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Author: search.filters.author.Boonmee, WimonmatSubject: search.filters.subject.Thermal decomposition

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    Bio-green synthesis of calcium acetate from oyster shell waste at low cost and reducing the emission of greenhouse gases
    (2023-12-01)
    Seesanong, Somkiat
    ;
    Seangarun, Chaowared
    ;
    Boonchom, Banjong
    ;
    Laohavisuti, Nongnuch
    ;
    Thompho, Somphob
    Biological wastes obtained from food, oyster shells, were recycled to calcium carbonate and then used as bio-green raw material to replace limestone/carbonate stone for calcium acetate (Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O) production. The conditions (ambient temperature occurred in an exothermic reaction, drying time, yield, and solubility) of the reaction between the bio-green CaCO<inf>3</inf> and three different acetic (CH<inf>3</inf>COOH) concentrations (8, 10, and 12 M) were investigated. The product's maximum yield (93%) with a shorter drying time (18 h) was obtained from the reaction between the bio-green CaCO<inf>3</inf> with 12 M acetic acid revealing a lower cost. The chemical compositions without any toxic metal impurity revealed by the X-ray fluorescence technique would be useful to suggest use in the specific application. The X-ray diffraction, Fourier Transform Infrared, and Thermogravimetric analysis data of Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O prepared by the bio-green CaCO<inf>3</inf> obtained from oyster shell wastes in this work and those in previous works used other calcium sources were consistent. The morphologies with different sizes of the obtained Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O depend on the CH<inf>3</inf>COOH concentrations reported in this work and were different from those reported in previous works because of different calcium sources. According to the observation, it can be concluded that the low-cost and bio-green technique without the environmental effects was successfully applied to produce cheap Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O and reduce greenhouse gas emissions, which can be used in the specific industry.
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    Recrystallization of Triple Superphosphate Produced from Oyster Shell Waste for Agronomic Performance and Environmental Issues
    (2022-02-01)
    Seesanong, Somkiat
    ;
    Seangarun, Chaowared
    ;
    Boonchom, Banjong
    ;
    Sronsri, Chuchai
    ;
    Laohavisuti, Nongnuch
    Calcium dihydrogen phosphate monohydrate (Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O) (a fertilizer) was successfully synthesized through a recrystallization process using prepared triple superphosphate (TSP) derived from oyster shell waste as the starting material. This bio-green, eco-friendly process to produce an important fertilizer can promote a sustainable society. The shell-waste-derived TSP was dissolved in distilled water and kept at 30, 50, and 80<sup>◦</sup>C. Non-soluble powder and TSP solution were obtained. The TSP solution fractions were then dried, and the recrystallized products (RCP30, RCP50, and RCP80) were obtained and confirmed as Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O. Conversely, the non-soluble products (NSP30, NSP50, and NSP80) were observed as calcium hydrogen phosphate dihydrate (CaHPO<inf>4</inf>·2H<inf>2</inf>O). The recrystallized yields of RCP30, RCP50, and RCP80 were found to be 51.0%, 49.6%, and 46.3%, whereas the soluble percentages were 98.72%, 99.16%, and 96.63%, respectively. RCP30 shows different morphological plate sizes, while RCP50 and RCP80 present the coagulate crystal plates. X-ray diffractograms confirmed the formation of both the NSP and RCP. The infrared adsorption spectra confirmed the vibrational characteristics of HPO<inf>4</inf><sup>2−</sup>, H<inf>2</inf>PO<inf>4</inf><sup>−</sup>, and H<inf>2</inf>O existed in CaHPO<inf>4</inf>·2H<inf>2</inf>O and Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O. Three thermal dehydration steps of Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O (physisorbed water, polycondensation, and re-polycondensation) were observed. Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> and CaH<inf>2</inf>P<inf>2</inf>O<inf>7</inf> are the thermodecomposed products from the first and second steps, whereas the final product is CaP<inf>2</inf>O<inf>6</inf>.