Recycling is a cornerstone of waste management. Despite its significance and growing interest, the US recycling rate has stagnated at around 35% for more than the past decade. In this study, we ...investigate an effective waste collection method as well as factors that may negatively affect recycling program management as a proxy measure of the recycling rate. To this end, recycling program managers and coordinators were surveyed since they play a pivotal role in the flow of recyclable materials. We found a combination of curbside and drop-off recycling to be the most cost-effective, but when managers’ experience level is factored in, the perceived significance of the combination approach decreases. Concerning barriers to recycling, we found that market variability for recycled materials, insufficient public participation in waste collection, and knowledge of best practices are critical inhibiting factors. In addition, China’s complete ban on waste import by 2030, an organizational framing effect of recycling, and a strong need for public education and outreach activities about recycling have emerged as new problems for recycling. Our findings point out recycling systems that reduce those setbacks to improve recycling performance and increase the recycling rate.
•3 out of 9 chemical recycling technologies have the highest TRL of 9.•Plasma gasification of plastics could soon be fully commercialized.•Economic feasibility of chemical recycling is still ...challenging to asses.•Chemical recycling is only a part of solution for plastic recovery.
Chemical recycling is considered an attractive technological pathway for reducing waste and greenhouse gas emissions, as well as promoting circular economy. In the EU, readiness to develop a full commercial plant is becoming increasingly important given the ambitious goal to recycle all plastics by 2030. Household packaging streams tend to be of lower quality and lower recycling performance compared to industrial and commercial waste streams, thus requiring particular attention. This paper assesses chemical recycling technologies available and identifies the most suitable for recycling of household plastic waste. We identify eight different technologies and compare them in terms of process temperature, sensitivity to feedstock contamination and level of polymer breakdown, three critical factors affecting the cost and attractiveness of a chemical process. In addition, we carry out a Technology Readiness Level (TRL) assessment for eight technologies based on the stage of their present development. The review is based on peer-reviewed scientific papers and information collected from technology developers and providers, as well as interviews with experts. Our analysis outlines advantages and disadvantages of technologies available for chemical plastic recycling and their TRL. The chemical recycling technologies with the highest TRL are pyrolysis, catalytic cracking and conventional gasification. However, the economic feasibility of these technologies is difficult to assess due to the low number of projects in operation and scarcity of data available for comparison. The results of this analysis provide timely information as policy makers and developers set targets for recycling, and contemplate investments on research and chemical plastic recovering plants.
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Closed‐loop recycling of polymers represents the key technology to convert plastic waste in a sustainable fashion. Efficient chemical recycling and upcycling strategies are thus highly sought‐after ...to establish a circular plastic economy. Here, we present the selective chemical depolymerization of polycarbonate by employing a vanillin derivative as bio‐based feedstock. The resulting di‐vanillin carbonate monomer was used in combination with various amines to construct a library of reprocessable poly(imine‐carbonate)s, which show tailor‐made thermal and mechanical properties. These novel poly(imine‐carbonate)s exhibit excellent recyclability under acidic and energy‐efficient conditions. This allows the recovery of monomers in high yields and purity for immediate reuse, even when mixed with various commodity plastics. This work provides exciting new insights in the design of bio‐based circular polymers produced by upcycling of plastic waste with minimal environmental impact.
Upcycling of polycarbonate (BPA‐PC) with a bio‐based vanillin derivative into novel dialdehyde monomer DVEC is shown. DVEC was further polymerized by using primary amines into high‐performance poly(imine‐carbonate)s. These modular polymers are reprocessable and chemically recyclable under acidic and energy‐efficient conditions, thereby enabling a closed‐loop recycling scheme.
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•There is a major environmental issue about the printed circuit boards throughout the world.•Different physical and chemical recycling techniques have been reviewed.•Nonmetallic fraction of PCBs is ...the unwanted face of this waste stream.•Several applications of the nonmetallic fraction of waste PCBs have been introduced.
E-waste, in particular waste PCBs, represents a rapidly growing disposal problem worldwide. The vast diversity of highly toxic materials for landfill disposal and the potential of heavy metal vapors and brominated dioxin emissions in the case of incineration render these two waste management technologies inappropriate. Also, the shipment of these toxic wastes to certain areas of the world for eco-unfriendly “recycling” has recently generated a major public outcry. Consequently, waste PCB recycling should be adopted by the environmental communities as an ultimate goal.
This article reviews the recent trends and developments in PCB waste recycling techniques, including both physical and chemical recycling. It is concluded that the physical recycling techniques, which efficiently separate the metallic and nonmetallic fractions of waste PCBs, offer the most promising gateways for the environmentally-benign recycling of this waste. Moreover, although the reclaimed metallic fraction has gained more attention due to its high value, the application of the nonmetallic fraction has been neglected in most cases. Hence, several proposed applications of this fraction have been comprehensively examined.
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•Cold recycling technology has obvious advantages but needs further investigation in details.•CIR method eliminates distresses, saves cost and energy and reduces project period.•Bitumen and ...cementitious stabilization agents are two main categories used in the construction.•Empirical and analytical designs are two major cold pavement design methods.•A series of laboratory and field test technologies are indispensable to characterize the material properties.
Due to the advantages of less raw materials and fossil fuel consumption, lower carbon footprint, and the capability of pavement performance improvement, the recycling technology of asphalt is developed and applied for road rehabilitation and construction in the western countries over the past two decades. However, some technical problems still need to be concerned about, for instance, the techniques in recycling process and the optimization of mix design. In order to promote the application of cold mixing technology in practice widely, and better follow up the research progress of cold recycling technology, this paper reviewed and discussed the classification of cold recycling, the scope of application, raw materials, mix design procedure and construction technology, test method, pavement performance.
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•Investigation of optimal timing of pricing in a dual-channel reverse supply chain.•Consideration of a supply chain consisting of a recycling company and a collector.•We have the following two major ...findings.•There is a first-mover advantage to acquisition price announcement.•The company should announce the online price before announcing the transfer price.
The rapid development of information technologies enables recycling companies to purchase and collect used products from consumers through both traditional and Internet-based online channels. Because an online channel transmits price information instantly to consumers, choosing the best time to announce the recycling price (i.e., acquisition price) of used products to consumers has become a critical problem for recycling companies. This paper seeks to solve this problem by developing a game-theoretic model describing a dual-channel reverse supply chain consisting of a recycling company and a third-party collector in which the recycling company purchases products not only through a third-party collector, but also directly from consumers online. We derive two major results by solving the model. The first is that first-mover advantage arises, which indicates that each firm constituting a dual-channel reverse supply chain should announce its own recycling price before the other. This first result is notable because it is exactly opposite to conventional wisdom that the second-mover advantage of pricing usually emerges when price competition occurs among firms in a horizontal relationship, which is well known in noncooperative game theory. The second result is that the recycling company can maximize its own profit and consumers' surplus by announcing its recycling price in the online channel before or upon, but not after, determining the transfer price paid to the collector for products collected in the offline channel. Both results can be used as practical decision-making guidelines in dual-recycling channel reverse supply chain management.
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The civil engineering sector accounts for a significant percentage of global material and energy consumption and is a major contributor of waste material. The ability to recycle and reuse concrete ...and demolition waste is critical to reducing environmental impacts in meeting national, regional and global environmental targets. Handbook of recycled concrete and demolition waste summarises key recent research in achieving these goals.Part one considers techniques for managing construction and demolition waste, including waste management plans, ways of estimating levels of waste, the types and optimal location of waste recycling plants and the economics of managing construction and demolition waste. Part two reviews key steps in handling construction and demolition waste. It begins with a comparison between conventional demolition and construction techniques before going on to discuss the preparation, refinement and quality control of concrete aggregates produced from waste. It concludes by assessing the mechanical properties, strength and durability of concrete made using recycled aggregates. Part three includes examples of the use of recycled aggregates in applications such as roads, pavements, high- performance concrete and alkali-activated or geopolymer cements. Finally, the book discusses environmental and safety issues such as the removal of gypsum, asbestos and alkali-silica reaction (ASR) concrete, as well as life-cycle analysis of concrete with recycled aggregates.Handbook of recycled concrete and demolition waste is a standard reference for all those involved in the civil engineering sector, as well as academic researchers in the field. * Summarises key recent research in recycling and reusing concrete and demolition waste to reduce environmental impacts and meet national, regional and global environmental targets * Considers techniques for managing construction and demolition waste, including waste management plans, ways of estimating levels of waste, the types and optimal location of waste recycling plants * Reviews key steps in handling construction and demolition waste
Platinum is one of the precious metals with many applications, including in catalysis, electronic devices and jewelry. However, its limited resources are becoming depleted. To meet the future demand ...and conserve resources, it is necessary to process spent platinum-containing materials, such as catalysts, electronic scraps and used equipment. These materials are usually processed by pyro/hydrometallurgical processes consisting of thermal treatment followed by leaching, precipitation or solvent extraction. This paper reviews platinum leaching from such resources using acidic and alkaline solutions in the presence of oxidizing agents, such as nitric acid and hydrogen peroxide, sodium cyanide and iodide solutions. The results of the study are described with respect to the recovery of platinum and other metals under the optimized conditions of leaching with lixiviants. Previous studies have achieved platinum recovery using aqua regia and acidic solution in the presence of chlorine to produce platinum from spent catalysts on a commercial scale; however, the process generates toxic nitrogen oxide and chlorine gases. This paper reports the salient findings of efforts to replace the aqua regia with hydrogen peroxide in acidic solution, chloride salts, sodium cyanide and iodide solution to improve the economics of the existing processes and reduce the environmental pollution.
► A critical review on platinum recycling from spent catalysts using leaching process. ► Salient findings and applications of various Pt lixiviants are reported. ► Selection of process route based on impurities present and environment concern.
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39.
Make scientific data FAIR Stall, Shelley; Yarmey, Lynn; Cutcher-Gershenfeld, Joel ...
Nature (London),
06/2019, Volume:
570, Issue:
7759
Journal Article
Peer reviewed
Open access
All disciplines should follow the geosciences and demand best practice for publishing and sharing data, argue Shelley Stall and colleagues.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This review focuses on the characteristics of the most widely used biopolymers that contain starch, polylactic acid, cellulose and/or polybutylene succinate. Because worldwide production of bio-based ...materials has grown dynamically, their waste is increasingly found in the existing waste treatment plants. The development of recycling methods for bio-based materials remains a challenge in the implementation of a circular economy. This article summarizes the recycling methods for bio-based materials, which, in the hierarchy of waste management, is much more desirable than landfilling. Several methods of recycling are available for the end-of-life management of bio-based products, which include mechanical (reuse of waste as a valuable raw material for further processing), chemical (feedstock recycling) and organic (anaerobic digestion or composting) ones. The use of chemical or mechanical recycling is less favourable, more costly and requires the improvement of systems for separation of bio-based materials from the rest of the waste stream. Organic recycling can be a sustainable alternative to those two methods. In organic recycling, bio-based materials can be biologically treated under aerobic or anaerobic conditions, depending on the characteristics of the materials. The choice of the recycling method to be implemented depends on the economic situation and on the properties of the bio-based products and their susceptibility to degradation. Thus, it is necessary to label the products to indicate which method of recycling is most appropriate.
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