Plastic Crisis Research Articles

Algae-based self-driven microrobot for efficient removal of nanoplastics from water environment

Nanoplastics (NPs) have the characteristics of various species, wide distribution, low concentration and difficult degradation. In recent years, the researches of NPs have mainly focused on its toxicity, origin and migration, and the quantitative detection and removal technology of NPs is an urgent technical problem to be solved. Here, an active biohybrid microrobots (DPA-algae robots, diphenolic acids-alage robots) was designed and developed for dynamic removal of NPs in water environment. Firstly, diphenolic acids were functionalized on algae to realize the specific adsorption of nanoplastics through hydrophobic force, electrostatic attraction and van der Waals force between diphenolic acids and nanoplastic particles. Secondly, to realize the rapid identification of NPs, the functionalized algae were assembled into microrobots through rapid click chemistry reaction, thus the self-propulsion ability of algae can be utilized to accelerate the identification and enrichment of target objects. The removal rate of nanoplastics by microalgae robots has increased to 83.1 % at the concentration of 0.125 mg/mL within 2 h compared with the unmodified algae, which is a very significant improvement. In addition, the removal rate was 84.1 % to 87.7 % in different media, so the dynamic removal of NPs is expected to be applied into the filtration process of waterworks by preparing a large number of algae-based microrobots. This multi-functional microrobot is cost-effective and biocompatible, providing a new solution to the global “plastic crisis”.

Product Selection Toward High-Value Hydrogen and Bamboo-Shaped Carbon Nanotubes from Plastic Waste by Catalytic Microwave Processing.

The escalating levels of plastic waste and energy crises underscore the urgent need for effective waste-to-energy strategies. This study focused on converting polypropylene wastes into high-value products employing various iron-based catalysts and microwave radiative thermal processing. The Al-Fe catalysts exhibited exceptional performance, achieving a hydrogen utilization efficiency of 97.65% and a yield of 44.07 mmol/g PP. The gas yields increased from 19.99 to 94.21 wt % compared to noncatalytic experiments. Furthermore, this catalytic system produced high-value bamboo-shaped carbon nanotubes that were absent in other catalysts. The mechanism analysis on catalytic properties and product yields highlighted the significance of oxygen vacancies in selecting high-value products through two adsorption pathways. Moreover, the investigation examined the variations in product distribution mechanisms between conventional and microwave pyrolysis, in which microwave conditions resulted in 4 times higher hydrogen yields. The technoeconomic assessment and Monte Carlo risk analysis further compared the disparity. The microwave technique had a remarkable internal rate of return (IRR) of 39%, leading to an income of $577/t of plastic with a short payback period of 2.5 years. This research offered sustainable solutions for the plastic crisis, validating the potential applicability of commercializing the research outcomes in real-world scenarios.

Promoting sustainable consumption and circular economy: the intention of Vietnamese youth consumers to purchase products made from recycled plastics

Recycling is viewed as a key component in a circular economy and serves as an ideal solution for promoting sustainability. During the global plastic crisis, plastic recycling practices have been adopted worldwide, leading to the production of various products made from recycled plastics (PRP). Nevertheless, a gap persists between consumption and demand for such products, which is primarily attributed to a lack of comprehension from the consumer perspective. Given the pivotal role consumers play in the adoption of these products, this study explores consumers’ intentions to purchase PRP. This is particularly significant in Vietnam, which is an emerging economy aspiring to achieve the objectives of a circular economy and sustainable development. Utilizing an integrated cognitive-emotional framework comprising the Valence Theory and the Norm Activation Model, data from 564 Vietnamese students were gathered and analyzed using structural equation modeling. The results show that awareness of consequences is a major driver of consumer purchase intentions, followed by perceived ease of application and monetary incentives. The results also indicate that health concerns have the strongest effect on purchase intention and in the negative side, meaning that the health-related risk is the primary concern for consumers during the decision-making process. This research holds substantial value for academics and managers, as it aids in the theoretical exploration and the formulation of strategies to improve consumer acceptance of PRP.

PLASTIC IN ARTISTIC FORMS: INTERPRETATION OF ARTWORKS RELATED TO PLASTIC CRISIS THROUGH STUDIO-BASED RESEARCH

Plastic is almost everywhere; in fact, it is hard to imagine life without plastic. However, although plastic is convenient to people, its difficulty in degrading as a petrochemical product, its production, consumption and random disposal has also put enormous strain on the environment in which humans live, resulting in a plastic crisis. This study analyses 20 artworks related to the plastic crisis and finds that most artistic production and focuses on marine plastic pollution. In particular, this study examines how artistic practice has brought attention to the plastic catastrophe and uses a studio method to highlight the plastic crisis in the mountains by using plastic bags as a material to demonstrate how widespread plastic pollution is. It presents the phenomenon of mountain plastic pollution and promotes a dialogue about mountain plastic waste pollution. Art can make the plastic crisis more visible and impart a more visceral, emotional message that encourages people to understand and reconsider it. Additionally, artistic practice helps people intuitively understand the plastic crisis and the viability of plastic as an artistic medium for expressing environmental concerns.

Enhancing the biodegradation of bis(2‐hydroxyethyl) terephthalate by an IsPETasePA and MHETase dual‐enzyme system

AbstractBACKGROUNDEnvironmental and ecological hazards caused by the accumulation of polyethylene terephthalate (PET) are becoming a global concern. The use of enzymes to address the plastic crisis has achieved many successes, but the difficulty in degrading high‐crystallinity PET has limited its application. Numerous studies have investigated the degradation of PET with arbitrary crystallinity to bis‐2‐(2‐hydroxyethyl) terephthalate (BHET) using chemical pre‐treatment methods such as glycolysis, but few have tested its biocompatibility with enzymatic alliances.RESULTSHerein, we report the enzymatic characterization and subsequent engineering of the state‐of‐the‐art IsPETasePA and MHETase (where MHET is mono(2‐hydroxyethyl) terephthalate), a dual‐enzyme system which can be used for the degradation from BHET to a single‐product terephthalate (TPA). Modulators, including surfactants, organic solvents and metal ions, enhanced the enzyme activity of IsPETasePA and MHETase by up to 1.1‐fold and 2.3‐fold, respectively. 100% TPA yield (BHET of 25 g L−1) was achieved within 5 h. We also analyzed the mechanism of optimal ion modulator modification by dynamics simulation, and it synergistically achieved enhancement of MHET degradation ability by improving stability and binding energy.CONCLUSIONThe introduction of modulators improves the efficiency of the dual‐enzyme system in degrading BHET. This work provides a valuable strategy for the complete degradation of BHET to TPA, laying the groundwork for the realization of PET recycling. © 2024 Society of Chemical Industry (SCI).

A model-driven approach to upcycling recalcitrant feedstocks in Pseudomonas putida by decoupling PHA production from nutrient limitation

Bacterial polyhydroxyalkanoates (PHAs) have emerged as promising eco-friendly alternatives to petroleum-based plastics since they are synthesized from renewable resources and offer exceptional properties. However, their production is limited to the stationary growth phase under nutrient-limited conditions, requiring customized strategies and costly two-phase bioprocesses. In this study, we tackle these challenges by employing a model-driven approach to reroute carbon flux and remove regulatory constraints using synthetic biology. We construct a collection of Pseudomonas putida-overproducing strains at the expense of plastics and lignin-related compounds using growth-coupling approaches. PHA production was successfully achieved during growth phase, resulting in the production of up to 46% PHA/cell dry weight while maintaining a balanced carbon-to-nitrogen ratio. Our strains are additionally validated under an upcycling scenario using enzymatically hydrolyzed polyethylene terephthalate as a feedstock. These findings have the potential to revolutionize PHA production and address the global plastic crisis by overcoming the complexities of traditional PHA production bioprocesses.

Ultrafast and selective chemical recycling of PLA to methyl lactate by using MHMDS as simple catalysts

The depolymerization of waste plastics into high-value products is a promising solution to address the plastic crisis. Among this field, catalytic activity and selectivity of depolymerization catalyst are of great concerns. Accordingly, in this work, a simple catalytic system was explored in detail to achieve the fast and selective chemical recycling of PLA into methyl lactate. Using commercially available M[bis(trimethylsilyl)amide] (MHMDS, M = Li, Na, K) as catalysts, the depolymerization of PLA was completed within a few minutes at room temperature. The selectivity and optical purity of the depolymerized product methyl lactate are greater than 99 %. The effect of conditions such as metal center, catalyst form, and solvent on depolymerization was investigated. Moreover, the gram-grade depolymerization, selective depolymerization of blended or mixed PLA plastic, and the recyclability of catalyst were further explored. This work accomplishes the path of highly selective and active depolymerization of PLA under mild conditions, thereby promoting sustainable development of PLA.

Wasting the restorative potential: Influences of plastic and biowaste on psychological restoration after real, virtual, and imagined walks

Nature experiences benefit human wellbeing by, for example, increasing subjective restoration and positive affect while reducing negative affect. However, natural environments are threatened by several crises, including pollution. In three preregistered studies, one correlational and two experimental, we investigated the relationship between (plastic) litter and restoration after a walk. In Study 1, participants did a self-selected restorative walk and afterwards reported observed litter. In two experimental studies, we manipulated the presence of plastic waste, biowaste (which served as an active control condition with human-sourced but degradable litter), and no waste in a virtual (i.e., video; Study 2) and an imagined (Study 3) forest walk. In all studies, we assessed subjective restoration, current affect and connectedness to nature, attractiveness and preference of scenery, as well as plastic-related problem awareness, intentions, and policy support. Results showed that litter, especially from plastic, is associated with harmful changes in subjective restoration, affect, and the perception of the scenery. Connectedness to nature, as well as plastic-related problem awareness, intentions, and policy support were not affected by the presence of plastic. Thus, plastic pollution influences human wellbeing negatively, but did not affect factors important to reduce consumption. Therefore, more research on tackling the plastic crisis is needed.

Media exposure and plastic-reducing behaviours in China: The mediating effect of environmental concern and locus of control.

The environmental problems caused by plastic pollution have increased at an astonishing speed. However, attempts to study the dynamics of plastic-reducing behaviours are few and far between. In this regard, based on the attitudinal-contextual-behavioural (ABC) theory of pro-environmental behaviours, this study conducts an online survey to analyse the functioning of media exposure on Chinese consumers' three types of plastic bag reducing behaviours during shopping, including saving inner plastic packaging bags by putting many goods into one bag, hand-carrying and bringing reusable bags. Employing the snowball sampling method, this study successfully collected 361 valid questionnaires for analysis. The findings of this study indicate that environmental concern and locus of control play mediating roles between media exposure and plastic-reducing behaviours. However, the study finds no supporting evidence for the mediating function of plastic pollution knowledge. These results have implications for plastic crisis managers and governmental officials. In designing media content for environmental education campaigns, it is advisable to prioritize strategies that evoke emotions over a sole focus on disseminating knowledge about plastic pollution.

The contribution of global waste picker organizations in responding to the plastic pollution crisis

Abstract The world is facing a global plastics crisis with more than 50% of plastics produced only being used once and then discarded. If nothing is done to put an end to plastic pollution, it is projected that by 2050, there will be more plastic (by weight) than fish in the ocean, affecting natural ecosystems, biodiversity and human health. While solutions often target governments and corporations, a crucial group is frequently ignored: informal waste pickers. Despite the limitations of recycling alone, waste pickers significantly impact the plastic recycling chain. This review addresses the gap in our understanding of their role. It argues that waste pickers are an essential component of the larger portfolio of solutions for the plastic crisis but face significant challenges.

Open Data Sources for Post-Consumer Plastic Sorting: What We Have and What We Still Need

The global plastic crisis is a significant concern. Addressing it requires a multi-faceted approach involving legislative, social, and technological measures to reduce post-consumer plastic waste and increase the recycling rate and material circularity. The EU Packaging Directive mandates a 50% recycling rate for plastics by the end of 2025 and 55% by 2030. Machine learning techniques are increasingly being explored to improve the efficiency of waste sorting, thereby contributing to achieving the aforementioned recycling rate goals. However, their effectiveness relies on the availability of high-quality and comprehensive datasets. One of the challenges in this field is the need for suitable datasets for training and testing machine learning models. Furthermore, access to detailed and real-world data, such as information from recycling plants, is often restricted due to paywalls, limiting the accessibility of critical data for research and development. This review sheds light on the situation of RGB (red, green, blue) image datasets and NIR (near-infrared) data availability to identify current dataset gaps and advocate for open access to relevant data sources. The target is to promote collaboration and innovation to combat the plastic crisis and promote sustainable practices collaboratively.

Application of PETase in Plastic Biodegradation and Its Synthesis

As a versatile chemical material, plastic is widely used in all aspects of human society with its excellent performance, in the development process of plastics, due to its difficult to degrade characteristics, coupled with the initial formation of a control system, the harm of plastics to the environment is gradually revealed. The current global plastic crisis poses significant environmental challenges, impacting both human health and marine ecosystems. Plastic waste circulates worldwide, exacerbating the issue. Recent advancements in microbiological plastic degradation methods offer promising solutions. These approaches encompass modifying PETase enzymes, establishing a sustainable PETase synthesis platform, and reevaluating PETase variants for enhanced plastic degradation and heightened thermal stability within plant compost environments. Additionally, the implementation of pollution control measures across agriculture, industry, and governmental policies is crucial. This comprehensive study highlights strategies to bolster PETase efficiency, aligning with present environmental plastic degradation needs. It holds potential for combatting plastic pollution, promoting closed-loop plastic cycles, and charting a course for future research endeavors.

Alternative Approaches to Plastic Production and Recycling Policies

Plastics offer convenience to businesses and the supply chain, but their improper disposal and low recycling rates pose significant environmental and health challenges. Each year, millions of tons of plastic end up in oceans, with a recycling rate below 9%. Thus, urgent action is required to tackle this global plastic crisis. This policy brief proposes a Europe-wide ban on colored plastics to promote a circular economy and enhance plastic recycling, drawing insights from successful recycling policies in Japan and South Korea. This approach, despite initial challenges, can yield long-term benefits such as reduced exports, energy conservation, and increased consumer awareness. Collaboration, funding, and material design innovation are key to promoting sustainable practices and combatting plastic pollution. By seizing this opportunity collectively, we can make a lasting impact in the fight against plastic pollution and address the climate crisis before it is too late.

Solving the Global Plastic Crisis: The Role of Policymakers and Collaborative Efforts towards Sustainability

Solving the Global Plastic Crisis: The Role of Policymakers and Collaborative Efforts towards Sustainability

Energy-environment-economic (3E) hub for sustainable plastic management – Upgraded recycling, chemical valorization, and bioplastics

This research aims to clarify the energy, environment, and economic (3E) aspects of petroleum-based plastics, bioplastics, and all end-of-life methods including landfill, incineration, composting, and recycling. Production and utilization of bioplastic, associated with recycling techniques to produce valuable building block chemicals, are considered as long-term solutions to the plastic crisis. However, this target seems to be unachievable in decades mostly due to unclear information on energy consumption and operational costs of different techniques. Although numerous studies of life cycle analysis (LCA) of bioplastics have been published in literature, the energy and environmental impacts of bioplastics are still uncertain, due to the non-standardization of the analyses. To standardize the current findings, this study proposed a novel standardization method and categorized the latest life cycle studies to correlate the energy requirement, global warming potential, and paramount factors which significantly influence the environmental impact of bioplastics production. Economic considerations were evaluated through standardization of independent techno-economic studies in literature, followed by a comparative analysis of the profitability between traditional waste management practices, such as landfilling and incineration, and recycling. Finally, it was found that recycling is beneficial from energy, environmental, and economic perspectives, but some assessments were based on ideal assumptions where efficiency of recycling and logistics of plastic waste collection was high. Real-life applications of recycling and bio-based plastics are hindered by various challenges. Overcoming these challenges may be the key to creating sustainable circular bioeconomy of plastics.

The Primacy of National Policies in Navigating the Local-Global Nexus: A Case Study of the Plastic Crisis

Against the backdrop of the escalating plastic crisis, exacerbated by human activities and posing a significant public concern, this study seeks to evaluate the role of various policy-making levels in environmental intervention. The core subject of investigation is the integral function of national lawmakers in spearheading effective environmental policy strategies while contextualizing the coordination of local and international policymakers. Using practical policy examples as primary tools for analysis, the study delves into the dynamics between the three tiers of policy-making and gleans evidence underlining the centrality of national players. Results indicate that while local and international policies offer solutions, they are often impeded by inherent policy limitations. National policies, powered by vast resources and political clout, emerge as pivotal, capable of overhauling plastic production, consumption, and disposal mechanisms. The research concludes that to holistically address the plastic crisis spawned by market failures, a blend of governmental intervention, primarily driven by national policymakers, and complemented by local and international cooperation, is imperative. Additionally, the future necessitates not only a reduction in plastic use but also the pursuit of viable plastic alternatives to combat pollution comprehensively.

Imagining circular carbon: A mitigation (deterrence) strategy for the petrochemical industry

Petrochemical producers both rely upon and generate some of the most problematic substances in the current age of socioecological crisis: fossil fuels and plastics. With mounting calls to cap fossil fuel extraction as well as plastics production, the industry appears to be caught between a rock and a hard place. Nonetheless, betting on continuously increasing global plastic demand, petrochemical production is expanding significantly. This predicament raises the question of how the industry attempts to square increasing petrochemical production with the need to address environmental issues. In recent years, leading actors in and around the industry have promoted notions of carbon circularity as a desirable mitigation strategy. In this paper, we examine this strategy, using discourse analysis to uncover what we refer to as the imaginary of circular carbon. We highlight how the circular carbon imaginary risks delaying climate mitigation by rendering alternative mitigation pathways undesirable. It does so by reconciling increased production, carbon neutrality, and circular economy in a vision of a circular carbon economy, framing the climate crisis as an issue of carbon management. In the circular carbon economy, carbon dioxide, petrochemicals, and plastics all fit as mere flows of carbon. The circular carbon imaginary thereby helps future-proof the petrochemical industry in legitimizing its carbon-intensive practises essential to the fossil world order and the plastic crisis.

Plastic packaging: Are German retailers on the way towards a circular economy? Companies’ strategies and perspectives on consumers

German retailers commit to promoting a circular economy (CE) to tackle the plastic crisis. Their strategies and perspectives on the role of consumers are qualitatively analyzed based on sustainability reports and press releases. Strategies include means of reduction and reuse but focus on recycling. Consumers are rather seen as barriers to realizing a CE.Environmental pollution caused by single-use plastic packaging waste is one of the major problems of our time. As a means of tackling environmental damage from plastic, many companies are voluntarily committing to promoting a sustainable use of plastic and the idea of a circular economy (CE). Among these companies, retailers play an interesting role. They are the point of sale of different manufacturers’ products and, thus, are in direct contact with consumers. This paper qualitatively analyzes retailers’ plastic strategies as published in sustainability reports and press releases. In particular, their understanding of the concept of a CE, their perspective on the CE-related role of consumers, and the consistency of their objectives regarding CE goals are investigated. The results indicate that there is a strong focus on recycling, although the retailers also consider means of reduction by avoidance and reuse. Consumers are rather seen as a barrier to implementing a circular economy at all three levels (reduction, reuse, recycling) and are assumed to need waste management education.

Discovery and mechanism-guided engineering of BHET hydrolases for improved PET recycling and upcycling

Although considerable research achievements have been made to address the plastic crisis using enzymes, their applications are limited due to incomplete degradation and low efficiency. Herein, we report the identification and subsequent engineering of BHETases, which have the potential to improve the efficiency of PET recycling and upcycling. Two BHETases (ChryBHETase and BsEst) are identified from the environment via enzyme mining. Subsequently, mechanism-guided barrier engineering is employed to yield two robust and thermostable ΔBHETases with up to 3.5-fold enhanced kcat/KM than wild-type, followed by atomic resolution understanding. Coupling ΔBHETase into a two-enzyme system overcomes the challenge of heterogeneous product formation and results in up to 7.0-fold improved TPA production than seven state-of-the-art PET hydrolases, under the conditions used here. Finally, we employ a ΔBHETase-joined tandem chemical-enzymatic approach to valorize 21 commercial post-consumed plastics into virgin PET and an example chemical (p-phthaloyl chloride) for achieving the closed-loop PET recycling and open-loop PET upcycling.

Beyond Plastics-to-Plastics to Waste-to-Products: Opportunities for Closing the Carbon Cycle via Chemical Recycling

AbstractThe plastic crisis is a key driver for chemical recycling (CR), with focus placed on plastics circularity via Plastics‐to‐Plastics. This neglects its potential in enabling circularity for a wide range of carbon‐containing waste and hinders a critical discussion of its broader contributions to decarbonizing the chemical sector. To address this gap, four CR routes and their integration in the conventional waste treatment and chemical production value chains are briefly reviewed, and reasons proposed for a focus expansion to Waste‐to‐Products to realize opportunities for closing the carbon cycle via chemical recycling.