Plastic Recycling

Topic Information

Dear Colleagues,

Plastic waste is ending up in the environment, and, unmanaged, is amongst the greatest global environmental challenge of our time.

One of the keys to tackling plastic waste is the creation of a circular economy. In contrast to the make, use, then dispose of process, of linear economy; in a circular economy, we keep resources in use for as long as possible, extract the maximum value from them whilst in use, then recover and regenerate products and materials at the end of their life. The circular economy is about recognizing and capturing the value of plastics as a resource, with the least impact on the climate. We have, in recent years, accelerated the transition to a circular economy, amongst other actions.

Plastic recycling is an important factor in the transition towards a circular economy. With recycling, countries can decouple its dependency on natural resources and work towards a more sustainable, autonomous economy. Key aspects of this transition are technology innovations, design of recyclable and durable products, increased separate collection, quality sorting and optimized recycling processes.

This Topic invites novel contributions in the form of critical reviews and research papers to address all key aspects of plastics recycling, such as: (i) develop strategies or technologies to improve the identification and separation of waste plastics; (ii) incorporate alternative feedstocks in the production of plastics; (iii) design materials with enhanced separation and recycling properties; (iv) develop improvements on separate collection; (v) evaluate the environmental impact of each recyclate; (vi) develop improvements of recycling processes, including mechanical and chemical recycling processes. This Topic also encourage the submission of papers within the topic of the recycling of plastic waste during the COVID-19 pandemic.

Dr. María Ángeles Martín-Lara
Prof. Dr. Mónica Calero de Hoces
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.5	5.3	2011	18.4 Days	CHF 2400
Pollutants pollutants	-	-	2021	25.3 Days	CHF 1000
Fibers fibers	4.0	7.0	2013	21.3 Days	CHF 2000
Energies energies	3.0	6.2	2008	16.8 Days	CHF 2600
Separations separations	2.5	3.0	2014	15.1 Days	CHF 2600

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Published Papers (5 papers)

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17 pages, 6779 KiB  

Open AccessArticle

Experiment and Analysis of Film-Soil Separation Motion Characteristics of a Chain Drive Residual Film Recovery Mechanism for the Tillage Layer

by Zenglu Shi, Xuejun Zhang, Jinshan Yan, Yanwu Jiang and Jieting Yao

Appl. Sci. 2022, 12(12), 5884; https://doi.org/10.3390/app12125884 - 9 Jun 2022

Cited by 5 | Viewed by 1928

Abstract

The working principle and key components of a chain drive residual film recovery machine were studied. A kinematic analysis of the chain drive soil separation mechanism was completed by applying ADAMS software to obtain the trajectory, displacement, velocity and acceleration of the center [...] Read more.

The working principle and key components of a chain drive residual film recovery machine were studied. A kinematic analysis of the chain drive soil separation mechanism was completed by applying ADAMS software to obtain the trajectory, displacement, velocity and acceleration of the center of mass of the chain plate link_1 in the x- and y-directions within the effective shaking displacement. A field test of the chain drive separation mechanism was carried out. When the shaking roller was in contact with the chain, the change in speed of the chain in the x- and y-directions was not significant, but the force in the y-direction was conducive to breaking the soil pieces and improving the rate of collecting the residual film. The change in the speed of link_1 in the y-direction speed with x-direction speed explained the action of the separation mechanism on conveying and throwing of the film-soil mixture in the horizontal and vertical directions, which revealed the mechanism of the chain drive film-soil separation equipment. The field test showed that the film collection rate of the chain drive separation mechanism was 68%, and the surface residue was 6%. The test results meet the relevant national and industry standards and design requirements. The results of this study provide guidance for the design and optimization of chain drive film-soil separation equipment. Full article

(This article belongs to the Topic Plastic Recycling)

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15 pages, 2717 KiB  

Open AccessArticle

Characterization of the Different Oils Obtained through the Catalytic In Situ Pyrolysis of Polyethylene Film from Municipal Solid Waste

by Lucía Quesada, Mónica Calero, María Ángeles Martín-Lara, Antonio Pérez, Marco F. Paucar-Sánchez and Gabriel Blázquez

Appl. Sci. 2022, 12(8), 4043; https://doi.org/10.3390/app12084043 - 16 Apr 2022

Cited by 5 | Viewed by 2699

Abstract

Nowadays, the thermal and catalytic decomposition of plastic wastes by pyrolysis is one of the best alternatives to convert these wastes into quality fuel oils, thus replenishing some petroleum resources. This work studied the catalytic pyrolysis of polyethylene film waste from the remaining [...] Read more.

Nowadays, the thermal and catalytic decomposition of plastic wastes by pyrolysis is one of the best alternatives to convert these wastes into quality fuel oils, thus replenishing some petroleum resources. This work studied the catalytic pyrolysis of polyethylene film waste from the remaining organic fraction on different catalysts under dynamic operating conditions in a batch reactor. These catalysts have been characterized through isotherms of adsorption-desorption with N₂ and X-ray powder diffraction for structural characterization to see the differences in their use. The results obtained have been compared with the pyrolysis of the same material without a catalyst. Special attention has been paid to the similarities and differences with thermal pyrolysis. The characterization of the liquid fraction, including physical and chemical properties, has been carried out. The liquid yield varies from 37 to 43%; it has good calorific values of 46–48 MJ/kg, an average density of 0.82 g/cm³, and a fairly low viscosity compared to the product without the catalyst. Other properties like the American Petroleum Institute (API) gravity or pH were also determined and found to be similar to conventional fuels. Oils are mainly composed of paraffins, naphthenes, and aromatic hydrocarbons. The general distribution of carbons is C7 to C31. Finally, a detailed analysis of the composition of liquid products shows they present heavy naphtha, kerosene, and diesel fractions in different proportions in the function of the catalyst used. Full article

(This article belongs to the Topic Plastic Recycling)

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21 pages, 6899 KiB  

Open AccessReview

Recycling of Plastic Waste, with Particular Emphasis on Thermal Methods—Review

by Agnieszka Kijo-Kleczkowska and Adam Gnatowski

Energies 2022, 15(6), 2114; https://doi.org/10.3390/en15062114 - 14 Mar 2022

Cited by 44 | Viewed by 11286

Abstract

The civilization development requires improvement of technologies and satisfaction of people’s needs on the one side, but on the other one it is directly connected with the increasing production of waste. In this paper, the authors dealt with the second of these aspects, [...] Read more.

The civilization development requires improvement of technologies and satisfaction of people’s needs on the one side, but on the other one it is directly connected with the increasing production of waste. In this paper, the authors dealt with the second of these aspects, reviewing the recycling of plastic waste, which can be processed without changing its chemical structure (mechanical recycling), and with changing its chemical structure (chemical recycling, of which thermal recycling). Mechanical recycling involves shredding the waste in order to obtain recyclate or regranulate that meets specific quality requirements. Chemical recycling consists of the degradation of the material into low-molecular compounds, and it can take place in the processes of hydrolysis, glycolysis, methanolysis by means of chemical solvents, and during thermal processes of hydrocracking, gasification, pyrolysis, combustion, enabling the recovery of gaseous and liquid hydrocarbons foundings in application as a fuel in the energy and cement-lime industry and enabling the recovery of thermal energy contained in plastics. The paper focuses on thermal methods of plastics recycling that become more important due to legal regulations limiting the landfilling of waste. The authors also took up the properties of plastics and their production in European conditions. Full article

(This article belongs to the Topic Plastic Recycling)

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14 pages, 5876 KiB  

Open AccessArticle

Design, Simulation and Experimentation of a Polythene Film Debris Recovery Machine in Soil

by Wei Jin, Jingyi Liu, Chunbao Xu, Xuejun Zhang and Shenghe Bai

Appl. Sci. 2022, 12(3), 1366; https://doi.org/10.3390/app12031366 - 27 Jan 2022

Cited by 14 | Viewed by 2195

Abstract

With the rapid development of planting techniques using plastic film mulching, the content of residual plastic film in soil increases year by year, which pollutes the soil and water, endangers the growth of crops and reduces the quality and yield of agricultural products. [...] Read more.

With the rapid development of planting techniques using plastic film mulching, the content of residual plastic film in soil increases year by year, which pollutes the soil and water, endangers the growth of crops and reduces the quality and yield of agricultural products. Therefore, in order to solve the problem that plastic film with a thickness of 0.008 mm, commonly used in China, is difficult to recycle, this study designed the residue film recycling machine based on the existing research results. After harvesting cotton in Xinjiang, the working performance of the residue film recovery machine of plough layer was measured. Through theoretical optimization and field experiments, the effects of conveyor speed, distance between elastic teeth and type of elastic teeth on residual film recovery were studied. The relationship between the parameters of the residual film recovery machine and the recovery effect of the residual film was analyzed. When the rotational speed and inclination angle of the conveying and separating device were 74 rpm, 35° and 120 rpm, 45°, respectively, under the condition that the distance between C-shaped elastic teeth was 59 mm, the recovery and separation rate of residual plastic film were 88.12% and 83.27%, respectively. Based on the study results, it is recommended to accelerate the development of naturally degradable agricultural plastic film or to popularize and apply thickened film. Relevant local standards and policies have been formulated to address the problem of residual film pollution, and a governance system has been established for the benefit of the government, scientific research institutions, enterprises and farmers. This study provides a reference for mechanized recovery of residual plastic film in soil and treatment of soil pollution. Full article

(This article belongs to the Topic Plastic Recycling)

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12 pages, 7910 KiB  

Open AccessArticle

Effect of the Intercalation and Dispersion of Organoclays on Energy Demand in the Extrusion of Recycled HDPE/PP Nanocomposites

by Andres Rigail-Cedeño, Javier Vera-Sorroche, Gladys García-Mejía and Raul Intriago

Energies 2022, 15(3), 859; https://doi.org/10.3390/en15030859 - 25 Jan 2022

Cited by 6 | Viewed by 3160

Abstract

Few studies have drawn on any systematic research into the energy demand to produce polymer-based nanocomposites. Regarding the problem, it is well-known that single screw extrusion is an energy-intensive process, so the incorporation of energy meters must be considered to examine the energy [...] Read more.

Few studies have drawn on any systematic research into the energy demand to produce polymer-based nanocomposites. Regarding the problem, it is well-known that single screw extrusion is an energy-intensive process, so the incorporation of energy meters must be considered to examine the energy efficiency of the process. In this study, the effect of a nanoclay addition on the energy demand of the extrusion process was examined by extruding recycled high-density polyethylene (rHDPE) and recycled polypropylene (rPP) with a gradual compression screw with both dispersive and distributive mixers. The rHDPE/rPP was modified by adding commercial organoclay (OMMT) (3 wt%) and olefin block copolymer (OBC) (5 wt%) as compatibilizers. The energy consumption was measured on the total energy of the extruder machine. Mass throughput (MT) and specific energy consumption (SEC) were obtained at different screw speeds (10, 20, 30, 40, 50 RPM). The SEC of OMMT and OMMT/OBC nanocomposites was 25–50% lower than rHDPE/rPP, especially at higher throughputs. X-ray diffraction (XRD) and scanning electron microscope (SEM) illustrated the degree of intercalation and dispersion of the organoclay at different screw speeds. Better organoclay intercalation and dispersion were found at lower temperatures. Rheological curves showed a decrease in the viscosity at extrusion rates of nanocomposite mixtures. Melt temperature measured at die exit was reduced in the presence of organoclay over the screw speeds studied. This work suggests that the processing of rHDPE/rPP based nanocomposites can result in minor costs when processing conditions are carefully selected. Full article

(This article belongs to the Topic Plastic Recycling)

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