Search

Copyright of Kemija u Industriji is the property of Croatian Society of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Household plastic waste is a major component of household municipal solid waste (HMSW). One major cause of increasing accumulation of plastic waste is the lack of proper segregation of HMSW, particularly into five separate categories, namely, recyclable, toxic, compostable organic, soiled, and wet (semisolid) wastes. Such segregation will help in appropriate identification and separation of household plastic waste from other HMSW for their recycling and reuse. The present study examines peoples' perception regarding handling of plastic waste with respect to the segregation of HMSW. Relevant data was obtained from a sample of 2,563 respondents in Assam, India. The findings indicate that a majority of people dispose household plastic waste, instead of recycling and reusing them. Also, they never segregate HMSW into the abovementioned five categories, indicating the need for raising awareness about the importance of such segregation among people. [ABSTRACT FROM AUTHOR]

The use of plastics has become deeply ingrained in our society, and there are no indications that its prevalence will decrease in the foreseeable future. This article provides a comprehensive overview of the global plastic waste disposal landscape, examining it through regional perspectives, various management technologies (dumping or landfilling, incineration, and reuse and recycling), and across different sectors including agriculture and food, textile, tourism, and healthcare. Notably, this study compiles the findings on life-cycle carbon footprints associated with various plastic waste management practices as documented in the literature. Employing the bio-circular-green economy model, we advocate for the adoption of streamlined and sustainable approaches to plastic management. Unique management measures are also discussed including the utilization of bioplastics combined with smart and efficient collection processes that facilitate recycling, industrial composting, or anaerobic digestion. Moreover, the integration of advanced recycling methods for conventional plastics with renewable energy, the establishment of plastic tax and credits, and the establishment of extended producer responsibility are reviewed. The success of these initiatives relies on collaboration and support from peers, industries, and consumers, ultimately contributing to informed decision-making and fostering sustainable practices in plastic waste management. [Display omitted] • Plastic waste management incorporated with bio-circular-green economy is discussed. • Global plastic recycling in different supply chains is examined. • Recycling methods including advanced integrated chemical recycling are analyzed. • Lifecycle carbon footprints of different waste management practices are summarized. • Pathways to decarbonize plastic waste recycling for carbon neutrality are proposed. [ABSTRACT FROM AUTHOR]

Plastic waste management has received significant attention in recent decades due to the urgent global environmental crisis caused by plastic pollution. The versatile and durable nature of plastic has led to its widespread usage across various sectors. However, its nonbiodegradable nature contributes to unsustainable production practices, leading to extensive landfill usage and posing threats to marine ecosystems and the food chain. To address these environmental concerns, numerous challenges have been recently addressed through investigating alternative approaches for disposing of plastic waste, with the construction sector emerging as a promising option. Incorporating plastic waste materials into concrete not only offers economic benefits but also provides a valid alternative to conventional disposal methods. This paper presents the results of different experimental studies, some of them available in the literature and others new, discussing the feasibility of integrating plastic waste into concrete and its impact on mechanical properties. The influence of different sizes, natures, treatments, and percentages of plastic waste in the concrete mixtures is dealt with in order to provide further data for helping to understand the nonunivocal results in the literature, under the conviction that only further observations can help to understand the mechanics of concrete with plastic aggregates. The experimental investigation highlighted that one parameter that is better than others and can be considered to compare different experimental investigations is the variation in weight (due to the effective volume of plastics in the mix), determining a sort of increasing of porosity that degrades the mechanical characteristics. However, this seems inconsistent in some cases. Therefore, the need for further research is highlighted to refine production methods and optimize mix designs. [ABSTRACT FROM AUTHOR]

Arbitrary disposal of plastic waste into landfills and oceans can disturb the ecological system and even challenge human survival. Centralized plastic recycling process only works for selected types of plastics (e.g., polyethylene) with limited contribution (<10%), because of high infrastructure requirement. Comparatively, photoreforming of plastic waste for commodity and fuels production is much more facile and decentralizable, and thus holds great potential to mitigate the plastic waste challenge. To this end, a fully solar powered photoelectrochemical system is developed to selectively upgrade polyimide waste (often appears in electronic waste) into valuable commodity chemicals, including succinic acid, acetic acid, and formic acid, and cogenerating green hydrogen fuels. It is also demonstrated that one of the key monomer, pyromellitic acid, and the precious metals (in electronic waste) can be fully recycled. This proof‐of‐concept demonstration provides a new viewpoint for designing decentralized photoelectrochemical system for simultaneous plastic waste upcycling and renewable fuel synthesis, critical for a sustainable plastic economy. Selective cleavage of benzene ring also opens a green route for other benzene ring‐containing waste upgrading. [ABSTRACT FROM AUTHOR]

Medical plastic waste threatens the environment and human health if not properly handled and disposed of. This study used field visits, multi-criteria decision analysis, material testing, and data analysis to assess the feasibility of recycling medical plastic waste. The study identified medical plastic products (syringes, intravenous bags, and infusion sets) with high recyclability potential and proposed targeted recommendations for improving waste management practices. Medical plastic waste generation rates in kg/bed/day were 0.486 and 0.428. 55 kg/day and 5 kg/day of recyclable medical plastic waste are generated at KATH and KNUST hospitals, respectively. The contextual relevance of this research extends beyond the Ghanaian healthcare system, with implications for waste management practices in low and middle-income countries by contributing to the advancement of sustainable waste management practices. [ABSTRACT FROM AUTHOR]

Chemical upgrading as a recycling technology for poly(ethylene terephthalate) (PET) waste plastic is an effective way to help solve the current challenges of plastic pollution. Catalytic methanolysis technology enables the depolymerization of PET into high-value dimethyl terephthalate (DMT) monomers under relatively mild conditions, thereby achieving closed-loop recycling of PET waste plastic. In this study, we compared the catalytic efficiency of Cu/SiO2 catalysts prepared by three different methods for the depolymerization of PET to DMT. Cu/SiO2-IM, prepared through the impregnation method, exhibited the highest activity, with PET conversion and DMT selectivity reaching 92.35% and 99.0%, respectively, at 200 °C without any initial gas pressure. The exceptional performance of Cu/SiO2-IM can be attributed to its small metal particles, substantial specific surface area, a high ratio of Brønsted acid sites (BAS) to Lewis acid sites (LAS) and the balance of Cu+ and Cu0 active sites on the catalytic surface. Furthermore, possible reaction mechanisms of Cu-based catalysts in the catalytic methanolysis of PET were investigated: Cu+ initiates the attack on the carbon groups along the long PET chain and enhances the nucleophilic attack during the depolymerization reaction, while Cu0 readily interacts with the hydroxyl group of methanol, leading to the formation of a new ester group between the oxygen atom in the hydroxyl group of methanol and the carbon atom in the C=O group of PET polyester. This low-cost and high-efficiency catalytic methanolysis study provides a practical approach to PET waste plastic recycling. [ABSTRACT FROM AUTHOR]

The growing population and rapid urbanization are significant challenges for Indian cities. Pune City generates nearly 2,258 tonnes of waste per day. Pune's informal waste sector has demonstrated remarkable efficiency, cost-effectiveness, and self-sustainability. Moreover, it contributes to favorable economic and social outcomes for the city. With the support of the self-help group SWaCH Seva Sahakari Sanstha Maryadit, Pune, the municipal solid waste management model has successfully achieved a remarkable 95 percent segregation rate. Implementing the Pune municipal solid waste management model showcases the active and efficient engagement of informal waste workers in the collection and resource utilization process. This underscores the possibility of favorable economic, social, and environmental results stemming from collaborations between municipalities and waste pickers. This paper looks at the role of SWaCH in line with Pune Municipal Corporation towards the present waste management system. Primarily reliant on labor, this model accomplishes recycling tasks at a notably lower cost compared to conventional mechanized and centralized waste management approaches. It can also accomplish high recycling levels and relatively considerable plastic waste segregation. Promoting the retrieval of valuable materials, especially plastics, for local and global recycling enterprises actively contributes to the advancement of a circular urban waste management approach. The objective of this research is to explore and provide a realistic understanding of Pune's current status of waste generation, collection, transportation, and disposal. Apart from the SwaCH-PMC model, the paper also focuses on plastic waste recycling, the Red Dot Campaign towards sanitary waste, and household e-waste management in Pune. [ABSTRACT FROM AUTHOR]

In recent decades, considerable attempts through geotechnical study have been made to reduce plastic waste by recycling and reuse. The aim of this study was to reuse waste plastic mixed with sand for geotechnical application. To this end, large-scale oedometer experiments were carried out to examine the compressibility of Bandar-e Anzali sands stabilised with plastic-waste-originated high-density polyethylene (HDPE). Bandar-e Anzali is a populated coastal city in the vicinity of the Caspian Sea (northern Iran). Large-scale oedometer and direct shear tests were performed to study the applicability of HDPE chips mixed with sand at various HDPE contents (0, 2, 4, 6 and 8%). Based on the experimental tests, the addition of plastic waste to the soil improved the soil's strength, significantly raised its compressibility and decreased the undrained elasticity modulus. By adding 8% HDPE, the constrained compression modulus decreased to 50% at a pressure of 300 kPa due to the elastic deformability of HDPEs. However, at higher relative density, adding HDPE by more than 4% did not affect the coefficient of lateral earth pressure at rest. [ABSTRACT FROM AUTHOR]

Internationally, several types of research have been conducted on plastic waste: forms, sources, composition, possible effects of inappropriate handling and international best practices of recycling. One issue that is still to be made clear and known is how much and how plastic is recycled in Namibia in order to reduce or eliminate the problem of "plastic landscape". Therefore, the objective of this paper is to examine plastic recycling in Namibia with a view to providing answers to policymakers, planners, academics and investors on how plastic can be managed. The paper employed an exploratory qualitative approach to provide answers to the research objectives. The research used face to face semi-structured interviews, document search (articles, journals, environmental organizations reports) and site visits. It was found that the spectrum of plastics (polymers) recycled in the country fell into two main categories; soft and hard which were sourced from different points of generation such as households, commercial businesses, industries and others. Plastic is the most widely used recyclable material. It is freely available in shops, but the most challenging material affecting urban environments where large volumes of plastic were generated. It was further found that total recycling of plastic was done according to the recycling symbol complete loop of recycling: collection, processing, manufacturing and subsequent re-sale of produced goods. The study recommends control of the availability of plastic through charges at the point of sale as well as having a buyback centre for recycling if the problem of the plastic landscape" is to be addressed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-pyrolysis of TPU and PAW greatly reduces the activation energy of decomposition. • PAW makes the degradation of TPU move to the low temperature range. • Co-pyrolysis increases the yield of char and pyrolysis oil. • PAW promotes cyclization of polyester polyols in TPU. Co-pyrolysis of plastics and biomass offers an effective approach for waste disposal. In this study, the synergistic effects during the co-pyrolysis of thermoplastic polyurethane (TPU) and paulownia wood (PAW) were investigated in terms of pyrolysis kinetics and product properties using tube furnace, TG-FTIR and GC/MS. The results revealed that co-pyrolysis promoted the material pyrolysis and facilitated the pyrolysis process taking place at low temperatures. By adopting the Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Starink methods, the average activation energies of pure TPU, PAW, and TPU/PAW blends with a 1:1 mass ratio were determined to be 139 kJ/mol, 288 kJ/mol, and 126 kJ/mol. It is indicated that co-pyrolysis significantly reduced the activation energies and enhanced reactivity. Tube furnace experiments demonstrated that TPU/PAW blend with 1:1 mass ratio exhibited the highest synergism. The TPU melt acted as a physical barrier, leading to increased production of char and oil, and lower production of volatile gas. In the pyrolysis oil, the synergistic effect effectively hindered a formation of alcohol phenols. In the meanwhile, the synergistic effect also boosted generations of aliphatic compounds and ketones, increasing the heat value use of pyrolysis oil. Furthermore, a reaction pathway and mechanism of co-pyrolysis of TPU and PAW was proposed. The active molecules and free radicals generated by the pyrolysis of PAW promote the hydrogen transfer cyclization of polyester polyols decomposed by TPU, and the hydrogen free radicals released by TPU promote the depolymerization and activation of PAW. Moreover, the catalytic effect of alkali metal elements in PAW promotes the synergistic effect. The results of the study provide a basis for the co-pyrolysis of waste plastics and biomass to achieve high value utilization of waste. [ABSTRACT FROM AUTHOR]

In the building sector, the low thermal conductivity of plastics makes them a viable option to increase the thermal resistance of construction materials. Incorporating recycled plastic in concrete panels can not only enhance the sustainability and circular economy of the buildings but also provide an affordable alternative to phase change materials (PCM) for thermal insulation. To evaluate the potential of waste plastic as a thermal insulation material, nine samples with varying thicknesses (1 mm, 2 mm, and 3 mm) and portions of shredded waste plastic were tested to determine their thermal and physical properties. The properties under investigation, such as density, water absorption, porosity, compressiveness, and thermal conductivity, have been tested. Upon completion of the physical and thermal assessments, it was determined that the PL.SH.layer.10% and PL.SH.layer.20% insulation samples exhibited higher thermal effective alternatives compared to the PCM samples. Additionally, the latter two options are deemed to be more cost-effective. Only the samples with with a melted plastic layer of 1 or 2 mm failed to boost their thermal efficiency in terms of heat insulation until the melted plastic was increased by more than 3 mm. The research emphasizes the capacity of recycled plastic to act as a cost-efficient substitute for thermal insulation. This substitution to boost the insulation of building envelopes, preserve energy, and enhance thermal comfort, boost increase the insulation of building envelopes, preserve maintain energy, and enhance thermal comfort, especially in hot developing countries. The results may provide valuable is for future investigations and advancements in sustainable construction materials, facilitating the shift towards a circular economic model. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Plastic waste in Indonesia increased significantly during the Covid-19 pandemic. With this surge in plastic consumption and waste, awareness of environmental sanitation becomes essential, especially regarding the use of plastic. Society must consider the impact of single-use plastics and implement good plastic waste management. This study aimed to determine the environmental awareness of a community and what factors contributed to its plastic waste utilization activities during the Covid-19 pandemic. METHODS: The data collection in this study was conducted using a questionnaire with a crosssectional analytical approach. The study was conducted in Makassar City, South Sulawesi, the largest city in Eastern Indonesia, and purposive sampling was used to determine selected respondents. Data analysis was carried out using chi-square to identify partial relationships and logistic regression to distinguish relationships simultaneously. FINDINGS: This study found that 53.2 percent of respondents frequently used plastic during the Covid-19 pandemic. Partial relationship analysis showed that general knowledge about waste and its impact was not significantly related to plastic use activities during the pandemic. Meanwhile, knowledge about plastic use during the pandemic, knowledge of protecting the environment, attitudes toward plastic use, attitudes toward waste management, behavior toward plastic use, and behavior regarding processing plastic waste were significantly related to plastic use activities during the Covid-19 pandemic, with respective test values of 0.000 each. Willingness to pay was also significantly related to plastic use activities during the pandemic, with a test value of 0.007. Simultaneous analysis showed that knowledge about plastic use during the pandemic was related to plastic use activities during the same time frame, with an odds ratio value of 0.398 and a negative relationship direction. Plastic wasteprocessing behavior was the most dominant factor influencing plastic use activities during the Covid-19 pandemic, with a test value of 0.000 and a positive relationship direction. Respondents who did not have good waste management behavior were 3.963 times more likely to use plastic frequently in their daily activities during the pandemic. CONCLUSION: The study results show the importance of increasing knowledge regarding plastic use and waste management. Good knowledge will intervene in attitudes that encourage good behavior. This study focuses on the relationship between plastic processing behavior and the intensity of plastic use during the Covid-19 pandemic. It emphasizes the need for intervention in the form of education about the importance of protecting the environment and providing facilities that enable people to implement good waste-processing behavior. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of plastic waste accumulation in both terrestrial and aquatic environments in Can Tho city, Vietnam, a nation with high per capita plastic consumption and significant plastic waste discharge. Focusing on urban residential areas, riverside communities, suburbs, and rural regions, the research investigates the extent and impact of plastic waste in these diverse settings. Additionally, the study examines the accumulation of plastics at barriers, under bridges, and in the Hau River, identifying the predominance of single-use plastics and their environmental implications. The key findings indicate that the plastic waste leakage at land-based-source emission sites is substantial, with waste persisting for extended periods without effective clean-up. The study reveals a significant accumulation of plastics at barriers and bridge bases in aquatic environments, including along the river. The pollution level was observed to be more influenced by the quantity of waste rather than its mass per unit area, emphasizing the need for targeted waste reduction strategies. The study also identifies seven types of plastic, each associated with different sources of accumulation or settlement. This variety presents both challenges and opportunities for waste management and recycling. Significantly, the research underscores the potential of repurposing plastic waste into recycled products, aligning with the circular economy model. This approach not only extends the lifecycle of plastic products but also contributes to reducing plastic waste generation and minimizing the environmental impact. Overall, the findings highlight the urgent need for improved waste management practices in Vietnam, particularly in urban and riverside areas, and advocate for innovative recycling solutions to mitigate the environmental challenges posed by plastic pollution. [ABSTRACT FROM AUTHOR]

Various waste streams including municipal solid waste (MSW), polymer waste from personal protective equipment (PPE) used in medical fields, and composite waste from wind turbine blades (WTBs) demand modern waste management and recycling approaches. Ultimate and proximate analysis of mentioned samples revealed a higher content of carbon—28.2 ± 8.0, 80.1 ± 2.3, and 50.3 ± 2.3, respectively—exhibiting sufficient potential to be converted into secondary carbon-based compounds. For this purpose, oxidative liquefaction of selected waste materials was carried out following a detailed experimental plan, a centred composite design for WTBs, and a central composite face-centred plan for MSW and PPEs. Temperature, pressure, oxidant concentration, reaction time, and waste-to-liquid ratio were the parameters of key interest, and their values were tested at a range of 200–350 °C, 20–40 bar, 15–60%, 30–90 min, and 3–25%, respectively, depending upon the type of waste. As a result, total polymer degradation (TPD) was recorded for three types of waste and the results were satisfactory, encouraging the decomposition of primary waste in liquid oxygenated chemical compounds (OCCs). Gas Chromatography with Flame Ionisation Detection (GC-FID) helped us quantify the number of OCCs for each waste sample. Energy consumption during the process was also recorded and optimisation of the experimental plan based on maximum TPD and OCCs yields against the minimum energy consumption was performed to make the process tech-economic. [ABSTRACT FROM AUTHOR]

This paper explores the integration of artificial intelligence (AI) technologies with human rights considerations in plastic waste recycling, focusing on the context of Nigeria. Using an explanatory design and a basic review of the literature, it examines how AI can enhance human rights protection among workers in plastic waste recycling firms. The paper emphasizes the role of government policies and regulations in ensuring human rights protection, the need for ethical guidelines for AI use, and the potential of AI to improve worker safety and reduce environmental pollution in recycling facilities. Key recommendations for future research include enhancing AI capabilities for waste sorting, integrating Internet of Things (IoT) devices for real-time monitoring, and prioritizing ethics in AI development. Collaboration between stakeholders is identified as crucial, with multi-stakeholder partnerships and policy coherence essential for the effective implementation of AI technologies in plastic waste recycling. In conclusion, integrating AI with human rights considerations in plastic waste recycling is pivotal for enhancing efficiency, reducing pollution, and ensuring sustainable waste management practices. This paper contributes to the growing body of literature on AI and human rights in waste management, offering insights for policymakers, industry stakeholders, and researchers in Nigeria and beyond. [ABSTRACT FROM AUTHOR]

Waste is considered a significant environmental issue in modern times thus the purpose of this paper is to compare the use of different waste materials in replacing aggregates in concrete. This study investigates the potential of incorporating plastic waste (PW), textile sludge (TS), and construction and demolition waste (CDW) into concrete as sustainable alternatives to traditional construction materials, by evaluating its mechanical, durability characteristics as well as the cost related to different process of the project. The study focuses on the use of PW and TS as a replacement for fine aggregate, and CDW as replacements for coarse aggregate. Thus, four concrete mixes incorporating PW and TS were prepared, using 0% 10%, 25%, 40% replacement levels. The compressive strength of concrete with 10% plastic waste as fine aggregate was 32.49 N/mm² showing higher results than that of TS. Furthermore, another four concrete mixes incorporating CDW were prepared, using 0%, 25%, 50%, 75% replacement levels. The compressive strength of concrete with 25% CDW was 30.90 N/mm² indicating an increase of 2% than the control block. The study concluded that the best strategy is to incorporate construction and demolition waste as a replacement for coarse aggregate in concrete. This is because it resulted in an increase in compressive strength as well as a decrease in cost. [ABSTRACT FROM AUTHOR]

The exponential growth of China's economy, coupled with the surge in online commerce, has led to a significant expansion of the logistics industry. In 2022, China's express delivery industry generated approximately 9 million tons of waste paper and 1.8 million tons of plastic. This study analyzed the current composition and utilization of logistics waste in China, with suggestions for recycling. Logistics waste can be defined as the packaging waste generated in the logistics industry. Corrugated paper and plastic waste were chosen as the objects for utilization. Due to its high cellulose content, corrugated paper can be utilized along with other paper waste for biomass resourcing. Biodegradable plastics can also be converted into biomass resources through the action of specific microorganisms. These polymers can be enzymatically depolymerized by certain bacteria and fungi, yielding valuable organic products. In general, logistics wastes all have potential for biomass resource recovery. By adopting appropriate recovery and conversion technologies, these waste streams can be transformed into high-value bio-based products, such as biofuels, biochemicals, and biopolymers, thus contributing to the development of a circular and sustainable economy. [ABSTRACT FROM AUTHOR]