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Thermochemically upcycling waste plastics to value-added products is emerging to alleviate the waste crisis. This study aims to develop highly active and stable Ni-based catalysts for coupling pyrolysis and catalytic reforming of waste plastics to produce syngas. A series of confined NiO@S-1 catalysts with various Ni loadings (5%, 10%, 15%, and 20%) were constructed by employing dissolution-recrystallization strategy. They were in situ reduced and 15%NiO@S-1 sample showed the highest catalytic activity in terms of yield of syngas with high CO selectivity and was superior to 15%NiO/S-1 and 15%NiO/SiO 2 samples prepared by impregnation method. The TEM images of 15%NiO@S-1 catalyst after reaction showed that metallic Ni nanoparticles with average size of 10.1 nm were kept dispersive due to the confinement effect. In contrast, the apparent agglomeration of Ni nanoparticles with average size of 54.9 nm were found on the surface of 15%NiO/S-1 after reaction. This provides an effective strategy for design robust Ni-based confined catalysts for thermochemically upcycling waste plastics. [Display omitted] • Pyrolysis and catalytic O 2 reforming technology was used to produce syngas from polypropylene. • NiO@S-1 catalyst showed higher catalytic activity than NiO/S-1 and NiO/SiO 2. • The migration and agglomeration of Ni particles was limited in NiO@S-1 catalyst. • No evident coke was observed on the surface of NiO@S-1 catalyst after reaction. [ABSTRACT FROM AUTHOR]

Plastic pollution is becoming a major health issue due to the recent discovery of microplastics and nanoplastics in living organisms and the environment, calling for advanced technologies to remove plastic waste. Here we review enzymes that degrade plastics with focus on plastic properties, protein engineering and polymers such as poly(ethylene terephthalate), poly(butylene adipate-co-terephthalate), poly(lactic acid), polyamide and polyurethane. The mechanism of action of natural and engineered enzymes has been probed by experimental and computation approaches. The performance of polyester-degrading enzymes has been improved via directed evolution, structure-guided rational design and machine learning-aided strategies. The improved enzymes display higher stability at elevated temperatures, and tailored substrate-binding sites. [ABSTRACT FROM AUTHOR]

Approximately 50% of global plastic wastes are produced from plastic packaging, a substantial amount of which is disposed of within a few minutes of its use. Although many plastic types are designed for single use, they are not always disposable. It is now widely acknowledged that the production and disposal of plastics have led to a plethora of negative consequences, including the contamination of both groundwater and soil resources and the deterioration of human health. The undeniable impact of excessive plastic manufacturing and waste generation on the global plastic pollution crisis has been well documented. Therefore, degradable polymers are a crucial solution to the problem of the non-degradation of plastic wastes. The disadvantage of degradable polymers is their high cost, so blending them with natural polymers will reduce the cost of final products and maximize their degradation rate, making degradable polymers competitive with industrial polymers that are currently in use daily. In this work, we will delineate various degradable polymers, including polycaprolactone, starch, and cellulose. Furthermore, we will elucidate several aspects of polyvinyl alcohol (PVA) and its blends with natural polymers to show the effects of adding natural polymers on PVA properties. This paper will study cost-effective and ecologically acceptable polymers by combining inexpensive natural polymers with readily accessible biodegradable polymers such as polyvinyl alcohol (PVA). [ABSTRACT FROM AUTHOR]

In this study, hydrothermal co-liquefaction of restaurant waste for biocrude production was conducted. The feedstock was resembled using the organic fraction of restaurant waste and low-density polyethylene, polypropylene, polystyrene, and polyethylene terephthalate, four plastic types commonly present in municipal solid waste. Using design of experiment and a face-centered central composite design, three factors (feedstock plastic fraction, temperature, time) were varied at three levels each: feedstock plastic fraction (0, 0.25, 0.5), temperature (290 °C, 330 °C, 370 °C), and reaction time (0 min, 30 min, 60 min). The literature reports positive synergistic interactions in hydrothermal co-liquefaction of biomass and plastics; however, in this work, only negative synergistic interactions could be observed. A reason could be the high thermal stability of produced fatty acids that give little room for interactions with plastics. At the same time, mass might transfer to other product phases. [ABSTRACT FROM AUTHOR]

Plastic biodegradation has emerged as a sustainable approach and green alternative in handling the ever-increasing accumulation of plastic wastes in the environment. The complete biodegradation of polyethylene terephthalate is one of the most recent breakthroughs in the field of plastic biodegradation. Despite the success, the effective and complete biodegradation of a wide variety of plastics is still far from the practical implementation, and an on-going effort has been mainly devoted to the exploration of novel microorganisms and enzymes for plastic biodegradation. However, alternative strategies which enhance the existing biodegradation process should not be neglected in the continuous advancement of this field. Thus, this review highlights various strategies which have shown to improve the biodegradation of plastics, which include the pretreatment of plastics using UV irradiation, thermal, or chemical treatments to increase the susceptibility of plastics toward microbial action. Alternative pretreatment strategies are also suggested and compared with the existing techniques. Besides, the effects of additives such as pro-oxidants, natural polymers, and surfactants on plastic biodegradation are discussed. In addition, considerations governing the biodegradation performance, such as the formulation of biodegradation medium, cell-free biocatalysis, and physico-chemical properties of plastics, are addressed. Lastly, the challenges and future prospects for the advancement of plastic biodegradation are also highlighted. [ABSTRACT FROM AUTHOR]

• Interaction of plastic and scrap tyre during co-pyrolysis is plastic-specific. • Mixing PP or LDPE with tyre can promote aliphatic hydrocarbon and suppress PAHs. • Mixing PS with tyre can suppress PAHs and enhance MAs production, especially BTEX. • 75 wt% LDPE or PS with tyre at 600 °C yields sulphur-free pyrolytic oil. • Tyre char can promote cracking reactions in LDPE thermal degradation. Fast co-pyrolysis offers a sustainable solution for upcycling polymer waste, including scrap tyre and plastics. Previous studies primarily focused on slow heating rates, neglecting synergistic mechanisms and sulphur transformation in co-pyrolysis with tyre. This research explored fast co-pyrolysis of scrap tyre with polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) to understand synergistic effects and sulphur transformation mechanisms. A pronounced synergy was observed between scrap tyre and plastics, with the nature of the synergy being plastic-type dependent. Remarkably, blending 75 wt% PS or LDPE with tyre effectively eliminated sulphur-bearing compounds in the liquid product. This reduction in sulphur content can substantially mitigate the release of hazardous materials into the environment, emphasizing the environmental significance of co-pyrolysis. The synergy between PP or LDPE and tyre amplified the production of lighter hydrocarbons, while PS's interaction led to the creation of monocyclic aromatics. These findings offer insights into the intricate chemistry of scrap tyre and plastic interactions and highlight the potential of co-pyrolysis in waste management. By converting potential pollutants into valuable products, this method can significantly reduce the release of hazardous materials into the environment. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the sustainable use of recycled plastics, specifically polypropylene (PP) and high-density polyethylene (HDPE), in the manufacture of geogrids for geotechnical and civil engineering applications. Plastics were collected from a recycling center, specifically targeting containers used for food, cleaning products, and other domestic packaging items. These plastics were sorted according to the Möbius triangle classification system, with HDPE (#2) and PP (#5) being the primary categories of interest. The research methodologically evaluates the mechanical properties of PP/HDPE (0/100, 25/75, 50/50, 75/25 and 100/0% w/w) composites through tensile and flexural tests, exploring various compositions and configurations of geogrids. The results highlight the superiority of pure recycled HDPE processed into 1.3 mm thick laminated yarns and hot air welded for 20 to 30 s, exhibiting a deformation exceeding 60% in comparison to the PP/HDPE composites. Through SolidWorks® Simulation, it was shown that the adoption of a trigonal geogrid geometry optimizes force distribution and tensile strength, significantly improving slope stabilization efficiency. Based on the results obtained, a laboratory-scale prototype geogrid was developed using an extrusion process. The results underscore the importance of careful composite design and yarn configuration selection to achieve the desired mechanical properties and performance in geogrid applications. It emphasizes the potential of recycled plastics as a viable and environmentally friendly solution for stabilizing slopes, contributing to the reduction in plastic waste and promoting sustainable construction practices. [ABSTRACT FROM AUTHOR]

Plastic accumulation is a severe threat to the environment due to its resistivity to thermal, mechanical and biological processes. In recent years, microbial degradation of plastic waste disposal is of interest because of its eco-friendly nature. In this study, a total of 33 fungi were isolated from the plastisphere and out of which 28 fungal species showed halo zone of clearance in agarized LDPE media. The fungus showing highest zone of clearance was further used to evaluate its degradation potential. Based on morphological and molecular technique, the fungus was identified as Cladosporium sphaerospermum. The biodegradation of LDPE by C. sphaerospermum was evaluated by various methods. The exposure of LDPE with C. sphaerospermum resulted in weight loss (15.23%) in seven days, higher reduction rate (0.0224/day) and lower half-life (30.93 days). FTIR analysis showed changes in functional group and increased carbonyl index in LDPE treated with C. sphaerospermum. SEMimages evidenced the formation of pits, surface aberrations and grooves on the LDPE film treated with the fungus whereas the untreated control LDPE film showed no change. AFM analysis confirmed the surface changes and roughness in fungus treated LDPE film. This might be due to the extracellular lignolytic enzymes secreted by C. sphaerospermum grown on LDPE. The degradation of polyethylene by Short chain alkanes such as dodecane, hexasiloxane and silane were identified in the extract of fungus incubated with LDPE film through GC–MS analysis which might be due to the degradation of LDPE film by C. sphaerospermum. This was the first report on the LDPE degradation by C. sphaerospermum in very short duration which enables green scavenging of plastic wastes. [ABSTRACT FROM AUTHOR]

Biodegradable plastics, represented by polylactic acid (PLA), are considered suitable alternatives to nondegradable commodity plastics; however, their degradation through microbial decomposition is seen as a waste of carbon resources and inevitably brings about CO2 emission. Alternatively, waste PLA plastics can be utilized as feedstocks for the sustainable production of value-added chemicals, which not only avoids a carbon footprint but also realizes upcycling of plastic waste. Here, we show a cascade system that combines alkali-induced depolymerization, pulsed electrooxidation, and electrochemical reductive amination to produce alanine with an overall yield of 69% under near ambient conditions. Specifically, we first implement an alkali catalyst in an aqueous solution to depolymerize PLA into lactate. The obtained PLA hydrolysate is directly utilized as both feedstock and electrolyte for pyruvate production over a nickel hydroxide-supported Pd electrocatalyst (Pd/Ni(OH)2) via a pulsed potential, which is followed by the transformation of pyruvate into alanine using a TiO2 catalyst. This cascade process for alanine production benefits from high efficiencies maintained in three consecutive processes, mild operation conditions, and the use of cost-effective feedstocks (plastic wastes), without suffering harsh conditions and expensive feedstock consumption required by conventional biological and chemical approaches for alanine synthesis, respectively. [ABSTRACT FROM AUTHOR]

Plastic degradation by biological systems emerges as a prospective avenue for addressing the pressing global concern of plastic waste accumulation. The intricate chemical compositions and diverse structural facets inherent to polyurethanes (PU) substantially increase the complexity associated with PU waste management. Despite the extensive research endeavors spanning over decades, most known enzymes exhibit a propensity for hydrolyzing waterborne PU dispersion (i.e., the commercial Impranil DLN-SD), with only a limited capacity for the degradation of bulky PU materials. Here, we report a novel cutinase (CpCut1) derived from Cladosporium sp. P7, which demonstrates remarkable efficiency in the degrading of various polyester-PU materials. After 12-h incubation at 55°C, CpCut1 was capable of degrading 40.5% and 20.6% of thermoplastic PU film and post-consumer foam, respectively, while achieving complete depolymerization of Impranil DLN-SD. Further analysis of the degradation intermediates suggested that the activity of CpCut1 primarily targeted the ester bonds within the PU soft segments. The versatile performance of CpCut1 against a spectrum of polyester-PU materials positions it as a promising candidate for the bio-recycling of waste plastics. IMPORTANCE Polyurethane (PU) has a complex chemical composition that frequently incorporates a variety of additives, which poses significant obstacles to biodegradability and recyclability. Recent advances have unveiled microbial degradation and enzymatic depolymerization as promising waste PU disposal strategies. In this study, we ident ified a gene encoding a cutinase from the PU-degrading fungus Cladosporium sp. P7, which allowed the expression, purification, and characterization of the recombinant enzyme CpCut1. Furthermore, this study identified the products derived from the CpCut1 catalyzed PU degradation and proposed its underlying mechanism. These findings highlight the potential of this newly discovered fungal cutinase as a remarkably efficient tool in the degradation of PU materials. [ABSTRACT FROM AUTHOR]

Frequently used protective items during the pandemics are prepared from plastics products, such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene, and polyester. Globally more than 57 million pounds of personal protective equipment along with other biomedical plastic waste are entering into the oceans per annum. Lots of economic benefits can be obtained by recycling the polymeric wastes by converting them into useful products through, reduced manufacture cost, bio converted products, and cleaner environment by developing a circular waste management model. Personal protective equipment's are prepared from different plastic products and the outer most surface of these free-floating plastics presents in the aquatic environment serve as colonization support to diverse microbial populations known as plastisphere. Microbial colonization starts with an initial attachment under different environmental conditions, subsequently by developing a permanent association on the plastic surface. The community structure of microorganisms in the plastisphere can be significantly influenced by the depth of water in the aquatic ecosystem where microplastics present and the nutrients availability. As microorganisms have been deeply investigated for their role in the biodegradation of several pollutants, the present review article focuses on microbial diversity on plastisphere in the aquatic ecosystem, the underlying mechanism of colonization, and their potential role in microplastic degradation. This review article also highlights on imminent research for sustainable management of aquatic microplastic pollution. [ABSTRACT FROM AUTHOR]

The non-degradable nature of petroleum-based plastics and the dependence on petroleum-based products in daily life and production are dilemmas of human development today. We hereby developed a plastic waste upcycling process to address these challenges. A multi-stream fraction strategy was developed to process poly (ethylene terephthalate) (PET) plastics into soluble and insoluble fractions. The soluble fraction was used as a sole carbon source for microbial fermentation to produce biodiesel precursor lipids with an appreciable bioconversion yield. The insoluble fraction containing fractionated polymers was used as the asphalt binder modifiers. The downsized PET additive improved the high-temperature performance of the asphalt binder by 1 performance grade (PG) without decreasing the low-temperature PG. Subsequent SEM imaging unveiled alterations in the micromorphology induced by PET incorporation. Further FTIR and 1H NMR analysis highlighted the aromatic groups of PET polymers as a crucial factor influencing performance enhancement. The results demonstrated the multi-stream fraction as a promising approach for repurposing plastic waste to produce biodiesel and modify asphalt. This approach holds the potential to tackle challenges in fuel supply and enhance infrastructure resilience to global warming. [ABSTRACT FROM AUTHOR]

• Economic assessment of pyrolysis plants for engineering plastics recycling. • Cost-covering prices: 418–1182 €/Mg pyrolysis oil, based on plant capacity. • Feedstock availability and quality are a challenge for a business case. • Producing high-quality pyrolysis oil also challenge for a business case. • Additional revenue streams like gate fees and subsidies vital for business case. Chemical recycling of complex plastic waste via pyrolysis can reduce fossil resource dependence of the plastics value chain and greenhouse gas emissions. However, economic viability is crucial for its implementation, especially considering challenging waste streams with high shares of engineering plastics that have lower pyrolysis product quality than standard thermoplastics waste. Thus, this study conducts a techno-economic assessment determining the profitability factors of pyrolysis plants for automotive plastic waste in Germany including different plant capacities and calculating cost-covering minimum sales prices for the resulting pyrolysis oil. Main findings are that due to economies of scale, the cost-covering minimum sales prices vary between 1182 €/Mg pyrolysis oil (3750 Mg input/year) and 418 €/Mg pyrolysis oil (100,000 Mg input/year). The pyrolysis technology employed must be robust and scalable to realize these economies of scale. Large plant capacities face challenges such as feedstock availability at reasonable costs, constant feedstock quality, and pyrolysis oil quality, affecting pyrolysis oil pricing. Due to the limited yield and quality of pyrolysis oil produced from these technically demanding feedstocks, policy implications are that additional revenue streams such as gate fees or subsidies that are essential to ensure a positive business case are necessary. Depending on the assessed plant capacity, additional revenues between 720 and 59 €/Mg pyrolysis oil should be realized to be competitive with the price of the reference product heavy fuel oil. Otherwise, the environmental potential of this technology cannot be exploited. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are highly sought after as they have the potential to reduce the issue of plastic waste and eventually lead to a circular economy. Yet, conciliating eco-friendliness with competitive properties is often challenging. Polymerization and processing techniques have been developed and optimized to improve such factors. Some of the common polymerization methods to obtain such materials are condensation, ring-opening, addition, and biocatalytic-assisted polymerization. Alongside that, processing techniques such as melt mixing/extrusion, solution castings, compression, and injection molding have also been employed for the manufacture of biodegradable polymers. While these traditional techniques are viable routes to market, there is still the need to further improve their properties to make them comparable to their petrochemical-based counterparts. To assist with that, the production of composites and blending techniques are facile approaches that demonstrated promising improvements in their properties. Based on these aspects, this review is aimed at discussing the main types of biodegradable polymers, followed by the compositing approaches reported in the recent literature, their structure-property relationships, and biodegradability mechanisms. The first section provides an introductory overview of biodegradable polymers and their composites. The second section focuses on the most prominent polymers used in the industry. Furthermore, the fabrication techniques, along with their property and application relationships are provided with an emphasis on mechanical reinforcements and the biomedical field. Finally, some future perspectives are given to clarify some of the known challenges and, possibly, provide some insights for the reader to develop novel ideas. [ABSTRACT FROM AUTHOR]

• PLA-based compounds for modulating degradation rate. • Analysis of hydrolysis on PLA-based compounds. • Composting in yard waste of PLA-based compounds. • Model for hydrolytic mechanism. The huge amount of plastics generated by the massive use of packaging makes it difficult to manage waste safely. Introducing biodegradable polymers, such as poly(lactic acid) (PLA), can at least partially reduce the environmental pollution from plastic waste. Biodegradable polymers must have a degradation rate appropriate for the intended use to replace durable plastics. This work aims to introduce PLA fillers that can modulate the degradation rate during hydrolysis and composting. For this purpose, fumaric acid and magnesium hydroxide have been proposed. The experimental findings demonstrated that magnesium oxide makes hydrolysis faster than fumaric acid. A model describing the hydrolysis reaction, which also considers the effect of crystallinity, is proposed. The model can capture the filler effect on the kinetic constants related to the autocatalytic part of the hydrolysis reaction. Degradation of the PLA and compounds was also conducted in a composting medium. The compound with fumaric acid shows faster degradation than the compound with magnesium oxide; this behavior is opposite to what is observed during hydrolysis. Degradation in a composting medium is favored in a narrow pH window corresponding to the optimum environment for microorganism growth. Magnesium oxide leads to a pH increase above the optimum level, making the environment less favorable to microorganism growth. Vice-versa, fumaric acid maintains the pH level in the optimum range: it represents an additional carbon source for microorganism growth. [ABSTRACT FROM AUTHOR]

• Raffia and mulching film hamper the direct reuse or plant residues in horticulture. • As a result, contaminated plant residues are often landfilled or incinerated. • We assess the use of biodegradable and compostable alternatives. • These alternatives are more expensive than conventional options. • They have a lower carbon footprint when conventional plastic waste is incinerated. Plastics and other materials commonly used in horticulture for plant support (e.g. raffia) and soil protection (e.g. mulching film) pose a challenge to achieving a circular economy. These materials contaminate plant residues, hampering their direct reuse due to the need for separation and cleaning. As a result, contaminated plant residues is often landfilled or incinerated. This study investigates the replacement of conventional plastic raffia and mulching film with biodegradable and compostable alternatives. Polypropylene raffia is compared with a biodegradable viscose polymer and compostable jute fibre, while polyethylene mulching film is compared with a biodegradable polylactic acid film. Conventional and novel alternatives are compared economically using Life-Cycle Costing and environmentally using Life-Cycle Assessment. The economic assessment is based on case studies with two horticultural companies in Almeria (south-eastern Spain), while the environmental analysis uses data from the Ecoinvent database. The use of biodegradable and compostable alternatives for raffia and mulching film proved to be 49% more expensive than conventional options. However, when conventional plastic waste is incinerated rather than landfilled, biodegradable and compostable alternatives have a lower carbon footprint. Although biodegradable and compostable options can be more expensive and have higher impacts in certain situations, proper waste management can lead to environmental benefits. With optimisation and incentives, these alternative options support the transition of horticulture to a sustainable circular economy. [ABSTRACT FROM AUTHOR]

The design and study of active microbial consortia able to degrade plastics represent an exciting area of research toward the development of bio-based alternatives to efficiently transform plastic waste. This forum article discusses concepts and mechanisms to inform emerging strategies for engineering microbiomes to transform plastics under controlled settings. [ABSTRACT FROM AUTHOR]

Conventional mechanical recycling technologies cannot recycle all types and amounts of generated plastic waste. Pyrolysis can convert these municipal mixed plastic streams into products with significant calorific value, which are likely to be used as energy sources. The present work describes a technology used to expand the portfolio of technical approaches to drive plastics circularity, i.e., thermochemical recycling. A base case scenario considered a capacity of 1.000 kg/h of municipal plastic waste, consisting of a mixture of polypropylene (PP), polystyrene (PS), polyethylene (PE), and plastic associated with paper, which were converted into non-condensable gases, oil, and char through a pyrogasification system. Based on mass and energy balances and experimental data from the literature, a total of 199.4 kg (48 MJ/kg) of liquid fuel and 832.85 kg (16 MJ/kg) of gas could be obtained with no need for external heating sources. The thermal requirement for the pyrolysis of 1.000 kg of municipal plastic waste (1.316 MJ) was supplied by the gasification of a fraction of the produced pyrolysis oil and gases. This feasibility analysis confirmed the technical adequacy of the proposed technology, which that will be further complemented by a technoeconomic study of the proposed solution. [ABSTRACT FROM AUTHOR]

Plastic waste is being manufactured for the production of hydrogen. The amount of plastic waste collected annually is 189,953 tonnes from adjacent nations like Indonesia and Malaysia. Polyethylene (PE), Polypropylene (PP), Polyethylene Terephthalate (PET), Polyvinyl chloride (PVC), and Polystyrene (PS) are the five most prevalent forms of plastic found in most waste. Pyrolysis, water gas shift and steam reforming reaction, and pressure swing adsorption are the three main phases utilized and studied. In this research, authors examines the energy consumption on every stage. The plastic waste can be utilized to manufacture many hydrocarbons using the pyrolysis reaction. For this process, fast pyrolysis is being used at a temperature of 500 °C. A neutralization process is also needed due to the presence of Hydrochloric acid from the pyrolysis reaction, with the addition of sodium hydroxide. This is being carried to prevent any damage to the reactor during the process. Secondly, the steam reforming process continues after the water gas shift reaction has produced steam and carbon monoxide, followed by carbon dioxide and hydrogen formation. Lastly, pressure swing adsorption is designed to extract H2S and CO2 from the water gas shift and steam reforming reaction for greater purity of hydrogen. From the simulation study, it is observed that using various types of plastic waste procured (total input of 20,000 kg per hour of plastics) from, Brunei Darussalam, Malaysia and Indonesia, can produce about 340,000 tons of Hydrogen per year. Additionally, the annual profit of the Hydrogen production is estimated to be between $ 271,158,100 and $ 358,480,200. As per the economic analysis, it can be said that its a good to start hydrogen production plant in these regions. [ABSTRACT FROM AUTHOR]

In response to fossil fuel concerns and the imperative of effective plastic waste management, this study investigates the impact of hydrogen-plastic oil (WPO) blends on a CRDI diesel engine. Six combinations (WPO10, WPO20, WPO30, WPO10 + H 2 , WPO20 + H 2 , WPO30 + H 2) are examined across varying loads and fuel injection timings. Notably, WPO10 + H₂ (H 2 energy share i.e., 8 lpm) exhibits a 15.1 % increase in brake thermal efficiency, an 11.2 % fuel consumption reduction, improved peak cylinder pressure (66 bar), and maximum heat release rate (40.16 J/°CA) compared to diesel. It also shows reduced emissions of CO, HC, CO 2 , and smoke opacity—34.8 %, 15.1 %, 10.7 %, and 28.5 %, respectively, relative to diesel. Elevated nitrogen oxide (NOx) emissions are observed across all blends. This study underscores the environmental benefits of blending waste plastic oil with diesel, promoting recycling, reducing reliance on traditional diesel, lowering greenhouse gas emissions, and supporting sustainability. Advanced fuel injection timing at higher loads slightly mitigates NOx emissions, while increasing the blend proportion leads to prolonged ignition delays, reduced thermal efficiency, and heightened emissions. [Display omitted] • Study analyses CRDI diesel engines with hydrogen-enriched waste plastic oil blends. • Focus on combustion, performance, and emissions at varying loads and FIT. • Hydrogen addition, especially WPO10 + H 2 , enhances engine performance and reduces emissions. • WPO blends, particularly WPO10, show improved emission, and performance characteristics. • Hydrogen-enriched WPO offers an eco-friendly alternative for reduced emissions and enhanced energy independence. [ABSTRACT FROM AUTHOR]

An increase in plastic waste pollution and the strengthening of global environmental policies have heightened the need for research on biodegradable plastics. In this regard, polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are notable examples, serving as alternatives to traditional plastics. In this study, the compatibility and mechanical properties of PLA/PBAT blends were improved by the chemical grafting of maleic anhydride (MAH). In addition, qualitative analyses were conducted, dynamic mechanical properties were investigated, and the structure and mechanical characteristics of the blends were analyzed. With an increase in the MAH concentration, the grafting yield of the blends increased, and significantly improved the compatibility of the PLA/PBAT blend, with an ~2 and 2.9 times increase in the tensile strength and elongation at break, respectively. These findings indicate that the modified PLA/PBAT blend demonstrates potential for applications that require sustainable plastic materials, thereby contributing to the development of environmentally friendly alternatives in the plastics industry. [ABSTRACT FROM AUTHOR]

Plastic products are an indispensable part of life and are widely used in different fields. However, plastic products have the characteristics of short average service life and not easy to degrade naturally, which are prone to cause serious environmental pollution by long-term accumulation in the environment. The use of low-cost catalysts is the goal pursued by enterprises. In this paper, polypropylene (PP), low-density polyethylene (LDPE), polystyrene (PS), mixed waste plastics (WPs) and spent FCC catalyst (a solid waste produced by oil refining enterprises) were used as research objects to simulate the pyrolysis and catalytic pyrolysis of waste plastics in real life. The results showed that compared with the direct pyrolysis of plastics, the addition of spent FCC catalysts could significantly reduce the initial pyrolysis temperature of PP, LDPE and WPs, with the largest decrease in the initial pyrolysis temperature of PP (about 59 K). The average activation energy of PP, LDPE and WPs decreased with the participation of spent FCC catalyst compared with the direct pyrolysis. Among them, the activation energy of LDPE decreased most significantly (about 22 mass%), followed by PP, and WPs decreased the least. However, the results of thermogravimetric analysis and kinetic calculations showed that the spent FCC catalyst was not suitable for catalytic pyrolysis of PS. The purpose of this experiment is to promote "circular economy". The solid waste products produced by oil refining enterprises are applied to the catalytic pyrolysis of waste plastics, which provides theoretical support and data reference for reducing the energy consumption of plastic pyrolysis and realizing the diversified application of spent FCC catalysts. [ABSTRACT FROM AUTHOR]

Degradable polymers offer a promising solution to mitigate global plastic pollution, but the degraded products often suffer from diminished value. Upcycling is a more sustainable approach to upgrade polymer waste into value‐added products. Herein, we report a β‐selenocarbonyl‐containing polyurethane (SePU), which can be directly degraded under mild conditions into valuable selenium fertilizers for selenium‐rich vegetable cultivation globally, enabling both plastic degradation and waste upcycling. Under oxidation condition, this polymer can be easily and selectively degraded via selenoxide elimination reaction from mixed plastic waste. The degraded product can serve as effective selenium fertilizers to increase selenium content in radish and pak choi. The SePU exhibits excellent mechanical properties. Additionally, we observed the formation of spherulites‐like selenium particles within the materials during degradation for the first time. Our research offers a successful application of selenoxide elimination reaction in the field of plastic degradation for the first time, endowing plastics with both degradability and high reusable value. This strategy provides a promising solution to reduce pollution and improve economy and sustainability of plastics. [ABSTRACT FROM AUTHOR]

Degradable polymers offer a promising solution to mitigate global plastic pollution, but the degraded products often suffer from diminished value. Upcycling is a more sustainable approach to upgrade polymer waste into value‐added products. Herein, we report a β‐selenocarbonyl‐containing polyurethane (SePU), which can be directly degraded under mild conditions into valuable selenium fertilizers for selenium‐rich vegetable cultivation globally, enabling both plastic degradation and waste upcycling. Under oxidation condition, this polymer can be easily and selectively degraded via selenoxide elimination reaction from mixed plastic waste. The degraded product can serve as effective selenium fertilizers to increase selenium content in radish and pak choi. The SePU exhibits excellent mechanical properties. Additionally, we observed the formation of spherulites‐like selenium particles within the materials during degradation for the first time. Our research offers a successful application of selenoxide elimination reaction in the field of plastic degradation for the first time, endowing plastics with both degradability and high reusable value. This strategy provides a promising solution to reduce pollution and improve economy and sustainability of plastics. [ABSTRACT FROM AUTHOR]

Substantial quantities of discarded plastic have resulted in detrimental effects on the environment and ecosystems, calling for effective recycling of plastic wastes. Chemical methods for managing plastic wastes have been extensively studied, and selective recycling of products has grown in popularity. Pyrolysis, photocatalysis, and supercritical fluids were the main chemical methods reported for processing plastics. This article reviews reaction mechanisms and representative studies of pyrolysis, photocatalysis and supercritical fluid disposal of plastics. Three challenges are identified: first, high temperatures, above 400 °C, pose safety risks and potentially release harmful gases. Second, the photocatalytic decomposition of plastics is generally economical and environmentally friendly, however, reaction rates are uncontrollable. Third, the exceptional solubility and mass transfer properties exhibited by supercritical fluids have the potential to significantly augment the decomposition of plastics. Supercritical fluids can also serve as reactants that directly influence the thermal or kinetic mechanisms of the reaction. Whereas individual treatment methods are limited, coupled methods enable efficient plastic management and facilitate the selective acquisition of products. In particular, this review suggests that coupling photocatalysis and supercritical carbon dioxide should allow to dispose of plastics and convert carbon dioxide into valuable resources. [ABSTRACT FROM AUTHOR]

Escalating global population and expanding industrialisation have significantly contributed to an increased demand for plastics. Methods for plastic waste disposal predominantly involve landfilling, which consumes space and pollutes soil and water bodies, posing a substantial threat to the environment and public health. The critical challenge herein lies in efficiently managing the abundant biomass and plastics waste. Here we review gasification and pyrolysis, two prominent waste treatment processes. Co-pyrolysis of plastics and biomass exhibits a synergistic effect, significantly enhancing the yield and quality of bio-oil, biochar, and syngas. Integration of gasification and pyrolysis reduces activation energy, increases hydrogen production during co-gasification, and improves bio-oil calorific value. The gasification of polyethylene terephthalate with air in the presence of activated carbon limits tar formation with enhanced syngas production. Steam gasification enhances hydrogen generation by up to 40.0% compared to air gasification. Selective catalysts in the integrated pyrolysis–gasification process of biomass and plastics mixtures demonstrate optimisation of the production of high-purity carbon nanotubes and bio-oil. Application of innovative approaches such as microwaves, steam purging, and catalysts like zeolite or composite catalysts enhance heat transfer mechanism, tar cracking, and devolatilisation. [ABSTRACT FROM AUTHOR]

Plastics are widely used synthetic materials in various industries worldwide. The abundance of plastics, which are mainly carbon‐based polymers, has led to a significant accumulation of plastic waste in landfills and the environment due to their durability and affordability. Although plastic pollution of the oceans has been known for many years, there is still limited knowledge about the composition, distribution, impact, and fate of plastic waste in the environment. In this review, the focus is on environmental pollution by plastics, highlighting the source (feedstock) and degradation behavior of these materials. The goal is to provide insights for material design strategies that address the management of plastic waste at the end of its life cycle. The authors argue that the development of materials labeled marine biodegradable or universally biodegradable is not a sufficient solution on its own to address plastic pollution. Instead, it is critical to incorporate practical plans for recovery and treatment into material and product design principles. These plans should be based on existing systems or possibly developed in parallel. In summary, this article highlights the widespread pollution of the environment by plastics and emphasizes the need for comprehensive material design strategies that include not only biodegradability but also practical recovery and treatment methods. By considering the entire lifecycle of plastics, we can work to reduce the harmful impact of plastic waste on our planet. [ABSTRACT FROM AUTHOR]

Kinetic triplets—apparent activation energy (Ea), pre‐exponential factor (A), and the reaction model—were estimated for the thermal degradation of three primary virgin and waste plastics, as well as mixed plastics waste. Model‐free iso‐conversional FWO, KAS, Starink, Kissinger and Vyzovkin and Friedman methods were employed for the kinetic analysis. The apparent activation energy was determined by the integral methods as 206.5‐209.1 kJ mol−1 and 195.6‐198.8 kJ mol−1 for the virgin and waste high‐density polyethylene (HDPE), 211.6‐214.1 kJ mol−1 and 183.1‐186.6 kJ mol−1 for the virgin and waste polypropylene (PP), 144.0‐163.1 kJ mol−1 and 159.7‐167.1 kJ mol−1 for the virgin and waste polystyrene (PS), and 173.6‐178.9 kJ mol−1 for the mixed plastics waste respectively. Ea was found to follow the trend HDPE > PP > PS with higher values for HDPE and PP virgin samples than that for their waste and marginally smaller for the virgin PS than its waste. Degradation of all plastic samples followed Avrami‐Erofeev equation with n varying between 1.0 and 1.8. The effect of conversion on Ea suggested the degradation of both virgin and waste HDPE to consist of multiple parallel reactions while that of others to be more complex. FTIR analysis of the evolved gases was used to explain the possible reaction mechanism. A small difference between the enthalpy change and the apparent activation energy (6‐7 kJ mol−1) for all plastic samples indicated favourable pyrolysis reactions. The estimated kinetic parameters and thermodynamic properties showed the stability of different plastics as HDPE > PP > PS. [ABSTRACT FROM AUTHOR]

Plastic waste is globally ubiquitous and ecologically harmful, but it can be recycled as an abundant carbon source to alleviate worldwide heavy dependence on fossil resources and reduce CO2 emissions. Therefore, research into the chemical recycling of plastic waste has become a critical and pressing area. Compared with polyolefins, polyesters, as represented by PET and PLA, can easily achieve selective depolymerization to their corresponding monomers due to the presence of weaker ester bonds, thus favoring their closed-loop recycling and upcycling. However, comprehensive reviews on this important topic remain scarce, especially from the standpoint of re/upcycling. In this review, we present significant progress in the catalytic depolymerization of different polyesters, including biodegradable polyesters and nonbiodegradable polyesters, and discuss the key factors that limit the efficacies of the different methods and formidable challenges towards closed-loop recycling and upcycling. Such insightful discussion may benefit the further development of advanced strategies to address the problems with the increasing polyester plastic wastes and stimulate their efficient recycling to value-added chemicals and materials. [ABSTRACT FROM AUTHOR]

In 2021, global plastics production was 390.7 Mt; in 2022, it was 400.3 Mt, showing an increase of 2.4%, and this rising tendency will increase yearly. Of this data, less than 2% correspond to bio-based plastics. Currently, polymers, including elastomers, are non-recyclable and come from non-renewable sources. Additionally, most elastomers are thermosets, making them complex to recycle and reuse. It takes hundreds to thousands of years to decompose or biodegrade, contributing to plastic waste accumulation, nano and microplastic formation, and environmental pollution. Due to this, the synthesis of elastomers from natural and renewable resources has attracted the attention of researchers and industries. In this review paper, new methods and strategies are proposed for the preparation of bio-based elastomers. The main goals are the advances and improvements in the synthesis, properties, and applications of bio-based elastomers from natural and industrial rubbers, polyurethanes, polyesters, and polyethers, and an approach to their circular economy and sustainability. Olefin metathesis is proposed as a novel and sustainable method for the synthesis of bio-based elastomers, which allows for the depolymerization or degradation of rubbers with the use of essential oils, terpenes, fatty acids, and fatty alcohols from natural resources such as chain transfer agents (CTA) or donors of the terminal groups in the main chain, which allow for control of the molecular weights and functional groups, obtaining new compounds, oligomers, and bio-based elastomers with an added value for the application of new polymers and materials. This tendency contributes to the development of bio-based elastomers that can reduce carbon emissions, avoid cross-contamination from fossil fuels, and obtain a greener material with biodegradable and/or compostable behavior. [ABSTRACT FROM AUTHOR]

Huge amounts of plastic products are produced, utilized, and discarded each year, contributing to the increasingly serious ecological problem. Photoreforming, a solar-driven technology, provides an uncomplicated route to simultaneously recycle plastics and facilitate hydrogen (H 2) production. Herein, we proposed innovative CdS/NiS composites which used visible light to drive H 2 evolution from plastic wastes. Results confirmed that the loading of NiS on CdS could facilitate the transmission of photoexcited electrons, which greatly improved the photocatalytic performance. The H 2 production capability of CdS/NiS was more than 6 times higher than that of pure CdS, and the highest H 2 yield reached 62.9 mmol g−1 h−1 under optimized conditions when polylactic acid (PLA) was treated. Typical polyester plastics, including polyethylene terephthalate (PET), polybutylene adipate (PBA), polybutylene terephthalate (PBT), and poly (butyleneadipate-co-terephthalate) (PBAT), as well as raw PLA drink straws, were also successfully employed as the hole scavenger to enhance H 2 generation. This system utilized abundant resources (solar energy and waste plastics) and worked under mild conditions, proffering a sustainable approach for H 2 synthesis together with waste plastic pollutant reduction for a carbon-neutral future. [Display omitted] • CdS/NiS composite photocatalyst was used for visible-light-driven H 2 generation. • Various polyester plastics were employed as feedstocks to produce H 2 and organics. • The highest H 2 yield reached 62.9 mmol g−1 h−1 when polylactic acid was used. • The hydroxyl-containing monomers worked as hole scavengers in the reaction process. • The reaction mechanism of waste plastics photo-reforming over CdS/NiS was proposed. [ABSTRACT FROM AUTHOR]

The flexibility and the low production costs offered by plastics have made them crucial to society. Unfortunately, due to their resistance to biological degradation, plastics remain in the environment for an extended period of time, posing a growing risk to life on earth. Synthetic treatments of plastic waste damage the environment and may cause damage to human health. Bacterial and fungal isolates have been reported to degrade plastic polymers in a logistic safe approach with the help of their microbial cell enzymes. Recently, the bacterial strain Ideonella sakaiensis (201-F6) was discovered to break down and assimilate polyethylene terephthalate (PET) plastic via metabolic processes at 30 °C to 37 °C. PETase and MHETase enzymes help the bacterium to accomplish such tremendous action at lower temperatures than previously discovered enzymes. In addition to functioning at low temperatures, the noble bacterium's enzymes have amazing qualities over pH and PET plastic degradation, including a shorter period of degradation. It has been proven that using the enzyme PETase, this bacterium hydrolyzes the ester linkages of PET plastic, resulting in production of terephthalic acid (TPA), nontoxic compound and mono-2-hydroxyethyl (MHET), along with further depolymerization of MHET to release ethylene glycogen (EG) and terephthalic acid (TPA) by the second enzyme MHETase. Enzymatic plastic degradation has been proposed as an environmentally friendly and long-term solution to plastic waste in the environment. As a result, this review focuses on the enzymes involved in hydrolyzing PET plastic polymers, as well as some of the other microorganisms involved in plastic degradation. [ABSTRACT FROM AUTHOR]

In recent years, the pyrolysis technique has been adopted for converting non-degradable materials into biofuels and the yields of this process, oil and gas can be substituted as a fuel in CI engine. In this study, the medical waste plastics such as masks, gloves, personal protective equipment (PPE) kit and other plastics associated with hospitals were seen as the feedstock material for the pyrolysis process. It is collected from Government Medical College Hospital Villupuram, Tamil Nadu, India. The proximate and ultimate characterization of these wastes shows the percentage of volatile matter in the mask, gloves, and PPE kit are 81.2%, 79.3%, and 79.6%, respectively, and carbon percentage lies in the range of 75% to 78%, which ensures that the feedstock can be used in this process. The pyrolysis technique is carried out separately for all the collected feedstock such as mask, glove and other PPE kits. In this research, the mask waste showed a higher pyrolytic oil yield rate and is 80.3 wt% at 350°C than other plastics wastes. Further, FTIR of all the plastic waste confirms that pyrolytic oil is in acidic nature and it contains carboxylic acids and other heavier compounds, which are unstable in nature. To improve the fuel characteristics of pyrolytic oil, blending it with diesel requires the utilization of surfactants such as Span 80, Tween 60 and Atlox 4916. In this analysis, 5% of surfactant is mixed with 15% of pyrolytic oil and 80% of diesel. Among the various surfactants Atlox 4916, shows better fuel properties than other pyrolytic oil of plastic waste used in the analysis. Emulsifier fuel blend is prepared from different pyrolytic oils such as masks, gloves and PPE kit with Atlox 4916 surfactant, and MA, GA and PA, respectively. However, the pyrolytic oil from mask with Atlox 4916 surfactant blend has a (42.26 MJ/kg) higher calorific value. The evaluation of performance and emissions is conducted for the test fuels with surfactants derived from mask (MA), gloves (GA) and PPE (PA). Among these blends, MA showed better results in performance and emission behavior. The BTE of MA is 28.4%, which is 4.69% lower diesel and it is 2.077% and 2.95% higher than blend GA and PA. Blend MA shows lower emissions than other blends. [ABSTRACT FROM AUTHOR]

Plastic substrates introduced to the environment during the Anthropocene have introduced new pathways for microbial selection and dispersal. Some plastic‐colonising microorganisms have adapted phenotypes for plastic degradation (selection), while the spatial transport (dispersal) potential of plastic colonisers remains controlled by polymer‐specific density, hydrography and currents. Plastic‐degrading enzyme abundances have recently been correlated with concentrations of plastic debris in open ocean environments, making it critical to better understand colonisation of hydrocarbon degraders with plastic degradation potential in urbanised watersheds where plastic pollution often originates. We found that microbial colonisation by reputed hydrocarbon degraders on microplastics (MPs) correlated with a spatial contaminant gradient (New York City/Long Island waterways), polymer types, temporal scales, microbial domains and putative cell activity (DNA vs. RNA). Hydrocarbon‐degrading taxa enriched on polyethylene and polyvinyl chloride substrates relative to other polymers and were more commonly recovered in samples proximal to New York City. These differences in MP colonisation could indicate phenotypic adaptation processes resulting from increased exposure to urban plastic runoff as well as differences in carbon bioavailability across polymer types. Shifts in MP community potential across urban coastal contaminant gradients and polymer types improve our understanding of environmental plastic discharge impacts toward biogeochemical cycling across the global ocean. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu(II)/PMS system was first applied to the upcycling of PP waste plastics. • Efficient PP conversion and selective production of ketone fuels were achieved. • Mechanism of PP oxidation by •OH-dominant active species was explored. • PP was oxidized to hydrocarbons and further converted to ketone fuels. Currently, the environmental and ecological risks associated with plastics are escalating. Conventional thermo-catalytic systems driven under harsh conditions lead to more carbon emissions. Herein, we first developed a Fenton-like system mediated by Cu(II)-activated peroxymonosulfate (PMS) for efficient conversion of polypropylene (PP) to ketone fuels (77.2 wt% conversion, 78.5 wt% selectivity) at 140 °C for 24 h. Cu(II) synergistic thermal activation achieved efficient PMS activation to produce radicals such as •OH, SO 4 •− and O 2 •−as well as 1O 2 and Cu(III). In the presence of •OH-dominated active species, PP was cleaved to hydrocarbons with the breaking of C-C bonds, and further oxidation of C-H bonds converted hydrocarbons to ketone fuels. This study enabled the conversion of plastics to chemicals under mild conditions, a significant step towards the establishment of an efficient recycling system for plastics recovery, leading to zero plastic waste and a carbon–neutral environment. [ABSTRACT FROM AUTHOR]

• Silica alumina (Kaolin) catalyst enhances pyrolysis oil yield by 4.4% instead of gas yield reduction. • The optimum temp. for LDPE catalytic(Kaolin) pyrolysis is 520 °C lower than 560 °C at sand pyrolysis. • Light oil fractions increased to 11.9% (2.58 time more) over kaolin LDPE pyrolysis in FB reactor. • Kaolin has the potential to serve as a reliable substitute for sand. Low-density polyethylene (LDPE) is the second most prevalent waste plastic globally, followed by polypropylene. The pyrolytic conditions required to obtain light oil(≤C12) from LDPE are more stringent than those for polypropylene, water plastics, acrylonitrile, butadiene, styrene, and other materials. Consequently, numerous researchers have underscored the necessity of employing catalysts in LDPE pyrolysis. This study explored the pyrolysis characteristics of LDPE at various temperatures in a non-catalytic fluidized bed reactor. The experiments employed a mixture of sand + kaolin, one of the Si-Al catalysts, to investigate the pyrolysis of LDPE in a fluidized bed reactor at different temperatures. The findings demonstrated that using sand + kaolin as a fluidized bed material significantly enhances the yield of pyrolysis oil while concurrently reducing the gas yield compared to using sand alone. Moreover, a higher light oil fraction was obtained using kaolin (16.67 wt%) at 560 °C compared with 8.6 wt%. In addition, the study revealed that elevated temperatures (520 °C, 560 °C, and 600 °C) led to a reduction in olefins and paraffin, coupled with an increase in the formation of naphthenes, aromatics, and ketones in the pyrolysis oil. Overall, the findings underscore the promising potential of kaolin as an alternative to sand, facilitating the enhanced production of valuable light oil fractions. The insights garnered from this study are invaluable for devising effective waste management strategies. [ABSTRACT FROM AUTHOR]

To solve the long-term environmental pollution caused by black liquor and waste plastics, and achieve high-value utilization, the method about co-pyrolysis of black liquid solid and waste plastics (Polypropylene, Polyethylene) catalyzed by Mo-Ni/HZSM-5 to prepare high-quality bio-oil is studied. The results found that hydrocarbons increased from 14.92% to 42.03% as Polyethylene was co-pyrolyzed with BLS, and hydrocarbons increased from 14.92% to 41.75% as Polypropylene was co-pyrolyzed with BLS, adding plastics can significantly improve the hydrocarbons yield of black liquor. Mo-Ni/HZSM-5 acts as a hydro deoxidizer in the pyrolysis of black liquid and waste plastics, the total hydrocarbons of black liquid solid, black liquid solid& Polypropylene, black liquid solid & Polyethylene increased by 6%, 78%, and 45%, respectively. An appropriate increase of pyrolysis temperature can promote the co-pyrolysis of BLS with PP, and BLS with PE, and can increase the yield of hydrocarbons. Compared with black liquor's pyrolysis, the yield of hydrocarbons can be increased by 59.65% and 24.52% as Polyethylene or Polypropylene is adapted to pyrolysis with black liquid solid, respectively, the high-quality bio-oil is obtained because of a large number of hydrocarbons and high hydrogen content. • Ni-Mo/HZSM-5 catalyst promoted the hydrodeoxygenation of oxygenated groups in black liquor. • Addition of waste plastics improves the Hydrocarbons contents of bio-oil significantly. • Co-pyrolysis of PP with BLS produces bio-oil with higher hydrocarbon content than PE with BLS. [ABSTRACT FROM AUTHOR]

Machine learning (ML) is a subtype of artificial intelligence that uses a computer's ability to learn from a given set of accessible data. ML is becoming prominent in almost every business, including the domain of chemical engineering, where there have been numerous researches and investigations. This article provides a detailed overview of the use of ML in the production and characterization study of biomass, polymers, and petroleum products. Categories of ML, including classification, regression, and clustering, are also investigated to get a deeper understanding of ML. From this review, it can be concluded that ML has aided in numerous domains, such as the prediction of biomass energy, the stability of crude oil based on NMR spectroscopy, the calculation of gasoline's octane number, the estimation of fuel oil's kinematic viscosity, the classification of waste plastics, and the estimation of drilling efficiency in petroleum reservoirs, among others. Apart from this, ML has also been playing a significant role in the microwave-assisted pyrolysis of biomass, polymers, and petroleum resources. ML substantially influences chemical engineering and is especially useful for enhancing system efficiency and monitoring processes that are difficult to understand manually. Although several obstacles are associated with ML, such as black box behavior, the need for a large amount of data, and the difficulty of understanding the predictions, deploying the model in the future is uncomplicated once the learning program has been trained. • Role of machine learning in modeling is explained. • Different types of machine learning algorithms compared. • Role of plastics, biomass, and petroleum resources in the energy domain is discussed. • Applications of machine learning in the microwave-assisted pyrolysis of biomass are explained. • Implementations of machine learning in biomass and plastic valorization are discussed. [ABSTRACT FROM AUTHOR]

Researchers from BASF Corp, the University of Georgia, and the University of California, San Diego have developed a method to make biodegradable plastic using bacteria. The team evolved bacteria to withstand the high temperatures of the manufacturing process, allowing them to survive in metabolically dormant spores. The resulting bacteria-incorporated plastic degrades faster than typical plastic, with about 90% of it degrading within five months. This development could provide a solution to the problem of plastic pollution in the environment. [Extracted from the article]

[Display omitted] • The post-consumer HDPE, LDPE and PP were subjected to pyrolysis. • Pyrolysis oil was hydroprocessed using a Pt/SO 4 /ZrO 2 catalyst to produce diesel. • Blending hydroprocessed fuel with heavy fuel oil yielded a low-carbon marine fuel. • Blended Marine Fuel Oil (BMFO) enhances performance and lowers marine pollution. Marine transport accounts for ninety percent of the world's cargo movement. Residual fuels power the diesel engines of ships, which are predominantly composed of heavy molecular hydrocarbon compounds. To produce a fuel with less carbon emissions, this investigation is the first to convert waste plastics into diesel and then blend it further with HFO. This study utilized gas chromatography and mass spectrometry to explore the chemical composition of heavy oil. The high carbon content of heavy oil motivated us to explore the options of blending the low carbon number fuel obtained from waste plastics. To create a diesel equivalent, the waste polymers, which included PP, LDPE, and HDPE, were pyrolyzed and hydroprocessed using platinum sulphate on zirconia oxide supports. The produced blended fuel's alkane concentration matched diesel by 91%. The carbon number ranges C11–C15 and C16–C20 had n-alkane contents that were, respectively, 28% and 11% less than diesel. However, as would be predicted from combining heavy fuel oil, the n-alkanes with carbon number of C21–C25 were significantly greater. Compared to diesel, the blended fuel had 11% less isoalkanes. The blending of hydroprocessed fuel and commercial heavy fuel oil produced low carbon fuel which can be utilized for powering ships. The alternative fuel will produce far fewer emissions, making it an optional replacement to help the maritime industry meet its carbon emission reduction goals. [ABSTRACT FROM AUTHOR]

Poly(ethylene furanoate) (PEF) plastic is a 100% renewable polyester that is currently being pursued for commercialization as the next-generation bio-based plastic. This is in line with growing demand for circular bioeconomy and new plastics economy that is aimed at minimizing plastic waste mismanagement and lowering carbon footprint of plastics. However, the current catalytic route for the synthesis of PEF is impeded with technical challenges including high cost of pretreatment and catalyst refurbishment. On the other hand, the semi-biosynthetic route of PEF plastic production is of increased biotechnological interest. In particular, the PEF monomers (Furan dicarboxylic acid and ethylene glycol) can be synthesized via microbial-based biorefinery and purified for subsequent catalyst-mediated polycondensation into PEF. Several bioengineering and bioprocessing issues such as efficient substrate utilization and pathway optimization need to be addressed prior to establishing industrial-scale production of the monomers. This review highlights current advances in semi-biosynthetic production of PEF monomers using consolidated waste biorefinery strategies, with an emphasis on the employment of omics-driven systems biology approaches in enzyme discovery and pathway construction. The roles of microbial protein transporters will be discussed, especially in terms of improving substrate uptake and utilization from lignocellulosic biomass, as well as from depolymerized plastic waste as potential bio-feedstock. The employment of artificial bioengineered microbial consortia will also be highlighted to provide streamlined systems and synthetic biology strategies for bio-based PEF monomer production using both plant biomass and plastic-derived substrates, which are important for circular and new plastics economy advances. • A comprehensive discussion on recent advances for semi-biosynthesis of bio-PEF. • Streamlined PEF biorefinery with microbial systems and synthetic biology approach. • A concise assessment of omics-driven pathway elucidation for FDCA production. • An up-to-date review of transporter proteins for improved substrate assimilation. • A new insight on artificial consortium strategy for PEF-based biorefinery. [ABSTRACT FROM AUTHOR]

[Display omitted] • PLA/PBAT underwent modification through covalent bonding with enzymes. • The anaerobic co-digestion performance of the modified biodegradable plastic with food waste was assessed and examined. • The degradation of enzyme modified biodegradable plastic could increase from 5.21% to 29.70% compare to unmodified plastic. • The hydrolysis process was enhanced by the presence of highly active Bacteroidota and Thermotogota. A modified biodegradable plastic (PLA/PBAT) was developed by through covalent bonding with proteinase K, porcine pancreatic lipase, or amylase, and was then investigated in anaerobic co-digestion mixed with food waste. Fluorescence microscope validated that enzymes could remain stable in modified the plastic, even after co-digestion. The results of thermophilic anaerobic co-digestion showed that, degradation of the plastic modified with Proteinase K increased from 5.21 ± 0.63 % to 29.70 ± 1.86 % within 30 days compare to blank. Additionally, it was observed that the cumulative methane production increased from 240.9 ± 0.5 to 265.4 ± 1.8 mL/gVS, and the methane production cycle was shortened from 24 to 20 days. Interestingly, the kinetic model suggested that the modified the plastic promoted the overall hydrolysis progression of anaerobic co-digestion, possibly as a result of the enhanced activities of Bacteroidota and Thermotogota. In conclusion, under anaerobic co-digestion, the modified the plastic not only achieved effective degradation but also facilitated the co-digestion process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microwave pyrolysis treated polyethylene terephthalate and low-density polypropylene simultaneously. • Coconut husk carbon showed favorable process features and product features as microwave absorbent. • This process enhances the synergistic production of monocyclic aromatics. • High yields of oil (42.50 wt%) were obtained with a high content of monocyclic aromatics (77.11 %). The application of biochar as microwave absorbers in microwave-assisted catalytic fast pyrolysis (MACFP) has been widely studied. It has been reported that coconut husk carbon (CHC) showed good process characteristics and product distribution as microwave absorbers. However, the existing studies did not pay much attention to the reusability of CHC absorbers. In this study, the CHC absorbers prepared from agricultural and forestry wastes were reused in multiple cycles in the MACFP of polyethylene terephthalate (PET) and low-density polyethylene (LDPE). Compared with typical microwave absorbers such as spherical silicon carbide (SiC) and granular activated carbon (GAC), CHC demonstrated favorable process characteristics with relatively high heating rate (29 °C/min) and short heating time (within 12 min). In terms of product properties, the highest liquid yield of 51.67 wt% and the highest content of monocyclic aromatic hydrocarbons (MAHs) of 82.82 % were obtained at the appropriate pyrolysis temperature (550 °C). After five consecutive uses, the CHC bed still produced comparable heating profiles and product distributions, compared to that of SiC. At the same time, a positive synergistic effect between PET and LDPE was observed. The co-feeding of PET and LDPE (50L50P) appropriately increased the liquid yield (42.50 wt% vs 38.75 wt%) and the relative content of MAHs (77.11 % vs 72.96 %) in comparison to their theoretical value. Finally, this study supplies a new strategy for utilizing recycled CHC as a microwave absorber for the treatment of hydrogen-rich and hydrogen-deficient mixed plastic wastes to produce MAHs products, which also reduces waste and realizes energy conversion. [ABSTRACT FROM AUTHOR]

Microplastics and nanoplastics are ubiquitous in rivers and undergo environmental aging. However, the molecular mechanisms of plastic aging and the in-depth effects of aging on ecological functions remain unclear in waters. The synergies of microplastics and nanoplastics (polystyrene as an example) with natural organic small molecules (e.g., natural hyaluronic acid and vitamin C related to biological tissue decomposition) are the key to producing radicals (•OH and •C). The radicals promote the formation of bubbles on plastic surfaces and generate derivatives of plastics such as monomer and dimer styrene. Nanoplastics are easier to age than microplastics. Pristine plastics inhibit the microbial Shannon diversity index and evenness, but the opposite results are observed for aging plastics. Pristine plastics curb pectin decomposition (an indicator of plant-originated refractory carbon), but aging plastics promote pectin decomposition. Microplastics and nanoplastics undergoing aging processes enhance the carbon biogeochemical cycle. For example, the increased carbohydrate active enzyme diversity, especially the related glycoside hydrolase and functional species Pseudomonas and Clostridium , contributes to refractory carbon decomposition. Different from the well-studied toxicity and aging of plastic pollutants, this study connects plastic pollutants with biological tissue decomposition, biodiversity and climate change together in rivers. [Display omitted] • Natural organic small molecules promote plastic aging. • Nanoplastics are easier to age than microplastics. • Aging plastics promote refractory carbon decomposition. • Aging plastics promote the carbon cycle in waters. • Carbohydrate active enzyme (CAZyme) diversity is boosted. [ABSTRACT FROM AUTHOR]

The traditional reliance on plastic as the principal packaging material for food poses important problems in the context of promoting sustainable development objectives, particularly SDG-12, which focuses on responsible consumption and production. Despite its cost-effectiveness and durability, research suggests that the non-biodegradable nature of plastic, stemming from robust carbon bonds in condensation polymerization and the use of terephthalic acid and ethylene glycol in polyethylene terephthalate production, contributes to plastic debris accumulation in ecosystems, harming wildlife. Utilizing animal byproducts, like feathers, feet, skin, bones, cartilage, and tendons, rich in proteins such as whey, keratin, and gelatin, offers potential for creating sustainable packaging films. This study assesses not just the environmental impact of plastic but also aligns with broader objectives like responsible consumption, production, and the promotion of a circular economy. This review investigates the distinct properties such as transparency, tensile strength, water/gas barrier properties, low cost, biodegradability and low toxicity, etc of waste proteins produced from animal industry wastes. These proteins, possessing essential functional groups and amide linkages, efficiently interact with various composites. Furthermore, they exhibit notable characteristics such as antioxidant and antibacterial activity, transparency, and exceptional physical and mechanical capabilities. The investigation highlights the films' potential to serve as a viable replacement for petroleum-based plastics, adding to the overarching objective of responsible use and production. This review supports the feasibility of composite materials with properties like transparency, tensile strength, antibacterial, and antioxidant features, akin to traditional plastic films. By using cost-effective organic waste proteins, these films offer an environmentally friendly substitute for petroleum-based plastics. The transformative potential lies in utilizing affordable organic waste proteins for eco-friendly packaging films, replacing conventional plastics, and endorsing sustainable alternatives aligned with responsible consumption and production practices. Challenges include raw material compatibility, strength attainment, source variability, and energy-intensive protein purification. Future studies are vital to refining purification techniques and ensuring economic viability. Embracing sustainable packaging enhances well-being and environmental health, aligning with responsible consumption. • Waste from animal industries could be a cost-effective approach for manufacturers. • High strength and antibacterial properties enhanced with specific filler inclusion. • Replacement of petroleum-based plastics with organic protein from different sources. • Suitable for conventional food packaging with high biodegradability after use. • Inconsequential concerns about migration and toxicity and environmental impact. [ABSTRACT FROM AUTHOR]