Increasing the stream of recycled plastic necessitates an approach beyond the traditional recycling via melting and re‐extrusion. Various chemical recycling processes have great potential to enhance ...recycling rates. In this Review, a summary of the various chemical recycling routes and assessment via life‐cycle analysis is complemented by an extensive list of processes developed by companies active in chemical recycling. We show that each of the currently available processes is applicable for specific plastic waste streams. Thus, only a combination of different technologies can address the plastic waste problem. Research should focus on more realistic, more contaminated and mixed waste streams, while collection and sorting infrastructure will need to be improved, that is, by stricter regulation. This Review aims to inspire both science and innovation for the production of higher value and quality products from plastic recycling suitable for reuse or valorization to create the necessary economic and environmental push for a circular economy.
Plastic fantastic: Plastic can rise again and again as a new product. Researchers now know methods with which new plastics can be produced from 100 % recycled material, products that can even be used for food applications. This development is possible thanks to chemical recycling, through which polymer chains are first broken to then be reformed into new molecules, such as plastics but also other chemicals.
•This paper reviews the current pathways for recycling of solid plastic waste, via both mechanical and chemical recycling.•The predominant industrial technologies, design strategies and recycling ...examples of specific waste streams are reviewed.•The main challenges and some potential remedies are discussed.
This review presents a comprehensive description of the current pathways for recycling of polymers, via both mechanical and chemical recycling. The principles of these recycling pathways are framed against current-day industrial reality, by discussing predominant industrial technologies, design strategies and recycling examples of specific waste streams. Starting with an overview on types of solid plastic waste (SPW) and their origins, the manuscript continues with a discussion on the different valorisation options for SPW. The section on mechanical recycling contains an overview of current sorting technologies, specific challenges for mechanical recycling such as thermo-mechanical or lifetime degradation and the immiscibility of polymer blends. It also includes some industrial examples such as polyethylene terephthalate (PET) recycling, and SPW from post-consumer packaging, end-of-life vehicles or electr(on)ic devices. A separate section is dedicated to the relationship between design and recycling, emphasizing the role of concepts such as Design from Recycling. The section on chemical recycling collects a state-of-the-art on techniques such as chemolysis, pyrolysis, fluid catalytic cracking, hydrogen techniques and gasification. Additionally, this review discusses the main challenges (and some potential remedies) to these recycling strategies and ground them in the relevant polymer science, thus providing an academic angle as well as an applied one.
Challenges in Metal Recycling Reck, Barbara K.; Graedel, T. E.
Science (American Association for the Advancement of Science),
08/2012, Letnik:
337, Številka:
6095
Journal Article
Recenzirano
Metals are infinitely recyclable in principle, but in practice, recycling is often inefficient or essentially nonexistent because of limits imposed by social behavior, product design, recycling ...technologies, and the thermodynamics of separation. We review these topics, distinguishing among common, specialty, and precious metals. The most beneficial actions that could improve recycling rates are increased collection rates of discarded products, improved design for recycling, and the enhanced deployment of modern recycling methodology. As a global society, we are currently far away from a closed-loop material system. Much improvement is possible, but limitations of many kinds—not all of them technological—will preclude complete closure of the materials cycle.
This paper reviews studies of the environmental impact of textile reuse and recycling, to provide a summary of the current knowledge and point out areas for further research. Forty-one studies were ...reviewed, whereof 85% deal with recycling and 41% with reuse (27% cover both reuse and recycling). Fibre recycling is the most studied recycling type (57%), followed by polymer/oligomer recycling (37%), monomer recycling (29%), and fabric recycling (14%). Cotton (76%) and polyester (63%) are the most studied materials.
The reviewed publications provide strong support for claims that textile reuse and recycling in general reduce environmental impact compared to incineration and landfilling, and that reuse is more beneficial than recycling. The studies do, however, expose scenarios under which reuse and recycling are not beneficial for certain environmental impacts. For example, as benefits mainly arise due to the avoided production of new products, benefits may not occur in cases with low replacement rates or if the avoided production processes are relatively clean. Also, for reuse, induced customer transport may cause environmental impact that exceeds the benefits of avoided production, unless the use phase is sufficiently extended.
In terms of critical methodological assumptions, authors most often assume that textiles sent to recycling are wastes free of environmental burden, and that reused products and products made from recycled materials replace products made from virgin fibres. Examples of other content mapped in the review are: trends of publications over time, common aims and geographical scopes, commonly included and omitted impact categories, available sources of primary inventory data, knowledge gaps and future research needs. The latter include the need to study cascade systems, to explore the potential of combining various reuse and recycling routes.
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•We reviewed 41 studies of the environmental impact of textile reuse and recycling.•In general, there are environmental benefits with textile reuse and recycling.•Textile reuse leads to greater environmental benefits compared to recycling.•Most benefits come from avoided production, so the replacement rate is a key factor.•We list sources of inventory data, reveal knowledge gaps and suggest research needs.
The plastics have produced a lot of serious environmental problems because there are large quantities of which the majority ends up in landfills or even in the seas. In addition, they are produced ...from exhaustible fossil fuels. For these reasons, recycling plastics is an alternative which may reduce environmental problems and resource depletion. Currently, the most common technique used for chemical recycling of plastics is pyrolysis. In this work, the pyrolysis process was carried out on a plastic waste (polyethylene film) from the fraction not collected selectively, with the aim of obtaining a liquid fuel. Both physical and chemical characterization of different oil samples was performed, which were obtained under different operating conditions. The main objective was to determine the quality of the fuel and whether this quality depended on the operating conditions used. It was determined that the properties of the fuel studied do not vary depending on the operating conditions used. The physical and chemical characteristics of the oil samples were very similar to those of commercial fuels (gasoline and diesel), with the exception of viscosity because the fuel studied has not been fractionated and therefore has light and heavy naphthas.
•PE film from not collected selectively municipal solid waste was pyrolyzed.•Physical and chemical characterization obtained oil samples was performed.•Studied operating conditions did not influenced main properties of oil samples.•The main characteristics of the oil samples were very similar to those of diesel.•Obtained oil samples could replace commercial diesel in future applications.
Based on 19 high-quality articles, this Special Issue presents methods for further improving the currently achievable recycling rate, product quality in terms of focused elements, and approaches for ...the enhanced mobilization of lithium, graphite, and electrolyte components. In particular, the target of early-stage Li removal is a central point of various research approaches in the world, which has been reported, for example, under the names early-stage lithium recovery (ESLR process) with or without gaseous CO2 and supercritical CO2 leaching (COOL process). Furthermore, many more approaches are present in this Special Issue, ranging from robotic disassembly and the dismantling of Li‐ion batteries, or the optimization of various pyro‐ and hydrometallurgical as well as combined battery recycling processes for the treatment of conventional Li‐ion batteries, all the way to an evaluation of the recycling on an industrial level. In addition to the consideration of Li distribution in compounds of a Li2O-MgO-Al2O3-SiO2-CaO system, Li recovery from battery slags is also discussed. The development of suitable recycling strategies of six new battery systems, such as all-solid-state batteries, but also lithium–sulfur batteries, is also taken into account here. Some of the articles also discuss the fact that battery recycling processes do not have to produce end products such as high-purity battery materials, but that the aim should be to find an “entry point” into existing, proven large-scale industrial processes. Participants in this Special Issue originate from 18 research institutions from eight countries.
The future of plastics recycling Garcia, Jeannette M.; Robertson, Megan L.
Science (American Association for the Advancement of Science),
11/2017, Letnik:
358, Številka:
6365
Journal Article
Recenzirano
Chemical advances are increasing the proportion of polymer waste that can be recycled
The environmental consequences of plastic solid waste are visible in the ever-increasing levels of global plastic ...pollution both on land and in the oceans. But although there are important economic and environmental incentives for plastics recycling, end-of-life treatment options for plastic solid waste are in practice quite limited. Presorting of plastics before recycling is costly and time-intensive, recycling requires large amounts of energy and often leads to low-quality polymers, and current technologies cannot be applied to many polymeric materials. Recent research points the way toward chemical recycling methods with lower energy requirements, compatibilization of mixed plastic wastes to avoid the need for sorting, and expanding recycling technologies to traditionally nonrecyclable polymers.
•Several regression models are used to estimate variables affecting on waste reduction.•Relevant causal factors regarding solid waste generation and recycling are analyzed.•Households variables ...present different challenges on generation and recycling goals.•Some economic and policy incentives are proved to be effective in waste management.
Economic development, urbanization, and improved living standards increase the quantity and complexity of generated solid waste. Comprehensive study of the variables influencing household solid waste production and recycling rate is crucial and fundamental for exploring the generation mechanism and forecasting future dynamics of household solid waste. The present study is employed in the case study of Prespa Park. A model, based on the interrelationships of economic, demographic, housing structure and waste management policy variables influencing the rate of solid waste generation and recycling is developed and employed. The empirical analysis is based on the information derived from a field questionnaire survey conducted in Prespa Park villages for the year 2014. Another feature of this study is to test whether a household’s waste generation can be decoupled from its population growth. Descriptive statistics, bivariate correlation analysis and F-tests are used to know the relationship between variables. One-way and two-way fixed effects models data analysis techniques are used to identify variables that determine the effectiveness of waste generation and recycling at household level in the study area. The results reveal that households with heterogeneous characteristics, such as education level, mean building age and income, present different challenges of waste reduction goals. Numerically, an increase of 1% in education level of population corresponds to a waste reduction of 3kg on the annual per capita basis. A village with older buildings, in the case of one year older of the median building age, corresponds to a waste generation increase of 12kg. Other economic and policy incentives such as the mean household income, pay-as-you-throw, percentage of population with access to curbside recycling, the number of drop-off recycling facilities available per 1000 persons and cumulative expenditures on recycling education per capita are also found to be effective measures in waste reduction. The mean expenditure for recycling education spent on a person for years 2010 and 2014 is 12 and 14 cents, respectively and it vary from 0 to €1. For years 2010 and 2014, the mean percentage of population with access to curbside recycling services is 38.6% and 40.3%, and the mean number of drop-off recycling centers per 1000 persons in the population is 0.29 and 0.32, respectively. Empirical evidence suggests that population growth did not necessarily result in increases in waste generation. The results provided are useful when planning, changing or implementing sustainable municipal solid waste management.
A comprehensive process of recycling of lithium ion battery from EVs.
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•Recycling of lithium ion batteries from EVs will be a big challenge by 2020.•The work summarizes mechanical and ...metallurgical procedures for recycling of packs.•Mechanical procedure comprises of intelligent disassembly system for battery packs.•Metallurgical processes includes new pyro-, hydro-,bio-metallurgy and hybrid methods.
Due to enormous growth of production of electric vehicles, it is estimated by the year 2020 about 250,000 tons of battery must be disposed or recycled. The technology to recycle this much amount of batteries in a single year does not exist., neither does the methods for recycling are standardized because of different configurations of battery packs. A challenge strictly poses on how to deal with lithium ion batteries, which are embedded in hundreds or more in a battery pack. Furthermore, the recovery of materials from the battery in the pack is essential to ensure the growth and sustainability of the electric vehicle market. It is desirable to establish a framework that is semi-automated/automated for ensuring faster disassembly of battery pack, identification and detection of residual energy of batteries in packs and recovery of materials from batteries. This review paper summarizes the two main basic aspects of recycling battery packs: mechanical procedure and chemical recycling (metallurgical). The work summarizes the existing recycling technology in these two aspects and identifies important research problems in the process of recycling of pack such as (i) automatic and intelligent recovery system, (ii) efficiency and safety disassemble of battery pack (iii) Adjustment of Chaos in recycling market (iv) Recovery processes for slag, electrolyte and anode, (v) Application in industrial scale, and (vi) development of recycling methods for new batteries having components with different properties. This paper also proposes a framework to push the recycling process from conception to practicality, both on government incentive polices and effective recycling technology.
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