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Recycling, Volume 8, Issue 3 (June 2023) – 8 articles

Cover Story (view full-size image): More than eight billion tons of plastic waste has accumulated around the world over the last 50 years. The majority (80%) of the waste goes directly into landfills and 3% ends up in the oceans. At the current rate, there will be more plastic than that are fish in the oceans by 2050. Plastics are persistent in the environment and degrade slowly (over a century), releasing fragments, microplastics, and toxic chemicals into our environment. Primary recycling is generally the preferable option, but tertiary recycling is still required for removing recalcitrant pollutants. A modified solvent-based method was developed with acetone to remove brominated flame retardants. The degradation of the rubbery dispersed phase corresponding to butadiene can be accumulated in the less-soluble fraction of the extracted acrylonitrile butadiene styrene copolymer. View this paper
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16 pages, 3757 KiB  
Article
Valuation of Plastic Waste as a Community Circular Economy Strategy in the Municipality of Choco–Colombia
by Angie Tatiana Ortega-Ramírez, Miriam Reyes Tovar, Nelly del Carmen Elmira Castro and Oscar Silva-Marrufo
Recycling 2023, 8(3), 52; https://doi.org/10.3390/recycling8030052 - 20 Jun 2023
Cited by 2 | Viewed by 2562
Abstract
A business solution is proposed for the accumulation of waste in the Municipality of Choco without prior treatment through the establishment of a center for the reception, classification, recovery and use of solid plastic waste in the Municipality of Quibdo, which would optimize [...] Read more.
A business solution is proposed for the accumulation of waste in the Municipality of Choco without prior treatment through the establishment of a center for the reception, classification, recovery and use of solid plastic waste in the Municipality of Quibdo, which would optimize and expand the management of plastic waste. In this study, the basic diagnosis of the practices that are currently carried out in Quibdo is evaluated with the appropriation of the knowledge of the population, the technical structuring of the conditions of production of plastic wood is carried out from the management of plastic waste, recognition of the market for waste generated as an alternative for development and sustainable growth and the financial feasibility of the project and the profitability of each of the investment plans for its implementation. The results of the investigation include the identification of weaknesses and opportunities in waste management practices and the proposal of two investment plans for the establishment of the center. It is concluded that investment plan 2 would require 46,590.50 USD less than investment plan 1, equivalent to a 2.21% return compared to investment plan 1. Full article
(This article belongs to the Special Issue Advances in the Recycling, Processing and Use of Plastic Waste II)
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20 pages, 2244 KiB  
Article
Effect of Virgin PP Substitution with Recycled Plastic Caps in the Manufacture of a Product for the Telephony Sector
by Beatriz Arioli de Sá Teles, Isadora Luiza Clímaco Cunha, Manoel Lisboa da Silva Neto, Hélio Wiebeck, Ticiane Sanches Valera, Simara Silveira de Souza, Alfredo Felipe de Oliveira Schmitt, Vinicius Oliveira and Luiz Kulay
Recycling 2023, 8(3), 51; https://doi.org/10.3390/recycling8030051 - 9 Jun 2023
Viewed by 3300
Abstract
This study investigated the effects of partial and total substitutions of fossil polypropylene (PP) for recycled plastic cap equivalents in the manufacture of signage labels used by the telephone industry. Four alternative scenarios to using virgin PP were evaluated considering recycled material in [...] Read more.
This study investigated the effects of partial and total substitutions of fossil polypropylene (PP) for recycled plastic cap equivalents in the manufacture of signage labels used by the telephone industry. Four alternative scenarios to using virgin PP were evaluated considering recycled material in flake and pellet forms based on environmental performance, degree of circularity, and technical behavior. The environmental analysis was performed by the life cycle assessment (LCA) technique, and for all impact categories evaluated, using recycled material to replace the virgin reduced adverse effects on the environment. The most significant results in this dimension, with gains of 81% in the Global Environmental Indicator, occurred when recycled PP flakes entirely replaced the fossil polymer. Once again, the highest values of the Materials Circularity Indicator (MCI) were achieved by scenarios with full recycled resin in processing the tags; however, this product must also be reused. The mechanical behavior of the tags measured technical performance, and in this case, the product made with virgin PP outperformed the recycled options except for elongation. An analysis that integrated the three dimensions into a single performance index pointed to the complete substitution of virgin material for recycled as the most balanced option. Full article
(This article belongs to the Special Issue Advances in the Recycling, Processing and Use of Plastic Waste II)
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15 pages, 618 KiB  
Article
Bioherbicide from Azadirachta indica Seed Waste: Exploitation, Efficient Extraction of Neem Oil and Allelopathic Effect on Senna occidentalis
by Larissa Macelle de Paulo Barbosa, Jorge Oliveira Santos, Rayssa Carolinne Mouzinho de Sousa, Jomar Livramento Barros Furtado, Pedro Vidinha, Marco Aurelio Suller Garcia, Hector Aguilar Vitorino and Daiane Fossatti Dall’Oglio
Recycling 2023, 8(3), 50; https://doi.org/10.3390/recycling8030050 - 24 May 2023
Cited by 2 | Viewed by 4669
Abstract
Bioherbicides are an alternative to minimize the damage caused to the environment using agrochemicals. This study had the objective of extracting neem oil from ripe waste fruits that Azadirachta indica A. Juss and optimizing the process using solvents (or a mixture of solvents) [...] Read more.
Bioherbicides are an alternative to minimize the damage caused to the environment using agrochemicals. This study had the objective of extracting neem oil from ripe waste fruits that Azadirachta indica A. Juss and optimizing the process using solvents (or a mixture of solvents) with different polarities. Then, through a solid-liquid extraction system (Soxhlet), the solvents hexane, methanol/hexane (1:1), ethanol, and hexane/ethanol (1:1) were used to determine the process with the highest yield and most efficiency. The physicochemical parameters of the extracted oil (density, acidity value, iodine value, saponification value, esters value, and molecular weight) and the % of free fatty acids were determined. In addition, the allelopathic properties of the oil (0%, 2%, 3%, and 4% m/v) on septic weed Senna occidentalis seeds were evaluated, analyzing their growth and development parameters (germination, germination speed, hypocotyl, and radicle length). Hexane was the most efficient (4 h) in neem oil extraction, with the highest yield (43%). It also provided a better oleic and linoleic acid content (41.3% and 18.6%), similar to ethanol extraction (41.1% and 20.22%). Moreover, the allelopathic properties were more prominent for the oils extracted with hexane and hexane/ethanol. This optimized process provides an efficient alternative to obtain a natural herbicidal potential for strategically controlling harmful plants. Full article
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17 pages, 1094 KiB  
Article
Costs of Gasification Technologies for Energy and Fuel Production: Overview, Analysis, and Numerical Estimation
by Gonçalo Lourinho, Octávio Alves, Bruno Garcia, Bruna Rijo, Paulo Brito and Catarina Nobre
Recycling 2023, 8(3), 49; https://doi.org/10.3390/recycling8030049 - 19 May 2023
Cited by 9 | Viewed by 12331
Abstract
During recent years, gasification technology has gained a high potential and attractiveness to convert biomass and other solid wastes into a valuable syngas for energy production or synthesis of new biofuels. The implementation of real gasification facilities implies a good insight of all [...] Read more.
During recent years, gasification technology has gained a high potential and attractiveness to convert biomass and other solid wastes into a valuable syngas for energy production or synthesis of new biofuels. The implementation of real gasification facilities implies a good insight of all expenses that are involved, namely investments required in equipment during the project and construction phases (capital expenditures, CapEx) and costs linked to the operation of the plant, or periodic maintenance interventions (operational expenditures, OpEx) or costs related to operations required for an efficient and sustainable performance of a gasification plant (e.g., feedstock pre-treatment and management of by-products). Knowledge of these economic parameters and their corresponding trends over time may help decision-makers to make adequate choices regarding the eligible technologies and to perform comparisons with other conventional scenarios. The present work aims to provide an overview on CapEx associated with gasification technologies devoted to convert biomass or solid waste sources, with a view of reducing the carbon footprint during energy generation or production of new energy carriers. In addition, an analysis of technology cost trends over time using regression methods is also presented, as well as an evaluation of specific capital investments according to the amount of output products generated for different gasification facilities. The novelty of this work is focused on an analysis of CapEx of existing gasification technologies to obtain distinct products (energy and fuels), and to determine mathematical correlations relating technology costs with time and product output. For these purposes, a survey of data and categorization of gasification plants based on the final products was made, and mathematical regression methods were used to obtain the correlations, with a statistical analysis (coefficient of determination) for validation. Specific investments on liquid biofuel production plants exhibited the highest decreasing trend over time, while electricity production became the least attractive solution. Linear correlations of specific investment versus time fitted better for electricity production plants (R2 = 0.67), while those relating the product output were better for liquid biofuel plants through exponential regressions (R2 = 0.65). Full article
(This article belongs to the Special Issue Recycling and Recovery of Biomass Materials II)
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41 pages, 6635 KiB  
Review
Emerging and Recycling of Li-Ion Batteries to Aid in Energy Storage, A Review
by Shammya Afroze, Md Sumon Reza, Kairat Kuterbekov, Asset Kabyshev, Marzhan M. Kubenova, Kenzhebatyr Z. Bekmyrza and Abul K. Azad
Recycling 2023, 8(3), 48; https://doi.org/10.3390/recycling8030048 - 8 May 2023
Cited by 16 | Viewed by 7990
Abstract
The global population has increased over time, therefore the need for sufficient energy has risen. However, many countries depend on nonrenewable resources for daily usage. Nonrenewable resources take years to produce and sources are limited for generations to come. Apart from that, storing [...] Read more.
The global population has increased over time, therefore the need for sufficient energy has risen. However, many countries depend on nonrenewable resources for daily usage. Nonrenewable resources take years to produce and sources are limited for generations to come. Apart from that, storing and energy distribution from nonrenewable energy production has caused environmental degradation over the years. Hence, many researchers have been actively participating in the development of energy storage devices for renewable resources using batteries. For this purpose, the lithium-ion battery is one of the best known storage devices due to its properties such as high power and high energy density in comparison with other conventional batteries. In addition, for the fabrication of Li-ion batteries, there are different types of cell designs including cylindrical, prismatic, and pouch cells. The development of Li-ion battery technology, the different widely used cathode and anode materials, and the benefits and drawbacks of each in relation to the most appropriate application were all thoroughly studied in this work. The electrochemical processes that underlie battery technologies were presented in detail and substantiated by current safety concerns regarding batteries. Furthermore, this review collected the most recent and current LIB recycling technologies and covered the three main LIB recycling technologies. The three recycling techniques—pyrometallurgical, hydrometallurgical, and direct recycling—have been the subject of intense research and development. The recovery of valuable metals is the primary goal of most recycling processes. The growth in the number of used LIBs creates a business opportunity to recover and recycle different battery parts as daily LIB consumption rises dramatically. Full article
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15 pages, 1594 KiB  
Article
The Use of Vacuum Residue as a Potential Rejuvenator in Reclaimed Asphalt Pavement: Physical, Rheological, and Mechanical Traits Analysis
by Zaid Hazim Al-Saffar, Ahmed Eltwati, Ehab Essam Aziz, Haryati Yaacob, Halah Abdulsattar Dawood, Ramadhansyah Putra Jaya, Mohammed S. Al Jawahery and Ekarizan Shaffie
Recycling 2023, 8(3), 47; https://doi.org/10.3390/recycling8030047 - 4 May 2023
Cited by 3 | Viewed by 2752
Abstract
Asphalt recycling technology with a high content of reclaimed asphalt pavement (RAP) is becoming more important as the price of paving materials rises and sustainable development and environmental conservation rules become more rigorous. Nevertheless, road authorities in numerous countries still prohibit the utilisation [...] Read more.
Asphalt recycling technology with a high content of reclaimed asphalt pavement (RAP) is becoming more important as the price of paving materials rises and sustainable development and environmental conservation rules become more rigorous. Nevertheless, road authorities in numerous countries still prohibit the utilisation of RAP in asphalt mixes due to the negative impacts of RAP on the performance of asphalt mixtures. Consequently, different rejuvenators have been introduced to reinstate the original attributes of aged asphalt to resolve this issue. This study incorporated vacuum residue (VR) into mixtures with 40% RAP. The physical, rheological, and mechanical traits of the resultant samples were assessed. The results show that the 7.5% VR rejuvenator minimised the RAP asphalt ageing impact. Furthermore, the rejuvenating agent demonstrated physical and rheological rehabilitative benefits for the aged asphalt. The mechanical attributes of the rejuvenated samples were also enhanced compared to the virgin asphalt (VA) specimens. Full article
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24 pages, 7305 KiB  
Article
Microfactory Design for Valorization of E-Waste Plastics (Acrylonitrile-Butadiene-Styrene, Polycarbonate, and Polypropylene) on Additive Manufacturing Sector
by Alejandro Moure Abelenda and Farid Aiouache
Recycling 2023, 8(3), 46; https://doi.org/10.3390/recycling8030046 - 1 May 2023
Cited by 2 | Viewed by 3682
Abstract
Less than half of e-waste plastics are sorted worldwide, and this rate is likely to decline as major processing countries have banned importation of e-waste plastics. This forces the development of decentralized processing facilities, also known as microfactories. The present work investigates the [...] Read more.
Less than half of e-waste plastics are sorted worldwide, and this rate is likely to decline as major processing countries have banned importation of e-waste plastics. This forces the development of decentralized processing facilities, also known as microfactories. The present work investigates the recyclability of different grades of acrylonitrile-butadiene-styrene (ABS) copolymer, polycarbonate, and polypropylene, which were found to be very abundant in a recycling site in the UK. The determination of the matrix relied on the resin identification codes imprinted in the e-waste plastics and subsequent Fourier-transform infrared spectroscopy (FTIR). Melt-blend extrusion technology enabled the valorization of the wasted thermoplastics as 3D filament without significant degradation of the polymers. The recycled materials maintained the tensile strength at around 2.5 MPa in agreement with the specifications offered by virgin polymers. Further characterization was done by means of laser microscope, thermogravimetric analysis, and X-ray fluorescence to determine the commercial viability of the recycled filament. A modified solvent-based method was developed with acetone to remove the brominated flame retardants: 25 g/100 mL, 30 min of contact time, and 4 extraction steps. The FTIR results show that the degradation of the rubbery dispersed phase corresponding to the butadiene can be accumulated in the less soluble fraction of the extracted ABS. Full article
(This article belongs to the Special Issue Advances in the Recycling, Processing and Use of Plastic Waste II)
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21 pages, 1147 KiB  
Article
Municipal Waste Recycling Customer Education and Communication in Slovenia and Croatia
by Boštjan Aver, Nikša Alfirević and Ajda Fošner
Recycling 2023, 8(3), 45; https://doi.org/10.3390/recycling8030045 - 1 May 2023
Viewed by 2788
Abstract
The aim of this paper is twofold: (a) to present the existing regional research related to customer education and communication in municipal waste recycling from the viewpoint of a comparative bibliometric analysis and (b) to illustrate how municipal waste recycling practices in the [...] Read more.
The aim of this paper is twofold: (a) to present the existing regional research related to customer education and communication in municipal waste recycling from the viewpoint of a comparative bibliometric analysis and (b) to illustrate how municipal waste recycling practices in the two countries mirror the theoretical trends identified in the literature and the EU institutional and policy requirements. We discuss the practical implementation of municipal waste recycling practices in the two European countries and provide practical recommendations for local governments, municipal companies, and other stakeholders of the municipal waste management process. Full article
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