Over the past 30 years, China has been suffering from negative environmental impacts from distempered waste electrical and electronic equipments (WEEE) recycling activities. For the purpose of ...environmental protection and resource reusing, China made a great effort to improve WEEE recycling. This article reviews progresses of three major fields in the development of China’s WEEE recycling industry: legal system, formal recycling system, and advanced integrated process. Related laws concerning electronic waste (e-waste) management and renewable resource recycling are analyzed from aspects of improvements and loopholes. The outcomes and challenges for existing formal recycling systems are also discussed. The advantage and deficiency related to advanced integrated recycling processes for typical e-wastes are evaluated respectively. Finally, in order to achieve high disposal rates of WEEE, high-quantify separation of different materials in WEEE and high added value final products produced by separated materials from WEEE, an idea of integrated WEEE recycling system is proposed to point future development of WEEE recycling industry.
Recycling of Bioplastics: Routes and Benefits Lamberti, Fabio M.; Román-Ramírez, Luis A.; Wood, Joseph
Journal of polymers and the environment,
10/2020, Volume:
28, Issue:
10
Journal Article
Peer reviewed
Open access
Continual reduction of landfill space along with rising CO
2
levels and environmental pollution, are global issues that will only grow with time if not correctly addressed. The lack of proper waste ...management infrastructure means gloablly commodity plastics are disposed of incorrectly, leading to both an economical loss and environmental destruction. The bioaccumulation of plastics and microplastics can already be seen in marine ecosystems causing a negative impact on all organisms that live there, ultimately microplastics will bioaccumulate in humans. The opportunity exists to replace the majority of petroleum derived plastics with bioplastics (bio-based, biodegradable or both). This, in conjunction with mechanical and chemical recycling is a renewable and sustainable solution that would help mitigate climate change. This review covers the most promising biopolymers PLA, PGA, PHA and bio-versions of conventional petro-plastics bio-PET, bio-PE. The most optimal recycling routes after reuse and mechanical recycling are: alcoholysis, biodegradation, biological recycling, glycolysis and pyrolysis respectively.
Increased media coverage of plastic pollution in the environment and import bans on plastic waste in several countries have resulted in plastic waste becoming one of the most discussed waste streams ...in recent years. In the European Union (EU), only about one-third of the post-consumer plastic waste is recycled; the rest goes to energy recovery and landfilling in equal parts. In connection to the necessary increase in efforts to achieve the ambitious EU recycling targets, chemical recycling is currently receiving more and more attention. The assumption is that chemical recycling processes could open up new waste streams for recycling and generate valuable raw materials for the chemical industry. Although there exists no legal definition for chemical recycling, there is more or less agreement that it covers the conversion of plastic polymers into their monomers or chemical building blocks. Techniques such as gasification, pyrolysis and liquefaction as well as solvolysis can be used for chemical recycling. So far, only few large-scale plants for chemical recycling exist worldwide. This article presents the different processes by means of examples from (formerly) running installations and their suitability for plastics recycling is assessed. However, to date, only few chemical recycling plants are in continuous operation, and further scientific evidence for the ecological and economic benefits is still necessary for final evaluation.
•Predictors of recycling behaviors are observed with respect to gender.•Behavioral intention of females is shaped by perceived behavioral control, attitude, past behavior and subjective ...norm.•Behavioral intention of males is shaped by past behavior, perceived behavior control, subjective norm.
This study aimed to assess the role of some socio-psychological attributes in explaining recycling behavior of Turkish university community from a gender perspective within the context of the theory of planned behavior with an additional variable (past experience). The recycling behavior of whole sample, females and males, has been examined in 3 sessions -depending on the arguments that explain gendered pattern of private and public environmental behavior and sticking to the fact why females’ stronger environmental values, beliefs, and attitudes do not translate consistently into greater engagement in public behavior. As a result of model runs, different variables shaping intention for behavior have been found, namely perceived behavior control for females and past behavior for males. Due to the low percent of the variance in explaining recycling behavior of females, they have been identified as the ones who do not carry out intentions (non-recyclers). Since intentions alone are capable of identifying recyclers accurately but not non-recyclers, there may be other factors to be considered to understand the reason for females not carrying out the intentions. The results of descriptive statistics supported the identification by attitudes toward recycling. Female attitudes were innate (recycling is good, necessary, useful and sensitive), whereas those of males were learnt (recycling is healthy, valuable and correct). Thus, it has been concluded that males’ intention for recycling is shaped by their past behavior and the conclusion is supported by males having learnt attitude toward recycling whereas females’ lack of intention for recycling is shaped by their perceived behavior control and is supported by their innate attitude for recycling. All in all, the results of the present study provide further support for the utility of the TPB as a model of behavioral prediction and concur with other studies examining the utility of the TPB in the context of recycling.
“Internet +” recyclable resources recycling is a new recycling program which developed quickly in China over the past three years. Indenting problems faced by internet recycling programs and ...summarizing typical modes are in need and necessary. To better realize and promote the new recycling way in China, we investigate related governmental departments and 10 represented enterprises that put “internet +” recycling into practice in China. From our investigation, we identify the problems faced by the enterprises and show four typical internet recycling modes. Based on the problems and cases analysis, the implications for sustainable “internet +” recycling are discussed. We suggest building a connection between online and offline, establishing a variety of profit models, educating older generations on the “internet +” recycling platform, and meeting the recycling requirements on low-value recyclable resources through the application of smart machines.
Over the past decades, China has been suffering from negative environmental impacts from distempered e-waste recycling activities. After a decade of effort, disassembly and raw materials recycling of ...environmentally friendly e-waste have been realized in specialized companies, in China, and law enforcement for illegal activities of e-waste recycling has also been made more and more strict. So up to now, the e-waste recycling in China should be developed toward more depth and refinement to promote industrial production of e-waste resource recovery. Waste printed circuit boards (WPCBs), which are the most complex, hazardous, and valuable components of e-waste, are selected as one typical example in this article that reviews the status of related regulations and technologies of WPCBs recycling, then optimizes, and integrates the proper approaches in existence, while the bottlenecks in the WPCBs recycling system are analyzed, and some preliminary experiments of pinch technologies are also conducted. Finally, in order to provide directional guidance for future development of WPCBs recycling, some key points in the WPCBs recycling system are proposed to point towards a future trend in the e-waste recycling industry.
The covalent cross‐linking is an essential prerequisite for achieving the unique entropic elasticity of rubber products; however, the formation of a 3D cross‐linked network and permanent cross‐links ...makes thermosetting rubbers difficult to be recycled, causing serious environmental pollution at the end of their life. Herein, a facile, green, and promising strategy to introduce the exchangeable and cleavable acetal bonds into the chemically cross‐linked networks of diene‐typed rubbers is reported. For the first time, the hydroxyl‐functionalized styrene‐butadiene rubber (ESBR‐HEMA) is prepared by introducing 2‐hydroxyethyl methacrylate (HEMA) during the emulsion polymerization of styrene‐butadiene rubber (ESBR). Then, based on hydroxyl‐vinyl ether addition reactions, divinyl ether (DVE) could serve as a cross‐linking agent to facilely and effectively cross‐link hydroxyl‐functionalized rubbers without additional additives, producing exchangeable and hydrolyzable acetal linkages. What's more, the acetal‐containing cross‐linked network in ESBR‐HEMA vulcanizates could rearrange their topologies at elevated temperatures, endowing them with malleable and thermal reprocessing abilities. Moreover, the hydrolyzable acetal bonds could be selectively cleaved into hydroxyl and aldehyde groups in acidic conditions, resulting in a closed‐loop chemical recycling of the ESBR‐HEMA rubber. Hence, this work provides a facile and green cross‐linking strategy for hydroxyl‐functionalized rubbers to address the inherent problems brought from the covalent cross‐linking of rubbers.
Based on hydroxyl‐vinyl ether addition reactions, a facile and green cross‐linking strategy for hydroxyl‐functionalized rubbers is put forward toward green curing process, thermal reprocessing, and closed‐loop recycling enabled by exchangeable and cleavable acetal linkages. This work provides a facile and green cross‐linking strategy for hydroxyl‐functionalized rubbers to address the inherent problems brought from the covalent cross‐linking of rubbers.
The traditional method of construction and demolition waste (CDW) consumes a substantial amount of land resources causing severe environmental and social problems. In Portugal, the low recycling ...rate, combined with a high use of landfill as a way of managing CDW, has resulted in a negative index of 39% in the waste hierarchy, thus making it impossible for Portugal to be classified as a country that implements waste hierarchy in practice. The main goal of this study is to investigate the benefits of CDW reuse and recycling and the factors that promote or hinder this practice in Portugal. Therefore, a comprehensive approach has been adopted by combining the analysis of secondary data collected through extensive bibliography research with the results of a survey by questionnaire conducted on a group of experts in CDW management. It was concluded that the main method of CDW management consists of its disposal in licensed landfills (47%), and the rate of CDW reuse on site is still low (6%). The results show a high consistency between the respondents’ answers, as well as consistency between the opinions of these participants from different areas of professional activity. The respondents do recognize a concern regarding the reduction of carbon emissions, as well as a cultural resistance to materials or buildings that use CDW. These problems are further compounded by the difficulty in installing or supporting recycling equipment for CDW reuse on site. Respondents agree that there should be more investment and support from the government in this area, as well as in the training of construction companies.
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