Advanced treatment of biologically pretreated coal gasification wastewater by a novel heterogeneous Fenton oxidation process

Sewage sludge from a biological wastewater treatment plant was converted into sewage sludge based activated carbon(SBAC) with Zn Cl2 as activation agent, which was used as a support for ferric oxides to form a catalyst(Fe Ox/SBAC) by a simple impregnation method.The new material was then used to improve the performance of Fenton oxidation of real biologically pretreated coal gasification wastewater(CGW). The results indicated that the prepared Fe Ox/SBAC significantly enhanced the pollutant removal performance in the Fenton process, so that the treated wastewater was more biodegradable and less toxic. The best performance was obtained over a wide p H range from 2 to 7, temperature 30°C, 15 mg/L of H2O2 and 1 g/L of catalyst, and the treated effluent concentrations of COD, total phenols,BOD5 and TOC all met the discharge limits in China. Meanwhile, on the basis of significant inhibition by a radical scavenger in the heterogeneous Fenton process as well as the evolution of FT-IR spectra of pollutant-saturated Fe Ox/BAC with and without H2O2, it was deduced that the catalytic activity was responsible for generating hydroxyl radicals, and a possible reaction pathway and interface mechanism were proposed. Moreover, Fe Ox/SBAC showed superior stability over five successive oxidation runs. Thus, heterogeneous Fenton oxidation of biologically pretreated CGW by Fe Ox/SBAC, with the advantages of being economical, efficient and sustainable, holds promise for engineering application.     

Disruption of iron homeostasis and resultant health effects upon exposure to various environmental pollutants: A critical review

Environmental pollution has become one of the greatest problems in the world, and the concerns about environmental pollutants released by human activities from agriculture and industrial production have been continuously increasing. Although intense efforts have been made to understand the health effects of environmental pollutants, most studies have only focused on direct toxic effects and failed to simultaneously evaluate the long-term adaptive, compensatory and secondary impacts on health. Burgeoning evidence suggests that environmental pollutants may directly or indirectly give rise to disordered element homeostasis, such as for iron. It is crucially important to maintain concerted cellular and systemic iron metabolism. Otherwise, disordered iron metabolism would lead to cytotoxicity and increased risk for various diseases, including cancers. Thus, study on the effects of environmental pollutants upon iron homeostasis is urgently needed. In this review, we recapitulate the available findings on the direct or indirect impacts of environmental pollutants, including persistent organic pollutants (POPs), heavy metals and pesticides, on iron homeostasis and associated adverse health problems. In view of the unanswered questions, more efforts are warranted to investigate the disruptive effects of environmental pollutants on iron homeostasis and consequent toxicities.     

我国环保产业研究现状分析——基于宏观视角的文献述评

通过文献研究法,基于宏观视角对我国环保产业研究成果进行梳理。当前,我国的环保产业研究成果初具规模,研究重点在于环保产业的现状分析、问题探讨以及对策研究,包括环保产业各主体间博弈均衡、环保产业的技术支持、投融资机制等内容。未来环保产业研究应注意环保产业竞争力的科学评价、环保产业主体间的良性互动及其合力的达成以及环保技术评价和兑现。     

某兽药厂废气治理改造工程实例

结合江苏常州某兽药厂废气污染的监测和改造经验,总结了兽药厂废气污染特点,并采用低温等离子体、碱液吸收和植物除臭剂等综合治理技术有效控制了废气污染。低温等离子体净化设备采用2组串联式布置,反应器内设计风速≤1 m/s,反应时间≥4 s。植物除臭净化设备利用原有活性炭吸附塔改造,改造成本较低。改造设备总投资约60万元,废气处理系统运行费用约788元/d。相关监测数据表明上述工艺在设备正常运行时可确保污染物达标排放。     

多相混输管道内水合物形成过程研究进展

针对由水合物造成的管道堵塞,特别是油-气-水多相混输领域水合物堵塞尤为严重的问题,系统调研了水合物在多相混输管道内形成机理的研究进展,着重介绍了富油相/富水相和富气相两个体系;基于水合物颗粒微观作用机理,详细阐述了水合物颗粒间的黏聚和水合物颗粒与管壁间的黏附作用;指出了多相混输管道内水合物形成过程的未来研究方向.     

高超声速钝锥等离子体鞘套电波传播特性研究

目的改进现阶段地面指控站对临近空间高超声速飞行器的通信和测控效果。方法采用计算流体动力学技术模拟钝锥体在不同高超声速飞行条件下的头身部绕流流场特性,并运用相关公式建立钝锥等离子体鞘套电磁模型。然后运用改进的移位算子时域有限差分方法计算电磁波经过等离子体鞘套的传播特性。结果计算结果表明,电磁波在等离子体鞘套内的传播特性在频率处于最大等离子体频率附近时发生转折,电磁波通过等离子体鞘套的透射效果与飞行工况和入射波条件密切相关。相对其他入射角度,当电磁波垂直于飞行体物面入射到等离子体鞘套尾部时的电磁波衰减较小。飞行高度增加或飞行速度减小时,等离子体鞘套对电磁波的衰减效应将减弱。结论该研究可为有效测控临近空间高超声速飞行器、缓解再入通讯中断现象提供一定的技术突破方法。     

钛白石膏危险特性鉴别及处置对策研究

钛白石膏是硫酸法钛白粉厂在酸性废水中和处理过程中产生的固体废物,是一种有毒有害废物.对某钛白粉厂排放的该固废进行腐蚀性、浸出毒性、急性毒性以及毒性物质含量鉴别,结果表明,该固废不属于危险废物.根据现阶段资源化利用和无害化处置技术水平和该钛白粉厂排放实际情况,结合当地土地开发利用状况,提出用于已围滩涂填方的处置对策方案,既使钛白石膏得到无害化处置,又能满足围垦造地对塘渣的需求,一举两得.     

Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust

Mineral dust is one of the major aerosols in the atmosphere. To assess its impact on trace atmospheric gases, in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO₂ on the surface of ambient Chinese dust over the temperature range from 258 to 313 K. The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence. Similar to a previous study on NO₂ uptake on mineral aerosols, the uptake coefficients are mainly on the order of 10^− 6 for the Chinese dust, when BET areas are taken into account. HONO was observed as a product, and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied. The complete dataset from this study was compiled with previous literature determinations. Atmospheric implications of the heterogeneous reaction between NO₂ and mineral dust are also discussed, in an effort to understand this important heterogeneous process.     

黑碳气溶胶的测量方法对比研究

大气黑碳气溶胶主要有光学分析法、热学分析法以及热光结合分析法。利用苏州南门国控子站的碳分析数据,对三种黑碳浓度测量方法进行对比并分析其差异来源。主要得出以下结论:黑碳仪衰减系数无普适标准,热学分析法使有机碳碳化、元素碳不完全分离,TOT法协议设置存在争议是三种方法存在差异的主要原因。     

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons, and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25th to 27th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th–8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene (T/B) during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was 5.8 ppb/ppb, significantly higher than the values of 0.2–1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and 0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.