天然沸石负载TiO2光催化降解敌敌畏和对硫磷

以钛酸丁酯为原料,以天然沸石作载体负载TiO2制备光催化剂;并采用高压汞灯为光源,用负载型TiO2光催化降解敌敌畏和对硫磷.结果表明,浓度为1.2×10-4mol/L的农药光照2 h左右可完全被光催化氧化为PO3-4.同时,还研究了合成光催化剂的处理温度、溶液的初始pH值、过氧化氢浓度等对负载TiO2光催化降解的影响.     

垃圾焚烧后的无机渣作水泥混合材料的研究

对垃圾焚烧后的无机渣粉末用作水泥混合材料进行了研究。结果表明．无机渣可作为火山灰质活性混合材用于水泥生产。水泥的安定性、凝结时间、标准稠度用水量均符合国家标准。     

典型联合处理技术去除甲基叔丁基醚污染的研究进展

甲基叔丁基醚(MTBE)作为汽油添加剂的广泛使用造成了世界范围内的环境污染.考虑到其毒性及高水溶性、抗降解性等,会在环境中造成持久性污染.因此,开发高效便捷的处理技术已刻不容缓.单一的降解方法存在不同的局限性,而将不同处理技术联合应用,取长补短,能够克服各方法单独应用时固有的问题,促进协同效应,提高甲基叔丁基醚的降解率...     

Purification of leachate from sludge treatment beds by subsurface flow constructed wetlands: effects of plants and hydraulic retention time

Environmental Science and Pollution Research - Sludge treatment beds (STBs) have been used widely in many countries due to low energy consumption, low operating and maintenance costs, and better...     

土壤腐殖酸慢热解表征实验影响因素研究

以土壤提取的腐殖酸为研究对象,进行了差式量热扫描(DSC)和热重分析(TGA)的可重复性实验、样品质量对比实验和预处理对比实验。综合分析了影响慢热解特征温度参数的因素和效应,并根据作用原理将其总结为热滞后效应和反应平衡滞后效应。结果表明,高级热分析技术用于土壤慢热解表征可重复性良好,差式量热扫描与热重分析结果可比性强,然而热分析曲线和热特征参数对实验条件的响应灵敏,其中样品质量和升温速率的影响尤其显著。研究结果表明,慢热解技术用于土壤有机质分析具有良好的准确性和重现性,提出了保障土壤腐殖酸慢热解质量控制的最佳样品量[DSC为(10±0.1)mg]、最佳气体氛围(He)和最佳升温速率(10℃/min)、精确压实程度等实验条件。     

Application of biochar in advanced oxidation processes: supportive,adsorptive, and catalytic role

Environmental Science and Pollution Research - The advanced oxidation processes (AOPs), especially sulphate radical (SO4•−)–based AOPs (SR-AOPs), have been considered more...     

Tropical surface water quality studies: Implications for the aquatic fate of N-methyl carbamate pesticides

Water quality assessment was conducted on the Ruiru River, a tributary of an important tropical river system in Kenya, to determine baseline river conditions for studies on the aquatic fate of N-methyl carbamate (NMC) pesticides. Measurements were taken at the end of the long rainy season in early June 2013. Concentrations of copper (0.21–1.51 ppm), nitrates (2.28–4.89 ppm) and phosphates (0.01–0.50 ppm) were detected at higher values than in uncontaminated waters, and attributed to surface runoff from agricultural activity in the surrounding area. Concentrations of dissolved oxygen (8–10 ppm), ammonia (0.02–0.22 ppm) and phenols (0.19–0.83 ppm) were found to lie within normal ranges. The Ruiru River was found to be slightly basic (pH 7.08–7.70) with a temperature of 17.8–21.2°C. The half-life values for hydrolysis of three NMC pesticides (carbofuran, carbaryl and propoxur) used in the area were measured under laboratory conditions, revealing that rates of decay were influenced by the electronic nature of the NMCs. The hydrolysis half-lives at pH 9 and 18°C decreased in the order carbofuran (57.8 h) > propoxur (38.5 h) > carbaryl (19.3 h). In general, a decrease in the electron density of the NMC aromatic ring increases the acidity of the N-bound proton removed in the rate-limiting step of the hydrolysis mechanism. Our results are consistent with this prediction, and the most electron-poor NMC (carbaryl) hydrolyzed fastest, while the most electron-rich NMC (carbofuran) hydrolyzed slowest. Results from this study should provide baseline data for future studies on NMC pesticide chemical fate in the Ruiru River and similar tropical water systems.     

Managing economic and social profit of cooperative models in three-echelon reverse supply chain for waste electrical and electronic equipment

In addition to maximizing economic benefits, reverse supply chains should further seek to maximize social benefits by increasing the quantity of waste electrical and electronic equipment (WEEE). The paper investigates cooperative models with different parties in a three-echelon reverse supply chain for WEEE consisting of a single collector, a single remanufacturer, and two retailers based on complete information. In addition, the optimal decisions of four cooperative models and the effect of the market demand of remanufactured WEEE products and the market share of two retailers on the optimal decisions are discussed. The results indicate that optimal total channel profit and recycle quantity in a reverse supply chain are maximized in a centralized model. The optimal total channel profit and recycle quantity increase with an increase in the market demand of remanufactured WEEE products. The three-echelon reverse supply chain consisting of duopolistic retailers maximizes total channel profit and recycle quantity in a reverse supply chain for WEEE.

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Isolation and identification of 3-bromocarbazole-degrading bacteria

In this study, a bacterial strain, CH-1, capable of degrading 3-bromocarbazole (3-BCZ) was isolated from a polluted soil. Based on its physio-biochemical characteristics and 16S rRNA genes, strain CH-1 was identified as a Stenotrophomonas sp. Strain CH-1 was able to degrade 70% of 50 mg/L 3-BCZ within 8 d at pH 7.0 and 30°C in mineral salt medium (MSM). During the process, the main intermediate metabolite was identified as (2E, 4Z)-6-(2-amino-5-bromophenyl)-2-hydroxy-6-oxhexa-2, 4-dienoic by gas (2E, 4Z)-6-(2-amino-5-bromophenyl)-2-hydroxy-6-oxhexa-2,4-dienoic via gas chromatograph-mass spectrometry (GC-MS) analysis. The metabolite disappeared after 14 d, suggesting that the metabolite can also be degraded by strain CH-1. 3-BCZ is a new persistent organic pollutant. This is the first report of the biodegradation of 3-BCZ. The results indicated that strain CH-1 may be a promising bacterial candidate for the bioremediation of environments polluted with polyhalogenated carbazoles (PHCs).     

Laser-induced breakdown spectroscopy application in environmental monitoring of water quality: a review

Water quality monitoring is a critical part of environmental management and protection, and to be able to qualitatively and quantitatively determine contamination and impurity levels in water is especially important. Compared to the currently available water quality monitoring methods and techniques, laser-induced breakdown spectroscopy (LIBS) has several advantages, including no need for sample pre-preparation, fast and easy operation, and chemical free during the process. Therefore, it is of great importance to understand the fundamentals of aqueous LIBS analysis and effectively apply this technique to environmental monitoring. This article reviews the research conducted on LIBS analysis for liquid samples, and the article content includes LIBS theory, history and applications, quantitative analysis of metallic species in liquids, LIBS signal enhancement methods and data processing, characteristics of plasma generated by laser in water, and the factors affecting accuracy of analysis results. Although there have been many research works focusing on aqueous LIBS analysis, detection limit and stability of this technique still need to be improved to satisfy the requirements of environmental monitoring standard. In addition, determination of nonmetallic species in liquid by LIBS is equally important and needs immediate attention from the community. This comprehensive review will assist the readers to better understand the aqueous LIBS technique and help to identify current research needs for environmental monitoring of water quality.