Fe掺杂A-TiO_2在溴甲酚绿中的可见光催化活性及动力学

以FeCl_3·6H_2O为Fe源,采用水热法制备了Fe掺杂锐钛型TiO_2(A-Ti O2)光催化剂。以溴甲酚绿为降解对象,考察溴甲酚绿的初始浓度、催化剂用量、掺Fe量等因素对自制催化剂可见光催化降解反应的动力学方程的影响。结果表明:在40 W白炽灯照射下,当溴甲酚绿初始浓度为10 mg/L(pH=7)、催化剂的用量为0.6 g/L、掺Fe量为4%(摩尔分数)、室温下反应时间为3 h时,溴甲酚绿的降解率最大为76.05%。溴甲酚绿光催化降解曲线符合一级反应动力学方程,于上述最佳条件下其表观反应速率常数k达到最大值,为0.389 7 h-1。     

生物慢滤系统对再生水中氮磷降解的试验研究

利用生物慢滤系统中菌-藻共生的特点,对用于景观补水的再生水中氮磷进行有效的去除,可有效预防由于再生水中氮磷营养盐浓度较高而引发的景观水体富营养化问题。通过生物慢滤系统净化再生水的试验研究表明,生物慢滤系统在保持上覆水深为80cm、滤层厚度为80cm、滤速为0.1m/h的条件下,对水体中总氮、氨氮、硝酸盐氮、总磷和高锰酸盐指数平均去除率分别为57.55%、50.16%、46.37%、66.32%和47.04%,叶绿素a的去除率可达95.75%;经生物慢滤系统处理后的再生水在景观储存过程中藻类的生长缓慢,叶绿素a含量始终维持在较低水平,氮磷含量较低且趋于稳定。经生物慢滤池处理的再生水用于景观水体的补充水源,可减少富营养化的发生频率。     

环境退化、市场非均衡与创业

文章提出了一种新的创业观,解释了环境问题创业。奥地利学派的创业理论认为,市场非均衡提供了创业机会。环境退化作为一种市场非均衡,为创业者提供了潜在机会。但是对这种机会的利用存在一系列障碍,文章将针对其中的不对称信息、不完全信息与公共产品,介绍创业者如何克服这两种障碍,利用环境退化所产生的机会进行创业,缓解环境退化。     

微电流电解对尿素降解的机理及影响因素研究

采用微电流电解技术对模拟游泳池水中的尿素进行降解处理,探索了电解对尿素的去除机理,研究了电流密度和氯离子浓度等因素对电解去除尿素效果的影响。结果表明:以钌钛和不锈钢分别做阳极和阴极材料,当水溶液中有较高浓度的氯离子存在时,电解过程中产生的活性氯使得尿素被氧化,尿素降解产物中无氨氮、氯胺等二次污染物,尿素极有可能通过电解生成了N2等气体挥发到空气中。电流密度和氯离子浓度对尿素的去除效率有很大影响,随着电流密度和氯离子浓度的增加,尿素去除效率逐渐上升。在500 mg/L的氯离子浓度条件下,电流密度为12 m A/cm2时,电解处理30 min时尿素去除率可达99.5%。将微电流电解技术应用于游泳池水中的尿素去除,无需添加电解质,即能达到较高的尿素去除效果,采用该技术对游泳池水中的尿素进行降解去除完全可行。     

基于水资源核算的太湖流域水环境退化成本分析

为合理制定流域水价,加强流域水资源统一管理,提高水资源节约利用水平,促进水资源可持续利用,对水环境与经济社会产生的关系进行综合考量;在核算太湖流域2010年水资源的基础上,分别利用基于防护费用的评估方法和基于损害的水环境退化估价方法,计算分析2010年太湖流域水环境退化成本。结果表明:对污染物进行源头治理不仅是出于对环境保护的考虑,更是尽可能地降低水环境退化成本、避免经济损失的最佳选择。水环境退化分析为合理制定水价及水资源统一管理提供了重要参考。     

Lake management organizations in China

The paper analyses the range of lake management organizations (LMOs) established in China and proposes management recommendations for different lake types and contexts. Based on functions, regional coverage and sectoral focus, nine LMO patterns are identified, ranging from existing agency approaches in which there is no specific lake focus or institutional responsibility to comprehensive and powerful lake basin authorities. LMO development in China faces many challenges, including a preoccupation with organizational form rather than function and objectives, duplication with existing agency functions, and insufficient lake basin management and trans-jurisdictional coordination. We therefore propose that LMOs should be tailored to specific situations and problems, drawing distinctions between plateau, urban, plain, inland and wetland lakes as well as other contexts.     

Socio-economic and biophysical determinants of land degradation in Vietnam: An integrated causal analysis at the national level

Recognizing the socio-economic and biophysical causes of land degradation at the national level is important for cause-targeted strategies when designing policies for combating land degradation. This study aims to identify the biophysical and socio-economic factors that significantly affect land degradation across Vietnam and to interpret the causalities underlying the effects. The dependent variables considered in the study are spatial, the extent and intensity of degradation in three land-use zones (agriculture, forest and severely degraded abandonment). The hypothesized explanatory variables are common economic and demographic drivers and bio-physical factors such as soil, terrain constraints, and neighborhood land-use structures that are often neglected in many large-scale land degradation assessments. Instead of using a single inferential statistic technique, we used multi-linear regression and binary logistic regression in a complementary manner to increase the detectability and credibility of the degradation cause analyses. The results showed agricultural production growth had strong and consistent effects on land degradation extent and intensity. Population growth, especially in rural areas, had a strong effect on the extent of overall land degradation. The importance of a neighboring forest was revealed for its ability to reduce land degradation intensity in abandoned, unproductive lands. The concrete faceting of the causal analysis for each land-use zone as social–ecological stratum allowed us to combine the defined social–ecological contexts, contemporary theories, and hypotheses in the field to clarify the causal factors of a complex phenomenon like land degradation. The study demonstrates these contemporary inferential statistics can be complementarily used to sufficiently detect and understand land degradation causes at the national level. The results suggest implications for national land management policy: internalizing land degradation costs in the farming system evaluation for payment for ecosystem services policy, restricting forest conversion, and improving extension services and education in agrarian communities.     

Knowledge management through the development of knowledge repositories: towards work degradation

This paper questions the consequences of the use of electronic knowledge repositories for work and employment. Drawing on critical research suggesting that knowledge management associated with such tools presents similarities to scientific management principles, it proposes to examine the following key research question: how do employees experience the transformation of the employment relationship when a knowledge repository is introduced to the workplace? The inquiry is grounded in an exploratory qualitative case study of a knowledge management system designed to foster knowledge‐sharing in a Belgian public administration. The findings illustrate two complementary outcomes: this system resulted in employees experiencing deskilling and work degradation, and was met with resistance. Significantly, this paper considers work degradation as a reflexive phenomenon in the context studied, where knowledge‐sharing systems produced deskilling and resistance as part of a specific re‐regulation process.     

Assessment through socioecological abstraction: The case of nutrient management models in Sudano-Sahelian West Africa

The sustainability of smallholder agriculture in the drylands of West Africa is a topic of long-lasting concern. This paper is focused on the scientific assessment of nutrient (mis)management affecting the long-term productivity of cropland. “Nutrient mining” is seen as a major mechanism for land degradation in the region. Two models will be the focus: that tied to the rangeland-to-cropland metric and the nutrient balance model. These tools of assessment follow a long history of environmental assessment and modeling that purposefully abstracts from the heterogeneity of the same farming practices that modeling efforts seek to assess. Abstraction is always part of modeling but the form of abstraction described here ignores any detailed understanding of farming practices and in so doing, demands very little information about farming practices. In this way, models serve as both the symptom and cause of continued ignorance of farming practices by most agronomists and soil scientists working in the region. The variables used in these models will be described and how these same variables are strongly influenced by the variation of farmers’ practices will be discussed. In addition, it will be shown that needless model abstraction results in research outcomes that provide very little insights to guide land policy formulation and agricultural extension. In short, these models point to the ultimate resource limits of the regional agricultural system but provide few insights of what could be changed to reduce rates of land degradation. The paper concludes by presenting alternative approaches that through their engagement with the diverse positionalities of farmers, provides insights useful for the development of effective land policies.     

氯离子对苯酚电化学氧化降解过程的影响分析

高级氧化技术是有机污染物处理的重要技术,而电化学氧化法是有机物降解中最理想的方法之一。本文研究了氯离子的存在环境下,苯酚在不同氧化物涂层的阳极上所发生电化学降解过程的分析,深入探讨氧化法降解有机物质中氯离子的作用。