scholarly journals Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

In order to study the kinetics and mechanism of the reaction, laboratory leaching was carried out with industrially produced gibbsite ?-Al(OH)3 in aqueous solutions containing an excess of sodium hydroxide. The results obtained reaction temperature, duration and base concentration varied. The basic kinetic parameters were determined from: the reaction rate constant k=8.72?107 exp (-74990/RT) and the process activation energy in the range Ea=72.5-96.81 kJ/mol.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

Kinetics of CO2 Absorption in MEA+DETA Blended Amine Solutions

2013 ◽  
Vol 864-867 ◽  
pp. 194-200
Author(s):  
Juan Wen ◽  
Chun Xiu Huo ◽  
Bin Zhang
Keyword(s):  
Activation Energy ◽  
Dynamic Model ◽  
Rate Constant ◽  
Absorption Rate ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Experimental Results ◽  
Kinetics Of ◽  
Amine Solutions

The kinetics of CO2absorption in unloaded aqueous MEA, MDEA, DETA single amine solutions and MEA+DETA blende amine solutions was studied with the amine concentrations of 3.0 kmol/m3and at temperatures ranging between 298K and 338K. A dynamic model of CO2absorption rate on the basis of the static absorption experimental results was established. The reaction rate constant of CO2absorption in blended amine solutions MEA+DETA is , and its activation energy is 32.89KJ/mol.

Effect of crystallographic orientation on the kinetics of reaction of aluminium single crystal in aqueous solution of sodium hydroxide

1987 ◽  
Vol 52 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Milica Miadoková ◽  
Magdalena Plchová ◽  
Ivan Halaša
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Apparent Activation Energy ◽  
Sodium Hydroxide ◽  
Crystallographic Orientation ◽  
Reaction Rate ◽  
Rate Of Reaction ◽  
Crystallographic Planes ◽  
Kinetics Of Reaction ◽  
Kinetics Of

The effect of the concentration of OH- ions, oxygen pressure, and temperature on the rate of reaction of aluminium in aqueous solution of sodium hydroxide was studied for surface planes corresponding to the (100), (110), and (111) crystallographic planes. Kinetic anisotropy was observed: the reaction rate increased and the apparent activation energy decreased in order (100)-(110)-(111). The kinetic parameters were related to some physical characteristics of the surface.

Kinetic Analysis of Alkaline Extraction on Sweet-Bamboo Leaves

2011 ◽  
Vol 332-334 ◽  
pp. 467-470
Author(s):  
Porntip Sae Be ◽  
Suesat Jantip ◽  
Sirisin Chum Rum
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Extraction Temperature ◽  
Alkaline Extraction ◽  
K Value ◽  
Bamboo Leaves ◽  
Kinetics Of

This study aimed to investigate the influence of NaOH concentration and temperature used for cellulose extraction from sweet-bamboo leaves on the kinetics of the extraction reaction. The NaOH concentration and the temperature used for the extraction were varied and their effect was examined. It was found that the extraction rate was accelerated by either the increase of NaOH concentration or extraction temperature. The NaOH concentration affected the reaction rate constant, k, and the activation energy, E and the order of the reaction, n. Increase of NaOH concentration enhanced the reaction to move forwards, thus reducing the k and E values of the reaction and the order of the reaction, n, was changed. The correlation of the temperature and the NaOH concentration with the k value showed that at the lower NaOH concentration, the temperature influenced on the k value more significantly. The influence of the NaOH concentration on the k value was lessened with increase of the extraction temperature.

Determination of the reaction rate constant and activation energy for pressure-induced 2+2 cycloaddition of the C60 fullerene

2002 ◽  
Vol 44 (3) ◽  
pp. 557-559 ◽  
Author(s):  
V. A. Davydov ◽  
L. S. Kashevarova ◽  
A. V. Rakhmanina ◽  
V. M. Senyavin ◽  
N. N. Oleinikov ◽  
...  
Keyword(s):  
Activation Energy ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
C60 Fullerene

scholarly journals Effect of Thermal Pretreatment on the Solubilization of Organic Matters in a Mixture of Primary and Waste Activated Sludge

2015 ◽  
Vol 10 (2) ◽  
Keyword(s):  
Activation Energy ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Rate Constant ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Waste Activated Sludge ◽  
Pre Treatment ◽  
Reaction Activation Energy

The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. Although the thermal pre-treatment presents high energy consumption, the main part of this energy to heat can be recovered from the biogas produced in the anaerobic process. In this research a mixture of primary and waste activated sludge was thermally pretreated at 100, 125, 150, 175 and 200 oC in order to determine the reaction kinetics for the increase of soluble organic fraction (expressed as CODs and VFAs). Experimental results proved that the solubilization of sludge is a 1st order reaction with respect to both CODs and VFAs, KCODs (reaction rate constant of CODs solubilization) increased from 4.59*10-3 (min-1) to 7.55*10-3 (min-1) as the temperature increased from 100 to 200 oC, with a reaction activation energy of 7447.21 (J/mole) and frequency factor of 0.051 (min-1), While KVFAs (reaction rate constant of VFAs solubilization) increased from 5.33*10-3 (min-1) to 7.97*10-3 (min-1) for the same increase in temperature, with a reaction activation energy of 5947.22 (J/mole) and frequency factor of 0.0364 (min-1).

Crystallization Kinetics of CaOx in Artificial Urine and in Saline System

2014 ◽  
Vol 881-883 ◽  
pp. 708-711
Author(s):  
Lan Qing Deng ◽  
Jun Fa Xue ◽  
Li Kuan ◽  
Jian Ming Ouyang
Keyword(s):  
Reaction Time ◽  
Calcium Oxalate ◽  
Crystallization Kinetics ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Reaction Rate Constant ◽  
Artificial Urine ◽  
Kinetics Of

The crystallization kinetics of calcium oxalate (CaOx) was comparatively studied by detecting the change of free Ca2+ ions concentration with the reaction time in artificial urine and in saline system. The dynamics equations of CaOx crystallization was r=kcα, and the average reaction order (α) was 3.3 regardless of the relative suprasaturation degree (RS) of CaOx in the range of RS=10.58~17.53. The average reaction rate constant (κ) was (0.97±0.1)×109 in artificial urine and κ=(3.1±1.8)×109 in saline system, due to the presence of inhibitors to CaOx crystallization in artificial urine.

Removal of Refractory Organic Compounds Using Peroxy Radical and Ozone Reaction in Aqueous Solution

2008 ◽  
Vol 569 ◽  
pp. 33-36
Author(s):  
Jong Tae Jung ◽  
Jong Oh Kim ◽  
Bum Gun Kwon ◽  
Dong Ha Song
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Humic Acid ◽  
Hydroxyl Radical ◽  
Organic Compounds ◽  
Acid Concentration ◽  
Rate Constant ◽  
Reaction Rate ◽  
Peroxy Radical ◽  
Reaction Rate Constant

This study was conducted to evaluate the treatment performance of the system using peroxy radical/ozone reaction for refractory organic compounds removal in aqueous solution. The effect of initial humic acid concentration was conducted under the conditions of humic acid concentration 10 mg/L, 30 mg/L, 50 mg/L and 100 mg/L. Reaction rate constant (k) in 30 mg/L of humic acid concentration was higher than that of humic acid concentration 10 mg/L, 50 mg/L amd 100 mg/L. However, it decreased over the range of 30 mg/L of humic acid concentration due to the action of internal filter of humic acid itself. Reaction rate constant (k) in the initial 20 minute of reaction time was accelerated by decreasing hydraulic retention time (HRT). This may be ascribed to increase the reaction time between peroxy radical and ozone. pH is a key for both ozone stability and TiO2 surface property in aqueous solution. Reaction rate constant (k) of acid solution on pH variation was smaller compared to that of neutral or basic circumstances because ozone decomposes easily into hydroxyl radicals in neutral or basic solution. At reaction rate constant (k) for humic acid degradation in each unit process, peroxy radical/ozone combined system was higher than that of ozone only due to the effective production of hydroxyl radical. An obvious difference between ozone and peroxy radical/ozone is the consequence of hydroxyl radical produced by the reaction of ozone molecules and peroxy radicals.

Kinetics of the thermal inactivation of the Lactococcus lactis bacteriophage P008

2005 ◽  
Vol 72 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Mareile Müller-Merbach ◽  
Horst Neve ◽  
Jörg Hinrichs
Keyword(s):  
Activation Energy ◽  
Thermal Resistance ◽  
Protective Effect ◽  
Regression Model ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Thermal Inactivation ◽  
Inactivation Kinetics ◽  
Kinetics Of ◽  
Phage Inactivation

The thermal resistance of the lactococcal bacteriophage P008 was investigated between 55 and 80 °C. Inactivation kinetics revealed an order of reaction above 1 and could be determined by a non-1st-order regression model. Phage inactivation was influenced by the medium (milk and Ca-M17-broth). Within the investigated temperature range, milk had a protective effect on phage P008. This was reflected in the rate constant and in the activation energy. Thermal phage inactivation studies reported in literature were re-analysed using non-1st-order regression. The obtained kinetic parameters showed that phage P008 belongs to the most heat resistant lactococcal phages investigated so far.

scholarly journals The Effect of Ingredients Mixing Sequence in Rubber Compounding upon Vulcanization Kinetics of Natural Rubber: An Autocatalytic Model Study

2018 ◽  
Vol 18 (4) ◽  
pp. 709
Author(s):  
Abu Hasan ◽  
Rochmadi Rochmadi ◽  
Hary Sulistyo ◽  
Suharto Honggokusumo
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Model ◽  
Reaction Rate Constant ◽  
Model Study ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Mixing Sequence

This study examined the effect of ingredients mixing sequence to the vulcanization kinetics of natural rubber. The effects of mixing temperature, vulcanization temperature, and the carbon black type upon the kinetics were also studied by using rheography and an autocatalysis reaction model approach. The results showed that this model is good in providing information on vulcanization reaction kinetics of natural rubber. High vulcanization temperature resulted in high reaction rate constant. The more black carbon mixed at the beginning of the rubber mixing process, the higher reaction rate constant would be. The mixing of carbon black and rubber chemicals mixed into the rubber subsequently resulted in the higher reaction rate constant compared with that of simultaneously.

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