DSA类电极催化降解硝基苯动力学及机理的研究

用新兴的电化学催化系统,以特殊工艺自制的DSA类电极作阳极,对模拟硝基苯废水进行了降解处理,得出了该试验范围内的最佳条件,降解过程符合一级反应模型.根据分析,推测硝基苯分子主要先被阴极产生的H还原为亚硝基苯、苯胺等,然后再扩散到阳极附近被HO*氧化为偶氮苯、氧化偶氮苯等,最后进一步氧化开环,生成苯基丁二酸等酸类物质以至二氧化碳,同时硝基苯分子也可以直接在阳极附近得到氧化生成2-硝基苯酚.最后,对硝基苯的降解途径进行了描述.      

全氟辛酸和全氟辛基磺酸的光降解技术及机理研究进展

目前,普遍存在于各种环境介质中的全氟辛酸(PFOA)和全氟辛基磺酸(PFOS)造成的环境污染问题已引起全球的广泛关注.PFOA和PFOS具有稳定性、持久性和生物累积性等特点.常规的方法如:超声降解法、电化学氧化法和微生物降解法等,很难将其彻底降解,因此开发有效的PFOA和PFOS降解技术成为了环境领域的研究重点.近年来...     

胜利油田井下压裂废水处理实验研究

井下压裂施工工艺复杂,压裂废液对环境会造成污染。针对压裂废水特点,采用絮凝-隔油法对其进行预处理,再用次氯酸钠结合紫外光对废水进行深度处理,可氧化降解难处理的部分高分子有机化合物。结果表明,在适宜的处理条件下,该法可有效去除水中CODCr和石油类,去除率分别为98.6%、98.1%,达到《污水综合排放标准》(GB8978—1996)二级标准。     

漂浮负载型光催化剂制备及降解草甘膦研究

以漂珠(FP)为载体,采用溶胶-凝胶-浸渍法制备了漂浮负载型CdS/TiO2/FP复合膜光催化剂,通过SEM、XRD对其结构进行了表征.以甘草膦农药的光催化降解为模型反应,使用不同光源研究了CdS/TiO2/FP的光催化性能,探讨了影响催化剂活性的因素及采用太阳光做光源处理草甘膦的可行性.结果表明,经4层镀膜500℃热处理的20%(w/w)CdS/TiO2/FP光催化剂具有良好的光催化性能,最佳降解条件为:催化剂加入量3 g/L,初始pH 7～9,Fe2 浓度为2.0×10-3 mol/L.通气量200 mL/min.在最佳条件下,对135 mg/L草甘膦溶液降解率可以分别达到96.3%(125 W高压汞灯,60 min)和82.4%(太阳光,180 min).     

三种偶氮染料降解历程在紫外-可见光谱上的表现

本文对基本结构相似的三种偶氮染料橙黄Ⅱ、活性艳红Ｘ－３Ｂ和活性黑Ｋ－ＢＲ水溶液在铁粉还原－光氧化两步法处理中的紫外－可见光谱图作对比分析,依据其结构与特征吸收的关系,初步推测还原铁粉－光氧化法降解染料的历程。     

草原退化与恢复过程中土壤有机矿质复合体分组研究

对采自处于不同发展方向和阶段的草原土壤分组提取有机矿质复合体,并对它的质量分数、腐殖质质量分数和组成、Ｃ／Ｎ比值等的变化做了分析,试图从土壤复合体变化的角度去认识草原的退化和恢复过程。研究发现土壤腐殖质绝大部分集中于粘粒和粉粒级复合体;退化草原恢复时,复合体腐殖质质量分数增加,并且组成也发生变化;而草原轻度退化时,复合体腐殖质质量分数会减少,但组成不会变化。     

Prognosis of the spatiotemporal dynamics of ecosystems by means of universal kriging

The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased     

Environmental degradation by mud in tropical estuaries

In wet tropical countries, the intense rainfall and the lack of effective restrictions on human activities in the river catchment leads to increased rates of soil erosion. This has increased the sediment loads many times over from the natural level. As a result, estuarine and coastal waters are becoming increasingly muddy with associated losses for society in terms of increased flooding and a degradation of the environment, the fisheries and the economic use of these waters. It is suggested that science-based models be used to predict the fate of mud in estuaries and coastal waters when planning development in river catchments, particularly in wet tropical countries. This would help integrate land and water management. Modelling technology is demonstrated by a combination of field and model studies in four turbid tropical estuaries, namely the Fly River in Papua New Guinea, the Mekong River in Vietnam, the Cimanuk River in Indonesia, and Hinchinbrook Channel in Australia. The final model is adapted to local conditions and extensively uses data assimilation especially for open boundary conditions. There can be a feedback between the hydrodynamics and the mud dynamics when the system silts; in wet tropical countries this can occur rapidly, sometimes in only 30 years. Electronic Publication     

土壤中4-溴苯胺降解动力学及其生态毒性追踪

秀谷隆是一种被广泛应用的取代脲类除草剂,其主要降解产物为４－溴苯胺（４－ＢＡ）,研究４－溴苯胺在不同土壤中的降解动力学规律,并用土壤环境指示动物弹尾目跳虫Ｃｏｌｌｅｍｂｏｌａ（Ｆｏｌｓｏｍｉａ ｃａｎｄｉｄａ）跟踪指示该化合物在进一步降解过程中的毒性,结果表明：４－溴苯胺在土壤中的降解行为可用一级反应动力学方程来较好地描述,其生态毒性明显高于母体化合物秀谷隆,该化合物在粘土中的残留量低于砂土,但毒     

三唑酮在油菜-土壤生态系统中的降解与建模

为评价三唑酮可湿性粉剂在土壤-油菜生态系统中使用后的残留行为和环境安全性,进行了2 a大田试验,并比较了指数模型、GM(1,1)灰色模型、阻滞动力学模型对三唑酮降解规律的描述。结果表明:3种模型的拟合结果均达到统计学意义上显著相关;对三唑酮在土壤和油菜中降解行为模拟结果最好的分别为GM(1,1)模型和阻滞动力学模型;三唑酮在土壤中2 a的半衰期分别为3.48和4.38 d,油菜植株中分别为1.98和3.78 d,其降解受温度影响较大。