Microwave-assisted synthesis and environmental remediation: a review

Environmental Chemistry Letters - Microwave irradiation has been intensively studied for environmental remediation, e.g., for wastewater treatment, and for synthesis, to take advantages of the...     

黄土高原发展与生态改善

“陇中之苦,甲于天下”。这是黄土高原对甘肃定西地区和宁夏的西吉、海原、固原(西海固)的历史性结论。政府和国际援助多年来的努力使这一带的贫困状况有所减轻。但是至今这种状况仍然没有全部改观,特别是在远离城市和道路的深山。“三西”依然是中国最贫困的地区。究其原因,降水少而干旱,是生产效率低下的主因。频繁的旱灾往往使粮食绝收,人畜干渴而死;而夏秋集中的豪雨及多发的冰雹,又往往毁坏农作物和冲毁田地。     

On some studies about the dynamic mechanisms of carbon monoxide flow and diffusion during high energy gas fracturing

High energy gas fracturing (HEGF) technique has been one of central stimulating measures to enhance oil recovery in low permeability reservoirs. But, in recently few years, some serious CO poisoning accidents took place in oilfields here in China. It is very important to reveal the dynamic mechanisms of carbon monoxide flow and diffusion to operating safety during high energy gas fracturing. In this paper, some dynamic mechanisms of carbon monoxide CO flowing inside a oil wellbore and diffusion on the top of the well during high energy gas fracturing were studied with fluid/gas hydrodynamics. The CO flow model within a wellbore and the diffusion model in air were established. The key factors affecting CO flow and diffusion such as wellbore pressure, gas-oil ratio, wind speed, leakage speed, air-permanence were inspected with mathematical simulation. It will be of significance to provide an important guidance for monitoring and preventing CO poisoning accidents during high energy gas fracturing.     

Effect of the chlortetracycline addition method on methane production from the anaerobic digestion of swine wastewater

Effects of antibiotic residues on methane production in anaerobic digestion are commonly studied using the following two antibiotic addition methods：（1） adding manure from animals that consume a diet containing antibiotics, and（2） adding antibiotic-free animal manure spiked with antibiotics. This study used chlortetracycline（CTC） as a model antibiotic to examine the effects of the antibiotic addition method on methane production in anaerobic digestion under two different swine wastewater concentrations（0.55 and 0.22 mg CTC/g dry manure）. The results showed that CTC degradation rate in which manure was directly added at 0.55 mg CTC/g（HSPIKE treatment） was lower than the control values and the rest of the treatment groups. Methane production from the HSPIKEtreatment was reduced（p 〈 0.05） by 12% during the whole experimental period and 15% during the first 7 days. The treatments had no significant effect on the pH and chemical oxygen demand value of the digesters, and the total nitrogen of the0.55 mg CTC/kg manure collected from mediated swine was significantly higher than the other values. Therefore, different methane production under different antibiotic addition methods might be explained by the microbial activity and the concentrations of antibiotic intermediate products and metabolites. Because the primary entry route of veterinary antibiotics into an anaerobic digester is by contaminated animal manure, the most appropriate method for studying antibiotic residue effects on methane production may be using manure from animals that are given a particular antibiotic, rather than adding the antibiotic directly to the anaerobic digester.     

砂石加工废水处理工艺研究

通过对砂石加工废水水质特性的研究可知,该类废水悬浮物浓度高、沉降性能好、且随时间推移,沉降泥渣的比阻呈增大趋势,泥渣的脱水越来越困难。在研究的基础上提出了处理该类废水的新工艺,并在中试规模将其与现行处理工艺进行了比较。结果表明,新工艺运行稳定、处理成本较低,为0.53元/吨水、泥渣脱水历时短、排泥管不易堵塞,较好地解决了废水中悬浮物沉降后泥渣的处理与排放之间的矛盾,SS去除率为99.8%,处理效果较好,可广泛应用于工程设计。     

城市生态文明建设评价指标体系构建

城市作为人类环境问题和危机产生的重要策源地,建立反映城市生态环境问题和生态文明建设状态的评价指标体系,依据评价结论,指导城市生态文明建设十分必要。文章在城市作为社会—经济—自然复合人工生态系统的理论基础上,分析了社会生态亚系统、经济生态亚系统及自然生态亚系统相互作用关系和城市生态系统主要生物成分组成、结构与功能关系,系统的构建了符合中国国情的城市生态文明评价指标体系。该体系以生态经济、生态环境质量、生态社会为评价要素,下设12个一级指标及42个二级指标,为评价中国城市生态文明建设水平提供科学依据。     

原子吸收分光光度计测定铜含量的不确定度评定

铜是机体必需的微量元素之一,对人体的身体健康影响巨大,若水中铜元素含量超过0．01mg/l,则可影响和制约水体自净能力的发挥,导致水体污染,并产生较大的毒性,致使水生生物难以生存与生长。本文结合废水中铜含量不确定度的评定情况,探讨原子吸收分光光度计测定铜含量的不确定度评定,为铜含量不确定度的评定提供一定的参考借鉴价值。     

石化行业挥发性有机物源强核算及LDAR技术的应用研究

石化行业排放的挥发性有机物(VOCs)是引发大气环境问题的重要污染物,有效控制VOCs的排放已经成为现阶段中国大气环境治理领域中的热点问题.泄漏检测与修复技术(LDAR)是发现和修复工艺装置泄漏的一种源项控制技术.通过对LDAR技术的文献及石化行业的应用调研,总结了LDAR技术国内外应用进展,挥发性有机物源强的核算方法,重点介绍了LDAR技术在石化行业开展的实施流程及潜在的效益.对石化行业开展泄漏检测与修复工作,减少挥发性有机物无组织的排放起到借鉴作用.