SERES 2000COD自动分析仪几个技术问题

影响SERES2000COD自动监测仪数据质量因素很多,现就实践中影响较大的关键性的几个技术问题提出来讨论:包括仪器工作原理,工作曲线的确立,配制的化学试剂准确性对监测数据结果的影响及蠕动泵管的使用和更换条件.严格遵守SERES2000COD自动监测仪操作程序最大限度地发挥它所具有性能,提高数据的准确性.     

畜禽养殖过程抗生素使用与耐药病原菌及其抗性基因赋存的研究进展

兽用抗生素在提高畜禽生产性能、防治疾病方面发挥着重要作用,目前全球超过一半以上抗生素用于畜禽养殖,畜禽养殖源耐药病原菌、抗性基因及其传播风险愈益得到人们的重视。我国是畜禽养殖和抗生素使用大国,但兽用抗生素使用、病原菌耐药水平及其抗性基因类型等数据却较为缺乏,不利于今后畜禽养殖源耐药病原菌及其传播风险的控制。因此,本文通过文献调研,对我国和主要发达国家的兽用抗生素使用情况、畜禽养殖源耐药病原菌及其携带的抗性基因、基因移动元件以及向环境传播的途径进行分析、总结,以期为规范合理用药、降低耐药病原菌及其抗性基因传播风险,建立从畜禽养殖场至公共环境全过程的抗性污染控制链条提供借鉴。     

矿山地质灾害及其对策

本文就矿山开发所产生的各种环境地质灾害及其对策进行了扼要介绍,并列举了国内外有关灾害实例加以论证。     

Kinetic analysis of photocatalytic oxidation of gas-phase formaldehyde over titanium dioxide

Degradation of formaldehyde with different initial concentration over titanium dioxide was carried out in a photocatalytic reactor. Photocatalytic rates were well described by the simplified Langmuir-Hinshelwood model. The kinetic analysis shows that the apparent first-order reaction coefficient is lower and half-life of photocatalysis is longer for low concentration than for high concentration formaldehyde. A network formation model of the photocatalytic products was established. Experimental results and analysis demonstrate that carbon dioxide concentration and carbon monoxide concentration in gas phase vary exponentially with the illumination time and may be even higher than gas-phase formaldehyde concentration if there is much pre-adsorbed formaldehyde in adsorption equilibrium on catalysts before illumination. Carbon monoxide is found to be one of the by-products during formaldehyde photooxidation.     

Heterogeneous activation of persulfate by CuMgAl layered double oxide for catalytic degradation of sulfameter

In this study, a series of CuMgAl layered double oxides (CuMgAl-LDOs) were obtained via calcination of CuMgAl layered double hy-droxides (CuMgAl-LDHs) synthesised via a co-precipitation method. The results show that CuMgAl-LDO can be prepared using an optimal Cu:Mg:Al molar ratio of 3:3:2, NaOH:Na2CO3 molar ratio of 2:1, and calcination temperature of 600 °C. CuMgAl-LDO is a char-acteristic of mesoporous material with a lamellar structure and large specific surface area. The removal efficiency of sulfameter (SMD) based on CuMgAl-LDO/persulfate (PS) can reach>98％over a wide range of initial SMD concentrations (5–20 mg L-1). The best removal efficiency of 99.49％was achieved within 120 min using 10 mg L-1 SMD, 0.3 g L-1 CuMgAl-LDO, and 0.7 mmol L-1 PS. Kinetic analysis showed that the degradation of SMD was in accordance with a quasi-first-order kinetic model. The stability of the CuMgAl-LDO catalyst was verified by the high SMD removal efficiency (> 97％ within 120 min) observed after five recycling tests and low copper ion leaching concentration (0.89 mg L-1), which is below drinking water quality standard of 1.3 mg L-1 permittable in the U.S. Radical scavenging experiments suggest that SO·4- is the primary active species participating in the CuMgAl-LDO/PS system. Moreover, our mechanistic investigations based on the radical scavenging tests and X-ray photoelectron spectroscopy (XPS) results indicate that Cu(II)–Cu(III)–Cu(II) circulation is responsible for activating PS in the degradation of SMD and the degradation pathway for SMD was deduced. Accordingly, the results presented in this work demonstrate that CuMgAl-LDO may be an efficient and stable catalyst for the activation of PS during the degradation of organic pollutants. ? 2020, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communi-cations Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).     

楼控系统中冷水泵节能优化控制分析

以某卷烟厂生产车间制冷站改造为例,通过对冷冻泵冷却泵的特性分析,提出具体节能优化改造措施.通过对水泵并联工况分析,提出相应的调频控制策略,增加旁通回路调节及水泵出口电动阀调节等技术手段,优化系统的工艺性能.通过对水泵优化控制,达到节能降耗的目的.     

不同通风条件下堆肥处理死鸡效果研究

利用强制通风密闭箱式堆肥系统处理死鸡,分别在冬季和春季进行两期堆肥处理死鸡试验,冬季试验设置0.035、0 025和0.015m3·m-3·min-13个通风量,春季试验设置0.045、0.035和0.025 m3,m-3·min-1 3个通风量,研究不同通风条件下堆肥处理死鸡过程中死鸡的分解效果.结果表明,冬季和春季堆肥试验过程中,各通风处理条件下死鸡的分解率均在85％以上,冬季堆肥试验通风量为0.035m3·m-3.min-1时,处理效果最好,死鸡分解率为90.5％;春季堆肥试验通风量为0.045 m3·m-3·min-1时,处理效果最好,死鸡分解率为90.2％     

Methyl siloxanes in road dust from a large silicone manufacturing site in China: implications of human exposure

Environmental Science and Pollution Research - Methyl siloxanes are becoming increasingly prevalent in the environment because of their extensive use in various consumer products. Little is known...     

Methyl siloxanes in soils from a large silicone-manufacturing site,China: concentrations,distributions and potential human exposure

Environmental Geochemistry and Health - Methyl siloxanes are widely found in the environment, but little is known about the distributions of these chemicals in soils especially in areas where they...     

热颗粒和热辐射共同作用阴燃点燃松针燃料床：数值研究

建立了热颗粒和热辐射共同作用下阴燃点燃松针燃料床的二维数值模型,计算得到了热颗粒和热辐射单独点燃以及共同作用点燃的临界条件,分析了燃料床的点燃过程。与前人实验数据对比表明数值模型能够较好预测临界点燃条件。金属热颗粒单独作用时点火所需的临界温度与颗粒直径呈双曲线关系。金属热颗粒与热辐射共同作用时,临界辐射热通量呈现出随颗粒温度和直径的增加而显著减小的趋势。热辐射持续供热能有效维持表层炭氧化反应,两者共同作用下点燃危险性增加。研究同时发现,燃料含水率对共同作用下的临界辐射热通量有较大影响。