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Recycling
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Advances in the Recycling and Processing of Plastic Waste
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Advances in the Recycling and Processing of Plastic Waste

A special issue of Recycling (ISSN 2313-4321).

Deadline for manuscript submissions: closed (31 July 2022) | Viewed by 144403

Special Issue Editors

Prof. Dr. Michele John

E-Mail Website
Guest Editor
Sustainable Engineering Group, Curtin University, Perth, WA 6845, Australia
Interests: resource recovery; sustainable materials; green manufacturing; transformation of waste collection; mining and agricultural waste value adding
Special Issues, Collections and Topics in MDPI journals
Dr. Wan-Ting (Grace) Chen

E-Mail Website
Guest Editor
Department of Plastics Engineering, UMass Lowell Francis College of Engineering, MA 01854, USA
Interests: chemical recycling; microplastics; biodegradable materials; ocean plastic waste; hydrothermal processing
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

More than eight billion tons of plastic waste has accumulated worldwide over the past 50 years. The majority (80%) of the waste goes directly into landfills and 3% ends up in the oceans. At the current rate, we are heading towards more plastic than fish in the ocean by 2050. Plastics are persistent in the environment and degrade slowly (over a century), releasing fragments, microplastics, and toxic chemicals into our environment.

The overall goal of this Special Issue is to shed light on the area of plastic waste recycling. Topics of interest include (but are not limited to) advanced mechanical recycling, chemical recycling, biodegradable plastic material development, microplastic characterization/mitigation, characterization advancement for plastic waste, and recycling policy analysis.

Prof. Dr. Michele John
Dr. Wan-Ting (Grace) Chen
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Recycling is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Mechanical recycling
  • Chemical recycling
  • Plastic waste
  • Microplastics
  • Plastic additives

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Published Papers (22 papers)

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8 pages, 1326 KiB  
Communication
Sustainable Bio-Composites Obtained from Recycling Post-Industrial PLA and Fillers Derived from Coffee Production
by Andrea Saccani, Maurizio Fiorini and Gianfranco Burzotta
Recycling 2022, 7(6), 89; https://doi.org/10.3390/recycling7060089 - 30 Nov 2022
Cited by 2 | Viewed by 2082
Abstract
Bio-composites have been formulated by exploiting post-industrial PLA derived from thin film production and silver skin, a by-product of the coffee’s roasting process. The mix design for the compounds exploits the effects of regrading and toughening agents. The mechanical properties of the materials [...] Read more.
Bio-composites have been formulated by exploiting post-industrial PLA derived from thin film production and silver skin, a by-product of the coffee’s roasting process. The mix design for the compounds exploits the effects of regrading and toughening agents. The mechanical properties of the materials have been investigated as well as the thermal and physical ones. The recycled material mixed with the regrading additive shows good mechanical properties. The filler addition increases the elastic modulus of PLA up to a 20% but decreases the mechanical properties (about 20% on tensile strength), leading to a brittle behavior (minus 35% of impact strength). The use of a toughening agent restores the plastic deformation ability of the matrix. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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20 pages, 3884 KiB  
Article
Manufacturing of a PET Filament from Recycled Material for Material Extrusion (MEX)
by Maximilian Bustos Seibert, Gerardo Andres Mazzei Capote, Maximilian Gruber, Wolfram Volk and Tim A. Osswald
Recycling 2022, 7(5), 69; https://doi.org/10.3390/recycling7050069 - 20 Sep 2022
Cited by 13 | Viewed by 8022
Abstract
Due to its low cost and easy use, the use of material extrusion (MEX) as an additive manufacturing (AM) technology has increased rapidly in recent years. However, this process mainly involves the processing of new plastics. Combining the MEX process with polyethylene terephthalate [...] Read more.
Due to its low cost and easy use, the use of material extrusion (MEX) as an additive manufacturing (AM) technology has increased rapidly in recent years. However, this process mainly involves the processing of new plastics. Combining the MEX process with polyethylene terephthalate (PET), which offers a high potential for mechanical and chemical recyclability, opens up a broad spectrum of reutilization possibilities. Turning used PET bottles into printable filament for MEX is not only a recycling option, but also an attractive upcycling scenario that can lead to the production of complex, functional parts. This work analyzes the process of extruding recycled PET bottle flakes into a filament, taking different extrusion screws and extrusion parameters into account. The filament is subsequently processed with MEX into tensile tests. An accompanying thermal, rheological and mechanical characterization of the recycled resin is performed to offer a comparison to the virgin material and a commercially available glycol modified polyethylene terephthalate (PETG) filament. The results show the importance of adequate drying parameters prior to the extrusion and the sensitivity of the material to moisture, leading to degradation. The recycled material is more prone to degradation and presents lower viscosities. Mechanical tests display a higher tensile strength of the recycled and virgin resin in comparison to the PETG. The extrusion of the used PET into a filament and the subsequent printing with the MEX process offers a viable recycling process for the discarded material. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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16 pages, 1761 KiB  
Article
New Terahertz Wave Sorting Technology to Improve Plastic Containers and Packaging Waste Recycling in Japan
by Jeongsoo Yu, Xiaoyue Liu, Gaku Manago, Tadao Tanabe, Shiori Osanai and Kazuaki Okubo
Recycling 2022, 7(5), 66; https://doi.org/10.3390/recycling7050066 - 09 Sep 2022
Cited by 3 | Viewed by 4351
Abstract
Plastic product consumption and disposal are widespread. Given that these products are derived from crude oil, it is critical to reduce their consumption and effectively recycle plastic waste as recycled resources to achieve a low-carbon society. Japan enacted the “Containers and Packaging Recycling [...] Read more.
Plastic product consumption and disposal are widespread. Given that these products are derived from crude oil, it is critical to reduce their consumption and effectively recycle plastic waste as recycled resources to achieve a low-carbon society. Japan enacted the “Containers and Packaging Recycling Law” in 2000, encouraging the recycling of plastic packaging and containers. However, material recycling of plastic waste has stalled due to recycling costs and technical challenges. This paper examines and evaluates the transition process and operational status of Japan’s recycling policy for plastic containers and packaging, as well as clarifies the limits of resources recycling. The limits and issues of current identification technology are discussed by analyzing the characteristics of plastic marks and detecting the material compositions of waste samples. The paper also discusses a new sorting technology that uses terahertz waves to improve plastic recycling. This analysis revealed that plastic containers are typically made of two or more plastic materials, which makes resources recycling more difficult. Terahertz waves are safer than other high-accuracy sorting technologies currently in use. Thus, material recycling can be expanded by accurately analyzing the composition of plastic waste and introducing sorting devices appropriate for achieving the circular economy with sustainable resource recycling. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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11 pages, 664 KiB  
Article
Plastics Crash Course: A Website for Teaching Plastics Recycling and Microplastics Prevention through Infographics
by Madison R. Reed and Wan-Ting Chen
Recycling 2022, 7(5), 65; https://doi.org/10.3390/recycling7050065 - 07 Sep 2022
Cited by 2 | Viewed by 3736
Abstract
Microplastic particles have been found virtually everywhere, including within our food and drinking water. While the implications of microplastics on human health are not fully known, early effects have been seen on marine life and the environment. Studies have shown that microplastics can [...] Read more.
Microplastic particles have been found virtually everywhere, including within our food and drinking water. While the implications of microplastics on human health are not fully known, early effects have been seen on marine life and the environment. Studies have shown that microplastics can cause changes in the reproductive habits of marine life by blocking digestive tracts, causing abrasions to the mouth and esophagi of small animals upon ingestion, and altering feeding behavior. While much of the blame for our plastics pollution problem should be shifted to irresponsible manufacturing, we as consumers must make choices to benefit the environment by reducing our use and learning how to effectively recycle plastic waste. The Plastics Crash Course combines visual learning with plastics recycling knowledge to educate the public about why we need plastics and why we should recycle them. Microplastics formation and general guides for plastic recycling were also included in the Plastics Crash Course. Out of 120 participants, 95% responded that they had learned new information. From the pre-survey, participants responded, saying they thought all plastic was the same and that it just varied in density to provide different properties, so they would recycle everything. After reading the infographics on the Plastics Crash Course website, most participants said they learned what plastics can be recycled and what their resin identifying codes mean, how microplastics form, and that there is more than one type of plastic. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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20 pages, 2329 KiB  
Article
The Current State, Challenges, and Opportunities of Recycling Plastics in Western Australia
by Ana María Cáceres Ruiz and Atiq Zaman
Recycling 2022, 7(5), 64; https://doi.org/10.3390/recycling7050064 - 06 Sep 2022
Cited by 4 | Viewed by 6514
Abstract
In 2018–2019, 85% of discarded plastics were landfilled in Australia. In Western Australia (WA), only 5.6% of plastics were recovered for reprocessing. With several Asian Countries imposing import restrictions, which were the prime destination for recyclables from Australia, the whole scenario for the [...] Read more.
In 2018–2019, 85% of discarded plastics were landfilled in Australia. In Western Australia (WA), only 5.6% of plastics were recovered for reprocessing. With several Asian Countries imposing import restrictions, which were the prime destination for recyclables from Australia, the whole scenario for the waste industry has changed. Australia has now adopted export bans for recyclables, including plastics. WA is at a fork in the road; WA needs to rethink its relationship with plastic materials. This study explores how to create local markets for recycled plastics underpinning circular principles. The study examines barriers and drivers to enable markets for recycled plastics in WA through questionnaires, surveys, and interviews with relevant stakeholders. Poor source separation, low and inconsistent plastic waste feedstock, and virgin plastic competition are some of the challenges, while new investments in recycling infrastructure, WA’s take-back scheme for beverage containers and circularity frameworks are drivers. This study concludes that a modulated fee-based product stewardship model focused on product design, along with strategies such as green procurement and landfill management modifications would promote a circular plastic waste economy in WA. This can create markets for secondary recycled plastics, minimize the over-reliance on fossil fuels and prevent plastics from leaking into ecosystems. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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27 pages, 2384 KiB  
Article
Analyzing Polyethylene Terephthalate Bottle Waste Technology Using an Analytic Hierarchy Process for Developing Countries: A Case Study from Indonesia
by Akhmad Amirudin, Chihiro Inoue and Guido Grause
Recycling 2022, 7(4), 58; https://doi.org/10.3390/recycling7040058 - 15 Aug 2022
Cited by 4 | Viewed by 3922
Abstract
PET bottle waste is easy to recycle because it is easy to separate, abundant, and competitively priced. Technologies for the treatment of PET bottle waste have been evaluated to date by using life cycle assessment (LCA), but this does not take into account [...] Read more.
PET bottle waste is easy to recycle because it is easy to separate, abundant, and competitively priced. Technologies for the treatment of PET bottle waste have been evaluated to date by using life cycle assessment (LCA), but this does not take into account all of the aspects that policymakers consider necessary when selecting an acceptable technology. Aspects such as society, economics, policies, and technical applicability need to be considered along with the environment and resource consumption to complement the LCA results for PET bottle waste. These aspects were selected as criteria for the analytical hierarchy process (AHP), and stakeholders were invited to make a comparison evaluation of the criteria and sub-criteria. Academics were involved to compare the technology options. The results show that society is the highest priority because it is the main actor that ensures the application of the technology, and that job creation is the most important indicator for the selection of the technology in society criteria. After comparing open landfills, sanitary landfills, incineration with energy recovery, pelletizing, glycolysis, and hydrolysis for the utilization of PET bottle waste, this study suggests pelletizing as the acceptable technology for Indonesia because pelletizing is dominant in all the criteria and sub-criteria which support sustainability in waste management. This is the first time that a single plastic fraction that is easy to collect and recycle has been studied with the AHP. The results show that this type of plastic could also be reused in developing countries through mechanical recycling. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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13 pages, 1502 KiB  
Article
Improving the Separation of PS and ABS Plastics Using Modified Induced Air Flotation with a Mixing Device
by Pattarasiri Fagkaew, Nattawin Chawaloesphonsiya, Saret Bun and Pisut Painmanakul
Recycling 2022, 7(4), 44; https://doi.org/10.3390/recycling7040044 - 04 Jul 2022
Cited by 1 | Viewed by 2528
Abstract
A dramatic increase in plastic waste has resulted in a strong need to increase plastic recycling accordingly. A selective flotation has been highlighted due to its outstanding efficiency for the separation of mixed plastics with analogous physicochemical characteristics. In this study, the effects [...] Read more.
A dramatic increase in plastic waste has resulted in a strong need to increase plastic recycling accordingly. A selective flotation has been highlighted due to its outstanding efficiency for the separation of mixed plastics with analogous physicochemical characteristics. In this study, the effects of design and operational factors on the bubble’s hydrodynamic and mixing parameters in induced air flotation (IAF) with a mixing device were investigated through a design of experiment method (DOE) analysis for improving the plastic separation efficiency (i.e., PS and ABS). As a result of DOE analysis, the increase in the induced air tube diameter together with the rotational speed could generate a smaller bubble size. This led to the enhancement of the ratio of interfacial area to velocity gradient (a/G), which was interestingly found to be a significant factor affecting plastic recovery apart from the chemical agents. It demonstrates that operating IAF with a mixing device at a greater a/G ratio improved the plastic separation performance. These findings suggest that operating an IAF process with a mixing device at suitable a/G conditions could be a promising technique for separating plastic wastes, which have similar physicochemical characteristics as PS and ABS. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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23 pages, 3067 KiB  
Article
Does Policy on Plastic Waste Support Higher Waste Management Hierarchy Options?
by Kunle Ibukun Olatayo, Paul T. Mativenga and Annlizé L. Marnewick
Recycling 2022, 7(3), 36; https://doi.org/10.3390/recycling7030036 - 08 Jun 2022
Cited by 4 | Viewed by 4509
Abstract
There is an urgent and growing need to further advance the plastic waste management system globally and in South Africa, due to the increasing impact of plastic waste. This study focused on the adequacy of plastic policies to sustainably manage plastic waste. Policies [...] Read more.
There is an urgent and growing need to further advance the plastic waste management system globally and in South Africa, due to the increasing impact of plastic waste. This study focused on the adequacy of plastic policies to sustainably manage plastic waste. Policies need to address the plastic material supply systems and the options up the waste hierarchy for them to be effective and support material circularity. The study used qualitative content analysis to assess how the evolution of plastic policies for plastic waste management in South Africa aligned with national plastic material flows and promoted options higher up the waste hierarchy. This was benchmarked with Norway and Germany, which have some of the highest plastic recycling rates. The results showed that the evolution of existing plastic policies for South Africa addresses stages of production, trade and consumption, and recycling. There is no focus on waste generation, collection and sorting. None aligned with the waste hierarchy options of rethink, reduce, reuse, repair, refurbish, remanufacture and repurpose. This policy gap supports the need for broader national plastic policy frameworks that embed a policy drive in the value chain points and promote the priority higher value measures of the waste hierarchy. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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12 pages, 3525 KiB  
Article
Analysis of Plastic-Derived Fuel Oil Produced from High- and Low-Density Polyethylene
by Chandni Joshi Jangid, Kevin M. Miller and Jeffrey R. Seay
Recycling 2022, 7(3), 29; https://doi.org/10.3390/recycling7030029 - 07 May 2022
Cited by 2 | Viewed by 4810
Abstract
The exponential growth of waste plastic accumulation has had an irreversible and lasting impact on the world. An imminent threat to marine and terrestrial ecosystems of massive proportions, plastic waste accumulation is a global problem that will not only have to be tackled [...] Read more.
The exponential growth of waste plastic accumulation has had an irreversible and lasting impact on the world. An imminent threat to marine and terrestrial ecosystems of massive proportions, plastic waste accumulation is a global problem that will not only have to be tackled by current generations but for many generations to follow. The scale of current recycling technologies and efforts to reduce consumption by for-profit and non-profit institutions, governments, and consumers will need to be rapidly increased to combat the negative impacts plastic waste has had on the planet since its conception. This is especially the case in areas with limited infrastructure to properly collect, manage, and dispose of plastic waste. Solutions to plastic waste accumulation crisis that are appropriate for the developing world are urgently needed. Conversion of plastic waste to liquid fuel by slow pyrolysis is a technology that is particularly suitable for developing countries due to its ability to convert polyolefin waste plastic into a useful product, thus preventing its eventual accumulation in the ecosystem. However, in developing countries, conversion techniques that do not rely on sophisticated technologies are needed. Since processing time and operating temperature are the simplest variables to control, an analytical study has been conducted to assess how the molecular composition of plastic derived fuel oil (PDFO) is impacted by these parameters. The results of gas chromatography-mass spectrometry (GC-MS) and thermogravimetric analysis (TGA) studies of PDFO from high- and low-density polyethylene plastic waste produced using appropriate technology techniques are presented alongside a comparison with traditional diesel fuel and kerosene. This approach is novel in that it differs from previously conducted research, which has studied the use of catalysts, additives, or single operating temperatures to assess the composition of PDFO. Therefore, this research contribution presents a simplistic and inexpensive approach for tuning PDFO composition in appropriate technology settings. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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12 pages, 2220 KiB  
Article
Recycling of Pretreated Polyolefin-Based Ocean-Bound Plastic Waste by Incorporating Clay and Rubber
by Shawn Martey, Keith Hendren, Nicholas Farfaras, Jesse C. Kelly, Matthew Newsome, Izabela Ciesielska-Wrobel, Margaret J. Sobkowicz and Wan-Ting Chen
Recycling 2022, 7(2), 25; https://doi.org/10.3390/recycling7020025 - 14 Apr 2022
Cited by 8 | Viewed by 4101
Abstract
Plastic waste found in oceans has become a major concern because of its impact on marine organisms and human health. There is significant global interest in recycling these materials, but their reclamation, sorting, cleaning, and reprocessing, along with the degradation that occurs in [...] Read more.
Plastic waste found in oceans has become a major concern because of its impact on marine organisms and human health. There is significant global interest in recycling these materials, but their reclamation, sorting, cleaning, and reprocessing, along with the degradation that occurs in the natural environment, all make it difficult to achieve high quality recycled resins from ocean plastic waste. To mitigate these limitations, various additives including clay and rubber were explored. In this study, we compounded different types of ocean-bound (o-HDPE and o-PP) and virgin polymers (v-LDPE and v-PS) with various additives including a functionalized clay, styrene-multi-block-copolymer (SMB), and ethylene-propylene-based rubber (EPR). Physical observation showed that all blends containing PS were brittle due to the weak interfaces between the polyolefin regions and the PS domains within the polymer blend matrix. Blends containing clay showed rough surfaces and brittleness because of the non-uniform distribution of clay particles in the polymer matrix. To evaluate the properties and compatibility of the blends, characterizations using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and small-amplitude oscillatory shear (SAOS) rheology were carried out. The polymer blend (v-LDPE, o-HDPE, o-PP) containing EPR showed improved elasticity. Incorporating additives such as rubber could improve the mechanical properties of polymer blends for recycling purposes. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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13 pages, 4000 KiB  
Article
Recovery and Use of Recycled Carbon Fibers from Composites Based on Phenol-Formaldehyde Resins
by Yuliya Kulikova, Natalia Sliusar, Vladimir Korotaev, Olga Babich, Viktoria Larina and Svetlana Ivanova
Recycling 2022, 7(2), 22; https://doi.org/10.3390/recycling7020022 - 02 Apr 2022
Cited by 3 | Viewed by 3279
Abstract
The technical feasibility of the recycling of specific polymeric composite materials was evaluated. Two types of carbon composites, both with phenol-formaldehyde resin but with different reinforcement, were studied. It was discovered that the solvolysis with the oxidizing agents used in an acidic environment [...] Read more.
The technical feasibility of the recycling of specific polymeric composite materials was evaluated. Two types of carbon composites, both with phenol-formaldehyde resin but with different reinforcement, were studied. It was discovered that the solvolysis with the oxidizing agents used in an acidic environment allowed for the achievement of a high-efficiency fiber extraction. The extracted secondary carbon fibers had a high degree of purity (95–99.5% of resin was removed). Fiber thickness slightly decreased during the process (on average, by 20%). The use of chopped secondary fibers (3–9 mm fiber length) for concrete reinforcement produced a positive effect. Hence, the compressive and bending strength of the concrete blocks were accordingly 1.5% and 16% higher in comparison with the control sample. The use of secondary carbon fabric for the production of composite materials a good result: the effective tensile strength of CFRP samples reinforced with recovered fabric is only lower by 4.5% in comparison with virgin fabric. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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26 pages, 2218 KiB  
Article
Assessment of Performance and Challenges in Use of Commercial Automated Sorting Technology for Plastic Waste
by Cesar Lubongo and Paschalis Alexandridis
Recycling 2022, 7(2), 11; https://doi.org/10.3390/recycling7020011 - 23 Feb 2022
Cited by 39 | Viewed by 13119
Abstract
Recycling plastic is an important step towards a circular economy. Attaining high-quality recycled plastics requires the separation of plastic waste by type, color, and size prior to reprocessing. Automated technology is key for sorting plastic objects in medium- to high-volume plants. The current [...] Read more.
Recycling plastic is an important step towards a circular economy. Attaining high-quality recycled plastics requires the separation of plastic waste by type, color, and size prior to reprocessing. Automated technology is key for sorting plastic objects in medium- to high-volume plants. The current state of the art of commercial equipment for sorting plastic as well as challenges faced by Material Recovery Facilities (MRFs) to sort post-consumer plastics are analyzed here. Equipment for sorting plastic recyclables were identified using publicly available information obtained from manufacturers’ websites, press releases, and journal articles. Currently available automated sorting equipment and artificial intelligence (AI)-based sorters are evaluated regarding their functionality, efficiency, types of plastics they can sort, throughput, and accuracy. The information compiled captures the progress made during the ten years since similar reports were published. A survey of MRFs, reclaimers, and brokers in the United States identified methods of sorting used for plastic, sorting efficiency, and current practices and challenges encountered at MRFs in sorting plastic recyclables. The commercial sorting equipment can address some of the challenges that MRFs face. However, sorting of film, multilayered, blended, or mixed-material plastics is problematic, as the equipment is typically designed to sort single-component materials. Accordingly, improvements and/or new solutions are considered necessary. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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13 pages, 2126 KiB  
Article
Embodied Energy in Pyrolysis and Solvolysis Approaches to Recycling for Carbon Fiber-Epoxy Reinforced Composite Waste Streams
by Komal Kooduvalli, John Unser, Soydan Ozcan and Uday K. Vaidya
Recycling 2022, 7(1), 6; https://doi.org/10.3390/recycling7010006 - 14 Feb 2022
Cited by 12 | Viewed by 5865
Abstract
Carbon fiber composites are increasingly used in aerospace, motorcycles, sporting, and high-performance vehicles, and their end of life recycling is of growing interest. This study deals with the life cycle assessment (LCA) of carbon fiber reinforced plastics (CFRP) waste streams. The embodied energy [...] Read more.
Carbon fiber composites are increasingly used in aerospace, motorcycles, sporting, and high-performance vehicles, and their end of life recycling is of growing interest. This study deals with the life cycle assessment (LCA) of carbon fiber reinforced plastics (CFRP) waste streams. The embodied energy (EE) of recycling CFRP via two viable methods—i.e., pyrolysis and solvolysis—is studied. Both pyrolysis and solvolysis were studied for EE with different variants. Alongside fiber recovery from CFRP, the pyrolysis process calculations consider energy recovery from syngas and oil produced within the system. For pyrolysis, electric furnace and natural gas were primarily considered. For solvolysis, different solvent scenarios were considered, including (a) deionized water, (b) water and potassium hydroxide, (c) acetone and water, and (d) water with acetic acid and potassium hydroxide. Energy reduction from one generation to the next has also been highlighted. The EE for recycling CFRP is quantified and discussed for these scenarios in this paper. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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15 pages, 4719 KiB  
Article
An Empirical Study on the Main Determinants of Recycling Plastic Waste in Tunisia
by Lamia Ben Amor and Sami Hammami
Recycling 2022, 7(1), 1; https://doi.org/10.3390/recycling7010001 - 06 Jan 2022
Cited by 2 | Viewed by 4344
Abstract
Over the past fifteen years, numerous policies for recycling and recovering waste have been implemented throughout the world. Tunisia is among the countries considering recycling as a sustainable development path. This empirical study aimed to investigate and examine the influence of financial determinants [...] Read more.
Over the past fifteen years, numerous policies for recycling and recovering waste have been implemented throughout the world. Tunisia is among the countries considering recycling as a sustainable development path. This empirical study aimed to investigate and examine the influence of financial determinants measured by the price of waste disposal (PDI), institutional determinants measured by the collection of waste (CW) and the number of drop-off recycling centers, and ordinance and demographic determinants measured by the population density and the recycling rate for plastic as a domestic waste based on a panel of 24 Tunisian governorates over the 2001–2020 period. It is concluded from the empirical findings that all exogenous variables except population density have a significant effect on the recycling rate. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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14 pages, 2394 KiB  
Article
Assessment of Biodegradation and Eco-Toxic Properties of Novel Starch and Gelatine Blend Bioplastics
by Marta Mroczkowska, Kieran Germaine, David Culliton, Thomais Kakouli Duarte and Adriana Cunha Neves
Recycling 2021, 6(4), 81; https://doi.org/10.3390/recycling6040081 - 16 Dec 2021
Cited by 7 | Viewed by 3953
Abstract
To combat the release of petroleum-derived plastics into the environment the European Commission has adopted the EU plastics strategy, which aims for a complete ban on single-use plastics by 2030. Environmentally friendly and sustainable packaging like bioplastic is being up taken at significant [...] Read more.
To combat the release of petroleum-derived plastics into the environment the European Commission has adopted the EU plastics strategy, which aims for a complete ban on single-use plastics by 2030. Environmentally friendly and sustainable packaging like bioplastic is being up taken at significant levels by companies and consumers. In this study, the environmental impact of novel gelatine–starch blend bioplastics is investigated. The assessments included ecotoxicology with different species that can be found in marine and soil environments to simulate natural conditions. Microalgae, plant, and nematode species were chosen as these are representative of their habitats and are known for their sensitivity to pollutants. Degradation rates of these novel bioplastics were assessed as well as microbiome analysis of the soil before and after bioplastic degradation. The main findings of this study are that (i) the bioplastic generated can be fully biodegraded in soil environments at moderate conditions (20 °C) leaving no physical traces; (ii) bioplastic did not exhibit significantly adverse effects on any organisms assessed in this study; (iii) microbiome analysis of the soil after biodegradation showed a decrease in alpha diversity and a significant increase of Actinobacteria and Firmicutes phyla, which were dominative in the soil. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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18 pages, 4360 KiB  
Article
Purchase Intentions for Brazilian Recycled PET Products—Circular Economy Opportunities
by Fernanda Cristina Barbosa Pereira Queiroz, Nilton Cesar Lima, Christian Luiz da Silva, Jamerson Viegas Queiroz and Gustavo Henrique Silva de Souza
Recycling 2021, 6(4), 75; https://doi.org/10.3390/recycling6040075 - 12 Nov 2021
Cited by 9 | Viewed by 4878
Abstract
Circular economy involves structural changes in traditional business models and consumers’ behavior toward recycled products. The recycling of PET products is increasing but there is still a gap between consumption and demand for PET packaging in Brazil. In this research, waste reduction was [...] Read more.
Circular economy involves structural changes in traditional business models and consumers’ behavior toward recycled products. The recycling of PET products is increasing but there is still a gap between consumption and demand for PET packaging in Brazil. In this research, waste reduction was examined under a projective scenario to the current ecological purposes in Brazil for reducing environmental pollution. In that manner, this paper aimed to comprehend the intention to purchase recycled PET products of Brazilian consumers. With a non-probabilistic and convenience sample, the study counts 422 participants. The method employed was based on structural equation modelling and partial least Squares, used to test the hypotheses of causality among the variables. Results showed the perception of low quality about recycled products reduced consumers’ intention to purchase. Additionally, the sustainability of recycled products positively influenced the intention to purchase. In addition, recycled products presented a negative impact on the perceived safety, which could influence the purchase of recycled products in Brazil. We conclude that the image that Brazilian consumers have about recycled products positively affects the intention to purchase. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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12 pages, 2979 KiB  
Article
Recycling of WEEE Plastics Waste in Mortar: The Effects on Mechanical Properties
by Alessandra Merlo, Luca Lavagna, Daniel Suarez-Riera and Matteo Pavese
Recycling 2021, 6(4), 70; https://doi.org/10.3390/recycling6040070 - 22 Oct 2021
Cited by 6 | Viewed by 3075
Abstract
This work focused on the recycling of WEEE plastic waste as a partial substitute for aggregate in light mortars. The plastic mix, provided by the IREN group, was used as a replacement of aggregate in 15, 30, 45, 60, 75, and 90%vol [...] Read more.
This work focused on the recycling of WEEE plastic waste as a partial substitute for aggregate in light mortars. The plastic mix, provided by the IREN group, was used as a replacement of aggregate in 15, 30, 45, 60, 75, and 90%vol in mortars. Worsening of the mechanical performance of around 50% was detected already at only 15%vol of mineral aggregate substituted with plastic waste. The explanation of this phenomenon was found in both the scarce mechanical properties of the used plastic and in the poor adhesion between matrix and plastics that resulted in extra-porosity formation, as also demonstrated by comparing the results with several models in the literature. However, the use of plastic waste as a partial replacement of natural aggregate contributes to the preservation of natural resources and, in any case, does not limit the application of these materials in non-structural applications. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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11 pages, 1059 KiB  
Article
How COVID-19 Could Change the Economics of the Plastic Recycling Sector
by Ibrahim Issifu, Eric Worlanyo Deffor and Ussif Rashid Sumaila
Recycling 2021, 6(4), 64; https://doi.org/10.3390/recycling6040064 - 26 Sep 2021
Cited by 10 | Viewed by 6528
Abstract
The price of oil has a great influence on prices of recycled plastics and, therefore, plastic recycling efforts. Here, we analyze the effects of the ongoing COVID-19 pandemic on crude oil price and how this, in turn, is likely to affect the degree [...] Read more.
The price of oil has a great influence on prices of recycled plastics and, therefore, plastic recycling efforts. Here, we analyze the effects of the ongoing COVID-19 pandemic on crude oil price and how this, in turn, is likely to affect the degree of plastic recycling that takes place. Impulse response functions and variance decompositions, calculated from the structural vector autoregression, suggest that changes in crude oil prices are key drivers of the price of recycled plastics. The findings highlight that because plastics are made from the by-products of oil, falling oil prices increase the cost of recycling. Therefore, the price of recycled plastics should be supported using taxes while encouraging sustained behavioral changes among consumers and producers to selectively collect and recycle personal protective equipment so that they do not clog our landfills or end up in our water bodies as plastic waste. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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22 pages, 35595 KiB  
Article
Effect of Hard Plastic Waste on the Quality of Recycled Polypropylene Blends
by Patrizio Tratzi, Chiara Giuliani, Marco Torre, Laura Tomassetti, Roberto Petrucci, Antonio Iannoni, Luigi Torre, Salvatore Genova, Valerio Paolini, Francesco Petracchini and Gabriella Di Carlo
Recycling 2021, 6(3), 58; https://doi.org/10.3390/recycling6030058 - 01 Sep 2021
Cited by 11 | Viewed by 7273
Abstract
The recycling of plastic waste is undergoing fast growth due to environmental, health and economic issues, and several blends of post-consumer and post-industrial polymeric materials have been characterized in recent years. However, most of these researches have focused on plastic containers and packaging, [...] Read more.
The recycling of plastic waste is undergoing fast growth due to environmental, health and economic issues, and several blends of post-consumer and post-industrial polymeric materials have been characterized in recent years. However, most of these researches have focused on plastic containers and packaging, neglecting hard plastic waste. This study provides the first experimental characterization of different blends of hard plastic waste and virgin polypropylene in terms of melt index, differential scan calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties (tensile, impact and Shore hardness) and Vicat softening test. Compared to blends based on packaging plastic waste, significant differences were observed in terms of melt flow index (about 10 points higher for hard plastic waste). Mechanical properties, in particular yield strain, were instead quite similar (between 5 and 9%), despite a higher standard deviation being observed, up to 10%, probably due to incomplete homogenization. Results demonstrate that these worse performances could be mainly attributed to the presence of different additives, as well as to the presence of impurities or traces of other polymers, other than incomplete homogenization. On the other hand, acceptable results were obtained for selected blends; the optimal blending ratio was identified as 78% post-consumer waste and 22% post-industrial waste, meeting the requirement for injection molding and thermoforming. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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20 pages, 9556 KiB  
Article
Incentives for Plastic Recycling: How to Engage Citizens in Active Collection. Empirical Evidence from Spain
by Denisa Gibovic and Andrea Bikfalvi
Recycling 2021, 6(2), 29; https://doi.org/10.3390/recycling6020029 - 26 Apr 2021
Cited by 29 | Viewed by 18934
Abstract
The recycling target for plastics is expected to increase Europe-wide from 22.5% to 55% by 2025, hence the relevance of incentive schemes and the need to reach conclusions about how to encourage families to recycle more. Following this objective, a pilot project was [...] Read more.
The recycling target for plastics is expected to increase Europe-wide from 22.5% to 55% by 2025, hence the relevance of incentive schemes and the need to reach conclusions about how to encourage families to recycle more. Following this objective, a pilot project was implemented and a virtual reward token called RECICLOS created to encourage recycling among families, using incentives and awards to improve recycling behaviour and a webapp prototype to register the recycled plastic. By the end of the 6-week pilot project, 1053 families were registered on the scheme, representing 10% of the targeted population in the pilot area of the county of Pla de l’Estany, Catalonia, Spain. The novelties were the introduction of a token, the gamification of incentives through raffles and lotteries, webapp-based direct communication with citizens, and feedback after collecting and registering the recycled material. The multidimensional aspects of recycling activities, their strong relation with human behavioural patterns, and the high demand for communication and interaction mean that mobile technologies find significant application in this field. The results show that people can be influenced and their recycling habits changed by means of varied, effective, and innovative incentive schemes. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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Review

Jump to: Research

20 pages, 458 KiB  
Review
Engineering Characterisation of Wearing Course Materials Modified with Waste Plastic
by Nuha Mashaan
Recycling 2022, 7(4), 61; https://doi.org/10.3390/recycling7040061 - 18 Aug 2022
Cited by 4 | Viewed by 3556
Abstract
This review paper shows several sections of bitumen, asphalt mixtures, polymers, and waste plastic in pavement engineering. The paper reviews and evaluates the influence of using waste polymer in improving the rheological and engineering properties of the modified binder and mixtures. Evaluation of [...] Read more.
This review paper shows several sections of bitumen, asphalt mixtures, polymers, and waste plastic in pavement engineering. The paper reviews and evaluates the influence of using waste polymer in improving the rheological and engineering properties of the modified binder and mixtures. Evaluation of properties and design of stone mastic asphalt mixtures are reviewed. Reports and studies had investigated the advantages and importance of using polymer in bitumen modification; however, they yet show a gap in research in terms of the role of waste polymer in improving the durability, aging, and fatigue life in the long term of service. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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22 pages, 18225 KiB  
Review
Informing the Public and Educating Students on Plastic Recycling
by Ethan M. Bennett and Paschalis Alexandridis
Recycling 2021, 6(4), 69; https://doi.org/10.3390/recycling6040069 - 21 Oct 2021
Cited by 15 | Viewed by 20236
Abstract
Approximately 300 million tons of plastic waste is generated per year. The major portion of this plastic waste is landfilled, while part of it leaks into the environment. When plastic waste enters the terrestrial or aqueous environment, it can have negative impacts on [...] Read more.
Approximately 300 million tons of plastic waste is generated per year. The major portion of this plastic waste is landfilled, while part of it leaks into the environment. When plastic waste enters the terrestrial or aqueous environment, it can have negative impacts on ecosystems, human health, and wildlife. Increasing the amount of plastic waste that is recycled will correspondingly reduce the amount of plastic waste that enters the environment. By educating the public and industry on plastic recycling, current recycling programs can be used more efficiently, and new programs can be created. Education material on plastic recycling is available through professional and industry associations, foundations with an environmental focus, university courses, and short courses offered with private companies. This review assembles and analyzes the current education material on plastic recycling that is available from these providers. The material compiled here can be used to gain insight into specific plastic recycling-related topics, to identify areas of recycling education that can be improved, and as a resource to help build university level courses. There is currently a dearth of plastic recycling courses offered at the university level. Educating more students on plastic recycling will equip them with the knowledge and skills to make informed decisions as consumers, and to implement plastic recycling systems at the professional level. Full article
(This article belongs to the Special Issue Advances in the Recycling and Processing of Plastic Waste)
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