scholarly journals NICKEL BIOSORPTION BY FINELY GROUND WASTE SLUDGE / NIKELIO BIOSORBAVIMAS SMULKIAI SUMALTU NUOTEKŲ DUMBLU / БИОСОРБЦИЯ НИКЕЛЯ МЕЛКО ИЗМЕЛЬЧЕННЫМ ИЛОМ СТОКОВ

2011 ◽  
Vol 19 (3) ◽  
pp. 208-214 ◽  
Author(s):  
Yasser Hannachi
Keyword(s):  
Experimental Data ◽  
Langmuir Isotherm ◽  
Treatment Plant ◽  
Second Order ◽  
The Other ◽  
Biosorption Capacity ◽  
Waste Sludge ◽  
Order Rate ◽  
Kinetics Of ◽  
Better Than

In this paper, removal of Ni (II) from aqueous solution by finely ground waste sludge (FGWS) was investigated. Waste sludge samples obtained from a varnishes and lacquers industry wastewater treatment plant was dried, ground and pre-treated with 1% H2O2 to improve the biosorption capacity. Kinetics of nickel biosorption onto FGWS was investigated by using the FGWS samples with particle size of 62.2 µm. The pseudo-first and second order rate expressions were used to correlate the experimental data. The kinetic constants were determined for both models and the second order rate expression was found to be more suitable. Three different biosorption isotherms were used to correlate the equilibrium biosorption data and the isotherm constants were determined. The Langmuir isotherm was found to fit the experimental data better than the other tested isotherms. The biosorption capacity (qm) and saturation constant (K) for the Langmuir isotherm showed that finely ground waste sludge has the largest capacity and affinity for removal of Ni(II) compared to the other Activated sludges. Santrauka Nagrinėjami Ni(II) šalinimo iš vandeninių tirpalų smulkiai sumaltu nuotekų dumblu (SSND) tyrimų rezultatai. Nuotekų dumblo pavyzdžiai imti iš glazūravimo ir lakavimo pramonės nuotekų valymo įrenginių, išdžiovinti, susmulkinti ir apdoroti 1% H2O2, kad padidėtų biosorbcijos tūris. Nikelio sorbcijos SSND kinetika tirta naudojant SSND bandinius, kurių dalelių dydis 62,2 µm. Pseudo pirmojo ir antrojo laipsnio greičio išraiškos buvo taikomos eksperimentinių duomenų koreliacijai apibrėžti. Kinetinė konstanta nustatyta abiejų modelių, tačiau antrojo laipsnio greičio išraiška buvo tinkamesnė. Pagal tris skirtingas biosorbcijos izotermes nustatyta biosorbcijos pusiausvyros duomenų koreliacija, rastos izotermių konstantos. Langmiuro (Langmuir) izotermė geriau atitiko eksperimentinius duomenis nei kitos tirtosios izotermės. Pagal Langmiuro izotermę biosorbcijos geba (q m) ir prisotinimo konstanta (K) rodė, kad smulkiai sumalto nuotekų dumblo geba šalinti Ni(II) yra didžiausia, palyginti su kitos rūšies aktyvintojo dumblo. Резюме Исследуется удаление Ni(II) из водных растворов мелко измельченным илом стоков (МИИС). Образцы ила стоковбыли взяты из оборудования по очистке стоков в промышленности по глазурованию и лакованию. Затем образцы были высушены, измельчены и обработаны 1-процентным H2O2, с целью увеличить объем биосорбции. Кинетика сорбции никеля МИИС исследовалась с применением образцов МИИС, величина частиц которых составляла62,2 μм. Выражения скорости псевдопервой и псевдовторой степени использовались для определения корреляции экспериментальных данных. Кинетическая константа была установлена для обеих моделей. Однако выражение скорости второй степени оказалось более приемлемым. Три разные изотермы биосорбции применялись для определения корреляции данных по равновесию биосорбции и констант изотерм. Изотерма Langmuir лучше совпала с экспериментальными данными, чем другие испытуемые изотермы. Способность биосорбции (q m) изотермы Langmuir и константа насыщения (K) показали, что мелко измельченный ил стоков обладает наибольшей способностью удалять Ni(II) по сравнению с другими видами активированного ила.

Determination of the Nucleophilicity of Tricarbonyliron Coordinated Cyclohepta-1,3,5-triene

1999 ◽  
Vol 64 (11) ◽  
pp. 1770-1779 ◽  
Author(s):  
Herbert Mayr ◽  
Karl-Heinz Müller
Keyword(s):  
Gibbs Energy ◽  
Ambient Temperature ◽  
Rate Constants ◽  
Second Order ◽  
Order Rate ◽  
Electrophilic Additions ◽  
Kinetics Of

The kinetics of the electrophilic additions of four diarylcarbenium ions (4a-4d) to tricarbonyl(η4-cyclohepta-1,3,5-triene)iron (1) have been studied photometrically. The second-order rate constants match the linear Gibbs energy relationship log k20 °C = s(E + N) and yield the nucleophilicity parameter N(1) = 3.69. It is concluded that electrophiles with E ≥ -9 will react with complex 1 at ambient temperature.

Thermal Model of a Thinned-Die Cooling System

2003 ◽  
Author(s):  
N. Boiadjieva ◽  
P. Koev
Keyword(s):  
Experimental Data ◽  
Thermal Model ◽  
Cooling System ◽  
Input Power ◽  
The Other ◽  
System Parameters ◽  
Air Intake ◽  
Optical Probing ◽  
Cooling Air ◽  
Better Than

For through-silicon optical probing of microprocessors, the heat generated by devices with power over 100W must be dissipated [1]. To accommodate optical probing, a seemingly elaborate cooling system that controls the microprocessor temperature from 60 to 100° C for device power up to 150W was designed [2]. The system parameters to achieve the desired thermal debug environment were cooling air temperature and air flow. A mathematical model was developed to determine both device temperature and input power. The 3-D heat equation that governs the temperature distribution was simplified to a case of a 1-D rod with one end at the device center and the other at the cooling air intake. Thus the cooling system was reduced to an analytical expression. From experimental data, we computed all coefficients in the model, then ran extensive tests to verify—the accuracy was better than 10% over the entire temperature and power ranges.

THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

KINETICS OF THE AQUEOUS ALKALINE HOMOGENOUS HYDROLYSIS OF HIGH EXPLOSIVE 1, 3,5,7-TETRAAZA- 1, 3,5,7-TETRANITROCYCLOOCTANE (HMX)

1994 ◽  
Vol 30 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Harro M. Heilmann ◽  
Michael K. Stenstrom ◽  
Rolf P. X. Hesselmann ◽  
Udo Wiesmann
Keyword(s):  
Temperature Dependence ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Elevated Temperatures ◽  
Second Order ◽  
Order Rate ◽  
Subsequent Calculation ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

In order to get basic data for the design of a novel treatment scheme for high explosives we investigated the kinetics for the aqueous alkaline hydrolysis of 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX) and the temperature dependence of the rate constants. We used an HPLC procedure for the analysis of HMX. All experimental data could be fit accurately to a pseudo first-order rate equation and subsequent calculation of second-order rate constants was also precise. Temperature dependence could be modeled with the Arrhenius equation. An increase of 10°C led to an average increase in the second-order rate constants by the 3.16 fold. The activation energy of the second-order reaction was determined to be 111.9 ±0.76 kJ·moJ‒1. We found the alkaline hydrolysis to be rapid (less than 2.5% of the initial HMX-concentration left after 100 minutes) at base concentrations of 23 mmol oH‒/L and elevated temperatures between 60 and 80°C.

Kinetics of Glyphosate Adsorption on Composite Resin from Aqueous Solution

2013 ◽  
Vol 803 ◽  
pp. 157-160
Author(s):  
Zhen Zhen Kong ◽  
Dong Mei Jia ◽  
Su Wen Cui
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Composite Resin ◽  
Order Equation ◽  
Second Order ◽  
First Order ◽  
Basic Resin ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Best Fit

The composite weakly basic resin (D301Fe) was prepared and examined using scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption kinetics of glyphosate from aqueous solution onto composite weakly basic resin (D301Fe) were investigated under different conditions. The experimental data was analyzed using various adsorption kinetic models like pseudo-first order, the pseudo-second order, the Elovich and the parabolic diffusion models to determine the best-fit equation for the adsorption of glyphosate onto D301Fe. The results show that the pseudo-second order equation fitted the experimental data well and its adsorption was chemisorption-controlled.

Kinetics of rapid reactions involving two pairs of consecutive second order steps

1953 ◽  
Vol 6 (3) ◽  
pp. 195 ◽  
Author(s):  
HG Higgins ◽  
EJ Williams
Keyword(s):  
Molecular Structure ◽  
Second Order ◽  
The Other ◽  
Rate Equations ◽  
Special Cases ◽  
Kinetics Of ◽  
Initial Reactivity

An examination is made of the kinetics of the reaction between A and B, where both reactants are capable of unifunctional behaviour, and A is also capable of bifunctional behaviour, for the general case in which the two reactive sites on A are not equivalent. Solutions are given of the appropriate rate equations for the two pairs of consecutive stages, and it is shown that the final concentrations of reactants and products can be related to given values of the initial concentrations and the velocity constants of the four second order stages. Relatively simple relations are established between the final concentrations and the ratio of the velocity constants for the case in which reaction at one position on A does not affect the reactivity of the other position. Some special cases of interest are considered. The results are related to the authors' earlier treatment of the case In which the initial reactivity of the two positions on A is initially the same. The theory is applied, by way of example, to the coupling of histidine with p-diazobenzenesulphonic acid, which appears to conform to the assumption of the same initial reactivity. The implications of the method in the correlation of molecular structure and reactivity are briefly discussed.

THE REDUCTION OF CYTOCHROMEcBY HYDROQUINONE

1963 ◽  
Vol 41 (1) ◽  
pp. 231-237 ◽  
Author(s):  
G. R. Williams
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Rate Equation ◽  
Second Order ◽  
Order Rate ◽  
Ferricytochrome C ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Order Rate Equation

The kinetics of reduction of ferricytochrome c by hydroquinone have been studied. The reaction does not conform to a simple second-order rate equation and it is demonstrated that the deviations are brought about by the presence of p-quinone, one of the products of the reaction. The accelerating effect of p-quinone is explained tentatively on the basis of an involvement of the semi-quinone. The effects on the reaction of pH, ionic strength, and temperature are reported and used to suggest features of the reaction mechanism.

scholarly journals Kinetic Model for Lead(II) Sorption on to Peat

1998 ◽  
Vol 16 (4) ◽  
pp. 243-255 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Kinetic Model ◽  
Second Order ◽  
Sorption Rate ◽  
Sorption Model ◽  
Order Rate ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Order Rate Equation

The kinetics of lead sorption on to peat have been investigated. The batch sorption model, based on the assumption of a pseudo-second order mechanism, has been developed to predict the rate constant of sorption, the equilibrium capacity and initial sorption rate with the effect of initial lead(II) concentration, peat particle size and temperature. An equilibrium capacity of sorption has been evaluated with the pseudo-second order rate equation. In addition, an activation energy of sorption has also been determined based on the pseudo-second order rate constants.

scholarly journals Rhodopsin photoproducts and rod sensitivity in the skate retina.

1977 ◽  
Vol 69 (1) ◽  
pp. 97-120 ◽  
Author(s):  
K P Brin ◽  
H Ripps
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Rate Constants ◽  
Dark Adaptation ◽  
Photochemical Reactions ◽  
The Other ◽  
Thermal Reactions ◽  
Rate Of Recovery ◽  
Spectral Absorbance ◽  
Kinetics Of

The late photoproducts that result from the isomerization of rhodopsin have been identified in the isolated all-rod retina of the skate by means of rapid spectrophotometry. The sequence in which these intermediates form and decay could be described by a scheme that incorporates two pathways for the degradation of metarhodopsin II (MII) to retinol: one via metarhodopsin III (MIII) and the other (which bypasses MIII) through retinal. Computer simulation of the model yielded rate constants and spectral absorbance coefficients for the late photoproducts which fit experimental data obtained at temperatures ranging from 7 degrees C to 27 degrees C. Comparing the kinetics of the thermal reactions with the changes in rod threshold that occur during dark adaptation indicated that the decay of MII and the fall in receptor thresholds exhibit similarities with regard to their temperature dependence. However, the addition of 2 mM hydroxylamine to a perfusate bathing the retina greatly accelerated the photochemical reactions, but had no significant effect on the rate of recovery of rod sensitivity. It appears, therefore, that the late bleaching intermediates do not control the sensitivities of skate rods during dark adaptation.

BERICHT: Self-Diffusion in Molten Salts. A Comparison Between Diffusion Theories and Experimental Data

1968 ◽  
Vol 23 (6) ◽  
pp. 933-939
Author(s):  
C.-A. Sjöblom
Keyword(s):  
Experimental Data ◽  
Molten Salts ◽  
Arrhenius Equation ◽  
Local Density ◽  
Cell Model ◽  
The Other ◽  
Self Diffusion ◽  
Free Volume Model ◽  
Hole Model ◽  
Better Than

A comparison between the available self-diffusion data on pure molten salts and the predictions by different liquid diffusion theories is made. It is found that the Arrhenius equation D=D0exp (— Q/R T) describes the experimental data equally well (or better) than any of the other theoretically predicted equations. The hole model prediction (Q=3.74 R Tm) is found to be inaccurate. The free volume model and the local density fluctuation models describe the data less well than the other models considered. The cubic cell model leads to a correct correlation between self-diffusion and kinematic viscosity for several salts (but not all).

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