scholarly journals KINETIC STUDY ON ADSORPTION OF CHROMIUM(lIl) TO DIATOMACEOUS EARTH PRE-TREATED WITH SULFURIC AND HYDROCHLORIC ACIDS

2010 ◽  
Vol 3 (1) ◽  
pp. 32-38
Author(s):  
Nuryono Nuryono ◽  
V.V.H. Susanti ◽  
Narsito Narsito

In this research, the effect of Sangiran diatomaceous earth pre-treatment with sulfuric acid (H2SO4) and hydrochloric acid (HCl) on the kinetics of adsorption for Cr(III) in aqueous solution has been studied. The research has been carried out by mixing an amount of diatomeaeous earth with HCl or H2SO4 in various concentrations for two hours at temperature of 150 - 200°C. The mixture was washed with water until neutral, and the residue was dried at 70°C for four hours. The result then was used as adsorbent. Adsorption was carried out by mixing an amount of adsorbent with Cr(III) solution in various contact times. Ion adsorbed was determined by analyzing filtrate using atomic absorption spectrophotometry. The effect of pre-treatment on adsorption kinetics was evaluated based on kinetic parameters, i.e. constant of adsorption rate by using Langmuir-Hinshelwood kinetics and using two-process kinetics (fast and slow processes). Adsorption kinetics calculated using LH equation gave negative value for adsorption rate constant of zero order (k0). On the other words, the LH kinetics might not be applied for adsorption of Cr(III) to diatomaceous earth adsorbent. Results of kinetics study approached using two processes (fast and slow) showed that adsorption of Cr(III) occurred in two processes with rate constant of fast adsorption, kc, 0.041/min, rate constant of slow adsorption, kl, 0.0089/min, and of slow desorption, k'l, 0.089/menit. Pre-treatment with HCl up to 10 M decreased either kc, kl or k'l, while pre-treatment with H2SO4 1M increased kc to 0.061/min, decreased kl to 0.00424 and k'l to 0.0139/min. On pre-treatment with H2SO4 higher than 6 M significantly decreased three constants above. Based on the Gibbs energy change (4.31 - 6.79 kJ/mole) showed that adsorption involved physical interaction.   Keywords: adsorption, chromium, diatomaceous earth, kinetics, Langmuir-Hinshelwood

2010 ◽  
Vol 2 (2) ◽  
pp. 107-112
Author(s):  
Nuryono Nuryono ◽  
Narsito Narsito

In this research, treatment of diatomaceous earth, Sangiran, Central Java using hydrogen chloride (HCl) and sulfuric acid (H2SO4) on kinetics of Cd(II) adsorption in aqueous solution has been carried out. The work was conducted by mixing an amount of grounded diatomaceous earth (200 mesh in size) with HCl or H2SO4 solution in various concentrations for two hours at temperature range of 100 - 150oC. The mixture was then filtered and washed with water until the filtrate pH is approximately 7 and then the residue was dried for four hours at a temperature of 70oC. The product was used as an adsorbent to adsorb Cd(II) in aqueous solution with various concentrations. The Cd(II) adsorbed was determined by analyzing the rest of Cd(II) in the solution using atomic absorption spectrophotometry. The effect of treatment was evaluated from kinetic parameter of adsorption rate constant calculated based on the simple kinetic model. Results showed  that before equilibrium condition reached, adsorpstion of Cd(II) occurred through two steps, i.e. a step tends to follow a reaction of irreversible first order  (step I) followed by reaction of reversible first order (step II). Treatment with acids, either hydrogen chloride or sulfuric acid, decreased adsorption rate constant for the step I from 15.2/min to a range of 6.4 - 9.4/min.  However, increasing concentration of acid (in a range of concentration investigated) did not give significant and constant change of adsorption rate constant. For step II process,  adsorption involved physical interaction with the sufficient low adsorption energy (in a range of 311.3 - 1001 J/mol).     Keywords: adsorption, cdmium, diatomaceous earth, kinetics.


2019 ◽  
Vol 22 (6) ◽  
pp. 310-316 ◽  
Author(s):  
Thamrin Azis ◽  
La Ode Ahmad ◽  
Fajrin E. Rosa ◽  
Laode Abdul Kadir

Heavy metals concentrations exceeding the recommended threshold are hazardous for the environment, so there is a need for handling it safely. The purpose of this research was to determine the adsorption capacity and kinetics of adsorption. This research uses an adsorption method in the process of removing Pb(II) heavy metal ions using persimmon tannin gel. Besides the influence of contact time, pH, and the concentration of Pb(II) metal ions on adsorption, a kinetics study was also carried out. The adsorption rate is obtained through the adsorption rate constant (K) and the reaction order generated from the kinetics model. Based on the results of the research, showed the optimum adsorption process, which is 20 minutes and at a pH of 5. The maximum adsorption capacity of 17.62 mg/g with the value of the standard energy changes of Gibbs adsorption (-ΔG° = -14.274 kJ/moll) indicates that the adsorption takes place through physical interaction. The kinetic adsorption gives the adsorption rates a constant of, k = 0.008231 g/mg.min.


2014 ◽  
Vol 809-810 ◽  
pp. 907-911
Author(s):  
Jun Long Wang ◽  
Jie Hou ◽  
Ting Jiang ◽  
Yong Jun He ◽  
Yao Dong Liang

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.


2012 ◽  
Vol 27 ◽  
pp. 19-25 ◽  
Author(s):  
Vinay Kumar Jha ◽  
Kiran Subedi

Activated charcoal was prepared from waste tire by using pyrolysis technique in three different atmospheres, viz, air, nitrogen and a combined atmosphere of nitrogen and water (steam). Methylene blue was then adsorbed on to these activated charcoals and the kinetics of adsorption was also studied. The adsorption isotherms of methylene blue were simulated by the mathematical equations of Langmuir and Freundlich. The Langmuir isotherms were found to have better fitting than that of Freundlich. The Qmax values obtained from Langmuir model were 0.032, 0.036, and 0.092 mmol/g for the activated charcoals prepared in air, nitrogen and nitrogen and water (steam), respectively. The overall reaction was found to be pseudo-second order with the rate constant of 4.2 × 10-2 L g/(mmolmin). The equilibrium adsorption value obtained from the kinetics data i.e. 0.072 (mmol/g) was found to be comparable with that obtained from Langmuir model.DOI: http://dx.doi.org/10.3126/jncs.v27i1.6437 J. Nepal Chem. Soc., Vol. 27, 2011 19-25Uploaded date: 16 July, 2012


2010 ◽  
Vol 8 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Milivoj Lovrić ◽  
Šebojka Komorsky-Lovrić

AbstractA model of electrode reaction complicated by slow adsorption of the reactant is developed for square-wave voltammetry with inverse scan direction. The relationship between the dimensionless net peak current and the logarithm of dimensionless rate constant of adsorption is a curve with a minimum and a maximum. For this reason the ratio of real net peak current and the square-root of frequency is a non-linear function of the logarithm of frequency and exhibits either a maximum or a minimum. The frequency of extreme serves for the estimation of the rate constant: log(k ads /D 1/2 ) = log(k*ads )crit + 0.5 log f crit , where (k*ads )crit is a critical dimensionless rate constant of adsorption. Square-wave voltammetry is sensitive to the kinetics of adsorption if k ads 2 cm s−1


2013 ◽  
Vol 781-784 ◽  
pp. 24-29
Author(s):  
Fei Fei Chen ◽  
Zhi Ming Xu ◽  
Xue Wen Sun ◽  
Suo Qi Zhao

It is important to find out how to strengthen the interaction between nickel porphyrins and asphaltene in the alkane solvents of the low molecular weight for raising the removal rate of nickel in the solvent deasphalting process. Therefore, the adsorption kinetics, which describes how the nickel etioporphyrins are adsorbed on asphaltene (the vacuum residue of Canadian oil sands bitumen (VTB)) in the n-pentane solvent, are investigated. The results show that a certain amount of nickel porphyrins is absorbed on the asphaltene of VTB, which means there is a certain adsorption between asphaltene and nickel porphyrins. The adsorption rate is affected by the dosage of asphaltene, the concentration of the n-pentane solution containing nickel porphyrins and the temperature. A comparison in the four kinds of kinetic models on the overall adsorption rate shows that adsorption process can be perfectly described by the pseudo second-order equation.


2019 ◽  
Vol 8 (2) ◽  
pp. 79-84
Author(s):  
Bode Haryanto ◽  
Warren K Sinaga ◽  
Febri T Saragih

This study aimed to analyze the adsorption ability of black sand in the metal ions adsorb cadmium (Cd2+) with a concentration of 70 ppm to a solution with a pH of 4,5. The black sand is used is 40 mesh. This research was conducted by batch adsorption system naturally and adsorption kinetics modeling. Kinetics of adsorption reached equilibrium at time t = 120 minutes with the percentage concentration of adsorbed Cd2+ 18,5%. In the adsorption kinetics modeling correlation coefficient is almost the same between the equations of first order and second order in the amount of 0.98 and 0.99. The result indicated that the type of interaction Cd2+ ions on the surface of black sands occur in chemistry and physics. The adsorption kinetics of diffusion modeling of internal and external diffusion of the correlation coefficient of 0,85 and 0,71. From this data it can be seen that in this study is modeling kinetic internal diffusion trend that shows adsorbent particles are inter sand surface area that experienced internal inter-particle pore diffusion.


2021 ◽  
Vol 316 ◽  
pp. 170-174
Author(s):  
Elena G. Filatova ◽  
Yury N. Pozhidaev

Adsorption isotherms of Ni (II) and Cu (II) ions by alumino-silicates, modified with N, N'-bis (3-triethoxysilylpropyl) thiocarbamide (BTM-3), and HCl, were obtained. The adsorption kinetics of heavy metal ions is studied, using the kinetic pseudo-first and pseudo-second order models. It is shown that, when alumino-silicates are modified, the rate and energy of adsorption increase. It is established that the kinetics of the adsorption of the studied ions is best described by a pseudo-second order model. The maximum value of the adsorption rate constant of 33.7∙10-5 g/ (mmol min) corresponds to nickel (II) ions for alumino-silicates, modified with HCl. The maximum value of the adsorption rate constant value of 2.91∙10-5 g/ (mmol min) for alumino-silicates, modified with BTM-3, corresponds to Cu (II) ions.


2010 ◽  
Vol 10 (1) ◽  
pp. 80-87
Author(s):  
Dewi Umaningrum ◽  
Uripto Trisno Santoso ◽  
Radna Nurmasari ◽  
Rahmat Yunus

Study on adsorption kinetics of of Pb(II), Cd(II) and Cr(III) on adsorbent which was produced by protected-crosslinking of humic acid-chitosan has been done. The Langmuir-Hinshelwood, pseudo first- and second-order kinetics models were used to describe the kinetic data, and the rate constants of adsorption were also evaluated. The experimental data fitted well the second-order kinetics model, indicating that the chemical sorption is the rate-limiting step, instead of mass transfer. The initial metal ion concentration significantly affects the adsorption rate. An increase in initial metal ion concentration results in the decrease in adsorption rate of the metals.   Keywords: kinetics, adsorption, crosslinking, humic acid, chitosan


2012 ◽  
Vol 550-553 ◽  
pp. 2625-2628 ◽  
Author(s):  
Yun Yi Lei ◽  
Wei Guo Cao ◽  
Kun Hua Lin ◽  
Ye Fei Jin

The paper analyzed the adsorption conditions of uranium on carboxylic acid fiber. The isotherms were drawn, and Langmuir and Freundlich equations were deduced. The adsorption kinetics of UO22+on carboxylic fiber was researched. The rate constant of adsorption was obtained and the apparent activation energy was determined. This research provides a theoretical basis for new adsorbents of uranium in nuclear wastes.


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