Environmental Applications

Hiraishi, Akira

doi:10.1002/9780470649848.ch30

Cited by 11 publications

(6 citation statements)

References 63 publications

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“…With the occurrence of environmental pollution owing to the accumulation of petroleum-based plastics, there is an urgent need to develop renewable and biodegradable materials as substitutes. − Polylactic acid (PLA), as a biomass-derived − and environmentally friendly polymer, has been widely used in biomedical and chemical products. − High-quality PLA is predominately produced by ring-opening polymerization of lactide, a cyclic dimer of lactic acid (La). ,− Industrially, lactide is produced through a two-step method that is costly and energy-intensive. , In this process, La is polymerized to form oligo-PLA ( M w < 3000 Da) by self-catalysis and then depolymerized into lactide via a back-biting mechanism in the presence of a metal catalyst, which can be a salt or an oxide of tin or zinc. − Among the catalysts developed, tin(II)-based compounds (SnCl 2 , SnOct 2 , and others) are considered to be the most efficient to synthesize lactide. − The lactide must be separated rapidly from the reaction system to avoid the thermodynamically favored reverse reaction. Since the viscosity of the substrate gradually increases with the progress of the reaction, it becomes difficult to remove water and lactide from the system.…”

Section: Introductionmentioning

confidence: 99%

Controlled Synthesis of l-Lactide Using Sn-Beta Zeolite Catalysts in a One-Step Route

Fang

Cao

et al. 2021

Ind. Eng. Chem. Res.

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Polylactic acid (PLA), as a biodegradable and renewable polymer, has been widely used in biomedical and commercial applications. The energy-efficient synthesis of lactide from lactic acid (La) via a one-step route is highly desired for megaton-scale PLA production. In this work, stereo-pure L-lactide was synthesized with high yield (88.2−95.8%) via a one-step route catalyzed by Sn-beta zeolites. Sn−O−Si bonds on tin−silica catalysts are indeed important for a high L-lactide yield. The Sn 4+ ions with four isolated coordinates in tetrahedral configuration of Sn-beta zeolites are more active for L-lactide synthesis than those with hexacoordinated polymeric Sn−O−Sn-type species. L-La was first converted into a lactic acid dimer (L 2 a) and then formed Llactide catalyzed by a Sn-beta zeolite, and the average reaction rate in first 20 min (R 20min av ) increased linearly with increasing Sn content. Importantly, lactic acid trimers (L 3 a) formed during the reaction could also be converted to L-lactide in the later stage of the reaction, and the diffusion of L 3 a to the active site within the Snbeta zeolite pore is the rate-limiting step. The lactic acid oligomer (L n a, n ≥ 4) was limited to form lactide with an R 20min av of only 0.013 mmol min −1 g cat −1.

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Section: Introductionmentioning

confidence: 99%

Controlled Synthesis of l-Lactide Using Sn-Beta Zeolite Catalysts in a One-Step Route

Fang

Cao

et al. 2021

Ind. Eng. Chem. Res.

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“…Moreover, PLA is used for environmental purposes as a sorbent that disposes harmful contaminants contained in water. Additionally, PLA takes part in bioremediation—a technique that uses microorganisms to remove environmental impurities [ 77 ].…”

Section: Biopolymer Matricesmentioning

confidence: 99%

Natural Biocidal Compounds of Plant Origin as Biodegradable Materials Modifiers

Pawłowska

Stepczyńska

2021

J Polym Environ

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The article presents a literature review of the plant origin natural compounds with biocidal properties. These compounds could be used as modifiers of biodegradable materials. Modification of polymer material is one of the basic steps in its manufacturing process. Biodegradable materials play a key role in the current development of materials engineering. Natural modifiers are non-toxic, environmentally friendly, and renewable. The substances contained in natural modifiers exhibit biocidal properties against bacteria and/or fungi. The article discusses polyphenols, selected phenols, naphthoquinones, triterpenoids, and phytoncides that are natural antibiotics. Due to the increasing demand for biodegradable materials and the protection of the natural environment against the negative effects of toxic substances, it is crucial to replace synthetic modifiers with plant ones. This work mentions industries where materials containing natural modifying additives could find potential applications. Moreover, the probable examples of the final products are presented. Additionally, the article points out the current world’s pandemic state and the use of materials with biocidal properties considering the epidemiological conditions.

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“…A green polymer that can replace the use of plastics made from petroleum is called PLA, which is produced via the lactic acid polymerization process (Batista da Mota et al, 2022). In the medical field, bioabsorbable PLA is employed as a biomaterial that regenerates tissue healing, sutures, and implants in addition to its role as a replacement for plastics such as rubbish bags, tarpaulins, agricultural plastics, and food packaging (Hiraishi, 2010;Mochizuki, 2010;Obuchi & Ogawa, 2010;Suzuki & Ikada, 2010).…”

Section: Introductionmentioning

confidence: 99%

Lactic acid fermentation of banana peel using Lactobacillus plantarum : Effect of substrate concentration, inoculum concentration, and various nitrogen sources

Abdullah

Amalia

2023

Reaktor

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Semeru Banana peel is an organic waste that is exclusively utilized as animal feed and does not harm the environment. The primary component of banana peels is carbohydrates, which can be used as a substrate during the fermentation process to produce lactic acid. The fermentation of banana peel flour with Lactobacillus plantarum strain FNCC 0020 was the main focus of this investigation. Variations in the concentrations of the substrate and inoculum as well as the impact of the type of nitrogen on lactic acid concentration were investigated. According to research findings, the big banana peel contains 70.52% carbs, 5.68% soluble protein, 3.115% fat, 6.74% water, 2.395% ash, and 13.38% crude fiber. While the inoculum variable was 0.5% v/v and the best substrate concentration variable was 17.5% w/v, the best lactic acid concentrations were 5.401 g/L and 8.586 g/L, respectively, as determined by HPLC (High-Performance Liquid) analysis. Banana peel flour only includes a modest amount of nitrogen (0.8295%), sulfate (0.037 grams), phosphate (1.6105%), and vitamin B1 (0.2315%), so additional nitrogen sources must be added. The production of lactic acid is shown to increase with the addition of various forms of nitrogen, with ammonium sulfate and ammonium phosphate (2:1) producing the greatest yields of 9.781 g/L and 14.255 g/L, respectively, of lactic acid, which is lower than lactic acid from yeast extract.

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Environmental Applications

Cited by 11 publications

References 63 publications

Controlled Synthesis of l-Lactide Using Sn-Beta Zeolite Catalysts in a One-Step Route

Controlled Synthesis of l-Lactide Using Sn-Beta Zeolite Catalysts in a One-Step Route

Natural Biocidal Compounds of Plant Origin as Biodegradable Materials Modifiers

Lactic acid fermentation of banana peel using Lactobacillus plantarum : Effect of substrate concentration, inoculum concentration, and various nitrogen sources

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