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Ultrahigh hydrogen storage using metal-decorated defected biphenylene
(2023-08-30)
Kaewmaraya, T.
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Thatsami, N.
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Tangpakonsab, P.
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Kinkla, R.
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Kotmool, K.
Hydrogen (H<inf>2</inf>) energy has emerged as a principal contender for renewable green energy applications because of the ultra-high energy density and natural abundance. The implementation of this prospective technology necessitates the ultra-high capacity of H<inf>2</inf> storage mediums. This work reports the exceptional H<inf>2</inf> storage capacities of two-dimensional (2D) carbon allotrope biphenylene (BPL) functionalized by Li, Na, K, and Ca. The combined theoretical approaches including the density functional theory (DFT), ab-initio molecular dynamics (AIMD), maximally localized Wannier functions (MLWFs), and thermodynamic analysis were employed to elucidate the storage efficiencies at operationally practical conditions. The findings reveal that pristine BPL decorated by the selected metals are all inefficient for H<inf>2</inf> storage because of the sensitive crystal instability caused by the energetic aggregation of the metallic dopants. On the other hand, point-defected BPL resolves this issue because it adequately magnifies the binding energies with all the decorated metals via the highly ionic bonds. Crucially, these binding energies exceed the cohesive counterparts of the parental metal bulks, consequently stabilizing the crystal integrity. Intriguingly, the Li- and Na-decorated divacancy BPL retain the ultimate H<inf>2</inf> storage capacities of 6.76 wt% and 6.66 wt% at the practical temperature and pressure, respectively, surpassing the goal value of 5.50 wt% to be achieved by 2025. Hence, metal-functionalized BPL are conclusively the promising carbon materials for the H<inf>2</inf> storage functionality.
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Simple synthesis, kinetics and thermodynamics of rod-like Cu2(OH)PO4 microparticles and rod-like Cu4O(PO4)2 nanoparticles
(2020-08-01)
Kullyakool, Saifon
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Boonchom, Banjong
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Chaiseeda, Kittichai
Rod-like Cu<inf>2</inf>(OH)PO<inf>4</inf> microparticles were synthesized via a simple wet chemical reaction by mixing the solutions of CuSO<inf>4</inf>·5H<inf>2</inf>O and Na<inf>3</inf>PO<inf>4</inf>·12H<inf>2</inf>O at 90 °C for 24 h. Thermal transformation of the prepared Cu<inf>2</inf>(OH)PO<inf>4</inf> microparticles were related to endothermic dehydroxylation and its final decomposed product rod-like Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> nanoparticles were obtained. The XRD results indicated that Cu<inf>2</inf>(OH)PO<inf>4</inf> and Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> crystallize orthorhombic (space group Pnnm, D<inf>2h</inf> 12) and triclinic (space group P1‾, C<inf>i</inf> 1) phases, respectively. The thermal transformation mechanisms from Cu<inf>2</inf>(OH)PO<inf>4</inf> to Cu<inf>4</inf>O(PO<inf>4</inf>)<inf>2</inf> were expressed thought the relation of the graphical shape of isothermal combined with the non-isothermal multi-heating rate equation and kinetic models (P<inf>3/2</inf> and R<inf>2</inf>) to discuss the change of morphologies from microparticles to nanoparticles. Kinetic parameters and triplet thermodynamic functions of activated compound were determined and fully discussed. The obtained data will be useful for academic scientists and industrial researchers to apply these copper phosphates for special applications.
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Kinetic, equilibrium and thermodynamic studies for adsorption of nickel ions onto husk of oryza sativa
(2019-11-01)
Zafar, Shagufta
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Khan, Muhammad Imran
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Khraisheh, Majeda
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Lashari, Mushtaq Hussain
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Shahida, Shabnam
This research focus onto batch adsorption of nickel ions (Ni(II)) onto husk of Oryza sativa (HOS) from aqueous solution at room temperature. Several techniques such as Fourier transform infrared, scanning electron microscopy and energy dispersive X-ray were employed to confirm adsorption of Ni(II) onto HOS. The effect of operational parameters such as contact time, amount of adsorbent, initial concentration of metal ions, temperature and pH on the percentage removal of Ni(II) was evaluated. The removal of Ni(II) was 62.32% under optimum amount of adsorbent (0.3 g) at room temperature. Adsorption kinetics study has exhibited that experimental data fitted-well to pseudo-second-order kinetic model. Linear and nonlinear forms of Langmuir, Freundlich and Dubinin-Radushkevivh isotherms were used to analyse experimental data and results showed that adsorption data fitted well to nonlinear and linear form of adsorption isotherms. Adsorption thermodynamic study has indicated that adsorption of Ni(II) onto HOS was an endothermic and spontaneous process.
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Adsorption kinetic, equilibrium and thermodynamic study for the removal of Congo Red from aqueous solution
(2017-12-01)
Khan, Muhammad Imran
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Zafar, Shagufta
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Khan, Muhammad Ali
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Buzdar, Abdul Rehman
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Prapamonthon, Prasert
In this study, the adsorption of Congo red (CR) dye from aqueous solution onto cationic polymeric film (BIII) was investigated at ambient temperature. The effect of operational parameters such as contact time, membrane dosage, initial dye concentration and temperature on the adsorption of CR from aqueous solution was studied. Adsorption kinetics has been studied by employing several kinetic models and attained results showed that the adsorption data fitted-well to the pseudo-second-order kinetic model. Nonlinear forms of two parameters and three parameters isotherms were applied on experimental data and the results indicated that the adsorption data fitted well to the various two and three parameters isotherms. Thermodynamic study showed that the adsorption of CR onto cationic polymeric film (BIII) was an exothermic process.
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Separation of platinum(IV) across hollow fiber supported liquid membrane using non-toxic diluents: Mass transfer and thermodynamics
(2017-10-25)
Wongkaew, Krirkratthawit
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Mohdee, Vanee
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Pancharoen, Ura
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Arpornwichanop, Amornchai
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Lothongkum, Anchaleeporn W.
Non-toxic diluents were studied and compared with toxic diluents for separation of platinum(IV) across hollow fiber supported liquid membrane. 91.41% extraction and 81% stripping of platinum(IV) was observed for sunflower oils at 328.15 K. Overall mass transfer resistance (R) was 146.612 × 104 s/cm. The separation process was exothermic (ΔH<inf>ex</inf> 0 = −975.20 kJ/mol) and spontaneous (ΔG<inf>ex</inf> 0 = −326.447 J/mol). The E<inf>a</inf> of 1.673 kJ/mol indicated that the diffusion of complex species across the liquid membrane controlled the mass transfer step. Moreover, a modified Apelblat model gave an excellent match for predicting the extraction behavior of platinum(IV) at 1.2818% RMSD.
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Thermodynamic relationships for homogeneous crystalline and liquid phases in the phase-field crystal model
(2017-07-01)
Chan, V. W.L.
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Pisutha-Arnond, N.
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Thornton, K.
We present thermodynamic relationships between the free energy density of the phase-field crystal (PFC) model and thermodynamic state variables that correspond to the model input parameters: temperature, lattice spacing, and an average value of the PFC order parameter, n¯. These relationships, derived for homogeneous phases under hydrostatic and nonhydrostatic stresses, are based on the thermodynamic formalism for crystalline solids of Larché and Cahn (1973). These relationships provide clear thermodynamic descriptions of the physical processes that are associated with changing PFC input parameters, and demonstrate that a crystalline phase from the PFC model can be considered a network of lattices occupied by atoms and vacancies, as described by Larché and Cahn. The equilibrium conditions between a crystalline phase and a liquid phase are imposed on the thermodynamic relationships for the PFC model to obtain a procedure for determining solid-liquid phase coexistence. The resulting procedure is found to be in agreement with the method commonly used in the PFC community. Finally, we apply the procedure to an eighth-order-fit (EOF) PFC model that has been parameterized to body-centered-cubic (bcc) iron (Jaatinen et al., 2009) to verify the applicability of the procedure. We demonstrate that the EOF-PFC model parameterization does not predict stable bcc structures with positive vacancy densities. This result suggests an alternative parameterization of the PFC model which requires the primary peak position of the two-body direct correlation function to shift as a function of n¯.
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Study of kinetics and thermodynamics of the dehydration reaction of AlPO4 . H2O
(2010-02-01)
Boonchom, Banjong
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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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Rapid synthesis, kinetics and thermodynamics of binary Mn 0.5Ca0.5(H2PO4)2 • H2O
(2009-12-01)
Boonchom, Banjong
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Danvirutai, Chanaiporn
The binary manganese and calcium dihydrogen phosphate monohydrate Mn <inf>0.5</inf>Ca<inf>0.5</inf>(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> • H<inf>2</inf>O was synthesized by a rapid and simple co-precipitation method using phosphoric acid, manganese metal, and calcium carbonate at ambient temperature. Thermal transformation shows complex processes and the final decomposed product was the binary manganese calcium cyclotetraphosphate MnCaP<inf>4</inf>O<inf>12</inf>. The activation energies of some decomposed steps were calculated by Kissinger method. Activated complex theory has been applied to each step of the reactions and the thermodynamic functions are calculated. These values for transformation stages showed that they are non-spontaneous processes without the introduction of heat. The differences of physical and chemical properties of the synthesized compound and its decomposed product are compared with M(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf> • H<inf>2</inf>O and M<inf>2</inf>P<inf>4</inf>O<inf>12</inf> (M = Mn and Ca), which indicate the effects of the presence of Ca ions in substitution of Mn ions and confirm the formation of solid solution. © 2009 Akadémiai Kiadó, Budapest, Hungary.

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