Adsorption and desorption of herbicide monosulfuron-ester in Chinese soils

Monosulfuron-ester is a new, low rate, sulfonylurea herbicide that is being promoted for annual broadleaf and gramineal weed control; however, there is a lack of published information on its behavior in soils. The adsorption and desorption of monosulfuronester by seven type soils were measured using a batch equilibrium technique. The results showed that the Freundlich equation fitted its adsorption and desorption well, and the Freundlich constant values (Kf-ads) ranged from 0.88 to 5.66. Adsorption isotherms were nonlinear with 1/nf-ads values < 1. Soil pH, organic matter (OM), and clay content were the main factors influencing its adsorption and desorption. Adsorption and desorption were negatively correlated with pH 4.0–8.0 while positively correlated with OM and clay content. The adsorption of monosulfuron-ester was mainly a physical process, because its free energy (ΔG) in seven soils was less than 40 kJ/mol. Monosulfuron-ester adsorption by three soils increased with increasing CaCl2 concentration using CaCl2 as a background electrolyte. Monosulfuron-ester desorption was hysteretic in all tested soils.     

Efficient degradation of chlorobenzene in a non-thermal plasma catalytic reactor supported on CeO2/HZSM-5 catalysts

Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO₂/HZSM-5 catalysts. The performance of catalysts was evaluated in terms of removal and energy efficiency. The decomposition products of chlorobenzene were analyzed. The results show that CeO₂/HZSM-5 exhibited a good catalytic activity, which resulted in enhancements of chlorobenzene removal, energy efficiency, and the formation of lower amounts of by-products. With regards to CO₂ selectivity, the presence of catalysts favors the oxidation of by-products, leading to a higher CO₂ selectivity. With respect to ozone, which is considered as an unavoidable by-product in air plasma reactors, a noticeable decrease in its concentration was observed in the presence of catalysts. Furthermore, the stability of the catalyst was investigated by analyzing the evolution of conversion in time. The experiment results indicated that CeO₂/HZSM-5 catalysts have excellent stability: chlorobenzene conversion only decreased from 78% to 60% after 75 hr, which means that the CeO₂/HZSM-5 suffered a slight deactivation. Some organic compounds and chlorinated intermediates were adsorbed or deposited on the catalysts surface as shown by the results of Fourier Transform Infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the catalyst before and after the reaction, revealing the cause of catalyst deactivation.     

新型人工合成膨润土防渗卷材的研制及其渗透性能

将膨润土和胶粘剂加以混合 ,结合国外先进的粘结工艺 ,制成防渗卷材 .对膨润土类型、外封装用材料及胶粘剂的确定 ,卷材的成型工艺及卷材的渗透性能研究结果表明 ,钠基膨润土的渗透性能优于钙基膨润土 .在人工钠土中无论是加入聚丙烯酸酯类乳液还是 PM植物胶 ,在掺加的比例一定时 ,随着密度的增大 ,渗透系数下降 ;在相同密度下 ,随着掺加的比例增大 ,渗透系数下降 .人工钠土的渗透系数与水力坡度呈线性关系 .膨润土及其胶粘剂卷材与模拟浸出液间的化学配伍性较好 .膨润土卷材具有良好的自封闭性 ,在材料受损的情况下也能够通过自封闭作用达到较好的“焊接”效果 .     

水生生态系统在污水处理中的应用

利用水生生态系统治理水体污染是污水处理领域的研究热点之一.综述了水生生态系统在处理污水中的应用现状,分析了影响处理效果的主要因素,并探讨了水生生态系统处理废水的运行机理,展望了水生生态系统的发展前景.     

水生生态系统在污水处理中的应用

利用水生生态系统治理水体污染是污水处理领域的研究热点之一.综述了水生生态系统在处理污水中的应用现状,分析了影响处理效果的主要因素,并探讨了水生生态系统处理废水的运行机理,展望了水生生态系统的发展前景.     

布袋除尘器和活性炭滤布对烟气中二噁英类的去除效果

通过实验研究了布袋除尘器、活性炭滤布吸附器以及二者的组合对小型垃圾焚烧炉烟气中二噁英类的去除效果.在炉膛温度850℃～900℃的条件下,3种方法对烟气中二噁英类的去除率分别为39.7%、61.9%、93.4%采用布袋除尘器+活性炭滤布吸附器能够在降低运行费用的同时使二噁英类的排放符合国家标准     

环境因素对土壤含硫气体释放的影响

研究了温度、光照条件两种环境因素对添加不同硫源（胱氨酸、硫酸二乙酯和硫酸钠）土壤含硫气体释放的影响。结果表明,随着培养温度升高,含硫气体释放量增大,而且释放气体种类增多。COS在各种不同处理的土样中均有释放。除添加硫酸二乙酯的土样外,其它各种土样COS释放量与培养温度有很好的相关性,相关系数在0．95以上。添加胱氨酸的土样,含硫气体释放明显高于其它土样,光照条件变化对各种含硫气体释放量影响不大,但在弱光和无光照条件下检出的含硫气体种类较多。     

低温下膜-生物活性炭工艺深度处理回用水的试验研究

开展低温下膜-生物活性炭工艺深度处理回用水的试验研究，探讨该工艺低温运行的可行性及作用机制。结果表明，采用HRT为3h的膜-生物活性炭反应器对回用水中有机物具有良好的去除效果，CODcr，UV254、UV410的去除率分别稳定在33％、35％、40％；对NH3-N的去除效果不明显，其平均去除率在15％左右，主要受原水浓度过高的影响。同时与其他工艺进行对比研究，结果表明，由于该工艺结合了膜分离、活性炭吸附、生物降解三者的综合作用而表现出明显的优势。     

Methane emissions responding to Azolla inoculation combined with midseason aeration and N fertilization in a double-rice cropping system

Environmental Science and Pollution Research - Methane (CH4) is an important greenhouse gas (GHG), and paddy fields are major sources of CH4 emissions. This pot experiment was conducted to...     

Comparison of PM2.5 emission rates and source profiles for traditional Chinese cooking styles

Environmental Science and Pollution Research - The number of restaurants is increasing rapidly in recent years, especially in urban cities with dense populations. Particulate matter emitted from...