This paper appraised divergent chemical depolymerization routes for reprocessing chemically synthesis polyethylene terephthalate (PET) plastics bottle waste and offer resolutions to control the ...environmental complications emanating attributable to its utilize and disposal to the habitat. The consciousness to prune environs contaminants and make it “green” demand for the reclaim and reprocessing it back to PET bottles, precursor products like glycolyzate, and other inventions such as unsaturated polyester resins, epoxy resins, composites etc. Controlling this necessitates assorted reprocessing methods of which chemical recycling that transform PET into monomer/oligomer is the most prosperous one. This review explored in detail current events in the PET chemical recycling using glycolysis method. The study was based on their current evolution concerning their depolymerization agents, reaction conditions, kinetics of reactions, catalysts used, products of reprocessing, and their prospective use. Benefits of PET recycling and glycolysis as well as criteria and necessitation factors that used to adjudge them as the best method and sub-method respectively were highlighted. The prospect for the conversion of glycolyzate into other PET recycling methods products were shown. PET recycling was concluded to be a partial resolution to wastes management, and also grants the conservation of natural petrochemical resources and energy.
The vast majority of commodity plastics do not degrade and therefore they permanently pollute the environment. At present, less than 20% of post-consumer plastic waste in developed countries is ...recycled, predominately for energy recovery or repurposing as lower-value materials by mechanical recycling. Chemical recycling offers an opportunity to revert plastics back to monomers for repolymerization to virgin materials without altering the properties of the material or the economic value of the polymer. For plastic waste that is either cost prohibitive or infeasible to mechanically or chemically recycle, the nascent field of chemical upcycling promises to use chemical or engineering approaches to place plastic waste at the beginning of a new value chain. Here state-of-the-art methods are highlighted for upcycling plastic waste into value-added performance materials, fine chemicals and specialty polymers. By identifying common conceptual approaches, we critically discuss how the advantages and challenges of each approach contribute to the goal of realizing a sustainable plastics economy.
•The recycling of the plastic waste can help in reducing it and its environmental threat.•The theory of planned behavior was adapted and extended to measure the determinants of recycling ...behavior.•Subjective Norms, Awareness Consequences and Convenience are major predictors of return/recycling intention.•Attitude, Perceived Behavioral Control and Moral Norms was found to have insignificant impact on return/recycling intention.
Plastic consumption has been increasing globally, creating large amount of litter and posing threat to the environment. The recycling of the plastic waste can help in reducing it and its environmental threat. The purpose of this paper is to identify the factors that influence the consumer’s return/recycling intention regarding plastic waste. Moreover, recycling behavior of consumer was explored in detail. The theory of planned behavior was adapted and extended to measure the determinants of recycling behavior. Survey research design was employed whereas data includes valid 243 households, collected through survey questionnaire, by employing purposive sampling. PLS-SEM was applied on the collected data for hypotheses testing. The finding of this study indicates that subjective norms, awareness consequences and convenience are major predictors of return/recycling intention. Whereas, hypothesis for the attitude, perceived behavioral control and moral norms were rejected and they all have insignificant impact on return/recycling intention. Moreover, return intention have positive significant impact on resell, reuse, dispose and donate. Reuse was the most predicted by the return intention. This study enriches the literature of reverse logistics helping to understand the consumers’ perspective. Provides the insights that will help government and organizations to understand consumers’ return/recycling intention and formulate such strategies that will increase the involvement of consumers in recycling activities.
Chemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most ...plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA‐PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a “greener” alternative feedstock for the synthesis of high added value molecules.
The energetic differences for the glycolysis of BPA‐PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enable the selective and sequential depolymerisation of these two commonly employed polymers. Functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend.
Carbon fiber reinforced polymers (CFRPs) with high Tg (>200 °C) are indispensable for aerospace industry where high service temperature is required. Chemical recycling of the matrix polymers for ...these CFRP composites is more difficult than that of their low Tg analogues. In this work, an efficient approach for mild chemical recycling of CFRP with a Tg of ∼210 °C was developed using a ZnCl2/ethanol catalyst system. The high efficiency of ZnCl2/ethanol was attributed to the strong coordination effect of ZnCl2 with the C-N bonds and the strong swelling ability of ethanol, which worked together to break down the chemical bonds of the cross-linked polymer. Also, mild degradation temperature (<200 °C) imparted little damage to the recovered fibers. The decomposed matrix polymer (DMP) was in the oligomer form and contained multifunctional reactive groups. When DMP was used as a reactive ingredient and added up to 15 wt% to the preparation of new epoxy materials, the resulting cross-linked polymers could still retain the high strength and modulus compared to the neat polymer without addition of DMP.
The rapid proliferation of electric vehicles equipped with lithium‐ion batteries (LIBs) presents serious waste management challenges and environmental hazards for recyclers after scrap. Closed‐loop ...recycling contributes to the sustainable development of batteries and plays an important role in mitigating raw material shortages and supply chain risks. Herein, current direct cathode regeneration methods for industrialized recycling are outlined and evaluated. Different regeneration methods for spent cathode materials are summarized, which provide a new perspective for realizing closed‐loop recycling of LIBs. A reference recycling route for retrofitting existing cathode production lines is proposed and minimizes the costs. In addition to promoting the industrialization of direct cathode recycling, the environmental, economic, and political benefits of battery recycling are also highlighted.
Direct cathode regeneration methods are summarized to highlight the technical challenges, current status, supply chain, carbon footprints, and possible solutions for closed‐loop battery recycling. The environmental, economic, and political benefits of the direct cathode regeneration methods are also considered, and a reference recycling route with available automated recycling technology is proposed and minimizes the costs.
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