基于工艺过程的金属包装业VOCs污染特征

识别金属包装业挥发性有机化合物(volatile organic compounds,VOCs)产生和排放节点,定量分析不同类型生产工艺所排放VOCs的物种及含量,结合最大增量反应活性法和修正的气溶胶生成系数法对行业二次污染进行核算.结果表明,金属包装业排放的VOCs主要为苯系物、醇类、酮类和酯类,苯系物和醇类在不同类型工序和排污节点中贡献较大,酮类和酯类贡献相对较少,单物种浓度最高的VOCs为正丁醇,浓度达269.08mg·m~(-3);生产线与相应的排气筒之间VOCs物种浓度相关性较好,但物种种类存在差异;行业的O_3和二次有机气溶胶(secondary organic aerosol, SOA)生成潜势(以O_3/VOCs和SOA/VOCs计)分别为(3.09±0.94)g·g~(-1)和(2.58±1.99)g·g~(-1),苯系物和内全涂烘干工序为O_3和SOA的主要前体物和首要生成节点.     

Waste-based composites—Poverty reducing solutions to environmental problems

This paper highlights an innovative model of waste management combined with poverty reduction, which has been developed by the organisation Waste for Life (wasteforlife.org) - a network of academics, students, practitioners and on the ground cooperative partners in low income communities. The Waste for Life teams work with local cooperatives to create waste-based composites, which may be sold in local markets, thereby creating an income stream. The application of this model to the context of cartoneros (waste picker) cooperatives in Buenos Aires, Argentina, reveals that viable products can be made from paper and plastic waste, with low-impact material preparation that circumvents the need for chemically intensive, polluting and mechanically degrading procedures, preserving recycled fibre integrity. Tests on material samples indicate mechanical properties comparable to products made with more complex processing. The production model is based on the philosophy that not only the waste materials, but also the production equipment should be locally sourced and manufactured and products created to suit local markets. A simple reproducible model has been developed for the local manufacture of composites from waste, which can provide an income source for waste pickers as well as providing an innovative waste management solution.     

Challenges in characterization of nanoplastics in the environment

Plastic pollution has been a legacy environment problems and more recently, the plastic particles, especially those ultrafine or small plastics particles, are widely recognized with increasing environmental and ecological impacts. Among small plastics, microplastics are intensively studied, whereas the physicochemical properties, environmental abundance, chemical states, bioavailability and toxicity toward organisms of nanoplastics are inadequately investigated. There are substantial difficulties in separation, visualization and chemical identification of nanoplastics due to their small sizes, relatively low concentrations and interferences from co-existing substances (e.g., dyes or natural organic matters). Moreover, detection of polymers at nanoscale is largely hampered by the detection limit or sensitivity for existing spectral techniques such as Transformed Infrared Spectroscopy (FTIR) or Raman Spectroscopy. This article critically examined the current state of art techniques that are exclusively reported for nanoplastic characterization in environmental samples. Based on their operation principles, potential applications and limitations of these analytical techniques are carefully analyzed.     

What have we known so far for fluorescence staining and quantification of microplastics: A tutorial review

• Fluorescence staining provides a fast and easy method to quantify microplastics. • Factors that influence staining are summarized to obtain an optimum staining effect. • Natural organic matter can be stained by dye and interfere with quantification. • Fluorescence staining is applied in both field and laboratory studies. • Future work involves developing new dyes and automated image-analysis methods. Understanding the fate and toxicity of microplastics (MPs,<5 mm plastic particles) is limited by quantification methods. This paper summarizes the methods in use and presents new ones. First, sampling and pretreatment processes of MPs, including sample collection, digestion, density separation, and quality control are reviewed. Then the promising and convenient staining procedures and quantification methods for MPs using fluorescence dyes are reviewed. The factors that influence the staining of MPs, including their physicochemical properties, are summarized to provide an optimal operation procedure. In general, the digestion step is crucial to eliminate natural organic matter (NOM) to avoid interference in quantification. Chloroform was reported to be the most appropriate solvent, and 10–20 μg/mL are recommended as optimal dye concentrations. In addition, a heating and cooling procedure is recommended to maintain the fluorescence intensity of MPs for two months. After staining, a fluorescence microscope is usually used to characterize the morphology, mass, or number of MPs, but compositional analysis cannot be determined with it. These fluorescence staining methods have been implemented to study MP abundance, transport, and toxicity and have been combined with other chemical characterization techniques, such as Fourier transform infrared spectroscopy and Raman spectroscopy. More studies are needed to focus on the synthesis of novel dyes to avoid NOM’s interference. They need to be combined with other spectroscopic techniques to characterize plastic composition and to develop image-analysis methods. The stability of stained MPs needs to be improved.     

包装印刷行业挥发性有机物控制技术评估与筛选

挥发性有机物(volatile organic compounds,VOCs)是造成我国城市大气污染的主要因素之一,包括包装印刷行业活动等在内的工业源是VOCs污染的重要来源.工业源的治理技术众多,如何选择合适的治理技术是面临的主要问题.本文在包装印刷行业VOCs排放特点及现有治理技术的研究基础上,针对包装印刷行业中典型的复合膜干复工艺VOCs排放与治理,以层次分析法为模型,构建该行业VOCs控制技术评估体系,对包装印刷行业现有治理技术进行综合评估,筛选出最佳可行控制技术,为包装印刷行业VOCs减排控制提供了技术支持.结果表明,包括吸附回收和热力焚烧在内的7种技术,其技术优先顺序为:碳纤维吸脱附>颗粒炭吸脱附>直接燃烧>蓄热燃烧>催化燃烧>转轮浓缩燃烧>活性炭浓缩燃烧,其中碳纤维吸脱附技术综合评估权重较高,为最优控制技术.     

Dimpling process in cold roll metal forming by finite element modelling and experimental validation

The dimpling process is a novel cold-roll forming process that involves dimpling of a rolled flat strip prior to the roll forming operation. This is a process undertaken to enhance the material properties and subsequent products’ structural performance while maintaining a minimum strip thickness. In order to understand the complex and interrelated nonlinear changes in contact, geometry and material properties that occur in the process, it is necessary to accurately simulate the process and validate through physical tests. In this paper, 3D non-linear finite element analysis was employed to simulate the dimpling process and mechanical testing of the subsequent dimpled sheets, in which the dimple geometry and material properties data were directly transferred from the dimpling process. Physical measurements, tensile and bending tests on dimpled sheet steel were conducted to evaluate the simulation results. Simulation of the dimpling process identified the amount of non-uniform plastic strain introduced and the manner in which this was distributed through the sheet. The plastic strain resulted in strain hardening which could correlate to the increase in the strength of the dimpled steel when compared to plain steel originating from the same coil material. A parametric study revealed that the amount of plastic strain depends upon on the process parameters such as friction and overlapping gap between the two forming rolls. The results derived from simulations of the tensile and bending tests were in good agreement with the experimental ones. The validation indicates that the finite element analysis was able to successfully simulate the dimpling process and mechanical properties of the subsequent dimpled steel products.     

液氯包装区事故预防措施的工艺改进

氯气液化能生产高纯氯气,在氯碱企业中起到平衡生产的作用。氯气外泄会严重污染环境,给人类生存与健康带来威胁,所以氯气泄漏事故的预防与处理成为氯碱企业安全生产的一项重要内容。通过工艺的改进,对液氯贮存包装区泄漏事故进行了有效的预防和处理。     

Gasification and smelting system using oxygen blowing for plastic waste including polyvinyl chloride

A new type of waste gasification and smelting system using oxygen blowing based on high-temperature metallurgy, was developed by Sumitomo Metals, Japan. This system can steadily gasify and melt not only municipal waste, but also plastic waste and polyvinyl chloride (PVC) waste by using a top-blow oxygen lance together with sideways-blow oxygen lances. As a result of gasification in the high-temperature reducing atmosphere and rapid gas cooling, dioxin-free, high-calorie purified gas was produced. Ash components in the wastes were smelted in a high-temperature reducing atmosphere, and high-quality slag free of heavy metals was produced. Most of the chlorine in the wastes was converted into hydrogen chloride in the off gas. The hydrogen chloride can be recovered as hydrochloric acid or chlorine, which are recyclable to PVC manufacturing.     

Biodegradability of a Selected Range of Polymers and Polymer Blends and Standard Methods for Assessment of Biodegradation

Synthetic polymers are important to the packaging industry but their use raises aesthetic and environmental concerns, particularly with regard to solid waste accumulation problems and the threat to wildlife. Some concerns are addressed by attention to problems associated with source reduction, incineration, recycling and landfill. Others are addressed by the development of new biodegradable polymers either alone or in blends. Materials used for biodegradable polymers include various forms of starch and products derived from it, biopolyesters and some synthetic polymers. Starch is rapidly metabolised and is an excellent base material for polymer blends or for infill of more environmentally inert polymers where it is metabolised to leave less residual polymer on biodegradation. This should help to improve the environmental impact of waste disposal. A number of standard methods have been developed to estimate the extent of biodegradability of polymers under various conditions and with a variety of organisms. They tend to be used mainly in the countries where they were developed but there is much overlap between the standards of different countries and wide scope for development of consistent and international standards.     

Marine Debris &; Plastics: Environmental Concerns,Sources, Impacts and Solutions

Marine debris (marine litter) is one of the most pervasive and solvable pollution problems plaguing the world’s oceans and waterways. Nets, food wrappers, cigarette filters, bottles, resin pellets, and other debris items can have serious impacts on wildlife, habitat, and human safety. Successful management of the problem requires a comprehensive understanding of both marine debris and human behavior. Knowledge is key for consumers to make appropriate choices when it comes to using and disposing of waste items. Education and outreach programs, strong laws and policies, and governmental and private enforcement are the building blocks for a successful marine pollution prevention initiative. The plastic industry also has a role to play in educating its employees and customers, and searching for technological mitigation strategies.