Feature Papers in Recycling 2023

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

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 26109

Special Issue Editors


E-Mail Website
Guest Editor
Department of Engineering, CIRIAF, University of Perugia, Via G.Duranti 67, 06125 Perugia, Italy
Interests: energy storage and energy systems; natural gas hydrates; clathrate hydrates; CO2 capture; energy efficiency; waste management
Special Issues, Collections and Topics in MDPI journals

E-Mail Website1 Website2
Guest Editor
Department of Engineering, University of Palermo, RU INSTM, Viale delle Scienze, 90128 Palermo, Italy
Interests: polymer processing; mechanical behaviour of polymer-based systems; rheological behaviour of polymer-based systems; green composites; biocomposites; nanocomposites; biodegradable polymers; polymer blends; degradation and recycling of polymer-based systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

It is our pleasure to announce a new Special Issue entitled “Feature Papers in Recycling 2023.” This is a collection of important high-quality papers (original research articles or comprehensive review papers) published in open access format by prominent scholars. Recycling is a peer-reviewed scientific journal in the area of waste reutilization and resource recycling. It provides an international online forum for studies related to recycling, resource recovery and waste utilisation across many industries, including glass, paper, metal, plastic, textiles, and electronics. We intend for this Special Issue to be an outstanding forum for disseminating excellent research findings, as well as sharing innovative ideas in the field.

In this Special Issue, we aim to collect contributions in the following main fields covered by the journal:   

  • Resource recycling;
  • Waste processing technologies;     
  • Circular economy;     
  • Zero waste programs;     
  • Environmental and social impact of recycling;     
  • Product (eco) design and recycling.

Dr. Beatrice Castellani
Prof. Dr. Francesco Paolo La Mantia
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

  • metal recycling
  • polymer recycling
  • biomass recycling
  • chemical recycling
  • E-waste recycling
  • energy recycling
  • waste management
  • recycling policies
  • the economics of recycling

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (8 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

17 pages, 1282 KiB  
Article
Considering Grouped or Individual Non-Methane Volatile Organic Compound Emissions in Life Cycle Assessment of Composting Using Three Life Cycle Impact Assessment Methods
by Ben Joseph and Heinz Stichnothe
Recycling 2024, 9(3), 35; https://doi.org/10.3390/recycling9030035 - 29 Apr 2024
Viewed by 1673
Abstract
Composting is a waste management practice that converts organic waste into a product that can be used safely and beneficially as a bio-fertiliser and soil amendment. Non-methane volatile organic compounds (NMVOCs) from composting are known to cause damage to human health and the [...] Read more.
Composting is a waste management practice that converts organic waste into a product that can be used safely and beneficially as a bio-fertiliser and soil amendment. Non-methane volatile organic compounds (NMVOCs) from composting are known to cause damage to human health and the environment. The impact of waste management on the environment and workers is recognised as a growing environmental and public health concern. Measurements of NMVOCs emitted during composting have been carried out only in a few studies. NMVOC emissions are typically reported as a group rather than as species or speciation profiles. Recognising the need to investigate the issues associated with NMVOCs, the objective of this study is to estimate variation in life cycle assessment (LCA) results when NMVOCs are considered individual emissions compared to grouped emissions and to compare midpoint and endpoint life cycle impact assessment (LCIA) methods. In general, the ReCiPe 2016 LCIA method estimated the highest impact from the composting process in comparison to IMPACT World+ and EF 3.0 for the impact categories of ozone formation, stratospheric ozone depletion, and particulate matter formation. For ReCiPe 2016 and IMPACT World+, the NMVOC emissions were not linked to human toxicity characterisation factors, meaning that the contribution from NMVOC towards human health risks in and around composting facilities could be underestimated. Using individual NMVOCs helps to additionally estimate the impacts of composting on freshwater ecotoxicity and human carcinogenic and non-carcinogenic toxicity potential. If ecotoxicity or toxicity issues are indicated, then LCA should be accompanied by suitable risk assessment measures for the respective life cycle stage. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

18 pages, 2240 KiB  
Article
Optimization of Pyrolysis Process Parameters for Fuel Oil Production from the Thermal Recycling of Waste Polypropylene Grocery Bags Using the Box–Behnken Design
by Balasubramaniam Prabha, Desikan Ramesh, Srinivasan Sriramajayam and Doraiswamy Uma
Recycling 2024, 9(1), 15; https://doi.org/10.3390/recycling9010015 - 6 Feb 2024
Cited by 4 | Viewed by 3542
Abstract
The impact of dumping plastic waste is realized in different ecosystems of the planet. Several methods have been adopted to dispose of these wastes for energy recovery. This study, for the first time, proposed the Box–Behnken design technique to optimize the pyrolysis process [...] Read more.
The impact of dumping plastic waste is realized in different ecosystems of the planet. Several methods have been adopted to dispose of these wastes for energy recovery. This study, for the first time, proposed the Box–Behnken design technique to optimize the pyrolysis process parameters for fuel oil production from waste polypropylene (PP) grocery bags using a semibatch-type pyrolytic reactor. The semibatch-type pyrolytic reactor was developed and employed to produce fuel oil from waste PP grocery bags. The effect of different process parameters on fuel oil production was comprehensively analyzed using the response surface methodology (RSM) with the conjunction of the Box–Behnken design (BBD). The BBD facilitates the prediction of the response variables with respect to changes in the input variables by developing a response model. The BBD was used to optimize the process parameters, such as the reaction temperature (400–550 °C), nitrogen flow rate (5–20 mL min−1), and substrate feed rate (0.25–1.5 kg h−1), and their effect on the responses were observed. The optimum response yields of the fuel oil (89.34 %), solid residue (2.74%), and gas yield (7.92%) were obtained with an optimized temperature (481 °C), a nitrogen flow rate (13 mL min−1), and a feed rate (0.61 kg h−1). The quadratic model obtained for the fuel oil response denotes the greater R2 value (0.99). The specific gravity and calorific value of the fuel oil were found to be 0.787 and 45.42 MJ kg−1, respectively. The fuel oil had higher research octane number (RON) (100.0 min) and motor octane number (MON) (85.1 min) values. These characteristics of the fuel oil were matched with conventional petroleum fuels. Further, Fourier transform infrared spectroscopy (FT-IR) and gas chromatography–mass spectroscopy (GC-MS) were used to analyze the fuel oil, and the results revealed that the fuel oil was enriched with different hydrocarbons, namely, alkane (paraffins) and alkene (olefins), in the carbon range of C4–C20. These results, and also the fractional distillation of the fuel oil, show the presence of petroleum-range hydrocarbons in the waste PP fuel oil. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Graphical abstract

14 pages, 4388 KiB  
Article
Carbon Fiber Composites Recycling Technology Enabled by the TuFF Technology
by Tekin Ozdemir, Joseph M. Deitzel, Roger Crane, Shridhar Yarlagadda, Chris Blackwell, Mark Davis, Rebecca Emmerich and Dirk Heider
Recycling 2024, 9(1), 11; https://doi.org/10.3390/recycling9010011 - 2 Feb 2024
Cited by 2 | Viewed by 2732
Abstract
Carbon Fiber Composites (CFCs) recycling has received increasing interest by the composites industry, but it is still in its early stages as an industry. There are two primary challenges that need to be addressed in order to achieve full property retention during CFC [...] Read more.
Carbon Fiber Composites (CFCs) recycling has received increasing interest by the composites industry, but it is still in its early stages as an industry. There are two primary challenges that need to be addressed in order to achieve full property retention during CFC recycling: (1) the ability to recover the fiber content without property loss; and (2) conversion of the recycled, short fiber material back into high-performance CFC structures. The ability to manufacture high fiber volume fraction CFCs with end-of-life products would provide an opportunity to reduce material cost and lifetime-embodied energy. In this paper, recycled, short carbon fibers are processed via solvolysis and converted into high-performance CFCs with fiber volume fraction of ~50% and excellent composite property retention. This is enabled through alignment of the discontinuous, recycled fiber feedstock using the Tailorable universal Feedstock for Forming (TuFF) process. The paper introduces the necessary steps to process the fibers in the wet-laid process and explores the resulting mechanical and microstructural properties. The importance of incoming fiber surface quality and the effect of surface contamination from residue left by the recycling process on both the TuFF process and final composite properties is discussed in detail. A pyrolytic process has been adopted to remove the residue that is a by-product of the recycling process from the incoming recycled fiber surface. The approach presents a promising pathway for the recycling of high-performance CFCs. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

14 pages, 2692 KiB  
Article
Recovery of Kish Graphite from Steelmaking Byproducts with a Multi-Stage Froth Flotation Process
by Ying-Liang Chen, Wei-Ping Chiang and Ping-Yu Hsieh
Recycling 2023, 8(6), 92; https://doi.org/10.3390/recycling8060092 - 18 Nov 2023
Viewed by 2371
Abstract
Steelmaking processes inevitably generate large amounts of byproducts, including slags, specks of dust, etc., and their treatment has been a critical issue for the steelmaking industry. Kish graphite is a valuable substance existing in steelmaking byproducts, and the recovery of Kish graphite has [...] Read more.
Steelmaking processes inevitably generate large amounts of byproducts, including slags, specks of dust, etc., and their treatment has been a critical issue for the steelmaking industry. Kish graphite is a valuable substance existing in steelmaking byproducts, and the recovery of Kish graphite has attracted more attention in recent years. The purpose of this study was to use a multi-stage froth flotation process for the beneficiation of Kish graphite and to investigate the influence of flotation conditions on the mass distribution of graphite and impurities. The results showed that the dust D2 contained ~34 wt.% of graphite and thus had the highest potential for the recovery of Kish graphite. The dosages of frother (methyl isobutyl carbinol, MIBC) at 0.005 kg/t and collector (kerosene) at 1 kg/t were optimal for the flotation of Kish graphite. After three-stage froth flotation, the graphite content of the concentrate was progressively increased to 84.09 wt.%, and the entire recovery rate was 93.05%. During the multi-stage froth flotation process, most of the impurities were separated in stage I, but the Fe-containing impurities were mainly separated in stage II. Some Ca2+, Na+, and K+ were leached out, and there were barely any heavy metals in the liquid phases. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

19 pages, 638 KiB  
Article
Exploring the 5Rs Holistic Model for Zero Food Waste in Saudi Arabian Food Service Outlets
by Abu Elnasr E. Sobaih and Ahmed E. Abu Elnasr
Recycling 2023, 8(6), 91; https://doi.org/10.3390/recycling8060091 - 11 Nov 2023
Cited by 2 | Viewed by 2633
Abstract
Background: The proportion of food waste in the Kingdom of Saudi Arabia, particularly in food service outlets, sends an important and urgent call for a holistic model to either prevent or at least properly manage this high level of food waste. This study [...] Read more.
Background: The proportion of food waste in the Kingdom of Saudi Arabia, particularly in food service outlets, sends an important and urgent call for a holistic model to either prevent or at least properly manage this high level of food waste. This study draws on the European Union Waste Hierarchy Framework and the United States Environmental Protection Agency Food Recovery Framework to develop a holistic model to manage the high rate of food waste in Saudi food service outlets. Methods: This study adopted the Standards for Reporting Qualitative Research using one-to-one interviews with food service experts to explore the current and appropriate practices for food waste prevention. The in-depth interviews discussed the implementation of the 5Rs hierarchy, which includes reducing food surplus and waste at the source, redistributing food surplus to needy people, reusing food surplus/waste, recycling food waste, and recovering food waste benefits, i.e., bioenergy production. Results: The successful implementation of the 5Rs hierarchy depends on effective collaboration between the key stakeholders, i.e., policy makers, food industry administrators, non-governmental organizations, and customers. The effective management of the food supply chain is also vital to avoid food surplus and prevent waste in food service outlets. Additionally, sustainable production by staff and responsible consumption by consumers contribute effectively to the implementation of the 5Rs model, which contributes to the achievement of zero food waste and, ultimately, to sustainable development. Conclusions: This study provided a novel hierarchy model, which has five tiers, aiming to avoid food waste. The successful implementation of this model will lead to several significant positive impacts on the economy, community, and environment. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

13 pages, 1178 KiB  
Article
Assessment of Three Recycling Pathways for Waste Cooking Oil as Feedstock in the Production of Biodiesel, Biolubricant, and Biosurfactant: A Multi-Criteria Decision Analysis Approach
by Giovanni De Feo, Carmen Ferrara, Luana Giordano and Libero Sesti Ossèo
Recycling 2023, 8(4), 64; https://doi.org/10.3390/recycling8040064 - 20 Aug 2023
Cited by 10 | Viewed by 4805
Abstract
The management of waste cooking oil (WCO) often poses significant challenges. The improper disposal of WCO results in negative environmental impacts and economic losses. However, from a circular economy perspective, WCO can be recycled and used as a sustainable feedstock for numerous industrial [...] Read more.
The management of waste cooking oil (WCO) often poses significant challenges. The improper disposal of WCO results in negative environmental impacts and economic losses. However, from a circular economy perspective, WCO can be recycled and used as a sustainable feedstock for numerous industrial products, replacing virgin vegetable oils. This approach enables the recovery of resources while simultaneously addressing the problem of WCO disposal. By employing a multi-criteria decision analysis (MCDA) approach, the study assesses three alternative recycling pathways for WCO used as a feedstock in the production of (A1) biodiesel, (A2) biolubricant, and (A3) biosurfactant. The aim is to identify the optimal alternative, taking into account environmental, economic, and technical factors. The procedure involved a team of chemical engineers working in the WCO recycling sector who were selected as decision makers. The ‘priority scale’ combined with the Paired Comparison Technique was employed as a weighting method to evaluate the selected criteria. The results revealed that the decision makers considered environmental sustainability as the most crucial evaluation criterion, followed by the economic criterion. In contrast, the aspect of process management was deemed less significant. Among the compared alternatives, utilizing WCO as a feedstock for biosurfactant production was assessed as the optimal WCO recycling solution. This alternative not only demonstrated the lowest coefficient variation but was also deemed the most favourable option. Biolubricant production was determined to be the second-best alternative. The adopted MCDA approach proved to be a reliable and effective tool, enabling the clear identification of the preferred WCO recycling alternative among those assessed. This was achieved through the utilization of the decision makers’ expertise and knowledge. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Graphical abstract

16 pages, 1646 KiB  
Article
Considering Waste Generation in the Energy Sector during the Transition to a Circular Economy
by Anzhelika Karaeva and Elena Magaril
Recycling 2023, 8(2), 42; https://doi.org/10.3390/recycling8020042 - 8 Apr 2023
Cited by 2 | Viewed by 4228
Abstract
The need to reduce the negative environmental impact of energetics with the growing energy demand in the world is the core objective of the industry for the upcoming decades. The global agenda in the field of environmental protection increases the requirements for evaluation [...] Read more.
The need to reduce the negative environmental impact of energetics with the growing energy demand in the world is the core objective of the industry for the upcoming decades. The global agenda in the field of environmental protection increases the requirements for evaluation of the energy investment projects, in particular for their environmental efficiency. Currently, much attention is paid to assessing the impact of the project on atmospheric air, water bodies and land resources, including the formation of industrial waste during the operational stage. The formation of production and consumption waste at other stages of the project life cycle is not considered either when generating cash flows or when conducting the assessment pf environmental efficiency. It might significantly reduce the reliability of assessment results. The purpose of this study is to develop a system of integrated accounting for all types of waste generated and the environmental costs incurred for handling them during the environmental and economic assessment of energy projects. The paper discusses modern waste management practices at energy enterprises, waste generation at various stages of investment projects implementation, and provides recommendations on waste accounting when assessing their environmental and economic efficiency. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

Review

Jump to: Research

17 pages, 2700 KiB  
Review
Review of the Policy, Social, Operational, and Technological Factors Affecting Cigarette Butt Recycling Potential in Extended Producer Responsibility Programs
by Aron Pazzaglia and Beatrice Castellani
Recycling 2023, 8(6), 95; https://doi.org/10.3390/recycling8060095 - 1 Dec 2023
Viewed by 2816
Abstract
Cigarette butts (CBs) are the most diffuse waste in the world, often abandoned into the environment without proper disposal. They are dangerous because of the numerous harmful chemicals potentially released by them into the environment. In the literature, there are several technological options [...] Read more.
Cigarette butts (CBs) are the most diffuse waste in the world, often abandoned into the environment without proper disposal. They are dangerous because of the numerous harmful chemicals potentially released by them into the environment. In the literature, there are several technological options for CB recycling, but some critical concerns could affect their effectiveness due to the quality and quantity of CB litter that is collected in the proper way. The extended producer responsibility scheme for CBs is proposed at the Europe level as an action to tackle CB litter and encourage sustainable product development. The present paper focuses on analyzing the existing literature to identify critical issues within the policy framework, social behavior, waste collection and transport, and technological processes. The collection and transport of CB waste is a major issue, being a key step for bringing CB to the recycling process. The main concern is the small quantity of CBs collected: 0.06% of the municipal waste and 0.18% of the unsorted waste in the case study’s administrative area of Perugia. Another crucial issue is the need for behavioral interventions to increase education and awareness of citizens that are smokers, addressing the discrepancy between smokers’ behaviors and beliefs. The main results, along with the critical issues related to the topics, are highlighted. Full article
(This article belongs to the Special Issue Feature Papers in Recycling 2023)
Show Figures

Figure 1

Back to TopTop