ZnO/氧化石墨烯的制备及其对亚硝酸盐的光催化降解

利用沉淀法制备了ZnO光催化剂,并将其负载在氧化石墨烯上,制得ZnO/氧化石墨烯复合材料,研究了该复合材料对亚硝酸钠的光催化降解效果。采用XRD和SEM技术对光催化剂进行表征。考察了初始亚硝酸钠质量浓度、溶液pH、ZnO/氧化石墨烯加入量对亚硝酸钠降解效果的影响。表征结果显示：ZnO/氧化石墨烯晶体的晶型发育良好、结晶度高;新生成的混晶结构提高了催化剂的光催化活性。实验结果表明：在初始亚硝酸钠质量浓度246 mg/L、溶液pH 5、ZnO/氧化石墨烯加入量1.0 g/L的条件下,经过150 min的紫外光降解,亚硝酸钠的质量浓度降至70 mg/L,亚硝酸钠的降解率为71.38%;ZnO与氧化石墨烯的协同效应有效提高了光催化反应体系的效率,ZnO/氧化石墨烯对亚硝酸钠的降解能力远高于氧化石墨烯和ZnO。     

加拿大的船舶油污损害赔偿机制及运行经验

加拿大是世界上最早通过立法建立船舶溢油赔偿机制的国家。现在加拿大采用国际机制和国内机制相结合的办法较好地解决了油轮和非油轮的油污损害赔偿问题，本言语概括总结了该机制的特点和经验。     

Molecular diversity of arbuscular mycorrhizal fungi at a large-scale antimony mining area in southern China

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the community composition of AMF under natural conditions in soils contaminated by antimony (Sb). The objective of this study was to investigate the characteristics of AMF molecular diversity, and to explore the effects of Sb content and soil properties on the AMF community structure in an Sb mining area. Four Sb mine spoils and one adjacent reference area were selected from around the Xikuangshan mine in southern China. The association of AMF molecular diversity and community composition with the rhizosphere soils of the dominant plant species was studied by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results from all five studied sites showed that the diversity of AMF decreased with increasing Sb concentration. Principal component analysis (PCA) indicated that the AMF community structure was markedly different among these groups. Further redundancy analysis (RDA) showed that Sb contamination was the dominating factor influencing the AMF community structure in the Sb mine area. However, the multivariate analysis showed that, apart from the soil Sb content, extractable nitrogen content and organic matter content also attributed to AMF sequence distribution type. Some AMF sequences were only found in the highly contaminated area and these might be ideal candidates for improving phytoremediation efficiency in Sb mining regions. Gene sequencing analysis revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant AMF genus in the studied Sb mining area.     

Characterization of coal burning-derived individual particles emitted from an experimental domestic stove

Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy(TEM) coupled with energy-dispersive X-ray spectrometry(EDX). The coal burning-derived individual particles were classified into two groups: carbonaceous particles(including soot aggregates and organic particles) and non-carbonaceous particles(including sulfate, mineral and metal particles). The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich,Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.     

新型絮凝剂SFC在污泥脱水中应用的研究

向污水处理厂的剩余污泥中投加相对于干污泥重量0.5％的SFC,在0.4bar的真空度下过滤,污泥的合水率由99.5％降至75％,污泥的体积降至原来的1/50,燃烧热值增大70倍,污泥比阻减少一倍多,而且泥饼的剥离性能好,滤液澄清度高.     

改性木屑对水中刚果红的吸附性能研究

对十六烷基三甲基溴化铵(CTAB)改性木屑用于水中刚果红(CR)的去除进行了研究.用扫描电子显微镜(SEM)和傅里叶红外光谱分析仪(FTIR)对木屑和改性木屑的性能进行表征.探讨了反应时间、pH、温度、剂量以及离子强度对改性木屑去除CR的影响.实验结果表明,CTAB改性后的木屑对刚果红的吸附量明显增大,改性前后木屑的最大吸附量分别为30.30和111.36 mg·g-1.反应过程在前20 min内反应速率很快,并约在120 min内达到吸附平衡.吸附动力学符合伪二级动力学模型.最佳反应温度为328 K,吸附剂最适投加量为0.09 g,吸附量的大小与溶液的初始pH值有关,且增加盐浓度,改性木屑的吸附能力增加.吸附等温线符合Langmuir方程,且吸附过程为吸热反应.     

Adsorptive removal of antibiotics from water using magnetic ion exchange resin

The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange(MIEX) resin was applied for removing three commonly-used antibiotics, sulfamethoxazole(SMX), tetracycline(TCN) and amoxicillin(AMX) from water.The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/m L at 25°C,respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model(R~2= 0.99), and the adsorption isotherm data were well described by the Langmuir model(R~2= 0.97). Solution p H exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral p H.The MIEX resin could be easily regenerated by 2 mol/L Na Cl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.     

环境因素对苏州河市区段底泥内源磷释放的影响

以苏州河市区段作为研究对象，利用实验模拟的方法，研究和探讨了环境因素(温度，pH，厌氧、好氧，微生物)对富含有机物的底泥内源磷释放的影响。结果表明：(1)在外界环境温度分别为5、10、15、25℃的条件下，底泥内源磷释放达到动态平衡时，上覆水中磷的含量分别为0．45、0．57、0．77、1．40mg／L，反映较低的环境温度不利于内源磷的释放；环境温度的升高，能够加速底泥磷的释放；(2)pH为5．0—8．0，底泥内源磷释放量较小；当pH升至11．0时，底泥的释磷量显著增加。(3)底泥中的有机物，在好氧状态下，能加速其内源磷的释放。(4)在微生物的作用下，底泥内源磷释放具有明显的增加趋势。     

烟道喷浆脱除烟气中二氧化硫的试验研究

在长３．５ｍ,断面积为１５０ｍｍ×１５０ｍｍ的立式反应吕中进行了烟道喷石灰浆和电石渣浆脱除烟气中ＳＯ２的模拟试验,得出出口温距,钙硫摩尔比,雾化气液比,ＳＯ２入口浓度,烟气入口温度和气体停留时间对脱硫效率的影响规律。     

生物絮凝剂在纸箱废水处理中的实验研究

文章将微生物絮凝剂产生单菌M－3和M－2共同培养,获取生物絮凝剂,进行提取生物絮凝剂粗品,处理某纸箱厂废水。对生物絮凝剂投加量、Ca^2＋离子浓度、pH值的影响条件进行较系统的研究,绘制出单一因素对生物絮凝剂处理效果影响的曲线,确定生物絮凝剂处理纸箱厂废水的最适条件,进行正交实验。实验表明单菌微生物絮凝剂絮凝率在92％以上,COD去除率接近55％,氨氮去除率也达到89％。