P-25纳米TiO2在含酚废水处理方面的应用

采用室内模拟研究,以P-25纳米TiO2作为光催化剂进行了苯酚水溶液的光催化降解性能探讨,初步考察了溶液的pH、P-25纳米TiO2用量对光催化降解苯酚过程的影响,以获得P-25纳米TiO2光降解含酚废水的较好反应条件.实验结果表明,当溶液pH=8时,降解水体中苯酚效果最佳,强酸和强碱条件均不利于苯酚的降解;在pH 8的反应体系中,当光催化剂用量为0.4g/L时,催化水体中苯酚降解的效果最好.     

超声波降解苯酚溶液的研究

以20mg/L的苯酚为研究对象,在超声波槽中对超声波作用于苯酚的降解效率和降解规律进行了初步研究。实验表明:单一的超声波对苯酚的降解率是很低的,不超过6.3%;而在苯酚溶液中加入H2O2后,降解率提高了大约3倍;酸性条件利于苯酚的降解,而在碱性条件下苯酚几乎没有降解。     

光催化氧化苯酚中间产物的分析与降解途径探讨

采用光催化氧化法降解苯酚溶液,利用液相色谱对苯酚及其中间产物进行了定性、定量分析。考察了投加H2O2对中间产物浓度变化的影响。根据中间产物的产生情况及浓度变化,推测了苯酚光催化降解的反应途径。     

树脂纳米零价铁催化过硫酸钠降解甲基橙的研究

采用树脂负载零价纳米铁（NZVI-resin）作为铁源,活化过硫酸钠,产生硫酸根自由基氧化降解偶氮染料甲基橙。考察了温度、NZVI-resin加入量、pH值及过硫酸钠的浓度等因素对甲基橙降解率的影响,并对其降解动力学规律作了初步探讨。结果表明：降解反应遵循准一级反应动力学,在pH=3.0、Fe0=0.2 g.L-1、Na2S2O8=1.33 g.L-1的条件下,30 mg.L-1的甲基橙溶液降解率为99.7%。     

UV/O3复合降解水中2,4-二氯酚的试验研究

以紫外光源为主要依托,变换反应器中的不同工艺条件,分别对紫外光、臭氧和紫外/臭氧三种不同于工艺条件对水中污染物2,4-二氯酚(2 ,4-DCP)的降解规律进行研究.结果表明,UV/O3复合对2,4-DCP的降解较UV、O3单独作用效果好;溶液的酸碱度影响UV/O3对2 ,4-DCP的降解;此外,溶液中含有细菌时,E. coli的杀灭效果仍表现为UV/O3＞O3＞UV.细菌的杀灭和2,4-DCP的降解均消耗羟基自由基,形成竞争反应,从而影响到2,4-DCP的降解效果.     

高效复合微生物菌剂对聚丙烯酰胺的无害化降解

聚丙烯酰胺(PAM)对环境的污染日趋严重,尤其是降解后的单体丙烯酰胺对人类的神经系统有很大的危害。筛选出的优势菌可对PAM溶液有良好的降解效果,降解率达到89%。但是,PAM不能成为菌种的最佳营养物,添加基础营养液可使其达到最佳降解的目的。通过对培养条件的优化,提高了菌种的降解能力。本复合菌剂在降解PAM的同时,迅速降解掉脱落的丙烯酰胺单体,不会对环境造成二次污染。     

光催化氧化法降解有机磷农药的研究

本研究采用负载型TiO2膜作为催化剂降解有机磷农药敌敌畏，探讨了光催化反应时间、溶液的初始浓度对敌敌畏降解率的影响。试验表明，不同初始浓度的敌敌畏在经过90minUV／TiO2处理后，降解率都能达到90％以上，而且降解率随光照时间的增长而增加，随初始浓度的增加而降低。本研究采用毛细管柱气相色谱检测敌敌畏的剩余浓度，检出效果较好，并通过色谱图探讨敌敌畏的降解过程。     

Fe_2O_3/TiO_2芬顿-光催化协同提高处理废水能力

通过高温煅烧制备复合光催化剂Fe_2O_3/TiO_2,加入H_2O_2构建芬顿-光催化协同体系,对有机废水进行深度降解处理。实验结果表明,Fe_2O_3含量为3%的复合光催化剂投加量1.0 g/L,H_2O_2浓度30 mmol/L,紫外光照射3 min,20 mg/kg亚甲基蓝溶液降解率为88.6%,比TiO_2单体活性提高5倍,芬顿体系3 min对MB几乎无降解,芬顿-光催化协同极大地提高了处理有机污染物的降解能力。紫外光照射20 min,能降解98.2%的20 mg/kg苯酚溶液,分别是单体TiO_2和芬顿体系活性的3倍和24.5倍。     

掺杂型二氧化钛纳米管光催化降解甲基橙研究

利用本实验室制备的N-F原子掺杂二氧化钛纳米管作催化剂,在可见光区对甲基橙(MO)进行光催化降解实验。在催化剂用量固定为3cm2时考察了不同初始浓度、pH值、溶解氧(DO)等对降解率的影响。结果表明,在可见光区该催化剂具有较高的光催化活性;当溶液DO为19.2mg/L、pH值为3、初始浓度为10mg/L、反应时间300min时,降解率可达82.3%。     

La掺杂TiO2/有机改性膨润土对TNT弹药废水的光催化降解性能研究

利用超声强化溶胶-凝胶法制备了La掺杂TiO2/有机改性膨润土复合光催化材料并进行了结构表征;以弹药废水中主要污染物质TNT作为目标物,考察了影响光催化降解性能的因素.结果表明：有机改性后复合材料的吸附性能和光催化性能均有所增加,对TNT的60min的吸附去除率和光催化降解率分别达到9.68％和94.53％;影响TNT光催化降解率的因素有光照时间、催化剂用量、TNT初始浓度、溶液pH值和光照强度.     

微生物对石油烃类的降解机理

文章分析了生物降解需要的条件、环境因素对石油烃微生物降解的影响,石油烃类的有氧降解机理、有氧降解方式,石油烃类的厌氧降解机理、厌氧降解过程中某些无机含氧化合物作受氢体的递氢过程,石油烃类化合物微生物降解难易程度,提出了以后应进一步重视原油的生物降解应用于我国微生物采油的研究。     

Combined use of GIS and environmental indicators for assessment of chemical, physical and biological soil degradation in a Spanish Mediterranean region

Soil is one of the main non-renewable natural resources in the world. In the Valencian Community (Mediterranean coast of Spain), it is especially important because agriculture and forest biomass exploitation are two of the main economic activities in the region. More than 44% of the total area is under agriculture and 52% is forested. The frequently arid or semi-arid climate with rainfall concentrated in few events, usually in the autumn and spring, scarcity of vegetation cover, and eroded and shallow soils in several areas lead to soil degradation processes. These processes, mainly water erosion and salinization, can be intense in many locations within the Valencian Community. Evaluation of soil degradation on a regional scale is important because degradation is incompatible with sustainable development. Policy makers involved in land use planning require tools to evaluate soil degradation so they can go on to develop measures aimed at protecting and conserving soils. In this study, a methodology to evaluate physical, chemical and biological soil degradation in a GIS-based approach was developed for the Valencian Community on a 1/200,000 scale. The information used in this study was obtained from two different sources: (i) a soil survey with more than 850 soil profiles sampled within the Valencian Community, and (ii) the environmental information implemented in the Geo-scientific map of the Valencian Community digitised on an Arc/Info GIS. Maps of physical, chemical and biological soil degradation in the Valencian Community on a 1/200,000 scale were obtained using the methodology devised. These maps can be used to make a cost-effective evaluation of soil degradation on a regional scale. Around 29% of the area corresponding to the Valencian Community is affected by high to very high physical soil degradation, 36% by high to very high biological degradation, and 6% by high to very high chemical degradation. It is, therefore, necessary to draw up legislation and to establish the policy framework for actions focused on preventing soil degradation and conserving its productive potential.     

加速退化试验方案优化问题经验参数估计方法

加速退化试验需要开展多组试验,投放多个试验样品,应力值的选取和样本量的投放以及截尾时间或截尾数的确定直接影响了加速退化试验的效率和质量,加速退化试验的最优设计问题成为试验方案设计的关键因素。在开展试验方案优化分析时,必须知道退化函数,而开展加速退化试验的目的就是估算退化函数中的未知参数,如何事先估计退化函数中未知参数的大致分布情况成为解决这一矛盾的关键。本文给出了一种基于可靠性预计的加速退化试验方案优化问题经验参数粗略估计方法,为解决这一问题提供了参考。     

简述二噁英降解方法的研究进展

二噁英是一类剧毒的持久性有机污染物和一级致癌物质。脱氯降解是降低二噁英毒性的有效途径之一。本文首先介绍了二噁英的种类、来源和危害,其次对二噁英的降解方法包括光降解、光-Fenton降解、生物降解、热降解、化学降解脱氯作了简要评述,比较了各种降解方法的优劣。     

Degradation–environment–society spiral: A spatial auto‐logistic model in Thailand

In this contemporary interpretation of the widespread land degradation problem in Southeast Asia, it is hypothesized that spatial interplay of environmental and socioeconomic predictors determines the occurrence of land degradation. Village surveys, remote sensing and spatial auto‐logistic modelling of the relationship between degradation and land use dynamics in Lam Phra Phloeng watershed of Thailand enabled 80.2% of land to be classified correctly in terms of the presence or absence of erosion and explained 53.2% of the total variation. Cultivation and dependence on agriculture for livelihood positively and significantly affect degradation. Lack of access to institutional credit and land titles significantly increased the probability of occurrence of degradation. On the other hand, education and social cohesion are negatively associated with the occurrence of degradation. The Relative Operating Characteristic (ROC) curve was used to measures the performance of the model. The calculated area under the curve (0.879) suggests that significant predictor variables in the model can be confidently used to forecast the likelihood of occurrence of degradation and thus to identify priority areas for intervention. Policies to reduce land degradation should include measures to reduce pressure on the land, including alternative income sources. Policies could mobilize capital to invest in encouraging nature‐based tourism and other off‐farm income options.     

How does economic complexity influence environmental degradation? New insights from African countries

This paper seeks to investigate the effect of economic complexity on environmental degradation in 20 selected African countries over the period 1991–2014. The Feasible Generalized Least Square (FGLS), and Driscoll-Kraay estimators (DK) are used to capture the objectives of the study. The results suggest that economic complexity and economic growth enhance environmental degradation. Also, natural resources rents and globalization improve environmental quality. Furthermore, the findings reject the U-shaped relationship between economic complexity and environmental degradation. In addition, the Dumitrescu-Hurlin panel causality test shows a bidirectional causal relation between economic complexity and environmental degradation. Taking into account the ecological deficit or ecological reserve status of country, it is shown that while the natural resource rents reduce environmental degradation in ecological reserve countries, they increase environmental degradation in ecological deficit countries. The results are robust when an alternative measure of economic complexity is used. Based on these findings, the paper suggests that the governments of African countries should take into account economic complexity when designing their environmental protection policies.     

Community resilience,land degradation and endogenous lock-in effects: evidence from the Alento region,Campania, Italy

This study analyses social, economic and political “lock-ins” for understanding community resilience and land degradation. The study focuses on lock-ins from within communities, using four case study communities in Italy affected by land degradation. The analysis highlights the complex interrelationships between various lock-ins, and suggests that the communities are on declining resilience pathways that may lead to increasing difficulties in addressing land degradation issues in future.     

石油降解菌的降解特性研究

以0#柴油为唯一碳源,对石油降解菌DSP菌的生长、疏水性、产表面活性剂、脱氢酶活性及降解能力进行研究。结果表明:DSP菌在生长过程中可产生糖脂类生物表面活性剂,对石油烃的降解有很好的促进作用,其脱氢酶活性与降解率有较好的相关性。当土壤中柴油含量为10%时,利用DSP菌经过40d的处理(30℃,pH值为6),油含量下降到1.82%,降解率最高可达65.4%。     

Degradation of methyl isothiocyanate and chloropicrin in forest nursery soils

Recent studies have observed enhanced degradation of methyl isothiocyanate (MITC) from repeated fumigation in agricultural soils. Little is known about fumigant degradation in forest and nursery soils. This study was conducted to determine degradation rates of MITC and chloropicrin (CP) in two forest soils and the impacts of nursery management on degradation of MITC and CP. The half-life values of MITC and CP were evaluated in the laboratory under isothermal conditions (22 +/- 2 degrees C). Three rates representing 0.5x, 1x, and 2x field application rates for each fumigant were used in laboratory incubations. Effect of microbial degradation was determined by conducting incubations with both fresh and sterilized soils. Soil moisture effects were also studied. There was no difference in MITC or CP degradation between fumigated and nonfumigated forest nursery soils. Soil sterilization and high soil moisture content (15% by wt.) reduced MITC and CP degradation. The degradation rates of MITC and CP varied with factors such as nursery history, fumigant application rates, and freshness of tested soils.     

聚丙烯酰胺降解的研究进展

聚丙烯酰胺(PAM)的降解一直是人们研究的重点。文章综述了PAM的主要降解方式,包括化学降解、热降解、机械降解和生物降解,分析了PAM各种降解的可行性及降解产物,并探讨了丙烯酰胺在环境中的降解情况,为以后PAM的扩大应用及其污染治理提供了充分的参考和依据。