附磷的EPC0小于相应水体的磷浓度0.0100.053 mg.L-1,而在渤海海水中却大于相应水体的磷浓度0.1090.074 mg.L-1,表明Y1吸附了黄河水中的磷,进入渤海后Y1原有吸附可交换态磷NAP转移到海水中.其它颗粒物与相应水体进行磷交换的过程中存在着解吸磷的现象,具有向相应水体释放磷的能力;④黄河入河沙漠颗粒物对磷酸盐的吸附等温线是过溶液浓度轴0.00的交叉型等温线,这种新型交叉型吸附-解吸模型较好地解释了其吸附特征和天然粒子的双重性作用.     

KMnO4修饰面包酵母菌对Cd2+的吸附研究

研究了用KMnO4修饰面包酵母菌对溶液中Cd2+的吸附作用,探讨了不同KMnO4浓度、pH、吸附时间、Cd2+初始浓度、修饰酵母菌用量等5个因素对KMnO4修饰面包酵母菌吸附Cd2+的影响.结果表明,随着修饰剂KMnO4浓度的增大,修饰面包酵母菌的吸附能力增强,KMnO4浓度达到20 mmol·L-1时,吸附能力是相同...     

Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period

Considerable variations may exist in CH4 emissions from the Three Gorges Reservoir.     

Decolorization of dye solutions with Ruditapes philippinarum conglutination mud and the isolated bacteria

Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp.     

Seasonal and diurnal variations of atmospheric peroxyacetyl nitrate, peroxypropionyl nitrate, and carbon tetrachloride in Beijing

Atmospheric peroxyacetyl nitrate(PAN), peroxypropionyl nitrate(PPN), and carbon tetrachloride(CCl4) were measured from September 2010 to August 2011 in Beijing. PAN exhibited low values from mid-autumn to early spring(October to March) with monthly average concentrations ranging from 0.28 to 0.73 ppbV, and increased from early spring to summer(March to August), ranging from 1.37–3.79 ppbV. The monthly variation of PPN was similar to PAN, with low values(below detection limit to 0.18 ppbV) from mid-autumn to early spring, and a monthly maximum in September(1.14 ppbV). The monthly variation of CCl4was tightly related to the variation of temperature, exhibiting a minimum in winter(69.3 pptV) and a maximum of 180.6 pptV in summer. Due to weak solar intensity and short duration, PAN and O3showed no distinct diurnal patterns from morning to night during winter, whereas for other seasons, they both exhibited maximal values in the late afternoon(ca. 15:00 to 16:00 local time) and minimal values during early morning and midnight. Good linear correlations between PAN and PPN were found in autumn(R = 0.91), spring(R = 0.94), and summer(R = 0.81), with slopes of 0.130, 0.222, and 0.133, respectively, suggesting that anthropogenic hydrocarbons dominated the photochemical formation of PANs in Beijing. Positive correlation between PAN and O3 in summer with the low slopes( O3 / PAN) ranging from 9.92 to 18.0 indicated serious air pollution in Beijing, and strong negative correlation in winter reflected strong O3consumption by NO titration and less thermal decompositin of PAN.     

多级过滤技术在汽车工业废水处理尾水回用中的应用

某大型汽车厂设计采用多级过滤技术对工业废水处理尾水进行深度处理,再生后的中水回用于工业循环冷却水系统。介绍了多级过滤工艺的系统组成、工艺原理及处理效果。实际运行情况表明:采用多级过滤技术处理汽车工业废水处理后的尾水,系统运行稳定,出水水质良好,满足GB/T 19923—2005《再生水用作冷却用水的水质控制标准》的要求。     

上海市环保行政审批系统的设计与实现

上海市环保局行政审批系统采用流程控制和数据传输交换技术,构建了申报系统、审批系统、业务管理系统、跟踪监控系统四部分,实现了包括建设项目环评、固废、辐射等15项行政审批和23项非行政审批事项的“一口受理、一办到底”,通过信息技术实现了外网申报、内网审批,实现了环保审批流程优化再造和审批全过程公开透明,实现了“便民审批”、“高效审批”、“阳光审批”。