Recycled Plastic Research Articles

In-Situ Product Removal for the Enzymatic Depolymerization of Poly(ethylene terephthalate) via a Membrane Reactor.

Poly(ethylene terephthalate) (PET) is a common single-use plastic and a major contributor to plastic waste. PET upcycling through enzymatic depolymerization has drawn significant interests, but lack of robust enzymes in acidic environments remains a challenge. This study investigates in-situ product removal (ISPR) of protons from enzymatic PET depolymerization via a membrane reactor, focusing on the ICCG variant of leaf branch compost cutinase. More than two-fold improvements in overall PET depolymerization and terephthalic acid yields were achieved employing ISPR for an initial PET loading of 10 mgPET mlbuffer-1. The benefit of ISPR was reduced for a lower initial loading of 1 mgPET mlbuffer-1 due to decreased need for pH stabilization of the enzyme-containing solutions. A back-of-envelop analysis suggests that at a modest dilution ratio, ISPR could help achieve savings on caustic base solutions used for pH control in a bioreactor. Our study provides valuable insights for future ISPR developments for enzymatic PET depolymerization, addressing the pressing need for more sustainable solutions towards plastic recycling and environmental conservation.

Mixing screw design and high density polyethylene toughening modification for recycled polypropylene based on screw 3D printing

AbstractThe recycling of waste plastics primarily involves physical modification and the addition of modifiers, often utilizing equipment such as twin‐screw extruders for miscible modification. Considering the widespread use of single‐screw 3D printing, improving the mixing efficiency of the single‐screw is crucial to achieve a “one‐stop” recycling modification that is suitable for 3D printing. This paper introduces a 3D printer equipped with a mixing screw (MS) and compares it with a conventional screw (CS). We conduct numerical simulations to investigate the pressure build‐up capacity, velocity streamline distribution, and the mixing effect of the MS. The mechanical properties, thermal characteristics, and molecular orientation of the recycled Polypropylene (rPP) and high density polyethylene (HDPE) mixture are investigated through experiments. The results show that the MS provides more effective elongational flows compared to the CS by breaking down the reinforcing materials into smaller particles. Additionally, toughening and modification experiments are performed on rPP and HDPE. The composites treated with the MS showed improved elongation at break (increased by ~111%), a stable melt crystallization temperature, and an enhanced mixing effect. This study on single‐screw 3D printers lays the groundwork for streamlining the plastic recycling process and increasing the reuse rate of recycled plastics.

Global stability and bifurcations in a mathematical model for the waste plastic management in the ocean

The use of plastic is very widespread in the world and the spread of plastic waste has also reached the oceans. Observing marine debris is a serious threat to the management system of this pollution. Because it takes years to recycle the current wastes, while their amount increases every day. The importance of mathematical models for plastic waste management is that it provides a framework for understanding the dynamics of this waste in the ocean and helps to identify effective strategies for its management. A mathematical model consisting of three compartments plastic waste, marine debris, and recycle is studied in the form of a system of ordinary differential equations. After describing the formulation of the model, some properties of the model are given. Then the equilibria of the model and the basic reproduction number are obtained by the next generation matrix method. In addition, the global stability of the model are proved at the equilibria. The bifurcations of the model and sensitivity analysis are also used for better understanding of the dynamics of the model. Finally, the numerical simulations of discussed models are given and the model is examined in several aspects. It is proven that the solutions of the system are positive if initial values are positive. It is shown that there are two equilibria E0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^0$$\\end{document} and E∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^*$$\\end{document} and if BR<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}<1$$\\end{document}, it is proven that E0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^0$$\\end{document} is globally stable, while when BR>1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}>1$$\\end{document}, the equilibrium E∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^*$$\\end{document} exists and it is globally stable. Also, at BR=1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}=1$$\\end{document} the model exhibits a forward bifurcation. The sensitivity analysis of BR\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}$$\\end{document} concludes that the rates of waste to marine, new waste, and the recycle rate have most effect on the amount of marine debris.

Compressive Strength Comparison Between Plain Concrete and Polyethylene Terephthalate (PET) Mixed Concrete

The construction industry continuously seeks innovative approaches to enhance the mechanical properties of concrete while addressing environmental concerns. This research investigates the quality, mechanical properties, compressive strength of concrete incorporating Polyethylene Terephthalate (PET), a plastic material usually Cold drinks bottle, and compares it with plain concrete. Study involves to replace natural aggregate by an artificial aggregate (PET). PET were introduced into the concrete mix at varying percentages by weight of fine aggregate, following the principle of design mix and comprehensive laboratory testing was conducted to determine the density, quality, Compressive strength and flexural strength of concrete with and without Polyethylene Terephthalate. Non-Destructive test was conducted using Rebound Hammer and Ultrasonic Pulse and Destructive test using Universal Testing Machine. The results reveal that PET mixed concrete slightly decreases the compressive strength of concrete with increasing the percentage of Polyethylene Terephthalate (PET). Density of concrete is 2400kg/m3and concrete up to 6% PET follows the standard value. Based on this study optimum 3.52% of PET by weight can be used in concrete mix. This study underscores the potential of PET fibers as an effective reinforcement material for concrete, contributing to the reduction of plastic waste in the environment. The findings provide valuable insights for the construction industry, highlighting the feasibility of incorporating recycled plastics into concrete mixes to enhance structural performance while promoting sustainability.

Microplastics Identification in Plastic Recycling Facility: Removal Efficiencies of the Treatment Plants and Its Potential Release to the Environment

Microplastics Identification in Plastic Recycling Facility: Removal Efficiencies of the Treatment Plants and Its Potential Release to the Environment

Unleashing high-volume waste plastic recycling in sustainable cement mortar with synergistic matrix enabled by in-situ polymerization

The substantial energy consumption and CO2 emissions associated with the production and transportation of concrete and its components have necessitated the search for suitable replacements, particularly waste materials such as plastic, to mitigate their environmental impact. The emergent challenge of employing recycled waste plastics (RWP) in concrete centers around their poor interactions with the cement matrix. Here, a synergistic approach with in-situ polymerization by using sodium acrylate (SA) at various doses (0 %, 0.5 %, 1 %, 2 %) was employed to produce environmentally-friendly mortars. Recycled polypropylene (PP) particles were adopted as the aggregate to replace natural sand in cement mortar. Results indicate decreased water contact angel by 46 % and increased pull-off strength by 25 % for SA-polymerized PP. Moreover, mortars with 2 % SA exhibited a 31 % increase in compressive strength, a 64 % increase in flexural strength, a 76 % reduction in water sorptivity, and a 13.6 % decrease in total porosity. The formation of interconnected polymeric networks in the cement matrix and interfacial transition zone (ITZ) contributes to structural densification, highlighting the superior engineering properties. These findings present a promising pathway towards sustainable and resource-efficient building materials, fostering a circular economy for plastics.

Recent advancement in microplastic removal process from wastewater - A critical review

Microplastics, small sized plastic particles having size <5 mm are formed through primary process including production of beauty products, microbeads and microfibres as well as secondary process including mechanical weathering, friction, aberration and fragmentation of large plastics. The major sources of microplastics are land-based and ocean-based sources. Microplastic pollution is a serious concern due to the persistent, low biodegradability and bio-accumulative behaviour. Microplastics can bioaccumulate in the food chain and can cause ecological and human health risk. Hence, it is important to remove from the aquatic ecosystems. Microplastics are removed from aquatic systems and wastewater through a series of processes such as physical, chemical and biological treatments. In the present articles, >250 articles are reviewed to collect the information regarding the various physical, chemical and biological methods for the removal of microplastics. Also, the probable control strategies to combat with plastic pollution were assessed. It was concluded that recent water treatment methods are efficient in removing microplastic pollution. The efficiencies to remove microplastic from the water ranged between 74 %-99.2 %, 65 %-99.20 % and 77 %-100 % for physical, chemical and biological treatment methods, respectively. Among the three treatment methods, physical methods especially the filtration of water from biochar is the most efficient way (efficiency up to 100 %) to remove microplastics. It was also concluded that creating public awareness, promoting reusing, recycling and reducing, and application of bioplastics can control the production of microplastics from plastic wastes. This review will be useful to add current knowledge regarding the abatement of microplastic pollution, and finding novel solution to control microplastics. This review will also help the policymakers to implement most effective and cost-efficient method to remove microplastics, and to find out new methods to reduce, reuse and recycle plastic wastes.

Statistical analysis of low-density and high-density polyethylene modified asphalt mixes using the response surface method

The common use of plastics in daily life has engendered gigantic amounts of waste plastics, which have a detrimental influence on the environment. Researchers have proposed several strategies for the recycling of waste plastics and their products. Among these, one strategy is to use them in the construction industry, particularly in asphaltic pavements. This study thus focused on the utilization of waste plastics, specifically Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE), as an additive in Asphalt Concrete (AC) mixes. Indirect Tensile Strength (ITS), Flow Time (FT), and Dynamic Modulus (DM) tests were used to investigate the moisture damage, permanent deformation, fatigue performance, and DM of the LDPE and HDPE modified AC mixes. According to the laboratory test results, the LDPE and HDPE modified AC mixes offer more resistance to moisture damage compared to the Control AC mixes. It was also concluded that asphalt mixes modified with the LDPE and HDPE attained 2.07 times and 1.26 times superior resistance to permanent deformation than the Control mixes. Furthermore, the LDPE and HDPE modified AC mixes outperformed the DM values of the Control mixes by 2.06 times and 1.41 times, respectively. In addition, it was determined that the LDPE and HDPE modified AC mixes exhibit 1.72 times and 1.39 times greater fatigue parameter values than their counterpart, suggesting superior fatigue resistance performance. The statistical models developed using Response Surface Methodology (RSM) revealed the highest values of the Coefficient of Determination (>0.80), adequate precision (>4.0), and lack-of-fit tests, indicating the model’s adequacy for predicting the response.

“Plastic recycling in a cotton candy machine” – a maker project for science education

AbstractTrotz engagierter politischer Initiativen sowie Forderungen und Förderungen für eine Kreislaufwirtschaft steigt das jährlich produzierte Volumen an Kunststoffen, während der Anteil im Kreislauf gehaltener Kunststoffe dem Wachstum nur bedingt gerecht wird. Im Rahmen einer Bildung für nachhaltige Entwicklung ist die Auseinandersetzung mit Kunststoffen und deren Recycling insbesondere in jungen Teilen der Bevölkerung essentiell, um die Relevanz einer zukunftsweisenden Circular Economy nachvollziehen und weitertragen zu können. Im naturwissenschaftlichen Regelunterricht jedoch werden Recyclingprozesse mitunter aufgrund ihrer Komplexität nur oberflächlich integriert. Im Rahmen des Make@thons „Nachhaltige Textilien“ entwickelte eine Schüler:innengruppe mit dem Kunststoffrecycling in der Zuckerwattemaschine eine niedrigschwellige und kostengünstige Möglichkeit zur Integration dieser Recyclingprozesse in den Unterricht.

Effects of soot and plastic fibers on the performance of SCC

Self-compacting concrete is regarded as one of the newest types of concrete due to its durability, efficiency, viscosity, stability, flowability, and resistance. Today, one of the most pressing environmental challenges is the disposal of solid waste, and one of the plastic materials discarded as waste after use is plastic packaging belts. These are made on the basis of polypropylene, as well as the factory Iron smelting mines are the main source of iron oxide waste production. Studies using recycled plastic fibers (30 mm × 0.3 mm) and waste iron oxide as cost-effective additives in self-compacting concrete (SCC) are presented. The effects on fresh and hardened properties were evaluated at various additive contents. Fresh and hardened properties of self-compacting concrete (SCC) were evaluated with and without fiber and iron oxide additives. Tests included workability (slump flow, funnel), strength (compressive, tensile), and durability (ultrasonic pulse speed, permeability). Experiments revealed that increasing the amount of recycled plastic fibers and waste iron oxide in self-compacting concrete (SCC) led to higher compressive and tensile strengths at both 7 and 28 days. These strength increases ranged from 2 to 9.68 MPa for compressive strength and 1.61–7.44 MPa for tensile strength, compared to the control specimen without additives.

Selection of sustainable construction material from recycled waste plastics by q-rung orthopair fuzzy SWARA-MABAC approach

Recycling of waste plastics and agro-industrial waste for the development of sustainable polymeric composites is recognized as a viable approach to overcome the detrimental environmental effects of plastics waste. Despite of immense potential of sustainable composites in the Circular Economy (CE), its implementation is still insignificant due to the lack of an effective material selection approach. The existence of several influencing aspects in the process of material selection considers it a multi-criteria decision making (MCDM) problem. In the present work, an Aggregation Operator (AO) based integrated Stepwise Weight Assessment Ratio Analysis (SWARA) and Multi-attributive Border Approximation Area Comparison (MABAC) has been proposed to deal with the issues of material selection for polymer based sustainable composites. Moreover, q-rung orthopair fuzzy numbers (q-ROPFNs) have been implemented to tackle the uncertainty in the information. The effectiveness of the proposed approach has been confirmed by different comparative and sensitivity investigations. The developed composites have shown excellent properties whereas the responses of the materials vary invariably with compositions. The proposed method has identified the amalgamation of 10 wt percentage of rice husk ash and 10 wt percentage of sand with 80 wt percentage of high-density polyethylene (HDPE) as an appropriate material for the development of sustainable floor tiles as the composites resulted to optimum mechanical performances and minimum abrasive wear. The proposed model gives reliable and robust results and is sensitive to the criteria weights and mathematical parameters. The outcome of the research has exposed that the suggested mathematical approach can be effectively applied for material selection of sustainable polymeric composites for different applications.

A Promising Recycling Strategy via Processing Polypropylene/Recycled Poly(ethylene terephthalate): Reactive Extrusion Using Dual Compatibilizers.

Enhancing interfacial adhesion in polypropylene (PP)/recycled polyethylene terephthalate (rPET) blends is crucial for the effective mechanical recycling of these commercial plastic wastes. This study investigates the reactive extrusion of PP/rPET blends using a dual compatibilizer system comprising maleic anhydride grafted polypropylene (PP-g-MA) and various glycidyl methacrylate (GMA)-based compatibilizers. The effects of backbone structure and reactive group on the morphological, mechanical, and thermal characteristics were systematically studied. This study sheds light on the effective compatibilization mechanisms using characterization methods such as Fourier Transform Infrared Spectroscopy (FTIR) and morphological analyses (SEM). The results indicate that GMA-based compatibilizers play a bridging role between rPET and PP-g-MA, resulting in improved compatibility between the blend components. A combination of 3 phr PP-g-MA and 3 phr ethylene-methyl acrylate glycidyl methacrylate terpolymer (EMA-GMA) significantly improves interfacial adhesion, leading to synergistic enhancements of mechanical performance of the blend, up to 217% and 116% increases in elongation at break and impact strength, respectively, compared to the uncompatibilized sample. Moreover, a significant improvement in onset temperature for degradation is observed for the dual compatibilized sample, with 40 °C and 33 °C increases in onset temperature relative to the uncompatibilized and the single compatibilized samples. These findings underscore the immense potential of tailored multi-component compatibilizer systems for upgrading recycled plastic waste materials.

Eco-economic analysis of utilizing high volumes of recycled plastic and rubber waste for green pavements: A comparative life cycle analysis

The strategic repurposing of substantial volumes of plastic waste and end-of-life tires into asphalt pavement presents a compelling practical solution to the growing waste accumulation problem. Adopting a comparative LCA and LCCA approach, this study focuses on the environmental, functional, and economic performance of hot mixed asphalt (HMA) produced with various compositions to determine the most sustainable solution in the local context. The compositions included unmodified, styrene butadiene styrene (PMB), and the novel recycled composite produced with devulcanized rubber and waste low-density polyethylene (DVR + LDPE composite) HMAs. Research findings indicate that HMA modified with DVR + LDPE composite outcompete the traditional counterparts by significantly reducing GHG emissions by 54.5 % and 14.4 % compared to unmodified and PMB HMAs, respectively. The same can be extended to the cost analysis. The discussion emphasizes the practicality and significance of the novel waste composite and stresses adopting a complete life cycle perspective for asphalt sustainability assessment.

Comparing tensile, bending and interlaminar shear performance of GFRP composites fabricated using recovered and virgin glass fibers: Optimization of the microwave assisted chemical recycling technique

AbstractGlobal glass fiber reinforced plastic (GFRP) recycling provides an effective solution to the end‐of‐life wastes and industrial scrap, by which we can construct a closed‐loop system that reduces environmental impact while increasing sustainability. This study reports the tensile, flexural and shear properties of GFRP composites fabricated from reclaimed fibers from the waste GFRP. A hybrid recycling technique that is, microwave assisted chemical recycling has been used for recovering the glass fiber fabrics. The quantity of solvents (a mixture of 30% H2O2 and CH3COOH in 1:1 ratio) required (in mL/g) for degrading the polymer is optimized with respect to the amount of microwave irradiation time. The microwave irradiation duration was varied at constant power of 900 W for optimizing the quantity of solvent used. SEM analysis of both virgin and reclaimed fiber surfaces indicate an almost complete degradation of polymer from the waste composites. RGFE laminates, fabricated from reclaimed glass fiber fabrics, exhibited marginally higher tensile strength (7%–8%) and significant lower tensile modulus (~29%). On the other hand, RGFE composites demonstrated a greater strain to failure of ~44% compared to VGFE composites during tensile testing, consequently leading to a subsequent increase in tensile toughness by ~28%. The ILSS values obtained from SBS tests and storage modulus and loss factor curves from DMA tests showed almost similar values. SEM studies revealed the probable causes of failures of the samples for tensile and flexural tests.Highlights Hybrid recycling technique using microwave irradiation is optimized. Amount of solvent used is optimized by varying the irradiation times. Tensile and flexural strengths exhibit a marginal increase of 7%–8%. Significant rise in strain at failure by 44% and tensile toughness by 28%. Fractography studies have been performed for analyzing failures.

Strategi Mengurangi Sampah Plastik di Desa Citasuk

This research shows that plastic bricks use plastic waste as a mixed material, offering an innovative solution in the construction sector that is more environmentally friendly and sustainable. The raw material used in making these bricks is plastic waste, which will reduce the amount of plastic waste thrown away in landfills. And the use of recycled plastic waste 5 (PP) polypropylene as a binding material in the paving block mixture produces maximum compressive strength.

Pharmaceutical residues in plastic tablet containers: Impacts on recycling and the environment

High-density polyethylene tablet containers are potentially very suitable for recycling, but no data are publicly available on active pharmaceutical ingredients’ (API) residues in empty containers and if they affect the recyclability of pharmaceutical packaging. Plastic tablet containers represented 15 % of pharmaceutical primary packages sold in Finland in 2020 and 2021, equalling 350 tons of plastic per year. We studied the residues of six APIs remaining or adsorbed inside plastic tablet containers. The effects of tablet coating and usage in dose-dispensing services versus households on the API residues, and rinsing water’s ability to remove the residues were evaluated. Up to 940,000 µg/kg of carbamazepine was detected in a container of uncoated carbamazepine tablets. The residues from coated tablets containing the other five APIs were 2.4–6,100 µg/kg. Ten times higher paracetamol residues were obtained in containers from household use than from a dose-dispensing unit. Rinsing can remove most API residues, but it leads to environmental emissions. For example, rinsing water can double carbamazepine emissions from a Finnish wastewater treatment plant where plastic packaging waste effluents are processed. Considering the API concentrations, decreasing residues by rinsing and dilution with other plastic packaging waste, the residues of the studied APIs are not considered an obstacle to the recycling of plastic tablet containers. However, further research is needed on more toxic APIs and the fate of APIs in the plastics recycling process.

The Artificial Neural Twin — Process optimization and continual learning in distributed process chains

Industrial process optimization and control is crucial to increase economic and ecologic efficiency. However, data sovereignty, differing goals, or the required expert knowledge for implementation impede holistic implementation. Further, the increasing use of data-driven AI-methods in process models and industrial sensory often requires regular fine-tuning to accommodate distribution drifts. We propose the Artificial Neural Twin, which combines concepts from model predictive control, deep learning, and sensor networks to address these issues. Our approach introduces decentral, differentiable data fusion to estimate the state of distributed process steps and their dependence on input data. By treating the interconnected process steps as a quasi neural-network, we can backpropagate loss gradients for process optimization or model fine-tuning to process parameters or AI models respectively. The concept is demonstrated on a virtual machine park simulated in Unity, consisting of bulk material processes in plastic recycling.

A step to microplastic formation: Microcracking and associated surface transformations of recycled LDPE, LLDPE, HDPE, and PP plastics exposed to UV radiation

Plastics when exposed to UV radiation start to degrade via photooxidative aging including free radical formation, oxidation, chain scission and/or crosslinking reactions. These chemical changes can cause loss in mechanical strength, surface embrittlement, and eventually surface erosion. The eroded particles are microplastics (MPs), which have been identified as a potentially serious threat to the environment and its inhabitants. In general, photodegradation of virgin plastics has been studied extensively, but there is not much literature on the degradation of recycled plastics. The goal of the study was to investigate the changes caused by photodegradation in recycled plastics and assess the potential risks of MPs formation. And eventually, knowing the chemical and physical transformations occurring on the surface understand the mechanism behind surface microcracking, which is the first step of MPs formation. Pellets of five industrially recycled plastics (low-density polyethylene (rLDPE), linear low-density polyethylene (rLLDPE), high-density polyethylene (rHDPE), and two polypropylenes (rPP)) from different waste sources were analysed. UV irradiation was performed in an accelerated weathering chamber for milled (< 400 µm) plastic powder to ensure homogeneous changes throughout the sample. The properties were investigated by ATR-FTIR, HT-SEC, XPS and DSC. Formation of microcracks was studied on plastic pellets by SEM. The results showed that the degradation significantly differed between the recycled plastics, and the waste source was more important than the plastic type. rLDPE and one of the rPP samples showed a significant increase in carbonyl index as well as decrease in molar mass during the first 500 h of UV exposure. The other rPP and rHDPE samples showed first considerable signs of degradation only after 1000 h of UV exposure. Minor changes were observed for the rLLDPE sample during the whole test. The SEM revealed microcracking on the surface of all samples, which also had noticeable degradation identified by other methods. These recycled plastics can be considered the ones with the highest potential of MPs formation. From the chemical and physical transformations identified on the surface, the mechanism leading to microcracking, which is the first step in the formation of MPs, is proposed.

Comparative assessment of waste-to-energy scenarios to mitigate GHG emission from MSW in a developing mega city

The search for sustainable municipal solid waste management in urban areas has become a dire need as the generated unprecedented volumes of waste eventually end up in landfills and emits greenhouse gas (GHG). To offer sustainable waste management in Dhaka, Bangladesh, the performance of incineration, anaerobic digestion, and hydrothermal carbonization (HTC) based Waste to Energy (WtE) processes were assessed and compared. The population and the GDP of Dhaka North City Corporation from 2015 to 2023 were used to estimate the MSW generation rate with an empirical multivariable linear regression model. In 2023 around 3600 tons/day of MSW was generated which was 35 % higher than in 2015. The IPCC decay models, ZODM, FODM, and modified triangular model (MTM) yielded 87.3, 41.3, and 38-k tonnes of CH4 generation, respectively. The power generation from incineration-based plants can fall from 30 MW to 3 MW if the moisture content of MSW increases from 70 % to 90 %. Anaerobic digestion produces 34 MW of power. The Optimization of the HTC operating parameters was done and it demonstrates substantial energy potential (up to 65 MW with co-feeding of 420 tons/day of hydrochar with 426 tons/day of plastic from MSW) and GHG emission reduction (221.5 %) compared to landfilling. Additionally, HTC-derived wastewater presents an opportunity for nutrient recovery with 8.16 and 2.66, 0.3 tons/day of K, Na, and P reclamation potential, respectively. A comparison of different scenarios in plastic recycling in incineration and sensitivity analysis for three WtE schemes were conducted. Thus, the study provides a rigorous assessment of different pathways to offer a comprehensive framework for sustainable MSW management that contributes to a cleaner urban environment.

‘Ignorance is Bliss’. Is that True? Unravelling the Determinants of Plastic Recycling Intentions and Behaviours

‘Ignorance is Bliss’. Is that True? Unravelling the Determinants of Plastic Recycling Intentions and Behaviours