scholarly journals PROCESS FOR REMOVAL OF CHROMIUM ION FROM LEATHER INDUSTRIAL WASTES BY ACTIVATED PURE RICE HUSK

2021 ◽  
Vol 4 (4) ◽  
pp. 334-338
Author(s):  
Yakubu Abdulkadir ◽  
A. Halid ◽  
A. Y. Abdulazeez ◽  
N. S. Gulumbe ◽  
M. Rukaiyat ◽  
...  
Keyword(s):  
Free Energy ◽  
Rice Husk ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Industrial Wastes ◽  
Solution Temperature ◽  
Chromium Ion ◽  
Exothermic Process ◽  
Stay Time ◽  
G Value

The removal of (Cr) ions from industrial wastage by adsorption on rice husk was investigated based on activated pure rice husk dosage, stay time, metal concentration and solution temperature. The optimum values of activated pure rice husk dosage and stay time were determined to be 0.5gm/50ml solution and 60 mins, respectively, for the adsorption of (Cr) ions. The constant for the Freundlich, D-R and Langmuir isotherms were 50%, calculated at 50 . The adsorption of (Cr) from industrial wastage was found to be exothermic. Thermodynamic parameters such as free energy change ( G°), enthalpy change ( H°) and entropy change ( S°) of adsorption also calculated and interpreted from the slope and intercept of the plots of lnkD vs I/T. The G° value decreases with rise in temperature and the negative values of H° indicate that the adsorption of (Cr) from industrial wastage was an exothermic process while positive values of change in entropy ( S°) were also observed

scholarly journals Thermodynamics of electrochemical reactions in Lead-acid Battery

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Adebayo Akinbulu ◽  
Toafeek Ogunbayo
Keyword(s):  
Free Energy ◽  
Temperature Coefficient ◽  
Electromotive Force ◽  
Electrochemical Reaction ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Electrochemical Reactions ◽  
Positive Entropy ◽  
Lead Acid Battery ◽  
Lead Acid

Thermodynamics of the electrochemical reaction in lead-acid battery was investigated. A negative value of change in Gibbs’ free energy, ?G, and a positive entropy change, ?S, were obtained for the reaction. ?G was more negative at increased temperature. The reaction was exothermic, with a negative value of enthalpy change, ?H. A relatively small value of temperature coefficient of the electromotive force of the cell, (?E/?T)_P, was also obtained for the reaction.

Separation of static and dynamic thermodynamic parameters for the interaction between pyropheophorbide methyl ester and copper

2014 ◽  
Vol 18 (04) ◽  
pp. 297-304 ◽  
Author(s):  
Saleh Al-Omari
Keyword(s):  
Free Energy ◽  
Methyl Ester ◽  
Fluorescence Quenching ◽  
Thermodynamic Function ◽  
Binding Constant ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Gibbs Free Energy Change ◽  
Quenching Process ◽  
Different Temperatures

The interaction between pyropheophorbide methyl ester (PPME) and the ionic metal of copper ( Cu 2+) was investigated using fluorescence and UV-vis techniques. By analysis of the fluorescence spectra, it was observed that Cu 2+ has a strong ability to quench the intrinsic fluorescence of PPME through dynamic and static quenching process. The binding constants of Cu 2+ with PPME were determined at different temperatures depending on the results of fluorescence quenching. Based on the modified form of the Stern–Volmer equation, static binding constant (kS) and the dynamic binding constant (kD) of Cu 2+-PPME association were obtained at different temperatures. The static thermodynamic function of the enthalpy change (ΔHS), the dynamic thermodynamic function of the enthalpy change (ΔHD), the static thermodynamic function of the entropy change (ΔSS), and the dynamic thermodynamic function of the entropy change (ΔSD) for the binding interaction were determined according to the van't Hoff equation. The values of static Gibbs free energy change (ΔGS) and dynamic Gibbs free energy change (ΔGD) were determined to be negative indicating that the interaction process was a spontaneous. ΔHD and ΔSD values were positive indicating that the dynamic quenching process of Cu 2+-PPME interaction was driven mainly by hydrophobic forces. For the static binding quenching, ΔHS and ΔSS values were negative which indicated that hydrogen bond, electrostatic interaction, and van der Waals interaction were important driving forces for PPME- Cu 2+ association. Both static and dynamic fluorescence quenching were related to the distance between PPME and Cu 2+ indicating that the electron transfer process occurred.

scholarly journals Treatment of Wastewater from a Dairy Industry Using Rice Husk as Adsorbent: Treatment Efficiency, Isotherm, Thermodynamics, and Kinetics Modelling

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Uttarini Pathak ◽  
Papita Das ◽  
Prasanta Banerjee ◽  
Siddhartha Datta
Keyword(s):  
Thermodynamic Parameters ◽  
Rice Husk ◽  
Adsorption Kinetics ◽  
Entropy Change ◽  
Solution Temperature ◽  
Batch Adsorption ◽  
Processing Unit ◽  
Adsorbent Dosage ◽  
Kinetics Modelling ◽  
Adsorbent Treatment

Effluent from milk processing unit contains soluble organics, suspended solids, and trace organics releasing gases, causing taste and odor, and imparting colour and turbidity produced as a result of high consumption of water from the manufacturing process, utilities and service section, chemicals, and residues of technological additives used in individual operations which makes it crucial matter to be treated for preserving the aesthetics of the environment. In this experimental study after determination of the initial parameters of the raw wastewater it was subjected to batch adsorption study using rice husk. The effects of contact time, initial wastewater concentration, pH, adsorbent dosage, solution temperature and the adsorption kinetics, isotherm, and thermodynamic parameters were investigated. The phenomenon of adsorption was favoured at a lower temperature and lower pH in this case. Maximum removal as high as 92.5% could be achieved using an adsorbent dosage of 5 g/L, pH of 2, and temperature of 30°C. The adsorption kinetics and the isotherm studies showed that the pseudo-second-order model and the Langmuir isotherm were the best choices to describe the adsorption behavior. The thermodynamic parameters suggested that not only was the adsorption by rice husk spontaneous and exothermic in nature but also the negative entropy change indicated enthalpy driven process.

scholarly journals PENENTUAN KESETIMBANGAN, TERMODINAMIKA DAN KINETIKA ADSORPSI ARANG AKTIF TEMPURUNG KELAPA SAWIT PADA ZAT WARNA REACTIVE RED DAN DIRECT BLUE

Alotrop ◽  
2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Rensy Aula Sari ◽  
M. Lutfi Firdaus ◽  
Rina Elvia
Keyword(s):  
Free Energy ◽  
Palm Oil ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Free Energy Change ◽  
Energy Change ◽  
Kinetics And Thermodynamics ◽  
Synthetic Dye ◽  
Direct Blue ◽  
Isotherm Adsorption

This perpose of this research was to know the isotherm, kinetics and thermodynamics adsorption of synthetic  dye onto activated carcoal from palm oil shell. The synthetic dye were Reactive Red and Direct Blue. The model of isotherm were Langmuir and Freundlich, kinetics adsorption tested were Pseudo orde-1 and Pseudo orde-2, and also thermodynamics were free energy change (?Go), enthalpy change (?Ho), and entropy change (?So). The dominant isotherm adsorption was isotherm Freundlich, kinetic adsorption Pseudo 2 th order  with the value (?So), (?Go) and (?Ho), Reactive Red were 0,0028 Kj/mol.K , -3,93 Kj/mol, and -36,12 Kj/mol respectively. Whereas in direct blue were 0,0034 Kj/mol.K, -1,67 Kj/mol,and -30,16 Kj/mol respectively. 

scholarly journals Adsorption of Tributyl Phosphate on Silica Gel

2001 ◽  
Vol 19 (3) ◽  
pp. 211-217 ◽  
Author(s):  
V.F. Sazonova ◽  
M.A. Kojemyak ◽  
O.V. Perlova
Keyword(s):  
Free Energy ◽  
Silica Gel ◽  
Tributyl Phosphate ◽  
Physical Nature ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Water Molecules ◽  
Adsorption Behaviour ◽  
Free Energy Of Adsorption ◽  
Adsorption Layers

The adsorption behaviour of tributyl phosphate (TBP) on silica gel was studied. It was found that the adsorption isotherm shapes were complicated, being considered as S- and L-type isotherms according to the Giles classification. Adsorption itself was polymolecular and of a physical nature, the first adsorptive layer involving hydrogen bonding between the protons of surface silanol groups and the electron-donating oxygen atom of the adsorbate molecule. Subsequent adsorption layers were formed via van der Waals interaction. The free energy of adsorption of the system lay between −22.1 kJ/mol and −23.8 kJ/mol. The enthalpy change was negative and very small, i.e. −6.3 kJ/mol, while the entropy change was positive and in the range 53.9 J/(mol K) to 55.4 J/(mol K). The increase in entropy was explained in terms of the mobility of the TBP molecules in the adsorptive layer arising from their replacement on the silica gel surface by water molecules derived from the aqueous medium.

The Equilibrium and the Determination of D00 (H—CN)

1975 ◽  
Vol 53 (16) ◽  
pp. 2365-2370 ◽  
Author(s):  
Don Betowski ◽  
Gervase Mackay ◽  
John Payzant ◽  
Diethard Bohme
Keyword(s):  
Free Energy ◽  
Standard Enthalpy ◽  
Transfer Reaction ◽  
Standard Free Energy ◽  
Proton Transfer Reaction ◽  
Enthalpy Change ◽  
Standard Free Energy Change ◽  
Flowing Afterglow ◽  
Standard Enthalpy Change

The rate constants and equilibrium constant for the proton transfer reaction [Formula: see text] have been measured at 296 ± 2 K using the flowing afterglow technique: kforward = (2.9 ± 0.6) × 10−9 cm3molecule−1s−1, kreverse = (1.8 ± 0.4) × 10−10 cm3 molecule1 s−1, and K = 16 ± 2. The measured value of K corresponds to a standard free energy change, ΔG296°, of −1.6 ± 0.1 kcal mol−1 which provides values for the standard enthalpy change, ΔH298°= −1.0 ± 0.2 kcal mol−1, the bond dissociation energy, D00(H—CN) = 124 ± 2 kcal mol−1, and the proton affinity, p.a.(CN−) = 350 ± 1 kcal mol−1.

scholarly journals Thermodynamics of ligand binding by the yeast mRNA-capping enzyme reveals different modes of binding

2004 ◽  
Vol 384 (2) ◽  
pp. 411-420 ◽  
Author(s):  
Isabelle BOUGIE ◽  
Amélie PARENT ◽  
Martin BISAILLON
Keyword(s):  
Ligand Binding ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Mrna Capping ◽  
Capping Enzyme ◽  
Eukaryotic Mrnas ◽  
Entropic Effect ◽  
A Minor ◽  
Rna Capping ◽  
Capping Enzymes

RNA-capping enzymes are involved in the synthesis of the cap structure found at the 5′-end of eukaryotic mRNAs. The present study reports a detailed study on the thermodynamic parameters involved in the interaction of an RNA-capping enzyme with its ligands. Analysis of the interaction of the Saccharomyces cerevisiae RNA-capping enzyme (Ceg1) with GTP, RNA and manganese ions revealed significant differences between the binding forces that drive the interaction of the enzyme with its RNA and GTP substrates. Our thermodynamic analyses indicate that the initial association of GTP with the Ceg1 protein is driven by a favourable enthalpy change (ΔH=−80.9 kJ/mol), but is also clearly associated with an unfavourable entropy change (TΔS=−62.9 kJ/mol). However, the interaction between Ceg1 and RNA revealed a completely different mode of binding, where binding to RNA is clearly dominated by a favourable entropic effect (TΔS=20.5 kJ/mol), with a minor contribution from a favourable enthalpy change (ΔH=−5.3 kJ/mol). Fluorescence spectroscopy also allowed us to evaluate the initial binding of GTP to such an enzyme, thereby separating the GTP binding step from the concomitant metal-dependent hydrolysis of GTP that results in the formation of a covalent GMP–protein intermediate. In addition to the determination of the energetics of ligand binding, our study leads to a better understanding of the molecular basis of substrate recognition by RNA-capping enzymes.

scholarly journals REMOVAL OF CU (II) FROM DYE EFFLUENT USING NATURAL AND PHOSPHATE-MODIFIED NIGERIAN KAOLINITE CLAY

2019 ◽  
Vol 7 (8) ◽  
pp. 402-414
Author(s):  
S. C. Olu ◽  
P. E. Dim ◽  
J. O. Okafor
Keyword(s):  
Free Energy ◽  
Metal Ion ◽  
Fourier Transforms ◽  
Lattice Structure ◽  
Enthalpy Change ◽  
Free Energy Change ◽  
Energy Change ◽  
Order Model ◽  
Acid Modification ◽  
Kaolinite Clay

This study indicates kaolinite clay as an effective adsorbent for the uptake of Cu (II) from wastewater. The adsorption process was studied with variation of time, temperature and adsorbent dosage at the effluent pH of 6. X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), Brunauer Emmett and Teller (BET) and Scanning electron microscopy (SEM) were used to characterize the adsorbents. XRD spectra showed that modification with KH2PO4 did not significantly change the crystal spacing on the lattice structure of the clay mineral; however, there were shifts in the intensity of the peaks for the modified kaolinite clay. The FTIR spectra showed that certain functional groups are responsible for binding the metal ions from solution. SEM indicated an increase in the porosity of the modified adsorbent as compared with the unmodified kaolinite, which enhances metal ion adsorption on modified kaolinite clay. The BET indicate that acid modification increased the surface area and total pore volume of the kaolinite clay. The kinetic study revealed that the pseudo-first-order model fitted poorly to the equilibrium data, however, the pseudo-second-order model had a good fit for all reaction time at different initial concentrations. The mechanism of the sorption process was evaluated using thermodynamic properties such as enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS), which were evaluated using Van’t Hoff equations. The negative values of free energy change (ΔG), suggests spontaneity and feasibility of the process. The positive values of enthalpy change (ΔH) indicate endothermic nature of the process.

scholarly journals Industrial Wastes in Soil Improvement

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
G. V. Rama Subbarao ◽  
D. Siddartha ◽  
T. Muralikrishna ◽  
K. S. Sailaja ◽  
T. Sowmya
Keyword(s):  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cost Effective ◽  
Dry Weight ◽  
Soil Improvement ◽  
Geotechnical Properties ◽  
Point Of View ◽  
Industrial Wastes ◽  
Engineering Structures

Soil existing at a particular site may not be appropriate for construction of engineering structures. The present study made an attempt to enhance the geotechnical properties of a soil replaced with industrial wastes having pozzolanic value like rice husk ash (RHA) and fly ash (FA). Soil is replaced with RHA in 2%, 4%, and 6% to dry weight of soil. It is observed that soil replaced with 4% RHA is the optimum for the soil used in this study from geotechnical point of view. To know the influence of fly ash, soil is further replaced with 4% FA along with 4% RHA. It is found that results of soil replacement by both RHA and FA proved to be soil modification and not the improvement. Hence, a cost-effective accelerator like lime is used for further replacing the above soil-4%, RHA-4% FA mix. The optimum lime content is found to be 4%.

Theoretical Thermodynamic Analysis and Phase Analysis of AZ91D/Flyash Composites

2014 ◽  
Vol 788 ◽  
pp. 604-607
Author(s):  
Hong Chao Chu ◽  
Si Rong Yu ◽  
Cui Xiang Wang ◽  
Qi Lou
Keyword(s):  
Free Energy ◽  
Gibbs Free Energy ◽  
Minimum Principle ◽  
Solution Treatment ◽  
Entropy Change ◽  
Treatment Temperature ◽  
Free Energy Change ◽  
Energy Change ◽  
Solution Treatment Temperature ◽  
Gibbs Free Energy Change

The thermodynamic calculation is valuable for judging the feasibility of a reaction. In the present paper, the enthalpy change (∆HR), entropy change (∆SR) and Gibbs free energy change (∆GR) among various components in AZ91D Mg alloy-Cenosphere composites (FAC/AZ91D) were calculated. Through the calculation, we obtained the relationships between the Gibbs free energy changes and temperatures. The difficulty degree of every potential reaction could be directly reflected by the correlation curve between the temperature and the Gibbs free energy change. The analysis result provided the theoretical basis for the reaction temperature and the solution treatment temperature of the FAC/AZ91D system. At the same time, the analysis based on the minimum principle of the reaction free energy revealed the final components (MgO, Mg2Si and MgAl2O4), which was partially similar to the result of XRD analysis (MgO, Mg2Si and Mg17Al12).

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