废弃电子塑料在超临界异丙醇中的液化特性

研究了废弃含溴化阻燃剂的电子塑料在超临界异丙醇中的液化特性.研究结果表明塑料在超临界异丙醇中发生了解聚,产生油、气以及固体残渣,塑料中的溴化阻燃剂发生了脱溴降解.反应时间、固/液比、溶剂填充度对塑料解聚及阻燃剂脱溴降解影响较大,在最佳工艺条件(温度:400℃,反应时间:60min,固/液比:1/10,溶剂填充度:50%)下获得60%的产油率及95.3%的脱溴率.油以苯系物及酚类物质为主要组成物质,其热值为37.5MJ/kg.超临界异丙醇处理含溴化阻燃剂塑料主要包括溴化阻燃剂的萃取、脱溴降解和塑料高温解聚等过程.     

日用塑料制品中PBDEs的污染特征及其人体健康暴露风险

采用气相色谱/质谱联用仪和健康风险评价模型,研究了北京居民日常接触的典型日用塑料制品中PBDEs(多溴二苯醚)的赋存特征及其人体健康暴露风险.结果表明:1塑料盆、垃圾桶、塑料垫、塑料板凳、拖把、热水壶壳、给水管、采暖管、排水管、拖鞋、收纳箱、文件框等12种日用塑料制品中w(∑21PBDEs)为0.45~21.30 mg/kg,平均值为5.98 mg/kg.2日用塑料制品中十溴二苯醚是主要的PBDEs同系物,w(十溴二苯醚)平均占w(∑21PBDEs)的82.51%;九溴二苯醚是次要PBDEs同系物,平均占9.76%;三溴~六溴二苯醚质量分数较低,平均占1.77%,日用塑料制品生产过程中添加含十溴二苯醚的废弃阻燃塑料是引起PBDEs污染的主要原因.3成人通过呼吸吸入、皮肤接触和手-口3种途径摄入的PBDEs暴露量分别为295.77、44.29、0.00pg/(kg·d),儿童通过3种途径的PBDEs暴露量分别为769.55、40.83、1.91 pg/(kg·d)表明呼吸吸入是主要暴露途径.4日用塑料制品中PBDEs对成人和儿童的释放暴露非致癌危害熵分别为2.28×10-4和5.46×10-4,低于美国标准中可接受风险熵(1.0),表明日用塑料制品中PBDEs对人体的健康风险影响很小.     

消费电子产品生产过程中挥发性有机物(VOCs)排放特征的研究

选取塑胶零件、印刷线路板及主板3类消费电子产品部件为研究对象,利用活性炭管采样,样品溶剂解吸后采用GC/MS分析,获得了各排气筒及车间内VOCs含量水平与组分特征.通过计算排放量,得出了分物种VOCs排放系数.结果表明,塑胶零件生产线排气筒总挥发性有机物(TVOCs)浓度为48.01~115.05 mg·m-3,印刷线路板为6.08~11.36 mg·m-3,主板为29.81~30.21 mg·m-3.塑胶零件生产车间内TVOCs浓度为4.23~120.58 mg·m-3,印刷线路板为1.50~2.02 mg·m-3,主板为7.01~9.93 mg·m-3.环烷烃类、酯类、苯类为主要排放物质.对于不同产品生产线的排气筒及车间废气,浓度和物种均有很大差异;对于相同产品,浓度有差异但物种基本相同.按产品分类,共计算得出了36个分物种VOCs排放系数,其中,塑胶零件、印刷线路板及主板TVOCs排放系数分别为0.626 kg·kg-1涂料用量、0.123 kg·kg-1油墨用量、0.028 kg·kg-1印刷线路板用量.通过排放量计算结果分析,3种产品中,塑胶零件生产为VOCs主要排放源,车间内无组织排放为主要排放方式.     

地表载荷对硬岩区埋地管道应力应变影响分析

为研究地表载荷对硬岩区埋地管道力学性能的影响,建立了管-土耦合三维数值模型,分析了地表载荷大小、作用面积、管道压力、管道径厚比及回填土弹性模量对管道应力分布、塑性应变、椭圆度的影响。结果表明:地表压载作用下,高应力区首先出现在管道顶部且呈椭圆形;随着地表载荷及其作用面积的增大,管道高应力区逐渐扩大,管道截面左右两侧也出现应力集中;随着回填土弹性模量、管道壁厚及内压的增加,管道顶部高应力区及最大等效应力均减小。塑性应变首先出现在管顶,且塑性区随地表载荷、载荷作用长度增加而增大,随回填土体弹性模量及管道壁厚增大而逐渐减小;当内压为0~4MPa时,管道塑性应变及塑性区随内压的增大而减小。管道椭圆度随回填土体弹性模量、管道内压、壁厚增加而逐渐减小,随地表压载增大而增大。     

Climate change,adaptation and Eco-Art in Singapore

Eco-Art has recently emerged as a potential means to place emphasis on environmental issues such as climate change, recycling and the metabolism of the city experienced both materially and conceptually within local, regional and global contexts. Such art presents the possibility of shaping civic practices in arenas beyond those of traditional planning domains. Adopting a pragmatic approach, which recognises the contextual pluralism that exists in debates regarding climate change, this paper is interested in how Eco-Art projects encourage the re-imagining of urban spaces within the context of sustainability, and flows of materials and the recycling of plastic in art specifically.     

Designing a policy package for the promotion of servicising: A case study of vineyard crop protection in Galicia (Spain)

The servicising approach in vineyard protection is considered a valid alternative to achieve decoupling between the economic and environmental performance of viticulture. In this paper, a policy package is designed to promote the uptake of a servicised model of vineyard protection in an area of smallholding viticulture. In doing so, a specific methodology based on a step by step protocol has been followed that aims to come up with a package that is effective, implementable and socially as well as politically acceptable. The paper concludes on the importance of combining several policy instruments in a policy package to realise the political objective. The proposed viable policy package includes incentives that support the companies’ shift towards offering crop protection solutions, further development of IPM solutions and instruments that encourage farmers to reduce the use of pesticides and collectively hire crop protection services.     

船舶塑料垃圾热解特性及动力学分析

利用热重分析(TGA)研究船舶塑料垃圾在不同升温速率和不同气氛下的热解特性,并得到了热解动力学参数。结果表明,船舶塑料垃圾的热解过程主要有3个阶段,比一般塑料热解复杂;随着升温速率增大,最大热解速率和最大热解速率温度等热解特性参数也增大,反应变得更剧烈;N2/CO2比为4∶1时,热解反应进行得最完全,固体残留率最少。动力学分析表明,采用3个连续一级反应模型能很好地拟合实验数据;不同的升温速率和气氛比对反应各阶段活化能均有不同程度的影响。     

Co-pyrolysis of swine manure with agricultural plastic waste: Laboratory-scale study

Manure-derived biochar is the solid product resulting from pyrolysis of animal manures. It has considerable potential both to improve soil quality with high levels of nutrients and to reduce contaminants in water and soil. However, the combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process. Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation. They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable. The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films (SPM) and the characteristics of its gas, liquid, and solid byproducts. The heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants. Energetically, sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids (25% m/m) with just 10% SPM. If more than 10% SPM is used, the co-pyrolysis would generate surplus energy which could be used for power generation. Biochars produced from co-pyrolyzing SPM and swine solid were similar to swine solid alone based on the surface area and the ¹H NMR spectra. The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (SPM and swine solids) while producing value-added biochar and a power source that could be used for local farm operations.     

A discussion to promote global sustainability techniques for motivating plastic waste to minimize carbon footprints

This paper emphasizes the significant challenges facing the sustainable environment, including managing and handling plastic waste and reducing carbon footprints. To tackle these challenges, it is essential to identify people's awareness levels of waste handling techniques and their pro-environmental behaviors. The study focuses on Guwahati, one of the most important cities in Northeast India, which generates increasing plastic waste daily. The paper aims to identify the factors contributing to the reduction of carbon footprints resulting from plastic waste management activities. The data collected from 1326 respondents was analyzed using factor analysis, and the reliability of the dataset was confirmed using Cronbach's alpha (0.84 for the awareness level of waste management techniques and 0.780 for the prevalent mode of plastic waste management techniques). KMO (0.796), Bartlett's test of sphericity (p < 0.001), and determinant score (0.019) were used to assess the data adequacy and factorability of the dataset, and the results were found to be satisfactory. Principal component analysis, exploratory factor analysis, and varimax orthogonal rotation method were used to identify high-loaded factors by reducing the number of variables. The results showed that two highly loaded components, namely awareness level of waste management techniques (AWMT) and prevalent mode of plastic waste management techniques (PWMT), explained 27.53% and 24.34% of the total variance, respectively, with eigenvalues of 3.35 and 2.88. The regression model confirmed the statistical significance of these factors (p < 0.001) and their relationship with the dependent variable, greenhouse reduction (GHGR). The study proposes that minimizing carbon footprints in the environment can be achieved by focusing on a limited number of controllable factors such as AWMT and PWMT. This study provides valuable insights to the authorities in controlling waste generation and achieving a pollution-free environment.     

昌吉州农田地膜污染现状及治理对策

通过对昌吉州农田地膜使用现状进行调查,阐述了地膜污染的危害,并提出了适期揭膜、残膜回收、推广新型生物膜等措施与防治对策。