零价铁类Fenton试剂氧化降解废水中有机污染物的研究进展

综述了近年来国内外Fe0类Fenton试剂氧化反应降解废水中有机污染物的研究现状,介绍了Fe0-H2O2体系、紫外光-Fe0-H2O2体系和可见光-Fe0-H2O2体系处理有机污染物的机理、特点和效果,并对未来Fe0类Fenton试剂氧化反应体系处理有机污染物的发展前景进行了展望。     

Air quality assessment by tree bark biomonitoring in urban, industrial and rural environments of the Rhine Valley: PCDD/Fs, PCBs and trace metal evidence

Tree barks were used as biomonitors to evaluate past atmospheric pollution within and around the industrial zones of Strasbourg (France) and Kehl (Germany) in the Rhine Valley. The here estimated residence time for trace metals, PCBs and PCDD/Fs in tree bark is >10 years. Thus, all pollution observed by tree bark biomonitoring can be older than 10 years. The PCB baseline concentration (sum of seven PCB indicators (Σ₇PCB_ind)) determined on tree barks from a remote area in the Vosges mountains is 4 ng g⁻¹ and corresponds to 0.36 × 10⁻³ ng toxic equivalent (TEQ) g⁻¹ for the dioxin-like PCBs (DL-PCBs). The northern Rhine harbor suffered especially from steel plant, waste incinerator and thermal power plant emissions. The polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) concentrations analyzed in tree barks from this industrial area range between 392 and 1420 ng kg⁻¹ dry-weight (dw) corresponding to 3.9 ng TEQ_PCDD/Fs kg⁻¹ to 17.8 ng TEQ_PCDD/Fs kg⁻¹, respectively. Highest PCDD/F values of 7.2 ng TEQ kg⁻¹ to 17.8 ng TEQ kg⁻¹ have been observed close to and at a distance of <2 km southwest of the chemical waste incinerator. However, very close to this incinerator lowest TEQ dioxin-like PCB (TEQ_DL-PCB) values of 0.006 ng TEQ g⁻¹ have been found. On the other hand close to and southwest and northeast of the steel plant the values are comparatively higher and range between 0.011 ng TEQ g⁻¹ and 0.026 ng TEQ g⁻¹. However, even stronger Σ₇PCB_ind enrichments have been observed at a few places in the city center of Kehl, where ΣDL-PCB values of up to 0.11 ng TEQ g⁻¹ have been detected. These enrichments, however, are the result of ancient pollutions since recent long-term measurements at the same sites indicate that the atmospheric PCB concentrations are close to baseline. Emissions from an old landfill of waste and/or great fires might have been the reasons of these PCB enrichments. Other urban environments of the cities of Kehl and Strasbourg show significantly lower Σ₇PCB_ind concentrations. They suffer especially from road and river traffic and have typically Σ₇PCB_ind concentrations ranging from 11 ng g⁻¹ to 29 ng g⁻¹. The PCB concentration of 29 ng g⁻¹ has been found in tree bark close to the railway station of Strasbourg. Nevertheless, the corresponding TEQ_DL-PCB are low and range between 0.2 × 10⁻³ ng TEQ g⁻¹ and 7 × 10⁻³ ng TEQ g⁻¹. Samples collected near road traffic are enriched in Fe, Sb, Sn and Pb. Cd enrichments were found close to almost all types of industries. Rural environments not far from industrial sites suffered from organic and inorganic pollution. In this case, TEQ_DL-PCB values may reach up to 58 × 10⁻³ ng TEQ g⁻¹ and the corresponding V, Cr, Co, Ni, and Cd concentrations are comparatively high.     

Nationwide monitoring of atmospheric PCDD/Fs and dioxin-like PCBs in South Korea

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured in ambient air samples collected from different parts of South Korea in 2008, and the measured levels were used for assessing the spatial and temporal distribution of atmospheric PCDDFs and DL-PCBs in South Korea. The average concentrations of atmospheric PCDD/Fs and DL-PCBs among the 37 sites were 28 fg I-TEQ m⁻³ (ND ∼ 617) and 1 fg WHO-TEQ m⁻³ (ND ∼ 0.016). Elevated atmospheric levels of PCDD/Fs and DL-PCBs observed at residential/industrial sites and in the north-west of Korea, indicated a potential contribution and impacts of anthropogenic sources of PCDD/Fs and DL-PCBs. These levels were similar or lower than those previously reported in other ambient air surveys. Average concentrations of PCDD/Fs showed small seasonal variations (ANOVA analysis, p = 0.144). The highest concentrations of PCDD/Fs were observed during winter, followed by spring, autumn and summer. Atmospheric PCDD/Fs and DL-PCBs in South Korea rapidly decreased during the last 10 years (1998-2008), demonstrating the efficiency of stricter regulations and the application of best available technologies/best environmental practices at emission sources. Comparison of the congener profiles and principal component analysis showed that current atmospheric PCDD/Fs are mostly influenced by industrial sources and PCBs from old commercial PCB uses. Nationwide POPs monitoring will continue and allows an effective evaluation of the implementation of the Stockholm Convention on POPs.     

等离子体固态可燃物液化反应动力学分析

本文利用介质阻挡放电等离子体技术,对以煤和生物质为代表的固态可燃物液化反应机理进行研究,以期探索能源利用新途径.借助碰撞理论和Boltzman方程,对高能电子碰撞引发多种离解反应的速率常数进行数值模拟,计算结果和实验曲线对比,证明模型具有一定的适用性和可靠性.在一定的电子温度下,通过不同离解反应速率常数的对比,可以判断...     

有机膨润土的制备及其在6-硝废水处理中的应用

以CTMAB为改性剂制备有机膨润土,并用改性后的膨润土吸附6-硝废水.膨润土改性条件为:液固体积(mL)质量(g)比6∶1,pH值为1,反应温度为60℃,反应时间为1 h进行酸活化;将上述酸活化的膨润土按膨润土阳离子交换容量的100%加人CTMAB,反应时间为80 min得到有机膨润土;6-硝废水吸附条件为:取上述有机...     

基于对应分析法的废弃金属尾矿库重金属污染原位监测点优化研究

重金属污染物原位监测是对废弃金属尾矿库重金属污染治理的基础,由于缺乏基础监测数据,基础数据采集工作量巨大.采用对应分析法建立某尾矿库的土壤样本和污染物之间的联系,以达到优化监测点和监测因子的目的.将监测点和监测因子反映到同一因子轴的图形上,能清晰直观地表述监测点和污染物间的内在联系和分布特征;确定主监测点和主监测指标,...     

Effects of alkyl polyglycoside (APG) on composting of agricultural wastes

Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured.Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent.     

地震救援行动的影响因素分析

从探讨救援行动的概念和响应过程出发,在分析国内外相关资料的基础上,结合我国的实际情况,分析了影响地震救援行动的方面和因素,以及它们对救援行动可能产生的影响,以期为地震救援的理论和实践提供有益的补充。     

Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments

The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO₃) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1 %, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p?<?0.05) evaluated by Tenax TA extraction and a three-compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and nitrogen, ATP production, denitrifying bacteria count, and nitrate reductase activity. Such similar trend between OCP biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.     

Flotability and flotation separation of polymer materials modulated by wetting agents

The surface free energy, surface tension and contact angles were performed to investigate the properties of wetting agents. Adsorption of wetting agents changes wetting behavior of polymer resins. Flotability of polymer materials modulated by wetting agents was studied, and wetting agents change significantly flotability of polymer materials. The flotability decreases with increasing the concentration of wetting agents, and the wetting ability is lignin sulfonate (LS) > tannic acid (TA) > methylcellulose (MC) > triton X-100 (TX-100) (from strong to weak). There is significant difference in the flotability between polymer resins and plastics due to the presence of additives in the plastics. Flotation separation of two-component and multicomponent plastics was conducted based on the flotability modulated by wetting agents. The two-component mixtures can be efficiently separated using proper wetting agent through simple flotation flowsheet. The multicomponent plastic mixtures can be separated efficiently through multi-stage flotation using TA and LS as wetting agents, and the purity of separated component was above 94%, and the recovery was more than 93%.