Effective catalysts derived from waste ostrich eggshells for glycolysis of post-consumer PET bottles

Yunita, Isti; Putisompon, Siraphat; Chumkaeo, Peerapong; Poonsawat, Thinnaphat; Somsook, Ekasith

doi:10.1007/s11696-019-00710-3

Cited by 30 publications

(21 citation statements)

References 28 publications

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“…To confirm that the fraction (C) is the BHET monomer, GC-MS, 1 H NMR, 13 C NMR, melting point, and DSC analysis were performed. As shown in Figure S3 (Supplementary Materials) , it is clear from the mass spectrum of fraction (C) that the most significant characteristic peaks are intense (at m / z 211.1, 193.1, 149, 121.1, and 104) and are attributed to the BHET monomer as reported in the literature [ 14 , 35 ]. 13 C NMR of faction (C) is shown in Figure S4 in which the signal at 167.18 ppm indicates carbon of the carbonyl group (–COO–), and signals at 135.44 and 130.68 ppm indicate aromatic carbon associated with carbonyl groups and hydrogen respectively.…”

Section: Resultssupporting

confidence: 52%

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

2023

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Glycolysis of post-consumer polyethylene terephthalate (PET) waste is a promising chemical recycling technique, back to the monomer, bis(2-hydroxyethyl) terephthalate (BHET). This work presents sodium methoxide (MeONa) as a low-cost catalyst for this purpose. BHET product was confirmed by gas chromatography-mass spectrometry (GCMS), Nuclear Magnetic Resonance (NMR) Spectroscopy, melting point, and Differential Scanning Calorimetry (DSC). It was shown, not surprisingly, that PET conversion increases with the glycolysis temperature. At a fixed temperature of 190 °C, the response surface methodology (RSM) based on the Box-Behnken design was applied. Four independent factors, namely the molar ratio of PET: MeONa (50–150), the molar ratio of ethylene glycol to PET (EG: PET) (3–7), the reaction time (2–6 h), and the particle size (0.25–1 mm) were studied. Based on the experimental results, regression models as a function of significant process factors were obtained and evaluated by analysis of variance (ANOVA), to predict the depolymerization performance of MeONa in terms of PET conversion. Coefficient of determination, R2 of 95% indicated the adequacy for predicted model. Afterward, the regression model was validated and optimized within the design space with a prediction of 87% PET conversion at the optimum conditions demonstrating a deviation of less than 5% from predicted response. A van ‘t Hoff plot confirmed the endothermic nature of the depolymerization reaction. The ceiling temperature (TC = 160 °C) was calculated from Gibbs’ free energy. A kinetic study for the depolymerization reaction was performed and the activation energy for MeONa was estimated from the Arrhenius plot (EA = 130 kJ/mol). The catalytic depolymerization efficiency of MeONa was compared under similar conditions with widely studied zinc acetate and cobalt acetate. This study shows that MeONa’s performance, as a glycolysis catalyst is promising; in addition, it is much cheaper and environmentally more benign than heavy metal salts. These findings make a valuable contribution towards the chemical recycling of post-consumer PET waste to meet future recycling demands of a circular economy.

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Section: Resultssupporting

confidence: 52%

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

2023

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“…Yunita et al 159 employed calcium oxide (CaO) as an efficient catalyst for glycolysis of post‐consumer PET obtained from discarded ostrich eggshells. Having depolymerized PET using 1 wt.% of ostrich eggshells calcinated at 1000°C, an EG/PET weigh ratio of 15:1, at 192°C, at atmospheric pressure, and during 2 hours, a BHET yield of 76.41% was reported.…”

Section: Chemical Recycling Of Petmentioning

confidence: 99%

Chemical recycling of PET: A stepping‐stone toward sustainability

Shojaei

Abtahi

Najafi

2020

Polymers for Advanced Techs

126

106

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This paper focuses explicitly on the chemical approaches involved in the recycling of polyethylene terephthalate (PET). Due to the high rate of consumption as well as nonbiodegradability, PET plays a crucial role as one of the most significant sources of accumulated waste in the landfill which jeopardizes our planet. To address this issue as well as increased environmentally conscious, running out of landfill space, natural resource, and energy conservation, and producing value-added chemicals to use as building block or co-products, the chemical recycling methods have been evolved. Therefore, there has been an attempt to have a comprehensive review of the five types of conventional recycling methods namely hydrolysis, methanolysis, glycolysis, aminolysis, and ammonolysis studied by researchers over the last two decades. In this regard, the influence of diverse depolymerization reaction variables for instance, traditional catalyst, temperature profile, ionic liquid catalysts, phase transfer catalyst, microwave assistance, etc was reported. Moreover, the upsides and downsides of each technique were considered.

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“…However, acetic acid derivatives (their activities regarding the ester bond cleavage lowering in the following order: Zn > Mn > Co > Pb) seem to give way to derivatives of phosphoric acid diesters that are more active and selective toward monomeric bis(ω-hydroxyalkyl) terephthalate [113]. In recent years, some efforts have been made to replace these toxic systems with more environmentally friendly catalysts such as weak bases (Na 2 CO 3 , NaHCO 3 ) and less reactive sodium or potassium sulfates [114,115], as well as a mixture of calcium oxide and hydroxide obtained during calcination of animal shells derived from oysters or chicken eggs [116]. For that purpose alkali or alkaline earth metal hydroxides {e.g.…”

Section: Catalysts Used In the Pet Glycolysis Processmentioning

confidence: 99%

Chemical recycling of polyesters

et al. 2019

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In the presented paper, two basic strategies that can be used in the processes of chemical recycling of polyester material were described. The first of them involves increasing the molar mass of recycled materials in the solid-state polycondensation (SSP) process and/or joining their chains with various types of substances easily reacting with the end groups of polyesters (so-called extending agents). The essence of the second strategy is the degradation of the material under the influence of various protogenic agents (such as water, alcohols, glycols and amines) to obtain low-molecular products or oligomers that can be used as raw materials in the synthesis of many classes of polymers. The methods that are already used in PET [poly(ethylene terephthalate)] recycling and the possibility of their extension to other types of polyesters are both shown.

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Effective catalysts derived from waste ostrich eggshells for glycolysis of post-consumer PET bottles

Cited by 30 publications

References 28 publications

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

Chemical recycling of PET: A stepping‐stone toward sustainability

Chemical recycling of polyesters

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