Boonchom, Banjong

Preferred name

Boonchom, Banjong

Alternative Name

BOONCHOM, Banjong

Boonchom, B.

Boonchom, And Banjong

Boonchoma, Banjong

Boomchom, Banjong

Main Affiliation

School of Science

banjong.bo@kmitl.ac.th

Now showing 1 - 10 of 102

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A rapid synthesis of cobalt cyclotetraphosphate Co2P 4O12 at low temperature
(2013-05-01)
Boonchom, Banjong
;
Vittayakorn, Naratip
The cobalt cyclotetraphosphate, Co<inf>2</inf>P<inf>4</inf>O<inf>12,</inf> was synthesized by evaporating a mixture of cobalt chloride hexahydrate, phosphoric acid and water at 70 °C, with further calcinations at 400 °C, 500 °C and 600 °C for 3 h. XRD results indicated that the Co <inf>2</inf>P<inf>4</inf>O<inf>12</inf> compounds obtained had only monoclinic phase with space group C<inf>2h</inf>6 (Z=4). From FT-IR spectra, vibrational modes corresponding to internal vibrations of the P <inf>4</inf>O<inf>12</inf>4- anion were identified. The morphologies and crystallite sizes for the Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> obtained from SEM data and X-ray line broadening showed non-uniform particles and 37-68 nm, respectively. All characterization methods showed that the monoclinic phase of Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> could be synthesized at the low temperature of 400 °C with short time consumption. The temperature was about 400 °C lower than that used in the previous synthesis method with CoCl <inf>2</inf> as reactant, and resulted in a cost-, energy-, and time-saving method. © 2012 Elsevier Ltd and Techna Group S.r.l.
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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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Boonchom, Banjong
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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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Study of kinetics and thermodynamics of the dehydration reaction of AlPO4 . H2O
(2010-02-01)
Boonchom, Banjong
;
Kongtaweelert, Samart
The kinetics and thermodynamics of the thermal dehydration of aluminum phosphate monohydrate, AlPO<inf>4</inf> . H<inf>2</inf>O were studied using thermogravimetry (TG-DTG-DTA) at four heating rates in dry air atmosphere. The activation energies of the dehydration step of AlPO<inf>4</inf> . H<inf>2</inf>O were calculated through the methods of Friedman (FR) and Flynn-Wall-Ozawa (FWO) and the possible conversion function has been estimated through the Achar and Li-Tang equations. The independent activation energies on extent of conversions and the better kinetic model of the dehydration reaction for AlPO<inf>4</inf> . H<inf>2</inf>O indicate single kinetic mechanism and the F<inf>2.05</inf> model as a simple n-order reaction of "chemical process or mechanism no-invoking equation", respectively. The positive values of ΔH# and ΔG# for the dehydration reaction show that it is endothermic and non-spontaneous process and it is connected with the introduction of heat. The kinetic and thermodynamic functions calculated for the dehydration reaction by different techniques and methods were found to be consistent. © Akadémiai Kiadó, Budapest, Hungary 2009.
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Dehydration behavior of synthetic Al0.5Fe0.5PO 4·2.5H2O
(2010-09-09)
Boonchom, Banjong
;
Vittayakorn, Naratip
The dehydration behavior of the experimentally produced Al <inf>0.5</inf>Fe<inf>0.5</inf>PO<inf>4</inf>·2.5H<inf>2</inf>O solid solution is assessed from thermogravimetrical (TG, differential thermogravimetric, DTG, and differential thermal analysis, DTA) and differential scanning calorimetry (DSC) analyses. The dehydration proceeded through a well-defined step at low temperatures (< 300 °C), which corresponds to the loss of 2.5 water molecules. The fluctuating dependence of the activation energies on fraction mass loss (α) for the dehydration reaction of Al <inf>0.5</inf>Fe<inf>0.5</inf>PO<inf>4</inf>·2.5H<inf>2</inf>O calculated through isoconversional methods (Ozawa and the Kissinger-Akahira-Sunose) indicates the existence of a complex multistep mechanism. The Avrami exponent value of 1.11 is indicative of one-dimensional growth as a phase boundary mechanism. The thermodynamic functions (ΔH*, ΔG*, and ΔS*) of the dehydration reaction calculated from the DSC technique are discussed for the first time. © 2010 American Chemical Society.
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Parallelogram-like microparticles of calcium dihydrogen phosphate monohydrate (Ca(H2PO4)2·H2O) obtained by a rapid precipitation route in aqueous and acetone media
(2009-08-12)
Boonchom, Banjong
Calcium dihydrogenphosphate monohydrate (Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O) was prepared by a rapid and simple precipitation method using CaCO<inf>3</inf> and H<inf>3</inf>PO<inf>4</inf> in aqueous and acetone media at ambient temperature. The thermal transformation of the synthesized Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O at 500 °C was obtained to be CaP<inf>2</inf>O<inf>6</inf> occurred through the dehydration and the phosphate condensation reactions, as revealed by thermoanalytical techniques (TG/DTG/DTA). The synthesized Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O and its decomposition product CaP<inf>2</inf>O<inf>6</inf> were characterized by X-ray powder diffraction (XRD), Fourier transfer infrared (FTIR) spectroscopy and scanning electron microscope (SEM). Thermal behavior and the morphology of the synthesized Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O in aqueous and acetone media are compared with those of other works. The SEM micrograph of Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O show parallelogram-like microparticles containing small and large grain sizes. The aqueous and acetone media are proposed to play an important role in the synthetic process of calcium phosphates in exhibiting different physical properties, which are important for specific applications. © 2009 Elsevier B.V. All rights reserved.
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Study of the dehydration of Co(H2PO4) 2-2H2O
(2009-04-09)
Boonchom, Banjong
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Danvirutai, Chanaiporn
The thermal transformation of Co(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> 2H<inf>2</inf>O was studied under a dry air atmosphere using TG-DTG-DTA. The TG-DTG-DTA curves show that the transformation occurs in three steps, which are dehydration processes. Co(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> · 2H<inf>2</inf>O and its thermal transformation product were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), and UV-vis near-IR techniques. The nonisothermal kinetics of Co(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> · 2H<inf>2</inf>O was studied by means of the Kissinger method. The specificity of the thermal transformation was characterized by identification of the bonds to be selectively activated because of energy absorption at the vibrational level, which are confirmed by the comparison of calculated wavenumbers and observed wavenumbers of the FTIR spectra. The activated complex theory has been applied to each step of the reactions, and the thermodynamic functions δH ≠, δG≠, and δS≠ are calculated. These values for three stages showed that they are connected with the introduction of heat and are nonspontaneous processes. © 2009 American Chemical Society.
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Thermal kinetic analysis of a complex process from a solid-state reaction by deconvolution procedure from a new calculation method and related thermodynamic functions of Mn0.90Co0.05Mg0.05HPO4·3H2O
(2018-09-01)
SRONSRI, Chuchai
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BOONCHOM, Banjong
Three individual peaks of thermal solid-state reaction processes of the synthesized Mn<inf>0.90</inf>Co<inf>0.05</inf>Mg<inf>0.05</inf>HPO<inf>4</inf>·3H<inf>2</inf>O were observed corresponding to dehydration I, dehydration II and polycondensation processes. An alternative method for the calculation of the extent of conversion was proposed from the peak area of the individual DTG peak after applying the best fitting deconvolution function (Frazer-Suzuki function). An iterative integral isoconversional equation was used to compute the values of the apparent activation energy E<inf>α</inf> and they were found to be 65.87, 78.16 and 119.32 kJ/mol for three peaks, respectively. Each individual peak was guaranteed to be a single-step kinetic system with its unique kinetic parameters. The reaction mechanism functions were selected by the comparison between experimental and model plots. The results show that the first, second and final individual peaks were two-dimensional diffusion of spherical symmetry (D<inf>2</inf>), three-dimensional diffusion of spherical symmetry (D<inf>3</inf>) and contracting cylinder (cylindrical symmetry, R<inf>2</inf>) mechanisms. Pre-exponential factor values of 3.91×106, 1.35×107 and 2.15×107 s−1 were calculated from the E<inf>α</inf> values and reaction mechanisms. The corresponded standard thermodynamic functions of the transition-state (activated) complexes were determined and found to agree well with the experimental data.
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Electrical and optical properties of p-type CuFe1-xSn xO2 (x = 0.03, 0.05) delafossite-oxide
(2013-01-14)
Ruttanapun, Chesta
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Boonchom, Banjong
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Thongkam, Montree
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Kongtaweelert, Samart
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Thanachayanont, Chanchana
The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> (x = 0.03, 0.05) delafossite samples have been synthesized by a solid-state reaction to investigate electrical and optical properties of the transparent conducting oxide materials. Crystal structure was characterized by XRD. The electrical conductivity and Seebeck coefficient were measured in the high temperature range of 300 to 960 K, while the Hall coefficient, XPS, and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks of the samples indicate the delafossite structure phase, and the XPS spectra reveal the stable Sn 2+-doping state. The Seebeck and Hall coefficient display a positive sign indicating the p-type conducting oxide. The optical allowed direct gap is 3.45 eV as a visible-transparent material. The activation energies for polaron hopping between Sn2+ sites and Fe3+ sites of 36 and 32 meV are obtained from the samples having x = 0.03 and 0.05, respectively. The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> delafossite oxide compounds, of which the Fe3+ sites in the CuFeO<inf>2</inf> are substituted by the Sn2+ ions, are p-type transparent conducting oxide materials. The activation energy is found to decrease with an increased in Sn content. © 2013 American Institute of Physics.
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Synthesis of MnNiP2O7 and nonisothermal decomposition kinetics of a new binary Mn0.5Ni0.5HPO4 · H2O precursor obtained from a rapid coprecipitation at ambient temperature
(2008-08-20)
Boonchom, Banjong
;
Danvirutai, Chanaiporn
The new binary metal hydrogen phosphate monohydrate Mn<inf>05</inf>Ni <inf>0.5</inf>HPO<inf>4</inf> · H<inf>2</inf>O was synthesized by a rapid and simple coprecipitation method using phosphoric acid, manganese metal, and nickel carbonate at ambient temperature. The kinetics of dehydration of Mn <inf>05</inf>Ni<inf>0.5</inf>HPO<inf>4</inf> · H<inf>2</inf>O was studied under nonisothermal heating by thermogravimetry (TG), and its final decomposition product was a binary metal pyrophosphate, MnNiP<inf>2</inf>O <inf>7</inf>. The activation energies of the dehydration step of Mn <inf>05</inf>Ni<inf>0.5</inf>HPO<inf>4</inf>·H<inf>2</inf>O were calculated through the isoconversional methods of Ozawa and Kissinger-Akahira- Sunose (KAS), and the possible conversion functions have been estimated through the Coats-Redfern method. The activation energies calculated for the dehydration of Mn<inf>05</inf>Ni<inf>0.5</inf>HPO<inf>4</inf> · H<inf>2</inf>O by different methods and techniques were found to be consistent. The possible conversion function of the dehydration reaction for Mn<inf>05</inf>Ni <inf>0.5</inf>HPO<inf>4</inf> · H<inf>2</inf>O was "spherical symmetry" of a "three-dimensional diffusion mechanism". © 2008 American Chemical Society.
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Synthesis and ferromagnetic property of new binary copper iron pyrophosphate CuFeP2O7
(2010-02-15)
Boonchom, Banjong
;
Vittayakorn, Naratip
The pyrophosphate of CuFeP<inf>2</inf>O<inf>7</inf> was synthesized through one step-thermal synthesis at 500 °C using the mixing of copper carbonate, iron metals and phosphoric acid. FTIR and XRD results indicate the dominant feature of pyrophosphate (P<inf>2</inf>O<inf>7</inf>4-) anion and a pure monoclinic phase with space group C<inf>2h</inf>6 (Z = 4), respectively. The crystallite size of 25 ± 9 nm for the CuFeP<inf>2</inf>O<inf>7</inf> was estimated by X-ray line broadening. Room temperature magnetization result shows ferromagnetic behavior of the CuFeP<inf>2</inf>O<inf>7</inf> powder, having hysteresis loop in the range of ± 10,000 Oe with the specific magnetization value of 1.57 emu g- 1. This property is important for specific application and is presented for the first time. © 2009 Elsevier B.V. All rights reserved.

Boonchom, Banjong

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