Hydrogen Production from Catalytic Polyethylene Terephthalate Waste Reforming Reaction, an overview

Background: Plastic waste (PW) is becoming increasingly hazardous to the environment as a result of its massive production, causing significant damage to both the ecosystem and its inhabitants. Managing plastic waste is a global concern due to its non-biodegradable nature. However, it is important to handle PWs properly to curtail the environmental emissions associated with their incineration and dumping into landfills. This research investigates the possibility of producing tiles from polyethylene terephthalate (PET) waste bottles and fly ash. The mechanical properties, as well as the chemical resistance of the manufactured PET polymer tiles, are reported in this study. Methods: PET waste was used in varying proportions (from 30% to 100%) by sand weight. The shredded PET waste was heated at 230 oC before being suitably blended with fly ash. It was then poured into the designated mold, removed after one hour, and cooled for 24 hours before testing. Results: The assessment of the physical and mechanical properties of the materials revealed that the tiles produced with 30% PET content performed better in terms of material density and strength compared to the samples with higher PET content. The highest compressive strength being 6.88 MPa. Based on the results of the tests, the produced PET tiles have a low water absorption efficiency of 80% lower when compare to cement and ceramic tiles (the water absorption values are between 0.98% and 0.09%). Conclusions: The results from this study indicate that PET waste bottles can be used to produce long-lasting, durable, and extremely low water absorption eco-friendly tiles for both residential and commercial applications. This prospect of tile production using polyethylene terephthalate (PET) waste and fly ash would not only minimize the cost of building products but will also act as a waste diversion to mitigate environmental emissions caused by plastic waste disposal.

: Reaction of poly (ethylene terephthalate) waste (PETW) powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol zinc acetate as a catalyst was carried out in a batch reactor at 470 K and at atmospheric pressure. Reactions were undertaken with various particle size ranges from 50–512.5 µm, and reaction time from 30–70 min at 10 min intervals for reaction of PETW. A low molecular weight product of PETW was obtained during this step. In the next stage hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide solution were introduced to convert the low molecular weight product of PETW into terephthalohydroxamic acid (TPHA) by introduction of HCl as per stoichiometric requirement. The TPHA is used as insecticide, and it is highly expensive. To increase the PETW conversion rate, an external catalyst (zinc acetate) was introduced during the reaction. The product was deposited on the surface of unreacted PETW that was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate DMSO, CHA, and THF were introduced during the reaction, which had an industrial significance. Depolymerization of PETW was proportional to the reaction time. Depolymerization of PETW was inversely proportional to the particle size of PETW. Analyses of value added products (TPHA and EG) as well as PETW were undertaken. A kinetic model was developed and experimental data simulated with it that were consistent with the model. A thermodynamic study was undertaken as this is required during transfer of laboratory data through a pilot plant for commercialization.

Plastic (Polyethylene Terephthalate, PET) is now used as packaging material for a whole range of consumer products in addition to carbonated beverages. Although plastics are very useful product, but the disposal of these wastes has become a problem and is of great concern, particularly in our country. One of the solutions to the disposal of plastic wastes is recycling it into useful products such as it may be used in bituminous (asphaltic) pavements construction, resulting in reduced permanent deformation in the form of rutting of the pavement surface. The present study discusses in detail about the effect of PET on various engineering properties of bitumen. The PET waste was added in the bitumen from 2 to 14% and various tests such as penetration, ductility, softening point, viscosity, flash and fire point and stripping tests were performed for the characterization of plain bitumen and PET modified bitumen. The most effective percentage of Polyethylene Terephthalate (PET) waste was obtained between 10 to 12% by weight of the bitumen. The results of the study indicated that the modified mixture possessed better performance as compared to the non-modified bitumen. The experimental results were also authenticated by conducting Scanning Electron Microscopy (SEM) on the most effective percentages mixtures. It is observed that the addition of PET waste in the bitumen improves its engineering properties such as ductility, penetration, softening point and viscosity values by 32.43%, 14.56%, 26%, and 34% respectively. It has also been observed that addition of 12% PET waste results in zero percent stripping even after 48 hours.

There is a tremendous increase in plastic waste that negatively impacts the environment due to various industrial activities. Furthermore, plastic waste has non-biodegradable properties that make it hard to reduce its accumulation around the globe. Hence, this study aims to investigate the possibility of incorporating Polyethylene terephthalate (PET) waste as a partial replacement material of sand to improve the thermal insulation properties of cement sand brick by looking at findings of low thermal conductivity value. The study uses a PET plastic bottle that has been cut into small flakes and grind using a granulator machine to produce PET waste granules whose size is not more than 5 mm, similar to the sand size. This waste was added to other raw materials, i.e., cement and sand. The percentages of PET waste vary from 2.5%, 5%, and 7.5% by weight. This study produced two types of samples, i.e., control brick and PET waste cement sand brick. All samples undergo laboratory works involving geotechnical gradation, physical, mechanical, and thermal conductivity testing. Based on the results obtained, the optimum proportion of PET waste replacement in cement sand bricks making is 5% by its having the lowest thermal conductivity value of 0.581 W/mK and meeting the standard requirements of 3.90 MPa > 3.45 MPa (ASTM C129-11 for compressive strength), and 2,146 kg/m3 > 2,000 kg/m3 (ASTM C129-11 for normal weight non-loadbearing brick). Thus, PET plastic bottle waste can be a potential partial sand replacement material in cement sand bricks. Its potential to enhance the thermal conductivity of existing cement sand brick reduces sand consumption, solves plastic waste problems, and promotes a better environmentally-friendly construction industry.

Plastic waste management is a global problem that threatens the health of our planet due to its high rate of development and non-biodegradability. Also, palm oil fuel ash (POFA) is a residue produced when waste products including palm oil fiber, palm kernel shells, and palm oil hush are burned. This study investigates the feasibility of making tiles out of polyethylene terephthalate (PET) waste bottles and POFA (Palm oil fuel ash). This study reports on the mechanical properties, durability, and chemical tolerance of PET-wall tiles. PET waste was used in different amounts with POFA by weight (from 30% to 100%). The physical and mechanical characteristics of the tiles were examined, and it was discovered that, in terms of material density and strength, tiles containing 30% PET, have highest compressive strength of 8.37 N/mm² while samples made with higher PET content (100%) have the least compressive strength lowest water absorption value (0.12%). All the tiles produced outperformed pure cement and ceramic tiles in terms of durability, and they have a very low water absorption efficiency; the water absorption values were between 1.82% and 0.12% and good chemical tolerance. In conclusion, based on this experimental result, PET waste bottles and POFA can be used to produce long-lasting, good strength, and highly low-water-absorption eco-friendly wall tiles for both residential and commercial applications. This possibility of producing tiles from polyethylene terephthalate (PET) waste and POFA would not only reduce the cost of construction materials but also serve as a waste diversion to reduce environmental pollution generated by plastic waste.

Catalytic processing of plastic waste on the rise

Geotechnical characterization of plastic waste materials in pavement subgrade applications

In this polymer‐governing era, polyethylene terephthalate (PET) has become one of the most demanding consumables. This growing interest in the production and consumption of plastic products results in an increase in the volume of post‐consumer plastic waste. However, due to the growing concern for environmental protection, recycling PET waste to the valuable ones has become one of the hot topics in contemporary research. In this study, PET waste was depolymerized using ethanolamine as a depolymerizing agent. N,N′‐Bis(2‐hydroxyethyl)terephthaldiamide (BHETA) (yield 77%) was obtained after depolymerization of PET via ethanolamine. The characterization of the monomer BHETA was done using FTIR, 1H NMR, and FE‐SEM. The thermal stability of PET and BHETA was done using TGA analysis. To avoid the extreme reaction condition (high temperature and high pressure) of conventional way to form terephthalic acid (TPA) via hydrolysis of PET waste, in this study, a facile way is performed. The monomer BHETA was converted to a main building block of PET (TPA) (yield 67%) using strong oxidizing agent KMnO4 in mild reaction conditions at room temperature and pressure. The synthesized TPA was characterized using FTIR and 1H NMR. This work also focuses on the anticipation of the reaction progress of aminolysis of PET using simple analytical tools namely, FTIR and TGA.

This study explores the development of a sustainable foam mortar incorporating recycled polyethylene terephthalate (PET) waste as a partial sand replacement to enhance thermal insulation and promote circular economy practices. Foamed mortars incorporating recycled polyethylene terephthalate (PET) waste were developed in this study, with the overall goal of addressing the dual challenge of waste management and resource depletion. PET waste, commonly discarded as environmental pollutants, was processed into fine aggregate sizes and used as a partial replacement for sand. There were six mix proportions with PET replacement ratios (0, 5, 10, 15, 20, and 25%). PET improved thermal insulation by lowering thermal conductivity from 0.31 W/mK to 0.26 W/mK and reducing density by up to 15%. At 28 days, the compressive strength varied between 12.5 MPa (0% PET) and 9.8 MPa (25% PET), suggesting that it is viable for non-structural applications. Similar declines of 25–30% and 20–25%, respectively, in flexural and tensile strengths were ascribed to weakened interfacial bonding between PET and the cement matrix. At higher PET levels, durability increased, with a 20% decrease in water absorption and a substantial decrease in chloride ion penetration. The use of PET significantly improved thermal properties, and microstructural analysis confirmed more refined pore structures and homogeneous dispersion of PET particles. These results show that PET can be a sustainable alternative to foam mortar, promoting environmentally friendly construction methods and the concepts of the circular economy.

Asphalt pavement is one of the main elements of transportation infrastructure. However, asphalt pavements often suffer from damage such as cracking, plastic deformation and peeling due to the influence of traffic loads and extreme temperature changes. With the extensive use of plastics in daily life leading to an increase in plastic waste which has become one of the serious problems in Indonesia, an alternative is needed to deal with the problem. By modifying the asphalt filler using Polyethylene Terephthalate (PET) waste, the AC - WC asphalt layer is one way to increase the stability of the road structure. The purpose of this study is to determine the comparison of the value of marshall characteristics in the AC-WC layer with the addition of Polyethylene Terephthalate (PET) waste filler fixed at 7%, and Polyethylene Terephthalate (PET) waste varies by 6%, 6.5%, 7%, 7.5%, and 8%, and analyze the addition of PET plastric waste to the value of Marshall characteristics as a mixture of asphalt filler in the AC - WC layer. The method used in this research is the experimental method, using a control variable at 5.3% asphalt content with a fixed PET combination of 7%. Based on the results of the study that the addition of PET waste in the AC-WC asphalt mixture has an influence on the marshall characteristics, it can be seen from the values of Stability, Flow, VIM, VFM, VFB, and Marshall Quentiont which have changed.

To address the excessive depletion of natural resources in Indonesia's civil construction sector, there's a rising trend in utilizing plastic waste from packaging, such as beverage bottles and plastic bags, alongside renewable energy sources like Modified Buton Asphalt (MBA). MBA serves as a partial substitute for both fine and coarse natural aggregates and non-renewable energy sources like petroleum bitumen. This study aimed to investigate the effects of incorporating polyethylene terephthalate (PET) and polypropylene (PP) waste as partial substitutes for coarse and fine aggregates through experiments and t-tests. The objective was to determine how the stress-strain behavior of asphalt mixtures formed using MBA changed with the addition of this mixture. Additionally, compressive strength and elastic modulus were calculated under mixed compressive loads. PET and PP plastic waste replaced natural coarse and fine aggregates at three volume percentages: 1%, 2%, and 3%, with a PET:PP ratio of 50%. A manual grater was used to shred PET and PP plastic bottles into shredded plastic waste, which was retained in sieve no. 50 after sieving. The study found that adding PET, PP plastic, and MBA waste enhanced the asphalt mixture's mechanical strength and modified relevant variables, resulting in a more elastic and ductile behavior. Doi: 10.28991/CEJ-2024-010-05-011 Full Text: PDF

Population expansion and the development of technology have led to an increase in construction activities. In many cases, foundation grounds do not have a high enough bearing capacity and are not capable of ensuring the safe exploitation of the construction. A soil with poor mechanical characteristics must be improved using various methods, such as adding hydraulic binders (lime and cement), natural fibres, or more recently, plastic waste materials. This work aims to study the behaviour of plastic waste materials made from polyethylene terephthalate (PET) in soil improvement. Thus, the mechanical characteristics of a clay improved with shredded PET were studied. PET was added in relation to the dry mass of the clay, in percentages of 2%, 4% and 6%. The studied clay was collected from a construction site around Cluj-Napoca, Romania, from a depth of 1 ÷ 10 m. PET was provided by a local plastic waste repository. It comes from recycled water, beer and soda bottles and was cleaned using specific methods for cleaning and recycling plastic waste. PET was shredded into irregular shapes with sizes ranging from 3 mm to 12 mm and was randomly distributed in the test specimens. Compression and direct shear tests were carried out to study the compressibility and shear parameters of the improved soil (internal friction angle and cohesion). The experimental results showed an improvement in the mechanical characteristics of the clay even at a low PET addition of 2% and 4%. This method can contribute to solving two current problems of the modern world: reducing pollution by recycling plastic waste materials and using them to improve the mechanical characteristics of soil.

The cost of construction materials, as well as the natural resources needed to manufacture the materials in an enabling climate, is affecting the world's construction industry, which is expanding at an unprecedented pace. Plastic wastes are a significant environmental concern due to their widespread use, non-biodegradability, and contamination from incineration and landfill, recycling these wastes into tiles would be a significant benefit. This investigation's goal is to study the mechanical qualities of tiles made from PET (Polyethylene Terephthalate) wastes, fly ash, and river sand aggregates. PET wastes were added to other aggregates in various percentages of 100 percent, 90 percent, 70 percent, 50 percent, and 30 percent by weight. The assessment of physical and mechanical properties reveals that, in terms of material density, weight, and flammability resistance, the tiles containing 30% plastic waste outperforms the other proportion of waste. According to the results, this composite tile has a very low percent porosity value (2.9 - 0.11 percent) as compared to cement or ceramic tiles. In addition, the composite tile (PT1) with 30% PET and 35% fly ash and sand demonstrated decreased flammability with a linear burning rate of 7.68 mm/min and enhanced compressive strength of 11.07 N/ mm2. There was no significant difference in weight after soaked in different acid and base solutions for seven days. Finally, as tile products, PET plastic tiles have good strength, chemical tolerance, low flammability, low water absorption, and are environmentally friendly. This possibility would not only reduce the cost of construction materials, but it would also serve as a waste diversion, reducing the environmental impact of plastic waste disposal.

Polyethylene terephthalate (PET) is widely used for packaging. However, improper disposal of PET has led to substantial environmental concerns, such as plastic pollution, microplastic generation, and considerable amounts of PET waste accumulation in landfills and aquatic environments. To address this issue, we develop a sustainable strategy to repurpose PET waste into antibacterial packaging material by applying polydopamine (PDA) coating and incorporating tannic acid (TA). The incorporation of PDA and TA leads to ~ 97% antibacterial efficacy against S. aureus without affecting the chemical and themral properties of PET. In summary, our work aims to contribute to sustainable waste management practices.Graphical abstract

In order to improve the sustainable construction in Peru, throughout the recycling of non-biodegradable materials, a study of the influence of glass and Polyethylene terephthalate (PET) wastes in the physic properties of concrete bricks was carried out. They were made with a 1:5:2 cement, fine aggregate, and waste relation. Three proportions were studied named P-01, P-02, and P-03. Each proportion had a different content of glass and PET wastes, as a result, it was found that the average brick’s absorption was increased with PET wastes and it was reduced with glass wastes. On the other hand, the compressive strength value increased with glass wastes and it was reduced with PET wastes. Finally, it was found that P-02 was the most efficient concrete brick proportion to develop a sustainable construction, obeying the requirements of the Peruvian national building regulations.