scholarly journals Kinetics and Thermodynamics of the Adsorption of Lead (II) on a Activated Carbon from Coconut Shells

2013 ◽  
Vol 15 (4) ◽  
pp. 283 ◽  
Author(s):  
L. Largitte ◽  
P. Lodewyckx
Keyword(s):  
Activated Carbon ◽  
Standard Enthalpy ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Effect Of Temperature ◽  
Standard Entropy ◽  
Exponential Factor ◽  
Different Temperatures ◽  
Coconut Shells

The effect of temperature on the adsorption of lead by an activated carbon from coconut shells is investigated. The pseudo second order equation is applied to the kinetic data obtained at different temperatures in order to determine the adsorption rate constants at these temperatures. Then, the Arrhenius equation is applied to the rate constants to determine the activation energy of the sorption reaction and the pre-exponential factor. By applying the Eyring equation to the rate constants, the standard thermodynamic activation parameters of the sorption reaction can also be calculated. In addition, the isotherms of lead adsorption on the activated carbon from coconut shells, at different temperatures, are determined and fitted by the Langmuir equation. The Van’t Hoff equation is applied to the Langmuir equilibrium constants in order to determine the standard enthalpy of the sorption reaction. The other standard thermodynamic parameters<br />(Gibbs standard enthalpy and standard entropy) are deduced. The isosteric standard sorption enthalpy is also determined by using both the classical approach and an adapted Clausius Clapeyron equation. The results are identical. The value obtained is higher, but more correct than that of Langmuir. On the basis of these<br />thermokinetic parameters, the activated carbon from Coconut shells can be considered as a very efficient carbon for the sorption of lead and its sorption efficiency (rate and quantity) increase with the temperature.

Effect of temperature on composite films made with activated carbon, graphite, or graphene oxide (GO) in a gelatin matrix

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 77-95
Author(s):  
Siqiao Yang ◽  
Haichao Li
Keyword(s):  
Contact Angle ◽  
Activated Carbon ◽  
Water Absorption ◽  
Composite Films ◽  
Effect Of Temperature ◽  
Gelatin Matrix ◽  
Vapour Permeability ◽  
Blending Method ◽  
The Matrix ◽  
Different Temperatures

Activated carbon, graphite, and GO/gelatin composite films were prepared by the blending method. The properties of composites were characterized by tensile strength (TS), elongation at break (EB), water vapour permeability (WVP), water-absorption ability, contact angle, scanning electron microscopy (SEM), and moisture at different temperatures. The properties of GO/gelatin composite films were better when each of three kinds of carbon materials were used as reinforcement phases and added into the matrix gelatin. The results showed that EB and TS of GO/gelatin composite films were both excellent. The moisture of GO/gelatin composite films was greater than the others. SEM micrographs showed that GO had better compatibility and dispersibility with gelatin than activated carbon and graphite. The water absorption of GO/gelatin composite films were low, at 15 °C and 25 °C, and the WVP was low at 35 °C. The WVP of GO/gelatin composite films was lower than the others at different temperatures. The contact angle of GO/gelatin composite films was larger than the others.

The decomposition of aliphatic N-nitro amines in aqueous sulfuric acid. Bisulfate as a nucleophile

1996 ◽  
Vol 74 (10) ◽  
pp. 1774-1778 ◽  
Author(s):  
Robin A. Cox
Keyword(s):  
Sulfuric Acid ◽  
Water Molecule ◽  
Rate Constants ◽  
Activation Parameters ◽  
Standard State ◽  
Aqueous Sulfuric Acid ◽  
Alkyl Groups ◽  
Different Temperatures ◽  
State Rate ◽  
Acid Catalyzed

In aqueous sulfuric acid, aliphatic N-nitro amines decompose to N2O and alcohols. An excess acidity analysis of the observed rate constants for the reaction shows that free carbocations are not formed. The reaction is an acid-catalyzed SN2 displacement from the protonated aci-nitro tautomer, the nucleophile being a water molecule at acidities below 82–85% H2SO4, and a bisulfate ion at higher acidities. Bisulfate is the poorer nucleophile by a factor of about 1000. Twelve compounds were studied, of which results obtained for nine at several different temperatures enabled calculation of activation parameters for both nucleophiles. The reaction appears to be mainly enthalpy controlled. The intercept standard-state rate constants are well correlated by the σ* values for the alkyl groups; the slopes are negative, with a more negative value for the slower bisulfate reaction. Interestingly the m≠m* slopes also correlate with σ*, although the scatter is bad. Key words: N-nitro amines, excess acidity, bisulfate, nucleophiles, acid-catalyzed, kinetics.

Kinetic and Equilibrium Studies of the Reactions of Cyanide Ion with 1,3,5-Trinitrobenzene, 2,4,6-Trinitroanisole, and 2,4,6-Trinitrotoluene in Isopropanol

1974 ◽  
Vol 52 (1) ◽  
pp. 8-17 ◽  
Author(s):  
Leong Huat Gan ◽  
Albert Richard Norris
Keyword(s):  
Standard Enthalpy ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Stopped Flow ◽  
Cyanide Ion ◽  
Equilibrium Studies ◽  
Kinetics Of Formation ◽  
Kinetics Of

Equilibrium constants for the formation of 1:1 cyanide ion σ-complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitroanisole, and 2,4,6-trinitrotoluene have been determined spectrophotometrically over a range of temperatures. Standard enthalpy (ΔH0) and entropy (ΔS0) changes associated with each reaction have been evaluated. The kinetics of formation of the σ-complexes have been investigated by means of a stopped-flow technique and the activation parameters characterizing the formation of each complex have been determined. Evidence is presented which indicates the cyanide ion – 2,4,6-trinitroanisole σ-complex formed in isopropanol contains the cyanide ion bonded exclusively at the C-3 position.

scholarly journals A method for investigating the effect of temperature on the 695 nm band of insoluble cytochrome c

1975 ◽  
Vol 149 (1) ◽  
pp. 169-177 ◽  
Author(s):  
T A Moore ◽  
C Greenwood
Keyword(s):  
Ionic Strength ◽  
Cytochrome C ◽  
Computer Analysis ◽  
Standard Enthalpy ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Effect Of Temperature ◽  
Standard Entropy ◽  
Ferricytochrome C ◽  
Standard Enthalpy Change

A method is described for computer analysis of simple spectrophotometric changes in particulate systems, and this has been applied to the bleaching of the 695 nm band of insoluble ferricytochrome c by temperature. The results show that insolubilization has no effect on the standard enthalpy change but lowers the value for the standard entropy change. This effect appears to be independent of the concentration of the gel matrix to which the cytochrome c is bound, but dependent on the ionic strength of the surrounding solution.

scholarly journals MANUFACTURING OF ACTIVATED CARBON USING DISPOSABLE COCONUT SHELLS FOR CATALYTIC ACTIVITIES AND WATER TREATMENT UTILIZATIONS

2020 ◽  
Vol 4 ◽  
pp. 6-9
Author(s):  
Suresh Aluvihara ◽  
C.S. Kalpage ◽  
P.W.S.K. Bandaranayake
Keyword(s):  
Activated Carbon ◽  
Water Treatment ◽  
Cost Effective ◽  
Optical Microscope ◽  
High Porosity ◽  
Catalytic Activities ◽  
Different Temperatures ◽  
Microscopic Studies ◽  
Coconut Shells ◽  
Black Color

Activated carbon is a black color solid compound which is fabricated using naturally occurring materials such as woods and species of coal that composed of the majority in carbon. The activated carbon is highly remarkable compound in the catalytic activities in most of chemical industries and water treatment activities because of the significant performances of such activated carbon due to the sufficiency of the surface property which is called as the adsorption with the couple of high porosity. The manufacturing of activated carbon from disposable coconut shells and the investigations of the physic-chemical characteristics of such activated carbon were the expectances of the existing research. Domestically collected coconut shells were burnt in the range of different temperatures 390°C–300°C after removing unnecessary constituents. The chemical composition of the powdered activated carbon was inspected using an X-ray fluorescence (XRF) spectrophotometer and the surfaces of prepared activated carbon were examined using an optical microscope. As the outcomes of the above experiments, it seems that the most adequate burning temperature for the manufacturing of that batch of coconut shells was in the range of 330°C–350°C, 68.85% of ferrous and 31.15% of potassium as the composed metallic element apart from the non metallic carbon and the pure black color non- composite surfaces were observed under the microscopic studies. It is encouraged to develop this production using cost effective materials such as the shells of fesults which are belonging to the palm cast while utilizing the productions through the various applications in chemical industries

scholarly journals On the reduced Redlich-Kister excess properties for 1,2-dimethoxyethane with propylene carbonate binary mixtures at temperatures (from 298.15 to 318.15) K.

2017 ◽  
Vol 6 (2) ◽  
pp. 33-41 ◽  
Author(s):  
Hanen Salhi ◽  
Shaik Babu ◽  
Nada Al-Eidan ◽  
Nejib H. Mekni ◽  
Noura Omar Al-Otaibi ◽  
...  
Keyword(s):  
Propylene Carbonate ◽  
Specific Interaction ◽  
Activation Parameters ◽  
Liquid Mixtures ◽  
Excess Properties ◽  
Effect Of Temperature ◽  
Present System ◽  
Molar Gibbs Free Energy ◽  
Free Energy Of Activation ◽  
Different Temperatures

Values of excess properties in 1,2-dimethoxyethane + propylene carbonate binary liquid mixtures at different temperatures from experimental density and viscosity values presented in earlier work, were used to test the applicability of the correlative reduced Redlich-Kister functions and the Belda equation, and to reveal eventual specific interaction hidden by the classical treatment of direct excess Redlich-Kister functions. Their correlation ability at different temperatures, and the use of different numbers of parameters, is discussed for the case of limited experimental data. The relative Redlich-Kister functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Values of limiting excess partial molar volume at infinite dilution deduced from different methods were discussed. Also, the activation parameters and partial molar Gibbs free energy of activation of viscous flow against compositions were investigated. Correlation between the two Arrhenius parameters of viscosity shows the existence of main different behaviors separated by a stabilized structure in a short range of mole fraction in 1,2-dimethoxyethane (0.45 to 0.83). In this context, the correlation Belda equation has also been applied to the present system for thermodynamic properties in order to reveal eventual solute-solvent interaction at high dilution.

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

1992 ◽  
Vol 70 (10) ◽  
pp. 2515-2519 ◽  
Author(s):  
Sharifa S. Alkaabi ◽  
Ahmad S. Shawali
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Order Conditions ◽  
Kinetics And Mechanism ◽  
Hammett Equation ◽  
Third Order ◽  
First Order ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

scholarly journals THE EFFECT OF TEMPERATURE ON THE PERFORMANCE OF ACTIVATED CARBON OVER CATALYTIC CRACKING OF CRUDE PALM OIL

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Nazarudin Nazarudin ◽  
Ulyarti Ulyarti ◽  
Oky Alfernando ◽  
Ira Galih ◽  
Susilawati Susilawati ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Palm Oil ◽  
Active Carbon ◽  
Catalytic Cracking ◽  
Effect Of Temperature ◽  
Crude Palm Oil ◽  
Carbon Catalyst ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Catalyst Increase

This research was carried out to investigate the effect of temperature in carbon production on its performance in the catalystic cracking of CPO to fuel.  The carbon was produced using palm shell at 2 different temperatures (450 and 550oC).  The cracking of CPO was carried out with and without the active carbon catalyst.  The result showed that the use of catalyst increase the conversion of both gas and liquid conversion.  The use of higher temperature in the production of active carbon catalyst increased the performance of the catalyst, in particular, for the liquid conversion. Keywords :Activated carbon, catalyst, catalytic cracking, crude palm oil

scholarly journals The Solubility and Hydrolysis of Aqueous Aluminium Hydroxides in Dilute Fresh Waters at Different Temperatures

1990 ◽  
Vol 21 (3) ◽  
pp. 195-204 ◽  
Author(s):  
Espen Lydersen
Keyword(s):  
Natural Waters ◽  
Equilibrium Constants ◽  
Relative Concentration ◽  
Amorphous Solid ◽  
Effect Of Temperature ◽  
Natural Soil ◽  
Exchange Reactions ◽  
Organic Complexes ◽  
Inorganic Species ◽  
Different Temperatures

This study is mainly focusing on the effect of temperature and pH on the chemistry of Al(OH)3(s) using available thermodynamic data. The calculations show that a doubling of the [H+] or a decrease in temperature by 15°C, approximately yields the same solubility increase of the various Al(OH)3(s) presented. The relative concentration of aqueous aluminium hydrolysis complexes is also highly temperature dependent. At 25°C and pH 5, the calculated distribution of dissolved, inorganic aluminium hydroxides corresponds to about 36% of Al3+, 37 % of Al(OH)2+, 26 % of Al(OH)2+ and 1 % of Al(OH)30. At the same pH but at 0°C, about 84%, 13%, 2% and 0% are present as Al3+, Al(OH)2+, Al(OH)2+ and Al(OH)30, respectively. This temperature effect is of major importance as the hydroxide species are supposed to be the most toxic species to aquatic biota. Literature reports on the equilibrium constants Al(OH)3(s), log*Ks, vary from about 8 to 11, a variation in the product by a factor of 1000. In natural soil/water systems the solubility products of crystalline and amorphous solid aluminium sources are unknown and the solubility may also be coupled to combined weathering/ion exchange processes. In addition substantial amount of aluminium may be present as organic complexes where aluminium by cation exchange reactions may enter the solution as monomeric inorganic species. Thus, if a low value for the equilibrium constants of Al(OH)3(s) is used as reference when calculating the degree of aluminium saturation, an apparent oversaturation will often be demonstrated. To estimate the degree of aluminium saturation in natural waters whould therefore only be of theoretical interest.

Kinetics and mechanisms of the reaction of 2,4,6-trinitrocumene and 2,4,6-trinitroethylbenzene with 1,1,3,3-tetramethylguanidine in N,N-dimethylformamide solvent

1987 ◽  
Vol 65 (5) ◽  
pp. 1007-1011 ◽  
Author(s):  
Mihir K. Biswas ◽  
Arnold Jarczewski ◽  
Kenneth T. Leffek
Keyword(s):  
Carbon Atom ◽  
Complex Formation ◽  
Proton Transfer ◽  
Equilibrium Constant ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Reaction Parameters ◽  
Deuterium Isotope Effect ◽  
Constant Rate

The reaction of tetramethylguanidine (TMG) with trinitrocumene (TNC) and trinitroethylbenzene (TNEB) in dimethylformamide solvent has been studied with respect to products and kinetics. For TNC only σ-complex formation with the benzene ring was observed, for which the equilibrium constant, rate constants, and activation parameters were measured. For TNEB, both σ-complex formation and proton transfer from the σ-carbon atom of the ethyl group were observed. The equilibrium constants, rate constants, and activation parameters were separately determined for each reaction and a primary deuterium isotope effect, kH/kD = 13.6 (at 20 °C), was found for the proton transfer. The reaction parameters are compared to those for proton transfer from TNT to tetramethylguanidine in DMF solvent.

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