Plastic Life Cycle Research Articles

Plastic Recycling: A Review on Life Cycle, Methods, Misconceptions, and Techno‐Economic Analysis

AbstractPlastics are embedded in every inch of the fabric of the society. Although they have played a tremendous role in the progress and development of mankind, they have done equal, if not more, harm to the environment, human health, and marine life. Omnipresence of plastics can be attributed to their low‐cost and scalable production that no other material has yet achieved. Once produced, they are used in almost every mundane as well as niche application. But the equation of its use to disposal is not sustainable and humungous quantities of plastic waste are generated each year. In this review article, the very problem of plastic recycling is explored and analyzed. The life cycle of plastics is explained to depict the vastness and peculiar problems associated with it. Various misconceptions are discussed on plastic use and recycling. False presumptions are challenged to show where efforts to solve this huge problem and need to be directed. Lastly, quantitative efficiency and economic analysis of the available recycling methods are shown to compare their feasibility and indicate potential development direction. Such analyses are very important for the societal transition to a sustainable economy that economically recycles most of its plastic at a commercial scale.

Exploring expert perceptions about microplastics: from sources to potential solutions

Concern about plastic pollution, including microplastics, is high amongst European citizens, and effective actions are needed to reduce microplastic pollution. However, there is still uncertainty and debate about the major sources, impacts, and in particular the solutions. The aim of the current study was to gather expert perceptions about the risks of different microplastic sources to the natural environment and human health (measured as the likelihood and severity of negative impacts resulting from exposure), as well as the feasibility and effectiveness of different solutions. Experts were identified as scientists working on plastic. Usable responses were received from 73 experts with an average of 5 years’ experience in plastic research. Experts thought that there was currently stronger evidence for microplastic impacts on the natural environment than on human health, that, accordingly, the risks were higher, and they were more worried about impacts on the natural environment than on human health. Experts perceived tyre particles and textile fibres to be the main sources of microplastics presenting risk for both natural environment and human health. Various solutions were rated as relatively effective and feasible overall. Solutions that were rated as above-average in terms of effectiveness and feasibility included education and awareness programmes, washing machine filters, bans of plastic items, simplified design of products, and circular economy approaches. However, experts were uncertain about the effectiveness and feasibility of recovery and clean-up solutions, with overall ratings for these being below-average in comparison to other solutions earlier in the plastic life cycle. An improved understanding of expert views on these matters could inform the distribution of limited research resources and help prioritise research questions, especially with regard to potential solutions and interventions which will be critical for the success of the UN Plastics Treaty.

Barriers to recycling plastics from the perspectives of industry stakeholders: a qualitative study

ABSTRACT Previous research exploring the psychological, social, and environmental barriers to recycling has predominantly focused on consumer attitude and behaviour. However, the plastic system involves a chain of stakeholders with a role in decision-making and actions in relation to plastic production and management post-use, affirming the need to explore the barriers to recycle across various other stakeholders implicated in the lifecycle of plastic product and packaging. To expand this evidence-base, N = 12 in-depth qualitative semi-structured interviews explored the perspectives of some of the stakeholders responsible for various aspects of the plastic life cycle (fast moving consumer goods industry, retailers, and waste management professionals). Using a semi-directed content analysis approach via NVivo, three overarching themes were extracted from the data: 1) Disempowerment and lost opportunities 2) Solutions and opportunities reside with use of legislation 3) The circular economy stakeholders need motivation, and to be more knowledgeable. The themes suggest that stakeholders implicated in the plastic lifecycle lack the drive and perceived personal and organizational efficacy to generate meaningful change in the plastic system. These barriers are exacerbated by a lack of collegial partnerships between stakeholders to facilitate knowledge transfer and collective action. This study recommends greater collaboration and communication between stakeholders implicated in the end-to-end plastic “chain”, and makes a renewed call for further legislation, having shed light on important socio-political and pragmatic barriers to reducing plastic waste.

In-situ and real-time nano/microplastic coatings and dynamics in water using nano-DIHM: A novel capability for the plastic life cycle research

A novel nano-digital inline holographic microscope (nano-DIHM) was used to advance in-situ and real-time nano/microplastic physicochemical research, such as particle coatings and dynamic processes in water. Nano-DIHM data provided evidence of distinct coating patterns on nano/microplastic particles by oleic acid, magnetite, and phytoplankton, representing organic, inorganic, and biological coatings widely present in the natural surroundings. A high-resolution scanning transmission electron microscopy confirmed nano-DIHM data, demonstrating its nano/microplastic research capabilities. The sedimentation of two plastic size categories was examined: (a) ∼10 to 700 µm, and (b) ∼ 1 to 5 mm. Particle size was the primary factor affecting the sedimentation for studied (a) microplastics and (b) pellets. Two types of silicone rubbers exhibited different sedimentation processes. We also demonstrated that inorganic ions in seawater and oleic acid organic coatings altered the sedimentation velocity of studied plastics by 9 – 13% and 5 – 9%, respectively. Semi-empirical probability functions were developed and incorporated into a numerical model (CaMPSim-3D) to simulate the transport of studied microplastics and pellets in the Saint John River estuary. Water dynamics was the driving force of plastic transport, yet the accumulation of plastics was selectively dependant on particle physicochemical properties such as size and density by ∼ 7%. The usage of nano-DIHM for targeted identification of nano/microplastic hotspots and aquatic plastic wastes remediation were discussed.

Systematizing Microbial Bioplastic Production for Developing Sustainable Bioeconomy: Metabolic Nexus Modeling, Economic and Environmental Technologies Assessment.

The excessive usage of non-renewable resources to produce plastic commodities has incongruously influenced the environment's health. Especially in the times of COVID-19, the need for plastic-based health products has increased predominantly. Given the rise in global warming and greenhouse gas emissions, the lifecycle of plastic has been established to contribute to it significantly. Bioplastics such as polyhydroxy alkanoates, polylactic acid, etc. derived from renewable energy origin have been a magnificent alternative to conventional plastics and reconnoitered exclusively for combating the environmental footprint of petrochemical plastic. However, the economically reasonable and environmentally friendly procedure of microbial bioplastic production has been a hard nut to crack due to less scouted and inefficient process optimization and downstream processing methodologies. Thereby, meticulous employment of computational tools such as genome-scale metabolic modeling and flux balance analysis has been practiced in recent times to understand the effect of genomic and environmental perturbations on the phenotype of the microorganism. In-silico results not only aid us in determining the biorefinery abilities of the model microorganism but also curb our reliance on equipment, raw materials, and capital investment for optimizing the best conditions. Additionally, to accomplish sustainable large-scale production of microbial bioplastic in a circular bioeconomy, extraction, and refinement of bioplastic needs to be investigated extensively by practicing techno-economic analysis and life cycle assessment. This review put forth state-of-the-art know-how on the proficiency of these computational techniques in laying the foundation of an efficient bioplastic manufacturing blueprint, chiefly focusing on microbial polyhydroxy alkanoates (PHA) production and its efficacy in outplacing fossil based plastic products.

Hangprinter for large scale additive manufacturing using fused particle fabrication with recycled plastic and continuous feeding

The life cycle of plastic is a key source of carbon emissions. Yet, global plastics production has quadrupled in 40 years and only 9 % has been recycled. If these trends continue, carbon emissions from plastic wastes would reach 15 % of global carbon budgets by 2050. An approach to reducing plastic waste is to use distributed recycling for additive manufacturing (DRAM) where virgin plastic products are replaced by locally manufactured recycled plastic products that have no transportation-related carbon emissions. Unfortunately, the design of most 3-D printers forces an increase in the machine cost to expand for recycling plastic at scale. Recently, a fused granular fabrication (FGF)/fused particle fabrication (FPF) large-scale printer was demonstrated with a GigabotX extruder based on the open source cable driven Hangprinter concept. To further improve that system, here a lower-cost recyclebot direct waste plastic extruder is demonstrated and the full designs, assembly and operation are detailed. The <$1,700 machine’s accuracy and printing performance are quantified, and the printed parts mechanical strength is within the range of other systems. Along with support from the Hangprinter and DUET3 communities, open hardware developers have a rich ecosystem to modify in order to print directly from waste plastic for DRAM.

Assessment of carbon emission potential of polyvinyl chloride plastics

Plastic pollution has become a global concern, and research has shown that carbon emissions during the lifecycle of plastics are rapidly consuming global carbon credits. This study focuses on the effective assessment of carbon emissions from polyvinyl chloride (PVC) plastics using a life cycle assessment (LCA) method during the production and recycling stages. The greenhouse gas emission potential is evaluated using 1kg PVC plastic as a functional unit. Research has shown that the total carbon emissions during the production stage of PVC plastic are 7.83kg CO2-eq. The carbon emissions during the production stage of hydrochloric acid, acetylene, electricity, and water vapor are 2.340 kg CO2-eq, 4.900 kg CO2-eq, 0.117 kg CO2-eq, and 0.468 kg CO2-eq, respectively. During the recycling phase, the carbon emissions from the power consumption zone are 0.184 kg CO2-eq, followed by 0.156 kg CO2-eq from natural gas. Research has shown that fossil materials contribute the largest carbon emissions during the production stage of PVC plastics. Therefore, how to effectively reduce the use of fossil fuels or seek alternative raw materials can effectively reduce carbon emissions.

Pakistan toward Achieving Net-Zero Emissions: Policy and Roadmap

Pakistan generated 12.17 million tons (Mt) of plastic waste in 2020, reaching 22.04 Mt in 2050. Plastic production emits about 0.8 billion tons (Bt) of greenhouse gases (GHGs) in Pakistan. An increase in production will lead this amount to 1.46 Bt in 2050. The eco-indicator 95, BEES, and ReCiPe methods investigated the life cycle of petroleum-based and corn-based plastics. Through technology, policies, and strategies implementations, Pakistan can control white pollution and environmental hazards until 2043–2050 with the recycling rate (i.e., 28%). The defined policy roadmap for net-zero emissions will limit the GHGs to 1.66 Bt in 2050. These emissions can be reduced through life cycle assessment, policy decisions, implementation strategies, and technology utilization. Rapid and widespread changes in policy and investment across many sectors of society, participation, and commitment by government, industry, and individuals are needed. The baseline technologies require renewable energy for production and carbon capture, storage, and utilization technology to reduce emissions into the atmosphere. Policy roadmaps and literature studies concluded that net-zero emissions are possible with available technologies until 2043. Identified the critical technological and socio-economic goals that must be achieved for net-zero carbon emissions through near-term critical actions defined from 2020 to 2050.

A Raman spectral reference library of potential anthropogenic and biological ocean polymers

Microplastics have been extensively documented in marine ecosystems and food webs with devastating impacts. To solve this global crisis, identifying the polymer composition is key for resolving the material origin, geographic source, and ecosystem life cycle of ocean plastics. Visually based techniques, importantly, are not diagnostic. Raman spectroscopy is an increasingly preferred identification method for its accuracy and reduced likelihood of misinterpretation, though it can be inaccessible due to cost of paywalled spectral libraries and availability of relevant polymer spectra for comparison. Here, we provide an open-access reference library of high-quality, broad-spectrum Raman spectra of major polymer categories germane to marine environments. The library includes high-quality spectra from: (a) pristine anthropogenic polymers newly sourced from manufacturers (n = 40), (b) weathered anthropogenic polymers collected from used consumer, beachcast, agricultural, and fishery sources (n = 22), and (c) biological polymers representing diverse marine taxa, trophic levels, and tissues (n = 17). We hope this reference library can help this rapidly expanding scientific community and facilitate progress in the global plastic pollution crisis.

Life cycle assessment of plastic packaging recycling embedded with responsibility distribution as driver for environmental mitigation

Life cycle assessment modelling of multi-cycle recycling systems is challenging. There is still neither consensus on applying allocation approaches nor a one-size-fits-all solution. This study proposes an allocation approach embedded with the responsibility distribution of stakeholders rather than the standard approach, which is assessed based on stages. It is applied to the case study of plastic packaging recycling and compared to simple and economic allocation cut-off methods. A total of four multiple recycling or cascade utilisation scenarios are assessed, consisting of the linear system (disposal), mechanical recycling, waste to energy and chemical recycling, for at least one of the cycles. Scenario 2, with mechanical recycling as the end-of-life management in all three multiple cycles, has the lowest overall GHG emissions (∼4.8 t CO2eq/t plastic packaging) regardless of allocation method, even after considering deducted savings due to the degraded quality along the cycles. The simple cut-off method could not drive the selection in the first cycle toward the recycling alternatives (Scenario 2–4) with overall lower emissions as the GHG saving from utilising recycled resources are accounted for in the second cycle. Regarding eutrophication potential, as the burdening impact of disposal is significantly higher, recycling options accounted for following the simple cut-off method are preferable even when the burdening effect is entirely embraced by the first cycle without the unburdening accounting. Economic allocation cut-offs provide a better incentive to recycle in the assessed cycles. However, the standard accounting is by stages such as material production, product manufacturing, recycling and disposal. It is unclear whose responsibility, either the raw material producer (MP), the product manufacturer (PM) or the consumer (C). The proposed method with defined responsibility (e.g. 6.2 t CO2eq/t by MP; 2.9 t CO2eq/t by PM; 0.5 t CO2eq/t by C in Scenario 1) is more effective for environmental mitigation strategies (e.g. taxation and incentives, deposit refund scheme) of the plastic life cycle. The scenarios assessment serves as a stepping stone to optimise the allocation among the identified stakeholders in future work according to local conditions.

Valorization of Lignocellulose by Producing Polyhydroxyalkanoates under Circular Bioeconomy Premises: Facts and Challenges

In light of the current concerns about environmental issues caused by the excessive use of fossil resources, more emphasis has been paid to the transition to a sustainable and circular economy. Bioplastics as eco-friendly products originating from biomass wastes have gained much attention to solve the problem of plastic pollution. Among them, polyhydroxyalkanoates (PHAs) are microbial polyesters produced using various feedstocks─renewable or recycled waste materials─contributing to a more sustainable commercial plastic life cycle by being a part of a circular bioeconomy. However, the scale-up of the PHA process cost effectively and sustainably remains challenging for large-scale industrial applications. This perspective provides a comprehensive overview of the current insights into lignocellulosic biomass’s role in achieving a circular bioeconomy. Emerging greener biomass conversion technologies are discussed to characterize energy demand, cost, and sustainability within biorefinery PHA production. In addition, recent advances in synthetic biology and fermentation processes for PHA production are discussed. Technological challenges, i.e., bioreactor setup, downstream operation, and inconsistent properties to improve the sustainable production of PHAs and to help transfer this technology to real-world applications, are also addressed.

Trade Flow Optimization Model for Plastic Pollution Reduction

Managing plastic waste from an international perspective is complex, with many countries in the trade network playing distinct roles at different stages of the life-cycle of plastics. Trade flows are therefore the key to understanding global plastic market and its supply chains. In this paper, we formulate an optimization problem from the perspective of reducing global ocean plastic pollution, and create a novel framework based on a network flow model to identify the optimal international trade flows over the life-cycle of plastics. Our model quantifies global flows of production, consumption, and trade across the life-cycle of plastics from raw inputs and subsequent plastic products to its final stage as waste. Using panel data on plastic consumption, waste, and production, we compare the trade flows in reality and the optimal trade flows determined by our model and find that the two are highly correlated. We highlight the policy implications based on our model: increasing trade capacity and improving recycle rates in developing countries.

Integrating a Chemicals Perspective into the Global Plastic Treaty.

Driven by the growing concern about plastic pollution, countries have agreed to establish a global plastic treaty addressing the full life cycle of plastics. However, while plastics are complex materials consisting of mixtures of chemicals such as additives, processing aids, and nonintentionally added substances, it is at risk that the chemical aspects of plastics may be overlooked in the forthcoming treaty. This is highly concerning because a large variety of over 10,000 chemical substances may have been used in plastic production, and many of them are known to be hazardous to human health and the environment. In this Global Perspective, we further highlight an additional, generally overlooked, but critical aspect that many chemicals in plastics hamper the technological solutions envisioned to solve some of the major plastic issues: mechanical recycling, waste-to-energy, chemical recycling, biobased plastics, biodegradable plastics, and durable plastics. Building on existing success stories, we outline three concrete recommendations on how the chemical aspects can be integrated into the global plastic treaty to ensure its effectiveness: (1) reducing the complexity of chemicals in plastics, (2) ensuring the transparency of chemicals in plastics, and (3) aligning the right incentives for a systematic transition.

Are sediment textural parameters an "influencer" of microplastics presence in beach environments?

Diverse litter studies on Colombia's Central Caribbean Coast have presented the Microplastic issues regarding typology, magnitudes, and distribution. No studies have examined MPs' presence and abundances in relation to sediment grain size and the sediments statistical parameters (mean, median, sorting, skewness, kurtosis). This work attempts to fill this information gap in a study of 15 sampling sites along Colombia's Central Caribbean Coast. Sediment samples were collected and analysed to determine sediment granulometric properties, in association with the presence, magnitudes, shapes, and impact of MPs, and their possible relationships. Within the study area, grain size distribution was similar between surveyed sites, with a dominance of three textural groups: sands, slightly gravelly sands, and slightly gravelly muddy sands. In terms of size-sorting categories, the percentages were moderately well sorted (60%), moderately sorted (20%), well sorted (13%), and very well sorted (7%). Microplastic abundances (densities) ranged from 160 to 1120 MPs/kg, similar to other global beaches. Microplastic fibers were the dominant typology at 86.8% of the combined beaches total. Multiple linear regression analysis suggested that approximately 30% of the MPs' presence could be related to changes in the five sediment statistics used in this work, being the most important statistical parameter sorting with 11% (r2=0.27 - F-Statistic=0.67). To manage the MP issue, reducing the current elevated plastic inputs into the environment is necessary/mandatory. Approaches to reach this goal must be focused on the entire plastic life cycle (extraction, design, production, use, disposal, recovery, recycling).

Challenges in marine plastic pollution regulation in Indonesia

Indonesia has ratified a number of international instruments related to marine plastic pollution (MPP); however, these international instruments are dependent on national and local regulations for effect. This study highlights challenges in MPP Regulations in Indonesia, grouped as regulation complexities, and technical challenges. Regulation complexities in MPP in Indonesia include the fact that laws do not specifically regulate MPP, and lack details on plastic pollution and MPP; that local governments do not have direct authority to managing their marine environments, and do not prioritize MPP in their activities; and that the current laws and regulations focus more on land-based waste management. This study shows that the current national laws in relation to MPP issues are fragmented and do not directly regulate MPP, except for the Presidential Decree no 82 of 2018 on Marine Waste Management, and there are only a few MPP-related laws at the local levels, for example in Jakarta and Surabaya. Both Jakarta and Surabaya have high levels of MPP, yet neither has adequate laws to prevent and manage it. Technical challenges include a lack of data on the life cycle of plastics (from manufacturing to waste management, including collection, recycling and disposal); gaps in monitoring and knowledge on MPP; lack of access to financial resources and technology; ineffective management of plastic waste; and lack of engagement with relevant industries and other stakeholders in general. Efforts from the government and related stakeholders are needed to prioritize regulating MPP in Indonesia.

Factors Affecting Mechanical Properties of Reinforced Bioplastics: A Review.

The short life cycle and recalcitrant nature of petroleum-based plastics have been associated with plastic waste accumulation due to their composition rather than worldwide overproduction. The drive to replace single-use products has sparked a considerable amount of research work to discover sustainable options for petroleum-based plastics. Bioplastics open up a new horizon in plastics manufacturing operations and industrial sectors because of their low environmental impact, superior biodegradability, and contribution to sustainable goals. Their mechanical properties regarding tensile, flexural, hardness, and impact strength vary substantially. Various attempts have been made to augment their mechanical characteristics and capacities by incorporating reinforcement materials, such as inorganic and lignocellulosic fibres. This review summarizes the research on the properties of bioplastics modified by fibre reinforcement, with a focus on mechanical performance. The mechanical properties of reinforced bioplastics are significantly driven by parameters such as filler type, filler percentage, and aspect ratio. Fibre treatment aims to promote fibre–matrix adhesion by changing their physical, chemical, thermal, and mechanical properties. A general overview of how different filler treatments affect the mechanical properties of the composite is also presented. Lastly, the application of natural fibre-reinforced bioplastics in the automobile, construction, and packaging industries is discussed.

Flow and stock accumulation of plastics in China: Patterns and drivers

Plastic pollution has always been a hot issue of global concern. Previous studies have mainly focused on the flow of plastics. However, information on the patterns and characteristics of flow, stock, and waste in the plastic life cycle and their driving factors is limited in China, and effective waste reduction and sustainable strategies are missing. Therefore, this research established a flow model of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET); further analyzed the driving factors; and proposed strategies for waste reduction and sustainable development. We found that the total consumption, stock, and waste of PET, PE, and PP in 2010–2017 reached 552.96, 292.70, and 257.18 Tg, respectively. Building and construction (B&C), packaging, and textiles were the sectors with the largest stock of PE, PP, and PET. From 2010 to 2013, the stock of PE increased by 440 %, which was mainly driven by the increase in material utilization intensity (MUI). Similarly, the growth of MUI was the main driving factor driving PP (351 %) and PET (367 %) stocks. Notably, from 2014 to 2017, economic growth was the main factor driving the plastic stock. These results will provide a scientific basis for promoting the sustainable utilization of PE, PP, and PET and be of great significance to achieve the strategic goal of a no-waste city.

Achieving sustainable production and consumption of virgin plastic polymers

The United Nations Environment Assembly (UNEA) recently adopted a resolution with a mandate to negotiate a new international legally binding instrument (a treaty) on plastic pollution. The mandate includes the need to ‘prevent’ as well as ‘reduce’ and ‘eliminate’ plastic pollution through a ‘comprehensive approach that addresses the full life cycle of plastic’. Unsustainable production and consumption of virgin (primary) plastic polymers represents the single greatest threat to preventing plastic pollution and risks undermining the incoming treaty. However, current discussions on a global plastics treaty overlook upstream measures that address virgin plastic production and consumption, focusing instead on midstream and downstream measures on product design and waste management. This article presents the justification for and benefits of a stepwise approach for controlling virgin plastic production and consumption internationally, inspired by the Montreal Protocol on Substances that Deplete the Ozone Layer;

Structural evolution of global plastic life cycle trade: A multilayer network perspective

International trade in plastics accounts for 5 % of total merchandise trade and involves all nations in modern society. To explore global plastic life cycle trade, a life cycle-based plastic trade multilayer network (LC-PTMN), including a raw materials layer, a semifinished products layer, a plastic products layer, and a plastic waste layer, is constructed. The structure of the global plastic trade is studied by analyzing each layer in the LC-PTMN from 1990 to 2019. The results reveal that the LC-PTMN has a prominent hierarchical structure and a small-world property, namely, a few countries occupy most trade channels and trade volume. The trade channels and trade volume in the plastic waste layer are the most concentrated. Countries with massive channels have a strong cooperative ability to prompt their trading partners to form close groups. Developing countries in Asia, such as Vietnam and Turkey, have outstanding performance in the LC-PTMN. The major trade flows have distinct geographical patterns, mainly occurring in intra-North American, intra-Asian and North American-Asian networks. Additionally, the community structures of the LC-PTMN have tended to stabilize. Dramatic changes are mainly caused by the merging of European countries with Asian and African countries and the split of North American countries from other countries. These findings will help policy makers encourage plastic sector transformation.

A new journey of plastics: Towards a circular and low carbon future

The plastic pollution to the environment, especially to the ocean, has been draw a lot of attention from the public which results some negative impact to the entire value chain of plastic industry. Circularity and low carbon have been perceived as the solution to tackle these challenges. Efforts required from the feedstock, polymerization, product design and recycling, are all need to be considered. Shifting to the low carbon feedstock is key to reduce the total emission of plastics, while make it recyclable is crucial to achieve low carbon emission for the entire life cycle of plastics. Mechanical recycling aims to make more post-consumer recycles (PCR) being used to some high-end applications to incentivize more plastics being collected and regenerated. The advanced recycling is the last stop for those unrecyclable, avoiding them to the undesired incineration or landfill, and generate value through the pyrolysis or gasification process. The scale is key to make it profitable and sustainable.