Addressing the environmental impact of poly(ethylene terephthalate) (PET) disposal highlights the need for efficient recycling methods. Chemical recycling, specifically alkaline hydrolysis, presents a promising avenue for PET waste management by depolymerizing PET into its constituent monomers. This study focuses on optimizing the pressurized alkaline hydrolysis process for post-consumer PET residues obtained from packaging materials. Post-consumer PET packaging waste was chemically recycled by means of an alkaline hydrolysis reaction in a 2 L pressurized reactor under varying conditions of the NaOH/PET ratio and temperature. The reaction's progress was monitored by sampling the liquid phase hourly over a four-hour period. The obtained products were purified, with a focus on isolating terephthalic acid (TPA). Higher temperatures (150 °C) resulted in superior TPA yields (>95%) compared to lower temperatures (120 °C). The NaOH/PET ratio showed minimal influence on the TPA yield. The optimal conditions (T = 150 °C; NaOH:PET = 2) were identified based on TPA yield and reaction cost considerations. This study demonstrates the feasibility of pressurized alkaline hydrolysis for PET recycling, with optimized conditions yielding high TPA purity and efficiency.
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http://dx.doi.org/10.3390/ma17112619 | DOI Listing |
J Agric Food Chem
January 2025
Faculty of Mechanical and Process Engineering, Hochschule Offenburg, 77652 Offenburg, Germany.
Protein hydrolysis under acidic conditions can improve the product quality, nutrient availability, and cost efficiency, particularly when neutral or alkaline enzymes are ineffective. Six fungal aspartic endopeptidases (FAPs) were recombinantly expressed as active enzymes in , with peak activity between 30-50 °C and pH 3.0-4.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Chemical Engineering, Bioengineering and Biomass Valorization Laboratory, Federal University of Ceará, Fortaleza, Ceará 60020-181, Brazil.
Cellulose nanostructures obtained from lignocellulosic biomass via enzymatic processes may offer advantages in terms of material properties and processing sustainability. Thus, in this study, cellulose nanoparticles with a spherical morphology were produced through the enzymatic hydrolysis of cashew apple bagasse (CAB). CAB was previously subjected to alkaline and acid-alkali pretreatment, and the pretreated solids were labeled as CAB-PTA and CAB-PT-HA, respectively.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Faculty of Science and Technology, Norwegian University of Life Sciences, P.O. Box 5003, Aas, 1430, Norway.
Primary sludge can serve as an internal carbon source for denitrification in wastewater treatment plants (WWTPs). This study explores the use of alkaline treatment to produce a fermentation broth from primary sludge, which predominantly contains short-chain volatile fatty acids (VFAs), with acetic acid and propionic acid making up over 65% of the total VFAs. The performance of this fermentation broth as a sole carbon source for denitrification was compared with that of sodium acetate, acetic acid, methanol, and ethanol in both biofilm and activated sludge systems.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China. Electronic address:
Silver nanoparticles (AgNPs) exhibit broad-spectrum antibacterial activity and serve as effective antimicrobial agents against antibiotic-resistant bacteria. In this study, agricultural waste corn straw was used as the raw material to obtain cellulose nanocrystal (CNC) through enzymatic hydrolysis. The hydrolysate was employed as reducing agents to synthesize CNC-AgNPs.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran.
Polymer-based catalysts have garnered significant interest for their efficiency, reusability, and compatibility with various synthesis processes. In catalytic applications, polymers offer the advantage of structural versatility, enabling functional groups to be tailored for specific catalytic activities. In this study, we developed a novel magnetic copolymer of methyl methacrylate and maleic anhydride (PMMAn), synthesized via in situ chemical polymerization of methyl methacrylate onto maleic anhydride, using benzoyl peroxide as a free-radical initiator.
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