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    Kinetics and thermodynamics of thermal decomposition of synthetic AlPO 4•2H2O
    (2009-12-01) ;
    Danvirutai, Chanaiporn
    The non-isothermal kinetics of dehydration of AlPO<inf>4</inf>•2H <inf>2</inf>O was studied in dynamic air atmosphere by TG-DTG-DTA at different heating rates. The result implies an important theoretical support for preparing AlPO<inf>4</inf>. The AlPO<inf>4</inf>•2H<inf>2</inf>O decomposes in two step reactions occurring in the range of 80-150 °C. The activation energy of the second dehydration reaction of AlPO<inf>4</inf>•2H<inf>2</inf>O as calculated by Kissinger method was found to be 69.68 kJ mol<sup>-1</sup>, while the Avrami exponent value was 1.49. The results confirmed the elimination of water of crystallization, which related with the crystal growth mechanism. The thermodynamic functions (ΔH*, ΔG*and ΔS*) of the dehydration reaction are calculated by the activated complex theory. These values in the dehydration step showed that it is directly related to the introduction of heat and is non-spontaneous process. © 2009 Akadémiai Kiadó, Budapest, Hungary.
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    Conversion of bivalve shells to monocalcium and tricalcium phosphates: An approach to recycle seafood wastes
    (2021-08-02) ; ;
    Chaiseeda, Kittichai
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    Laohavisuti, Nongnuch
    The search for sustainable resources remains a subject of global interest and the conversion of the abundantly available bivalve shell wastes to advanced materials is an intriguing method. By grinding, calcium carbonate (CaCO<inf>3</inf>) powder was obtained from each shell of bivalves (cockle, mussel, and oyster) as revealed by FTIR and XRD results. Each individual shell powder was reacted with H<inf>3</inf>PO<inf>4</inf> and H<inf>2</inf>O to prepare Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O giving an anorthic crystal structure. The calcination of the mixture of each shell powder and its produced Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O, at 900 °C for 3 h, resulted in rhombohedral crystal β-Ca<inf>3</inf>(PO<inf>4</inf>)<inf>2</inf> powder. The FTIR and XRD data of the CaCO<inf>3</inf>, Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O, and Ca<inf>3</inf>(PO<inf>4</inf>)<inf>2</inf> prepared from each shell powder are quite similar, showing no impurities. The thermal behaviors of CaCO<inf>3</inf> and Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O produced from each shell were slightly different. However, particle sizes and morphologies of the same products obtained from different shells were slightly different—but those are significantly different for the kind of the obtained products. Overall, the products (CaCO<inf>3</inf>, Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O, and Ca<inf>3</inf>(PO<inf>4</inf>)<inf>2</inf>) were obtained from the bivalve shell wastes by a rapidly simple, environmentally benign, and low-cost approach, which shows huge potential in many industries providing both economic and ecological benefits.
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    Influence of Organic Solvent on the Physicochemical Characteristics of Calcium Citrate Prepared from Mussel Shell Waste
    (2025-06-01)
    Punthipayanon, Sirichet
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    Chanwetprasat, Pantita
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    ; ;
    A green and mild chemical reaction of calcium citrate (CC) was successfully prepared from reactions between mussel shell waste and citric acid in the presence of acetone (AC), ethanol (Et), and isopropyl alcohol (IPA). All the synthesized CCs contained the same functional groups such as citrate (C<inf>6</inf>H<inf>5</inf>O<inf>7</inf><sup>3−</sup>), water (H<inf>2</inf>O), and calcium–oxygen (Ca–O). However, the differences in the spectra pointed out the differences in the crystal environment and structure of CCs. CC-AC and CC-IPA mainly crystallized in the monoclinic [Ca<inf>3</inf>(C<inf>6</inf>H<inf>5</inf>O<inf>7</inf>)<inf>2</inf>(H<inf>2</inf>O)<inf>2</inf>]·2H<inf>2</inf>O crystal system, whereas CC-Et mainly crystallized in the triclinic Ca<inf>3</inf>(C<inf>6</inf>H<inf>5</inf>O<inf>7</inf>)<inf>2</inf>∙(H<inf>2</inf>O)<inf>4</inf> structure. The molecular alignments of triclinic CC-Et were different from monoclinic CC-AC and CC-IPA, resulting in differences in thermal behaviors. Two dehydration steps were observed for the monoclinic CC-AC and CC-IPA, whereas the triclinic CC-Et showed a single dehydration process. The TG mass losses further demonstrated that anhydrous Ca<inf>3</inf>(C<inf>6</inf>H<inf>5</inf>O<inf>7</inf>)<inf>2</inf> phase, in addition to the Ca<inf>3</inf>(C<inf>6</inf>H<inf>5</inf>O<inf>7</inf>)<inf>2</inf>∙4H<inf>2</inf>O, was also observed for CC-AC and CC-IPA, whereas CC-Et contained a single Ca<inf>3</inf>(C<inf>6</inf>H<inf>5</inf>O<inf>7</inf>)<inf>2</inf>∙(H<inf>2</inf>O)<inf>4</inf> phase. The morphologies of CC-AC and CC-IPA also differed from that of CC-Et. The differences in some properties of the synthesized CCs could be attributed to the change in the supersaturation state of the reaction solution. Due to the superior polarity, ethanol is more compatible with citric acid. The presence of ethanol could suppress the supersaturation rate of the reaction solution, causing the modulation of the precipitation mechanisms and reducing the particle growth rate of CC-Et, thereby explaining the difference in vibrational, structural, thermal, and morphological characteristics of CC-Et, compared to CC-AC and CC-IPA.
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    Characterization, Kinetic Using Deconvolution Techniques and Thermodynamic Study of Synthetic MgHPO4·3H2O
    (2023-04-01)
    Kullyakool, Saifon
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    Thompho, Somphob
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    ;
    MgHPO<inf>4</inf>·3H<inf>2</inf>O was synthesized via a simple wet reaction and transformed to its final decomposed product, Mg<inf>2</inf>P<inf>2</inf>O<inf>7</inf> at 873 K. The thermal properties, vibrational modes of block units, and solid phases of the synthetic compounds have been investigated by TG/DTG/DTA, FTIR, and XRD techniques. The temperature dependence of thermodynamic properties estimated from the DSC data occurred in two regions (before and after the dehydration reaction) indicating a characteristic of the prepared MgHPO<inf>4</inf>·3H<inf>2</inf>O sample. The dehydration reactions of 3.5 mol of water molecules in the structure overlapped in the temperature of 363–823 K and showed the phase transition at 921 K as revealed by TG/DTG/DTA. The deconvolution technique using the newly modified co-mathematical functions was used to separate the overlapped dehydration steps in the DTG curve, which obtained the three steps. Only the first and second steps were estimated using kinetic triplet parameters (E<inf>a</inf>, A, and model), which indicate the single dehydration mechanism with the A<inf>1.25</inf> model and the multi-step of a parallel mechanism with the A<inf>1.6</inf> model, respectively. The data of kinetics and thermodynamics play key points in theoretical study, application development, and industrial production of magnesium phosphates as a theoretical basis.
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    Simple Rapid Production of Calcium Acetate Lactate from Scallop Shell Waste for Agricultural Application
    (2025-05-01)
    Mongkol, Sorakit
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    ; ;
    Laohavisuti, Nongnuch
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    Calcium acetate lactate (CAL) was rapidly synthesized for the first time using the reaction between the scallop shell-derived calcium carbonate (CaCO<inf>3</inf>) and the binary phase of acetic and lactic acids. Calcium acetate (CA) and calcium lactate (CL) synthesized from the reaction of scallop shell-derived CaCO<inf>3</inf> with each acid by similarity routes are compared with the obtained CAL product. The production yields are 88.24, 79.17, and 96.44%, whereas the solubilities are 93.77, 90.18, and 95.08% for CA, CL, and CAL, respectively. All the synthesized CA, CL, and CAL samples were characterized and confirmed by X-ray fluorescence (XRF) to examine the calcium main element and other impurities of minor elements, X-ray diffraction (XRD) to investigate the crystallography, Fourier transform infrared (FTIR) to characterize the vibrational characteristics of the functional groups, scanning electron microscope (SEM) to observe the sample morphologies, and the thermogravimetric analysis (TGA) to investigate the thermal decomposition processes of samples. The experimental results pointed out that the synthesized CA, CL, and CAL were the monohydrate, pentahydrate, and dihydrate forms with chemical formulae of Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O, Ca(CH<inf>3</inf>CHOHCOO)<inf>2</inf>·5H<inf>2</inf>O, and Ca(CH<inf>3</inf>COO)(CH<inf>3</inf>CHOHCOO)·2H<inf>2</inf>O, respectively. The final thermal decomposition product of all calcium compounds was calcium oxide (CaO). The CAL sample’s vibrational characteristics, crystal phases, and morphologies show the binary acetate and lactate anion phases, confirming the new binary anionic calcium acetate lactate obtained. In conclusion, this research proposes an easy and low-cost technique to prepare a new valuable CAL compound using scallop shell waste as a cheap and renewable calcium source.
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    A simple synthesis and room temperature magnetic properties of new binary Mn0.5Fe0.5(H2PO4)2·xH2O obtained from a rapid co-precipitation at ambient temperature
    (2009-02-01) ;
    Maensiri, Santi
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    Youngme, Sujittra
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    Danvirutai, Chanaiporn
    A new binary Mn<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·xH<inf>2</inf>O powder was synthesized by simple and cost-effective method using phosphoric acid, manganese and iron metals as starting chemicals. The synthesized solid shows the complex thermal transformations and the final decomposition product is a new binary manganese iron cyclo-tetraphosphate, MnFeP<inf>4</inf>O<inf>12</inf>. The X-ray diffraction and FTIR results indicate that the synthesized new binary Mn<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·xH<inf>2</inf>O and the decomposition MnFeP<inf>4</inf>O<inf>12</inf> powders are a pure monoclinic phase with space group P2<inf>1</inf>/n (Z = 2) and C2/c (Z = 4), respectively. The particle morphologies of Mn<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·xH<inf>2</inf>O and MnFeP<inf>4</inf>O<inf>12</inf> powders appear as the rod-like tetragonal shape and show a high agglomeration of small particles, which are similar to the case of Mn(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·2H<inf>2</inf>O and Fe<inf>2</inf>P<inf>4</inf>O<inf>12</inf>, respectively. Room temperature magnetization results show a ferromagnetic behavior of the Mn<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·xH<inf>2</inf>O and MnFeP<inf>4</inf>O<inf>12</inf> powders, having the hysteresis loops in the range of -10,000 Oe < H < +10,000 Oe with the specific magnetization values of 25.63 and 13.14 emu/g at 10 kOe, respectively. The lower magnetizations of Mn<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·xH<inf>2</inf>O and MnFeP<inf>4</inf>O<inf>12</inf> than those of Fe(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·2H<inf>2</inf>O and Fe<inf>2</inf>P<inf>4</inf>O<inf>12</inf> powders indicate the presence of Mn ions in substitution position of Fe ions. © 2008 Elsevier Masson SAS. All rights reserved.
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    Phase transition behaviour and electrical properties of lead-free (K 0.5Na0.5)NbO3-LiNbO3-LiSbO 3 piezoelectric ceramics
    (2011-05-01) ;
    Niemcharoen, Surasak
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    Sutapun, Manoon
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    ;
    The ternary system of 0.945(K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>)-(0.055 - x)LiNbO<inf>3</inf>-xLiSbO<inf>3</inf> [0.945KNN-(0.055 - x)LN-xLS]; x = 0.0-0.055 lead-free piezoelectric ceramics was fabricated by the conventional mixed oxide method with normal sintering. The crystal structure was studied by means of X-ray diffraction (XRD). The results of XRD patterns show that complete solid solutions of the mixed phase between the orthorhombic and tetragonal perovskite phase were observed. The DSC and dielectric data show that the amount of LiSbO<inf>3</inf> in K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>-LiNbO<inf>3</inf> solid solution slightly decreases the paraelectric cubic-ferroelectric tetragonal phase transition (T<inf>C</inf>) to a low temperature. Furthermore, good dielectric and piezoelectric properties were observed at composition, x = 0.03. The polymorphic phase transition between the orthorhombic and tetragonal phases plays a very important role in enhancement of the piezoelectric properties of KNN-LN-LS ceramics. © 2010 Elsevier B.V. All rights reserved.
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    A simple route to synthesize nickel ferrite (NiFe2O4) nanoparticles using egg white
    (2007-05-01)
    Maensiri, Santi
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    Masingboon, Chivalrat
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    Seraphin, Supapan
    NiFe<inf>2</inf>O<inf>4</inf> nanoparticles were synthesized by a simple and cost-effective method using Ni and Fe nitrates and freshly extracted egg white (ovalbumin) in an aqueous medium. The X-ray diffraction and selected-area electron diffraction results indicated that the synthesized nanoparticles have only the inverse spinel structure without the presence of any other phase impurities. Room temperature magnetization results showed a ferromagnetic behavior of the NiFe<inf>2</inf>O<inf>4</inf> nanoparticles, with saturation-specific magnetization values in the range of 26.4-42.5 emu/g at 10 kOe. © 2006 Acta Materialia Inc.
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    A simple synthesis and characterization of binary Co0.5Fe 0.5(H2PO4)2·2H2O and its final decomposition product CoFeP4O12
    (2011-01-01) ;
    Danvirutai, Chanaiporn
    ;
    This paper reports the synthesis of binary Co<inf>0.5</inf>Fe <inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·2H<inf>2</inf>O by a simple, rapid and cost-effective method using CoCO<inf>3</inf>-Fe(c)-H <inf>3</inf>PO<inf>4</inf> system in water-acetone media at ambient temperature. Thermal transformation of the synthesized powder was investigated by TG/DTG/DTA and DSC techniques, which indicate that its final decomposed product was a binary cobalt iron cyclotetraphosphate CoFeP<inf>4</inf>O<inf>12</inf>. The FTIR and XRD results of the synthesized Co<inf>0.5</inf>Fe<inf>0.5</inf>(H <inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·2H<inf>2</inf>O and the decomposed CoFeP<inf>4</inf>O<inf>12</inf> indicate the pure monoclinic phases with space group P2<inf>1</inf>/n and C2/c, respectively. The morphologies of Co<inf>0.5</inf>Fe<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>) <inf>2</inf>·2H<inf>2</inf>O and CoFeP<inf>4</inf>O<inf>12</inf> powders appear non-uniform particle shapes and high agglomerates, which are different from the cases of the single compounds M(H<inf>2</inf>PO<inf>4</inf>) <inf>2</inf>·2H<inf>2</inf>O and M<inf>2</inf>P<inf>4</inf>O<inf>12</inf> (where M = Co, Fe). The magnetic properties of the studied compounds are superparamagnetic behaviors, which are important for specific applications. The physical properties of the studied powders are comparable with those reported in our previous study, affected by medium and condition of preparation method. © 2010 Elsevier Masson SAS. All rights reserved.
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    A rapid synthesis of blue-pigment copper cyclotetraphosphate (cu2P4O12) ricelike grain nanoparticles at low temperature
    (2012-12-01)
    Chatjuthamanee, Warunthip
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    ; ;
    A blue-pigment copper cyclotetraphosphate Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> was synthesized by a simple wet preparation method using copper oxide and phosphoric acid at 350 °C. The crystallite size obtained from X-ray line broadening is 53 ± 11 nm for the Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf>. The FTIR spectrum of Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> is assigned a base on the P<inf>4</inf>O<inf>12</inf><sup>4-</sup> ion in the structure, which indicates the most striking feature of cyclotetraphospate. XRD and FTIR results of the synthesized CuCu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> indicate the pure monoclinic phase with space group C<inf>2h</inf><sup>6</sup> (C2/c). SEM micrographs of the synthesized Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> show rice-like grains, a porous structure and agglomerations, which are important for a specific application. The UV-Vis-NIR spectrum confirms the octahedral coordination of the Cu (II) ion and blue pigment.