Polyethylene Terephthalate Bottles Research Articles

Upcycling waste polyethylene terephthalate (PET) bottles into high-performance activated carbon for electrochemical desalination

Upcycling waste polyethylene terephthalate (PET) bottles has attracted intensive research interests. This simultaneously alleviates plastic pollution and achieves a waste-to-resource strategy. Waste PET water bottles were used to fabricate value-added activated carbon (AC) electrodes for capacitive deionization (CDI). The KOH activation temperature (greater than 700 °C) prominently affected the physi-chemical properties and desalination performance of PET-derived activated carbons (PET-AC). Profiting from a large Brunauer–Emmet–Teller specific surface area (1448 m2 g−1) with a good mesoporous structure (the ratio of the mesopore volume to the total pore volume was 41.3%), PET-AC-1000 (activated at 1000 °C) possessed a huge specific capacitance of 108 F g−1 for capacitive ion storage. Moreover, when utilized as the electrode material in single-pass CDI, PET-AC-1000 exhibited a maximum electrosorption capacity of 10.82 ± 0.11 mg g−1 and a low level of energy consumption (0.07 kWh mol−1), associated with good electrochemical charging-discharging cyclic stability. The results provide a promising facile approach to tackle the challenge of plastic pollution and promote the advancement of electrode materials for economic affordable and energy-efficient electrochemical desalination process, which meets the United Nations (UN) sustainable development goals (SDGs).

Ammonia-Borane Dependent Transfer Hydrogenation of Carboxylic Esters to Primary Alcohols.

Here, we present a user-friendly protocol that uses bench-stable NH3·BH3 (AB) as the hydrogen transfer agent for the reduction of both aromatic and aliphatic esters without an external catalyst and base, delivering a structurally diverse array of primary alcohols (80-98% yields). The broad functional-group tolerance (halogen, boronic ester, -NO2, -OH, etc.) under environmentally acceptable conditions implies high practical utility. Further, a tandem catalytic conversion of a plastic waste polyethylene terephthalate (PET) bottle to 1,4-benzenedimethanol including fatty esters into respective fatty alcohols was shown.

Innovative solutions for potential use of waste polyethylene terephthalate bottle cap as aggregates in concrete

Innovative solutions for potential use of waste polyethylene terephthalate bottle cap as aggregates in concrete

Electrocatalytic Upgrading of Plastic and Biomass-Derived Polyols to Formamide under Ambient Conditions.

Electrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value-added chemicals, such as organonitrogen compounds, being scarcely explored. Herein, we reported an electrocatalytic oxidation strategy to transform polyethylene terephthalate (PET) plastic-derived ethylene glycol (EG) and biomass-derived polyols into formamide, in the presence of ammonia (NH3) over a tungsten oxide (WO3) catalyst. Taking EG-to-formamide as an example, we achieved a high formamide productivity of 537.7 μmol cm-2 h-1 with FE of 43.2 % at a constant current of 100 mA cm-2 in a flow electrolyzer with 12-h test, representing a more advantageous performance compared with previous reports for formamide electrosynthesis. Mechanistic understanding revealed that the cleavage of the C-C bond in the EG was facilitated by nucleophilic attack of in situ formed nitrogen radicals from NH3, with resultant C-N bond construction and eventually formamide production. Furthermore, this strategy can be extended to transformation of PET bottle and a series of biomass-derived polyols with carbon number from three (glycerol) to six (glucose), producing formamide with high efficiencies. This work demonstrates a sustainable upgrading strategy of plastic and biomass that may have implications to more value-added chemicals production beyond carbohydrates.

Electrocatalytic Upgrading of Plastic and Biomass‐Derived Polyols to Formamide under Ambient Conditions

AbstractElectrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value‐added chemicals, such as organonitrogen compounds, being scarcely explored. Herein, we reported an electrocatalytic oxidation strategy to transform polyethylene terephthalate (PET) plastic‐derived ethylene glycol (EG) and biomass‐derived polyols into formamide, in the presence of ammonia (NH3) over a tungsten oxide (WO3) catalyst. Taking EG‐to‐formamide as an example, we achieved a high formamide productivity of 537.7 μmol cm−2 h−1 with FE of 43.2 % at a constant current of 100 mA cm−2 in a flow electrolyzer with 12‐h test, representing a more advantageous performance compared with previous reports for formamide electrosynthesis. Mechanistic understanding revealed that the cleavage of the C−C bond in the EG was facilitated by nucleophilic attack of in situ formed nitrogen radicals from NH3, with resultant C−N bond construction and eventually formamide production. Furthermore, this strategy can be extended to transformation of PET bottle and a series of biomass‐derived polyols with carbon number from three (glycerol) to six (glucose), producing formamide with high efficiencies. This work demonstrates a sustainable upgrading strategy of plastic and biomass that may have implications to more value‐added chemicals production beyond carbohydrates.

Production of thermostable recombinant cutinase using mixed food waste: A sustainable approach toward environmental remediation

Recently, there has been a significant surge in the utilization of single-use plastics. Cost-effective degradation of plastics is imperative to reduce the ecological burden. This study explores the overproduction and characterization of a PET (Polyethylene terephthalate) a degrading enzyme, cutinase, in the E. coli BL21 (DE3) expression system. Furthermore, this research delves into the utilization of mixed food waste (MFW) as a sustainable substrate for the production of Cutinase, replacing commercial glucose. The newly isolated strain, Aspergillus terreus, showed the highest glucoamylase activity of 76.10 ± 3.10 U/g. The enzymatic hydrolysis of mixed food waste resulted in 50 ± 0.4 g/L of glucose, used as feedstock for cutinase production. The crude enzyme activity was evaluated to be 11.64 U/mg, and a further 14.11-fold purification was achieved through IMAC. The purified recombinant enzyme showed its maximum activity at 70℃ and pH 7. The metal ion Na+ increased the enzyme activity by 26 % while Zn+2 significantly inhibited the same (47 % inhibition); other ions had little or no effect. Taguchi’s optimization of five variables showed that the concentration of food waste hydrolysate has the maximum impact on enzyme production. The treatment of commercially available PET bottles using the purified enzyme showed characterizable surface degradation effects. This is the first time food waste hydrolysate was used as a sole carbon source to produce recombinant cutinase. This approach can potentially pave the way for sustainable biorefinery and waste management.

Waste PET bottles derived carbon black as electrode material for supercapacitor application

This study explores the conversion of polyethylene terephthalate (PET) waste into carbon black for its use in supercapacitors, offering a sustainable solution to waste management and energy storage needs. PET bottles were pyrolysed in an inert environment to produce carbon black. This plastic waste derived carbon was then characterised and used for electrode fabrication to explore its potential in supercapacitor applications. The supercapacitive properties of these electrodes were evaluated using cyclic voltammetry and charge–discharge techniques in various “Water-in-salt” electrolytes (WIS). WIS are the electrolytes in which the concentration of water is less than the concentration of salts by weight and volume. electrolytes. Sodium acetate (CH3COONa) exhibited the highest potential window and specific capacitance among the tested electrolytes. The derived carbon black demonstrated promising electrochemical performance, with a specific capacitance of 233 F/g and an energy density of 186.6 Wh/kg. These findings underscore the potential of carbon black derived from waste PET bottles as an effective material for supercapacitors, contributing to sustainable energy storage solutions and waste reduction.

Upgrading and Enhancement of Recycled Polyethylene Terephthalate with Chain Extenders: In-Depth Material Characterization.

Chemical chain extenders (CEs) can be used to restore the properties of recycled low-molecular-weight polyethylene terephthalate (PET). The aim of this work is to investigate the influence of the type and concentration of the CEs Joncryl and pyromellitic dianhydride (PMDA) on the viscosity and other rheological properties with a unique combination of different methods based on industrial samples originating from recycled PET bottles and trays. The resulting chain-extended thermoplastics were characterized by a combination of differential scanning calorimetry, viscometry, cone plate rheometry, pyrolysis-gas chromatography-mass spectroscopy, optical photothermal infrared spectroscopy, 13C solid-state- and 1H NMR liquid spectroscopy, and size exclusion chromatography. For a recycled PET mixture containing bottle and tray materials, our investigations have shown that a significantly better effect for chain elongation can be achieved with Joncryl compared to PMDA. This can presumably be attributed to water molecules formed during the use of PMDA, which accelerate the degradation of PET. The storage modulus values are therefore significantly higher for the samples with Joncryl compared to PMDA. The results of this study show that chain extension with Joncryl proceeds better compared to the reaction with PMDA.

Effects of chain extender types and contents on the properties of modified recycled polyethylene terephthalate

AbstractRecycling polyethylene terephthalate (PET) bottles post‐consumption is highly desirable but remains challenging because of their poor properties after recycling. Using a chain extender to rejoin the cleaved polymer chains is considered a reasonable solution to this issue. However, the functionality of the chain extenders affects the cross‐linking and properties of the resulting products. Therefore, this study focuses on the effects of functional groups and number of chain extenders on the properties of recycled polyethylene terephthalate (rPET). Three commercial chain extenders—methylene diphenyl diisocyanate (MDI), triphenyl phosphite (TPP), and Joncryl (JC), represented as di‐, tri‐, and multi‐functional chain extenders, respectively—are introduced into rPET by reactive blending. The intrinsic viscosity, rheological properties, thermal properties, and mechanical properties of the chain‐extended rPET are investigated. The results indicate that all the chain extenders increase the molecular weight of rPET. Di‐ and multi‐functional chain extenders (MDI and JC) induce branching and cross‐linking owing to the highly reactive functional groups, whereas a tri‐functional chain extender (TPP) showed the lowest improvement in mechanical properties, owing to chain scission from by‐products occurring during chain extension. Furthermore, increasing the content of all chain extenders significantly increased their intrinsic viscosity, cross‐linking, and mechanical properties.

Release Characteristics of Small-Sized Microplastics in Bottled Drinks Using Flow Cytometry Sorting and Nile Red Staining

Small-sized microplastics (MPs) pose concerns about potential risks to both the environment and human health. However, research on MP pollution is hampered by limitations in the detection techniques. Also, few studies have provided insight into the release of small-sized MPs from disposable polyethylene terephthalate (PET)-bottled drinks for outdoor usage. Thus, PET bottles’ potential to release small MPs sized 1–100 μm outdoors was studied in relation to physical and chemical parameters (temperature, sunlight irradiation, and drink characteristics) using flow cytometry and Nile Red dye. The results showed that temperatures below 80 °C had little effect on the release of MPs from PET bottles. Sunlight irradiation and alkalinity were prone to promote the generation of MPs, mostly 1–5 μm in size. Moreover, the combined impact test implied that two pairings—acidity with temperature and alkalinity with sunlight—positively affected MP release, with maximum releases of 21,622 ± 2477 particles/L and 31,081 ± 7173 particles/L, respectively. Based on the rapid quantification of small-sized MPs using flow cytometry after Nile Red selection, the results hereby presented will assist researchers in reducing MP release and aid them in the evaluation of MPs’ contamination of aquatic environments.

Preparation of graphene from polyethylene terephthalate (PET) bottle wastes and its use for the removal of Methylene blue from aqueous solution

We present a method to produce graphene flakes (GFs) from polyethylene terephthalate (PET) bottle wastes by the pyrolysis method using modified bentonite as a catalyst. The as-synthesized GFs are analyzed in terms of crystal phase, morphology, and surface chemistry. The synthesized GFs have a porous, thin, and leaf-like morphology with a length ranging from a few hundred nanometers to a few tens of micrometers. The XRD and FT-IR results confirm the graphitization of PET and the presence of oxygen-containing functional groups on the surface of synthesized GFs. The obtained GFs are used as adsorbents for the removal of methylene blue (MB) from aqueous solution. The effects of various factors including, contact time, pH, and initial MB concentration, on the MB removal efficiency are examined. In addition, the adsorption isotherm models of Langmuir and Freundlich are studied. The best-fitting model is observed with the Freundlich isotherm model.

Modeling moisture change of packaged dry tablet dosage forms under consumer use condition

A simple mathematical model based on product’s moisture sorption isotherm and package’s moisture transmission was developed to predict moisture content of dry solid tablets during consumers’ use, which is useful for determination of in-use shelf life (ISL) or secondary shelf life. The moisture increase depending on amount of product remaining in the package was accounted for in the mass balance equation on the package. The model was first verified by literature data of desiccant canisters in a plastic bottle of high density polyethylene exposed to two environmental conditions (25 °C and 60% relative humidity (RH); 40 °C and 75% RH) simulating in-use of removing one canister each day. Then an experimental work was conducted on dry refresher candies in a polyethylene terephthalate bottle at 25 °C with two tablets taken out every day, which confirmed the model’s capability to predict the product moisture content during in-use storage of 76% and 90% RH. Its use can provide science-based accurate determination of ISL, which may work as consumer guideline. The model is also expected to be helpful for recommending management scheme of whole product life.

Process Parameter Optimization of Waste Polyethylene Terephthalate Bottle Neutral Hydrolysis Depolymerisation Using Process Simulation and Response Surface Methodology

The global surge in plastic production has led to a concerning accumulation of durable plastic waste in landfills and the environment. To address this issue, the depolymerization of waste polyethylene terephthalate (PET) through neutral hydrolysis has been proposed as a chemical recycling solution. Despite its potential environmental benefits, the endothermic nature of this process at high temperatures has raised doubts about its commercial feasibility. In response, this study was conducted to assess optimal conditions for waste PET depolymerization using neutral hydrolysis in a continuous stirred tank reactor with zinc acetate as a catalyst. Process simulation, aimed to manufacture pure terephthalic acid (TPA) and ethylene glycol from pelletized post-consumer PET bottles, was conducted with Aspen Plus Version 11. Sensitivity analysis explored the impact of factors such as reaction temperature, reaction time, PET flake size, and catalyst to PET ratio on both PET conversion and TPA yield. The study found that PET depolymerization increased with decreasing particle size, longer reaction times, increasing catalyst to PET ratio and reaction temperatures within the range of 200–240°C. Optimizing the process through response surface modelling revealed that key parameters for neutral hydrolysis considering a mean particle size of 20 mm were the ratio of water to PET, temperature, pressure, and reaction time with optimal values of 5:1, 225°C, 30 bar, and 67.5 min respectively. The model's reliability was confirmed through variance analysis, emphasizing the significance of main and interaction effects in the regression model.

Evaluating strategies to increase PET bottle recycling in the United States

AbstractIn the United States, polyethylene terephthalate (PET) bottle collection rates have not increased in a decade. Recycling rates remain abysmal while industry commitments and policy targets escalate the demand for recycled plastics. We investigate the PET bottle recycling system, where collection is a critical bottleneck and recycled PET supply is not meeting the expected demand. We characterize demand for recycled PET (R‐PET), analyze scenarios of expanding deposit return systems (DRS), and quantify cost barriers to improving PET bottle recycling. We find that a nation‐wide DRS can increase PET bottle recycling rates from 24% to 82%, supplying approximately 2700 kt of recycled PET annually. With stability in demand, we estimate that this PET bottle recycling system can achieve 65% bottle‐to‐bottle circularity, at a net cost of 360 USD/tonne of PET recycled. We also discuss environmental impacts, stakeholder implications, producer responsibility, and complimentary policies toward an efficient and effective recycling system.

Investigating the Impact of temperature and storage time on antimony release from polyethylene terephthalate (PET) plastic used for bottled drinking water

In last decade, Prosperity in contemporary Saudi Arabia and the consequent stresses on renewable freshwater resources resulted in the bottled drinking water market. Over the period, sustainable water resources planning (SWRP) has become an essential requirement for the development of places where these resources are highly constrained. To meet this market growth in Saudi Arabia is augmented by increasing demand for bottled water. This drastic increase, leads some countries to develop an alternative sources including desalinated water and treated wastewater for landscaping irrigation, industrial reuse, street cleaning, and aquifer recharge. There are claims on health concerns the possibility of chemicals migration from polyethylene terephthalate (PET) bottles into drinking water. In this paper, inductively coupled plasma -optical emission spectrometry (ICP-OES) was utilized and applied to determine the antimony (Sb) release from PET bottles into mineral water of 8 local brands at different temperature degrees within 8 months storage time.

Praseodymium orthovanadate-waste PET bottle derived sulfur doped carbon for efficient Z-scheme photocatalytic CO2 reduction

Escalating amounts of carbon dioxide (CO2) in the Earth's atmosphere are a major cause of climate change and its negative consequences, making it a global concern. The present work highlights the intersection of waste management, resource utilization, and climate change mitigation, showcasing the potential for an additional sustainable and circular economy. Synthesizing carbon from waste polyethylene terephthalate (PET) bottles is an eco-friendly approach. X-ray diffraction, Raman spectroscopic, scanning electron microscopic, tunnelling electron microscopic, infrared fourier transform spectroscopy (FTIR) and X-ray photoelectron spectroscopic results indicate the effective extraction of carbon doped with sulfur (S@C) and the successive formation of nanocomposite with PrVO4 (PrV/S@C). Superior photocatalytic activity was observed under visible light compared to UV light. PrV/S@C showed enhanced light-driven CO2 reduction compared to pristine materials and was found to evolve 39, 56, and 98 µmol h−1 g−1 of H2, CH4 and CO, respectively. The effect of reaction temperature was examined and optimized at 100 °C. The enhanced activity in PrV/S@C compared to PrV and S@C probably due to the increased surface area, conductivity and synergy. In-Situ Diffused reflectance (DRIFT-IR) and liquid chromatography mass spectroscopy (LC-MS) confirm the evolution of CO and CH4. The optical, photo/electrochemical, Scavenger studies, Electron spin resonance (ESR) and Mott-Schottky studies suggest the formation of a direct Z-scheme photoredox reaction in the presence of PrV/S@C and sacrificial gent. The reusability studies for 5 cycles indicate good stability with a slight deviation in structure and morphology of PrV/S@C, as observed in XRD and SEM. Tackling plastic pollution and generating value-added carbonaceous products through CO2 reduction is the twin application of the present work that has piqued the interest of several researchers in environmental remediation.

Utilizing PET bottles for sustainable cellular reinforcement: A study on enhancing fly ash backfill bearing strength with innovative geocell alternative

The slow degradation rate is one of the major global concerns. Only, 60 % produced is being recycled. Among these waste materials, Polyethylene Terephthalate (PET) bottles contribute around 10 % to the total plastic waste produced. The recycling process of PET bottles considering existing capacity in environmentally responsible ways is limited. It is estimated that 60 % of PET bottles produced are being disposed of in landfills. To overcome this, past studies have suggested novel approaches for using it as substitute for conventional geocell as soil reinforcement and stability. However, past studies mostly focused on application of PET bottles as flaked, shreds and sliced form. The present study attempts on application of PET bottles under fly ash (FA) backfills without mechanical alterations. Full-scale experiments were conducted on FA backfill system, for both unreinforced and reinforced conditions. A comparative study was performed between high-density polyethylene (HDPE) geocell and PET bottle mattress to assess the bearing strength of the FA backfill. Experiments were performed in a 1 m3 tank with a loading plate width of 200 mm. Vertical loading was applied onto the backfill footing (for all the trial series), till the footing settlement of 40 mm is achieved. An aspect ratio of 2 was considered for HDPE geocell and PET bottles. Rock quarry dust (RQD) was considered as cell infill and overlay material on FA backfill. The test results showed that settlement accumulation rate was low under reinforced scenario compared to the unreinforced condition, with higher resilient (elastic) settlement. RQD over the PET-reinforced zone was also seen to have enhanced the load distribution aspect, thereby reducing deformation in PET reinforcement. This usage of waste material will contribute towards sustainable development. This work demonstrates the feasibility and effectiveness of PET reinforcement to be used as replacement for HDPE geocell, which eventually can agument the design methodology of structural backfills.

A waste-to-wealth conversion of plastic bottles into effective carbon-based adsorbents for removal of tetracycline antibiotic from water

Currently, plastic waste and antibiotic wastewater are two of the most critical environmental problems, calling for urgent measures to take. A waste-to-wealth strategy for the conversion of polyethylene terephthalate (PET) plastic bottles into value-added materials such as carbon composite is highly recommended to clean wastewater contaminated by antibiotics. Inspired by this idea, we develop a novel PET-AC-ZFO composite by incorporating PET plastic-derived KOH-activated carbon (AC) with ZnFe2O4 (ZFO) particles for adsorptive removal of tetracycline (TTC). PET-derived carbon (PET-C), KOH-activated PET-derived carbon (PET-AC), and PET-AC-ZFO were characterized using physicochemical analyses. Central composite design (CCD) was used to obtain a quadratic model by TTC concentration (K), adsorbent dosage (L), and pH (M). PET-AC-ZFO possessed micropores (d ≈ 2 nm) and exceptionally high surface area of 1110 m2 g−1. Nearly 90% TTC could be removed by PET-AC-ZFO composite. Bangham kinetic and Langmuir isotherm were two most fitted models. Theoretical maximum TTC adsorption capacity was 45.1 mg g−1. This study suggested the role of hydrogen bonds, pore-filling interactions, and π-π interactions as the main interactions of the adsorption process. Thus, a strategy for conversion of PET bottles into PET-AC-ZFO can contribute to both plastic recycling and antibiotic wastewater mitigation.

Sulfonated cobalt phthalocyanine/NH2-MIL-125 heterojunction modified electrospun nanofiber membrane for emulsion separation and PMS-photocatalysis synergistic degradation

Membrane technology for wastewater remediation has generated significant interest, however, the single functionality, dull wettability and easy fouling property of the membrane hinder its practical application. Herein, a self-cleaning and multi-use superwetting nanofiber membrane was prepared by electrospinning and subsequent spraying technique. The sulfonated cobalt phthalocyanine/NH2-MIL-125 (CoPcS/NMIL) heterojunction was uniformly enrobed over polyethylene terephthalate (PET) electrospun membrane derived from waste PET bottles. The unique CoPcS/NMIL heterojunction exhibited a dual driving effect in photocatalytic activity and membrane wettability. Therefore, the fabricated CoPcS/NMIL@PET composite membrane demonstrated its capability to address complex water pollution issues effectively. The composite membrane exhibited notable flux permeation ability (538–3180 L m−2 h−1) and achieved excellent separation efficiency of over 99 % for diverse oil-in-water emulsions under the gravity filtration condition. Notably, the membrane can efficiently deal with stubborn high-viscosity crude oil fouling profiting from the photocatalytic self-cleaning function. A high flux recovery ratio of 93.6 % and a low irreversible fouling resistance ratio of 6.4 % can be obtained after 30 min of visible light irradiation. Impressively, CoPcS/NMIL@PET membrane exhibited enhanced permeation flux, separation efficiency and self-cleaning capacity compared to NMIL@PET membrane. Meanwhile, the CoPcS/NMIL@PET-activated peroxomonosulfate (PMS) system exhibited extremely high degradation performance for RhB under visible light with the degradation efficiency of 98 % within 10 min, suggesting its potential in the rapid purification of water-soluble organic pollutants. In addition, the CoPcS/NMIL@PET membrane has good chemical stability and mechanical properties for potential long-term use. Moreover, the demulsification mechanism in oil-water separation and PMS-photocatalysis synergetic mechanism over the fabricated CoPcS/NMIL@PET membrane were also investigated in detail. The research offers a promising approach for the design and fabrication of novel nanofiber membranes that incorporate photosensitizers and MOFs functional surfaces to address the challenges associated with such wastewater treatment.

Development of predictive model for compressive strength of eco-brick masonry walls using numerical method

The usage of waste plastics in the form of eco-bricks for the construction of buildings is gradually gaining traction. However, the performance of eco-brick masonry walls is not sufficiently known, and the process of setting up experimental rigs for the conduct of compressive strength test of masonry are usually cumbersome and expensive. This study investigated the compressive strength performance of eco-brick masonry walls and developed a predictive model for evaluating the strength of eco-brick masonry walls. Waste polyethylene terephthalate (PET) bottles were physically recycled and utilised to manufacture four samples of eco-bricks, strength grades 40.5, 21.02, 13.52 and 3.05 N/mm2 using stone dust, sharp sand and laterite at predetermined moisture contents. The eco-bricks were laid with seven grades of mortar to build 54 eco-brick masonry prisms. A quasi-static compressive loading test was carried out on the masonries, and predictive models were developed using multiple non-linear regression. The study found that eco-brick masonry prisms supported large loads and failed due to the propagation of tensile cracks and debonding of the units. The study also found that the compressive strength of eco-brick masonry is a power function of the compressive strength of eco-bricks and the mortar used for the bonding. It was determined that the mean ratio of the expected to experimental prism strength was 1.002. The mathematical model developed in this study for predicting the strength of eco-brick masonries can significantly evaluate the compressive strength of eco-brick masonry.