Recycling Of Plastic Waste Research Articles

Analysis of engineering performance of concrete comprising recycled crushed plastic waste and fly ash

This study investigated the attributes of blending of recycled crushed polypropylene plastic coarse aggregates (PPCA) and fly ash (FA) towards the fresh and hardened properties of concrete. Natural coarse aggregate was partially replaced with PPCA at volumetric replacement levels up to 30% and cement was replaced with FA up to 20%. Initially, the performance of PPCA and FA in concrete was investigated distinctly. The incorporation of 30% of PPCA in concrete rather impaired the workability (from 95 mm – 50 mm: 47%) and the compressive strength (from 44.6 MPa to 31.4 MPa: 29.7%). By appropriate using of a superplasticizer, the loss in the workability could be recovered. Microstructural investigation was conducted employing scanning electron microscope analysis; it showed that the formation of a weak interfacial transition zone between PPCA and cement paste to be the reason for strength reduction in PPCA concrete. In contrast, the addition of 10 – 20% of FA in concrete improved the workability by 63.2% – 100%, but yet again, the 28-day compressive strength reduced by 15.8 – 35.6%. Meanwhile, thermal conductivity results and constitutive relationships proved that the use of PPCA enhanced the thermal insulation property and ductility of PPCA concrete, respectively. Eventually, a total of six concrete batches with binary blended PPCA and FA were cast to find the optimum replacement levels. The optimum binary combination with reasonable strength and workability at a minimal cost was achieved to be 10% PPCA and 20% FA.

PENERAPAN TEKNOLOGI DRYING DENGAN GREEN HOUSE EFFECT UNTUK PENINGKATAN EFISIENSI PRODUKSI DAUR ULANG PLASTIK PADA DR PLASTIK GUNUNGKIDUL

DR Plastik is a creative industry in the field of plastic recycling located in Putat Village, Patuk District, Gunungkidul. The number of employees at DR Plastik is 25 people, both as waste sorters, shredding machine operators, washers and administrators. The production capacity of recycled plastic waste is ± 2 tons/day. The plastic waste is processed in the form of dry plastic shreds and resold. Current conditions, the drying process at DR Plastik still takes 2-3 days manually (during the rainy season). This condition makes production run ineffectively and causes product quality to decrease due to uneven drying. The aim of the program is to create drying room technology with a green house effect. This program involves several stages such as coordination with DR Plastik partners regarding the drying room area, procurement of materials and tools, manufacturing a drying room with green house effect, training, and monitoring and evaluation. The result of implementing the program is a drying room with a green house effect measuring 6x10 m2 with a transparent galvalum roof. Galvalum has advantages in terms of resistance to impact, high structural strength, and has good heat absorption capacity, so that the temperature in the building remains comfortable. Apart from that, the production of rainwater channels is centralized in the production process, so that the dried plastic is safe from rainwater. This program shows a significant increase in employee knowledge and skills regarding the use of drying rooms. Apart from that, the drying process has become more effective and efficient from 2-3 days (during the rainy season) to 1 day (during the rainy season) and the production of dry plastic shreds ready for sale has increased by 75%.

Polyethylene hydrogenolysis by dilute RuPt alloy to achieve H2-pressure-independent low methane selectivity

Chemical recycling of plastic waste could reduce its environmental impact and create a more sustainable society. Hydrogenolysis is a viable method for polyolefin valorization but typically requires high hydrogen pressures to minimize methane production. Here, we circumvent this stringent requirement using dilute RuPt alloy to suppress the undesired terminal C–C scission under hydrogen-lean conditions. Spectroscopic studies reveal that PE adsorption takes place on both Ru and Pt sites, yet the C–C bond cleavage proceeds faster on Ru site, which helps avoid successive terminal scission of the in situ-generated reactive intermediates due to the lack of a neighboring Ru site. Different from previous research, this method of suppressing methane generation is independent of H2 pressure, and PE can be converted to fuels and waxes/lubricant base oils with only <3.2% methane even under ambient H2 pressure. This advantage would allow the integration of distributed, low-pressure hydrogen sources into the upstream of PE hydrogenolysis and provide a feasible solution to decentralized plastic upcycling.

Providing a new route for chemical recycling of plastics by aspen plus simulation, energy, and its carbon dioxide emissions analysis

In this research, a new complex is proposed for chemical recycling of plastic. After determining the plastic waste entering this process, the sections in which chemical reactions occur have been simulated through aspen plus, such as: gasification of plastic waste and purifying, methanol production, methanol decomposition to various chemicals such as ethylene, propylene, and methane, separation processes for these products, methane decomposition to benzene and the separation of the products of this part, single-step production of styrene from benzene and ethylene, and the polymerization processes. Furthermore, the impacts of this complex on issues such as plastic recycling, energy consumption, and carbon dioxide emissions are studied and compared to conventional methods of plastic production. Results indicate that plastic waste recycling will be more than 98% in the proposed model. Energy consumption is decreased by 29%, carbon dioxide in this part is decreased by 53% by using renewable energy for its power consumption. These results show the sustainability, and circularity of the proposed model.

Monomer production from supercritical ethanol depolymerization of PET plastic waste using Ni-ZnO/Al2O3 catalyst

Plastic waste poses a serious threat to the global environment, with recycled polyethylene terephthalate (PET) plastic accounting for a considerable portion. The application of supercritical ethanol depolymerization technology presents an effective method for recycling PET waste. This study investigated using Ni as an additive to enhance the catalytic activity of ZnO/Al2O3 catalyst for PET waste depolymerization. The effects of different catalysts, catalyst dosage, reaction temperature, and reaction time on PET waste depolymerization were studied using the single-factor controlled variable method. The results showed that the 3Ni-ZnO/Al2O3 was the optimal catalyst, and under the optimal conditions with catalyst dosage of 4 %, reaction temperature of 260 °C, and reaction time of 60 min, the depolymerization efficiency of PET waste could reach 100 %, with the highest yields of diethyl terephthalate (DET) and ethylene glycol (EG) of 93.6 % and 90.2 %, respectively. Response surface methodology (RSM) was used to optimize the operating conditions to obtain the highest monomer yields. The predicted optimal parameters from RSM were as follows: reaction temperature = 262.8 °C, reaction time = 63.2 min, catalyst dosage = 3.8 wt%, with the predicted highest DET and EG yields of 95.9 % and 90.7 %, respectively. The analysis of variance (ANOVA) results for DET and EG possessed the R2 values of 0.9921 and 0.9885, respectively, with p-values < 0.0001, indicating a good fit for the models. Furthermore, after five times reuse, the 3Ni-ZnO/Al2O3 catalyst still exhibited good catalytic activity and stability. In conclusion, this study offers a clean, green, and sustainable alternative to recycling plastic waste.

Leveraging Waste Banks for Green Environment Sustainability: A Case Study of Community Collaboration in the Gemuruh District, Bandung City, Indonesia

Waste management is a critical issue worldwide, including in Indonesia. In recent years, there has been a growing focus on waste management due to population growth and rapid urbanization. This initiative emphasizes the implementation of technology and innovation in waste management and its impact on communities. The results show that the use of organic waste shredding machines, waste banks, and compost bags has improved waste management efficiency. Training on sorting inorganic and organic waste, as well as using shredding machines, has enhanced the knowledge and skills of the community. Pre-tests and post-tests indicate an increase in understanding and skills in waste management, highlighting the effectiveness of the training program. The community has positively responded to the implementation of technology and innovation. This initiative demonstrates that empowering creative economy through plastic waste recycling can have a positive impact on communities, particularly in raising awareness and skills in waste management.

MAl-X [M-Zn, Mg, Ni; X- Cl, NO3, CO3] layered double hydroxides: Catalytic applicability in plastic waste recycling and wastewater treatment for the sustainable environment

MAl-X [M-Zn, Mg, Ni; X- Cl, NO3, CO3] layered double hydroxides: Catalytic applicability in plastic waste recycling and wastewater treatment for the sustainable environment

Upcycling expanded polyethylene waste for novel composite materials: physico-mechanical, hygrothermal and life cycle assessment

Recycling plastic waste is a major challenge today, but it also offers an opportunity to create sustainable building products and promote a circular economy in construction. The aim of this article is to evaluate a new lightweight plaster composite incorporating expanded polyethylene (EPE) packaging waste for lightweight steel frame (LSF) partition walls. Mechanical and hygrothermal characterization and environmental life cycle assessment are carried out on these composites with a replacement of up to 30% of the original raw material by volume. The results show that the alternative plaster has 21.7% grater flexural strength in plates than required by standards. In addition, the reduced water vapour permeability of these materials makes them more resistant to damage in high humidity environments. On the other hand, the lightened composites have 43.9% lower thermal conductivity than the reference material, increasing the thermal resistance of LSF partition walls by 20.3%. Finally, cradle-to-gate global warming potential is reduced by up to 30% compared with the 100% virgin EPE. These results are encouraging and present a significant opportunity to advance the development of sustainable novel prefabricated modular building products.

Renewable Fuels and Chemical Recycling of Plastics via Hydrothermal Liquefaction.

ConspectusHydrothermal liquefaction (HTL) converts a wide range of biomass feedstocks into a renewable bio-oil via reactions in hot, compressed water. Other products that form partition into the gas, aqueous, or solid phases. The reactions taking place during HTL include hydrolysis, decarboxylation, condensations, additions, deamination, and dehydration. Bio-oil production from HTL has been demonstrated for many renewable materials including microalgae, macroalgae, sludge from water treatment, food waste, agricultural residues, bacteria, yeast, and a wide variety of lignocellulosic materials. HTL of whole biomass is an energy densification process as it generally recovers about 70-80% of chemical energy in an oil product that is just 20-50 wt % of the mass of the original feedstock. The oil is typically rich in oxygen (10 -20 wt %) and also in nitrogen (about 5 wt %), if the biomass contains protein. The oil also contains metals such as iron. Therefore, an upgrading and/or refining process would be required to convert the crude bio-oil to a finished fuel. Each biochemical component in biomass (e.g., polysaccharides, protein, lipids, lignin) contributes different proportions of its initial mass to biocrude. Lipids provide the highest biocrude yields whereas polysaccharides and lignin provide the lowest. Kinetics models have been developed that incorporate different reactivities for the different biochemical components. These models, which are effective in correlating and predicting the yields of biocrude and other product fractions from HTL, can be used in technoeconomic analysis and life-cycle assessments to advance commercial adoption of the technology.HTL is also effective in producing an oil product from decomposition of many different plastics. Thus, it can be used for chemical recycling or valorization of post-consumer waste plastics. Polyolefins and polycarbonates can give oil yields exceeding 90 wt %. Polyethylene terephthalate (PET) gives very low oil yields. The major product from PET hydrolysis, terephthalic acid, is a solid at room temperature and not soluble in the organic solvents typically used to recover oil.Hydrothermal decomposition of isolated biochemical components of biomass and individual synthetic polymers provides insights into the governing chemical reaction pathways. Results from such experiments also enable development of component additivity models that can predict oil yields and other outcomes from HTL of biomass, plastics, and their mixtures.Research needs in this field include more detailed, molecular-level kinetics models, experimental work on HTL and hydrolysis of the many synthetic plastics that have not yet been adequately explored, and experiments and modeling for mixtures of different plastics and mixtures of plastics with biomass.

Performance evaluation of controlled low-strength blended cement concrete modified with recycled waste materials

Purpose This work aims to investigate the feasibility of recycling waste plastic (polyethylene terephthalate) as a coarse aggregate for producing blended cement concrete modified with fly ash and pond ash. Design/methodology/approach The low, medium and high controlled strength blended cement concrete modified with varied proportions of fly and pond ashes were produced. Manufactured sand and recycled plastic coarse aggregate (RPCA) replaced normal fine and coarse aggregates. Concrete samples were tested for workability, mechanical and durability characteristics. Microstructural analysis was performed on cement concrete blended with fly and pond ashes and compared to conventional concrete samples. Findings All concrete mixes showed better flowability with values greater than 200 mm. Besides, the maximum flow time was approximately 8 s. The wet density of blended cement concrete-RPCA-based concretes was approximately 30% lower than that of conventional concrete. The compressive strengths of the controlled strength mix at 7 and 28 days were within the specified ranges. While the conventional concrete had slightly higher permeability, the blended cement concrete-RPCA-based concretes had better thermal resistivity and lower thermal conductivity. The scanning electron microscopy analysis revealed the densification of the microstructure due to the filler effects of fly and pond ashes. Originality/value This study establishes the prospects of substituting RPCA with normal coarse aggregate in the production of controlled low-strength blended cement concrete, offering benefits of structural fill concrete, lower permeability and thermal conductivity, higher thermal resistivity and reduced density and shrinkage.

Experimental Study on the Mechanical Properties of Sustainable Concrete using Recycled Plastic and Glass Waste

This study explores using recycled waste glass and plastic fibers as substitutes for fine aggregates in concrete to meet the growing need for sustainable building materials. The basic materials consist of OPC 43 grade and locally obtained river sand. The research incorporates glass powder from crushed beer bottles and plastic fibers from recycled plastic bottles into the concrete mixture. Various tests, including slump, compressive strength (CS), and split tensile strength (STS) assessments, are performed to ascertain the characteristics of the modified concrete in both its fresh and hardened states. The findings demonstrate a significant enhancement in the ease of handling when glass powder is used, exhibiting a surge of 170% and 270% for mixtures, including 15% and 25% glass powder, respectively, compared to conventional OPC concrete. Although including these recycled materials reduces compressive strength (19.95% for SP15 and 21.39% for SP25); tensile strength is significantly improved, with gains of 35% for SP15 and 53.75% for SP25. This research emphasizes the feasibility of integrating waste glass and plastic fibers into concrete as a practical method for sustainable building.

A green and efficient method to prepare oleic acid–modified CaCO3/reHDPE composites

Industrial recycling of waste plastics frequently utilizes mechanical recovery and recycling. However, plastics recycled through mechanical recovery tend to have reduced properties, limiting their applications. In this study, modified calcium carbonate (OA-CaCO3) was prepared using different amounts of oleic acid (OA) (0.5, 1.0, and 2.0 wt%). Infrared spectroscopic characterization showed OA was successfully adsorbed on the CaCO3 surface. Particle size, micromorphology, oil absorption value, and activation tests indicated that CaCO3 modified with 1.0 wt% OA yielded optimal results. Melt blending 1.0 wt% OA-modified CaCO3 with recycled high-density polyethylene (reHDPE) produced composites. Scanning electron microscopy results showed OA modification enhanced interfacial compatibility between the two phases. Mechanical property tests revealed at high filling levels, the impact strength of OA-modified composites increased considerably, reaching 42.6 kJ/m2 with 40 wt% OA-CaCO3 filling. Melt flow rate test results showed that OA-modified composites had increased melt flow and modified processing properties. Filling OA-CaCO3 to compensate for reHDPE properties caused by mechanical recycling is essential to expand mechanical recycling applications in plastics recycling.

Recycling of puffed polystyrene beads waste as a low‐cost antifouling ultrafiltration membrane for water purification

AbstractCurrently, plastic waste, limited water resources, and water contamination are challenges of universal concerns. Recycling plastic waste as a membrane for water/wastewater treatment is of great significance from the perspective of environmental protection and safe drinking water supply. In this study, we used for the first time the puffed polystyrene beads waste (PPSBW) as a basic material for the fabrication of an ultrafiltration membrane and Pluronic F127 (PF127) as a plasticizer and hydrophilizing agent. Different ratios of PF127 were added to the casting solution, and the characteristics of the blank PPSBW and PF127‐modified membranes (PPSBW‐PF127) were evaluated in detail. The addition of PF127 increased the turbidity and viscosity of the casting solution, decreased the contact angle (increased the hydrophilicity), decreased the pure water flux, and increased the rejection of humic acid. The PPSBW membrane with 3 wt.% of PF127 showed the highest antifouling properties, the highest cleaning efficiency, and kept a satisfactory BSA and pure water flux for 4 runs. Overall, PF127 improved the hydrophilicity, organic matter separation, and enhanced the antifouling properties of the PPSBW‐derived membrane.Highlights Renew flow: Repurposing plastic waste as a UF membrane was successfully achieved. The PPSBW‐PF127 membrane was applied for wastewater treatment. Mechanical properties showed reasonable response by adding Pluronic F127. The PPSBW‐PF127 membrane demonstrated a significant rejection and permeability. The PPSBW‐PF127 membrane showed the highest antifouling and cleaning properties.

The Properties of Bricks Made from Recycled HDPE

Plastic waste, particularly high-density polyethylene (HDPE), poses significant environmental challenges due to its non-biodegradable nature. Recycling HDPE into building materials, such as bricks, offers a sustainable solution to mitigate these impacts. This study investigates the properties of bricks made from recycled HDPE, focusing on their compressive strength, water absorption, and durability. The results indicate that HDPE bricks exhibit superior mechanical properties, including higher compressive strength and lower water absorption compared to traditional clay bricks. These bricks are lightweight, cost-effective, and demonstrate excellent durability, making them a viable alternative for sustainable construction. The research highlights the potential of recycled HDPE bricks in reducing plastic waste and promoting environmental sustainability. The intensifying generation of plastic waste presents a significant environmental challenge worldwide. Plastic waste, due to its non-biodegradable nature, contributes to land and water pollution, requiring the exploration of sustainable waste management solutions. Recycling plastic waste into building materials, such as bricks, offers a potential solution to mitigate environmental impacts. This research aimed to investigate the integration of plastic waste into building materials through a comprehensive study using experimental testing, software analysis, and structural design. The ETAB analysis demonstrated that the HDPE model exhibited lower bending moments and axial loads compared to the concrete model, suggesting superior mechanical properties and load-carrying capacity. This research contributes to the understanding of the behaviour and performance of plastic bricks in structural applications, enabling the development of sustainable and efficient building designs that incorporate plastic waste materials. Key Words: Plastic Waste, Environmental Challenge, Non-Biodegradable, Sustainable Solutions, Experimental Study, Plastic Bricks, Alternative Building Materials, Methodology, Comparable Strength, Plastic Waste Crisis.

Super Tough PA6/PP/ABS/SEBS Blends Compatibilized by a Combination of Multi-Phase Compatibilizers.

Development of multi-component blends to prepare high-performance polymer materials is still challenging, and is a key technology for mechanical recycling of waste plastics. However, a multi-phase compatibilizer is prerequisite to create high-performance multi-component blends. In this study, POE-g-(MAH-co-St) and SEBS-g-(MAH-co-St) compatibilizers are prepared via melt-grafting of maleic anhydride (MAH) and styrene (St) dual monomers to polyolefin elastomer (POE) and poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS), respectively. Subsequently, these compatibilizers are utilized to compatibilize the PA6/PP/ABS/SEBS quaternary blends through melt-blending. When POE-g-(MAH-co-St) and SEBS-g-(MAH-co-St) are added, respectively, both can promote the distribution of the dispersed phases, significantly reducing the dispersed phase size. When adding 10 wt% POE-g-(MAH-co-St) and 10 wt% SEBS-g-(MAH-co-St) together, compared to the non-compatibilized blend, the fracture strength, fracture elongation, and impact strength surprisingly increased by 106%, 593%, and 823%, respectively. It can be attributed to the hierarchical interfacial interactions which facilitate gradual energy dissipation from weak to strong interfaces, resulting in the improvement of mechanical properties. The synergistic effect of the enhanced phase interfacial interactions and toughening effect of elastomer compatibilizer achieved simultaneous growth in strength and toughness.

Plastic waste in dense asphalt mixes for road pavements

Recycling plastic waste in asphalt pavements records increasing statistic figures of application during the last decade worldwide. Due to environmental constraints, but also, to some beneficial properties of plastic waste, recycling in asphalt tends to become current practice, in several countries. In the Aristotle University of Thessaloniki (AUTH), the first attempt to produce asphalt mix using plastic waste consisted of mixing recycled plastic flakes with non-modified binder. Following an asphalt mix design in the laboratory, the whole mass of conventional aggregates was replaced by PET flakes. Recycled PET flakes were chosen to be introduced in the asphalt mix since they are hard, resilient and water repellent. Bitumen emulsion was first preferred as a binder to produce a cold asphalt mix. At a second stage of experimental research, plastic flakes replaced a part of the limestone sand while conventional asphalt 50/70 was used as a binder. At this stage, the experimental research provided more encouraging outcomes. Stability of asphalt mixes decreases as the plastics content in the mix increases, but all recorded values were still within limits of acceptance. At a third stage of research, LDPE recycled material of fine gradation was used to replace a part of the asphalt binder in dense mixes. The objective was to produce a modified binder and a more durable asphalt structure. Test results showed a significant improvement of the performance of asphalt mixes, in terms of strength and deformability of the asphalt mix structure. The research is completed by comparing the conventional techniques with the outcomes of the recycling process and by delineating potential fields of application of the recycled plastics in asphalt pavements.

Recovery of Bis(2-hydroxyethyl) terephthalate and terephthalic acid from waste PET bottles for synthesis of cerium-based metal-organic frameworks: A study towards supercapacitor applications

Controlled chemical recycling of plastic waste is a most important concern to reduce plastic waste as well as effective recovery of the various byproducts without toxic emission. In this study, we focused on effective recovery of Bis-2-hydroxyethylene terephthalate (r-BHET) from polyethylene terephthalate (PET) waste via solvent free melt depolymerization process. Recovered BHET was converted into terephthalic acid (r-TPA) by hydrolysis. Both r-BHET and r-TPA were used to construct a metal organic framework (MOF) with cerium metal for potential energy applications. Extensive characterization, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy-Dispersive X-ray Spectroscopy (EDX) were confirmed the structural integrity and purity of the r-BHET and r-TPA and provides insights into the well-defined structure and elemental composition of the MOFs. The specific capacitances of BHET and TPA-Ce-MOF were found to be 91.5 and 220.1 F/g respectively. Comprehensive characterization ensures the quality of the recovered products and synthesized MOFs, promoting environmentally conscious strategies in materials synthesis and energy storage applications.

Effects of acid and sulphate attack on concrete containing recycled plastic waste fine aggregate

Effects of acid and sulphate attack on concrete containing recycled plastic waste fine aggregate

The Factors Influencing the Recycling of Plastic and Composite Packaging Waste

The Factors Influencing the Recycling of Plastic and Composite Packaging Waste

Anodic Commodity Polymer Recycling: The Merger of Iron-Electrocatalysis with Scalable Hydrogen Evolution Reaction.

Plastics are omnipresent in our everyday life, and accumulation of post-consumer plastic waste in our environment represents a major societal challenge. Hence, methods for plastic waste recycling are in high demand for a future circular economy. Specifically, the degradation of post-consumer polymers towards value-added small molecules constitutes a sustainable strategy for a carbon circular economy. Despite of recent advances, chemical polymer degradation continues to be largely limited to chemical redox agents or low energy efficiency in photochemical processes. We herein report a powerful iron-catalyzed degradation of high molecular weight polystyrenes through electrochemistry to efficiently deliver monomeric benzoyl products. The robustness of the ferraelectrocatalysis was mirrored by the degradation of various real-life post-consumer plastics, also on gram scale. The cathodic half reaction was largely represented by the hydrogen evolution reaction (HER). The scalable electro-polymer degradation could be solely fueled by solar energy through a commercially available solar panel, indicating an outstanding potential for a decentralized green hydrogen economy.