Plastic waste management practices pertaining to India with particular focus on emerging technologies

Comprehensive Review on Bio-Based Treatments for Polyvinyl Chloride Plastic

Polyvinyl chloride (PVC) plastics are widespread around the globe, and each year, thousands of tons of PVC end up in the environment in the form of micro-/nanoplastics. Literature has reported extensively on the biodegradation of its PVC additives/plasticizers; however, bio-based treatment approaches for its polymers have been scanty. The current review has discussed elaborately all possible PVC degradation processes and the toxicity challenges faced during its mitigation. This review has also delineated and assessed all physical, chemical, and biological approaches reported for PVC treatments. All the biodeterioration, biocatalysis, and biodegradation mechanisms reported for PVC have been comprehensively discussed. Recent advances have also been highlighted like the direct application of invertebrate species and selective enzymes like peroxidases, alkane monooxygenase, and laccase during PVC treatment. Insights of functional genomes/genes and OMICS have been recommended, which might help predict and address any future issues during the mitigation of PVC pollution in the environment.

Sustainable valorization of waste plastic into nanostructured materials for environmental, energy, catalytic and biomedical applications: A review

The extensive production and utilization of plastic products are inevitable in the current scenario. However, the non-degradable nature of waste plastic generated after use poses a grave concern. Comprehensive efforts are being made to find viable technological solutions to manage the escalating challenge of waste plastic. This review focuses on the progress made in transformation of waste plastic into value-added nanomaterials. An overview is provided of the waste plastic issue on a global level and its ecological impacts. Currently established methodologies for waste plastic management are examined, along with their limitations. Subsequently, state-of-the-art techniques for converting waste plastic into nanostructured materials are presented, with a critical evaluation of their distinct merits and demerits. Several demonstrated technologies and case studies are discussed regarding the utilization of these nanomaterials in diverse applications, including environmental remediation, energy production and storage, catalytic processes, sensors, drug delivery, bioimaging, regenerative medicine and advanced packaging materials. Moreover, challenges and prospects in the commercial level production of waste plastic-derived nanomaterials and their adoption for industrial and practical usage are highlighted. Overall, this work underscores the potential of transforming waste plastic into nanostructured materials for multifaceted applications. The valorization approach presented here offers an integration of waste plastic management and sustainable nanotechnology. The development of such technologies should pave the way toward a circular economy and the attainment of sustainable development goals.

Integrated analytical hierarchy process-grey relational analysis approach for mechanical recycling scenarios of plastics waste in India

Mechanical recycling is an indispensable tool for plastic waste (PW) recycling and has the highest share in the PW recycling sector in India. The transition to the circular economy of plastics (CEoP) needs a systemic perspective on the mechanical recycling processes. Nevertheless, the assessment of multiple parameters influencing the mechanical recycling of PW is a complex decision-making problem for the development of triple-bottom-line mechanical recycling. A systemic perspective of various mechanical recycling scenarios was performed by employing a multi-criteria decision-making approach to examine the complexity of interlinked factors in the present investigation. Analytical hierarchy process (AHP) integrated with grey relational analysis (GRA) was used to evaluate the criteria that directly influence quality-oriented mechanical recycling. Data were collected by conducting semi-structured interviews using a framed questionnaire in stakeholder engagement with mechanical recyclers of PW. The first level hierarchy included economy, technical, resource consumption and environmental criteria. These criteria were further categorized into various significant indices such as quality of recyclate, recyclability, water and energy consumption during recycling. The results of the integrated grey relational analysis indicated that the technical parameters including quality of recyclate, resource efficiency, PW processing rate and recyclability have a significant influence on mechanical recycling. Based on AHP-GRA, scenario MR6, i.e. manufacturing of PET strap from recycled PET flakes, was ranked the optimal mechanical process amongst the various scenarios. MR6 was followed by Straps and Films at the second and third rank. The lowest ranking was observed for polymer blend recycling. These processes with higher ranks produced good quality recyclate with better efficiency and recyclability. Moreover, these processes consumed optimal resources during manufacturing. These processes also exhibited less maintenance cost, high production rate, low chemical consumption and waste generation as well as implemented pollution control practices.

Bio-straw or not? Determinants of consumption intention under the plastic straw ban

A new plastic ban has banned the use of single-use non-degradable plastic drinking straws in China's food and beverage industry by the end of 2020. However, this has caused widespread discussion and complaints on social media. What are consumers' reactions and what factors influence consumers to choose bio-straws (substitutes for plastic straws) are unclear. Therefore, this research collected 4367 effective comments (177,832 words in total) on "bio-straws" from social media and extracted keywords based on grounded theory to generate questionnaires. Structural equation modeling was used to analyze the consumption intention and influencing factors of 348 consumers regarding the ban. The results indicate the following: (1) consumer opinion on straws can be summarized into five main categories, namely, consumers' user experience, consumer subjectivity, policy awareness, policy acceptance, and consumption intention; (2) consumer subjectivity, policy awareness, and policy acceptance directly affect consumption intention significantly, while user experience affects consumption intention indirectly; and (3) user experience and consumer subjectivity play significant roles in mediating these relationships. From the perspective of consumers, this study provides an important basis for policymakers to formulate single-use plastic alternative policies in the future.

The escalated potential of the novel isolate Bacillus cereus NJD1 for effective biodegradation of LDPE films without pre-treatment

This study focused on the biodegradation of LDPE films using a novel isolate of Bacillus obtained from soil samples collected from a 20-year-old plastic waste dump. The aim was to evaluate the biodegradability of LDPE films treated with this bacterial isolate. The results indicated a 43% weight loss of LDPE films within 120 days of treatment. The biodegradability of LDPE films was confirmed through various testing methods, including BATH, FDA, CO₂ evolution tests, and changes in total cell growth count, protein content, viability, p^H of the medium, and release of microplastics. The bacterial enzymes, including laccases, lipases, and proteases, were also identified. SEM analysis revealed biofilm formation and surface changes in treated LDPE films, while EDAX analysis showed a reduction in carbon elements. AFM analysis demonstrated differences in roughness compared to the control. Furthermore, wettability increased and tensile strength decreased, confirming the biodegradation of the isolate. FTIR spectral analysis showed changes in skeletal vibrations, such as stretches and bends, in the linear structure of polyethylene. FTIR imaging and GC-MS analysis also confirmed the biodegradation of LDPE films by the novel isolate identified as Bacillus cereus strain NJD1. The study highlights the potentiality of the bacterial isolate for safe and effective microbial remediation of LDPE films.

Sustaining circular economy practices in supply chains during a global disruption

Purpose

Circular economy (CE) practices are critical to achieving sustainable development goals. However, the recent global disruption caused by the COVID-19 pandemic has significantly impacted sustainable practices. The literature shows a significant research gap in analyzing factors that sustain CE practices in supply chains during a global disruption. This study fills the research gap by developing a mix-method approach to analyze factors for sustaining CE practices during a global disruption.

Design/methodology/approach

To fulfill the objectives of this study, the list of factors that sustain CE practices was first identified by conducting a literature review and finalized through an expert opinion survey. The survey finalized 18 different factors for sustaining CE practices. The finalized factors were further analyzed using the grey decision-making trial and evaluation laboratory (DEMATEL) method. The quantitative analysis confirmed the priority of the factors and their cause-and-effect relationships.

Findings

The results revealed that continued stakeholder pressure, retention of CE and sustainability culture, continued implementation of cleaner technology, feedback system and ongoing CE training for resilience issues are the top five factors that sustain CE practices during a global disruption. The study also revealed ten factors as belonging to the cause group and eight to the effect group.

Originality/value

This study contributes to the literature by exploring factors for sustaining CE practices during a global disruption. Moreover, the study’s findings are important in real-life situations, as decision-makers can use the findings to formulate strategies for sustaining CE practices during future global disruptions.