scholarly journals The kinetics of adsorption binding of Ba2+ ions by trimethylsilylated silica

2018 ◽  
Vol 19 (1) ◽  
pp. 66-73 ◽  
Author(s):  
I. F. Myronyuk ◽  
H. V. Vasylyeva ◽  
V. I. Mandzyuk ◽  
N. A. Bezruka ◽  
T. V. Dmytrotsa

It was established that incomplete substitution of free silanols of fumed silica surface on (CH3)3Si-groups leads to an increase in the ability of modified SiO2 to adsorb Ba2+ cations from an electrolyte solution. Silica with 48.3% of trimethylsilyl (TMS) groups adsorbs 1.8 mmol·g-1 of Ba2+ cations from 0.01 M BaCl2 solution, that in 3 times more than the adsorption of these cations by unmodified silica. It was found that the adsorption of cations by basic and modified silica is well described by the pseudo-second order Lagergren equation. The high adsorption activity of silica with chemisorbed TMS-groups is due to the formation of local regions with relatively large values of negative and positive electrostatic potentials in the vicinity of grafted TMS-groups.

DYNA ◽  
2016 ◽  
Vol 83 (196) ◽  
pp. 223-228 ◽  
Author(s):  
Jhonnathan Machado-Infante ◽  
Gustavo Ramírez-Caballero ◽  
Martha Juliana Barajas Meneses

<p>In Colombia, a mineral rich in MnO<sub>2</sub> is extracted from the mines of Mallama, Nariño. In this work we studied the adsorption capacity of this mineral for Fe(II) dissolved in aqueous solution of open systems. The characterization was done through ICP-AES, XRF and Raman spectroscopy. The effect of different pretreatments on the mineral with oxidizing agents such as KMnO<sub>4</sub> and NaClO was evaluated. Studies of equilibrium and kinetics of adsorption showed that the mechanism fits well to the Langmuir isotherm and its kinetics to a model of pseudo-second order. At the conditions studied was found that the adsorption capacity for the mineral modified with KMnO<sub>4</sub> and NaOCl were 59.209 and 51.279 mg/g respectively. It is concluded that the mineral is a potential alternative in water treatment.</p>


2010 ◽  
Vol 160-162 ◽  
pp. 1804-1809
Author(s):  
Qiang Bi ◽  
Juan Qin Xue ◽  
Ying Juan Guo ◽  
Yu Jie Wang ◽  
Yun Feng Xue

The adsorption of cadmium in simulated wastewater by chitosan was investigated. The influence of temperature, contact time and pH on adsorption efficiency of cadmium was examined. Some related mathematical models were used in the fitting of experimental data. The results showed that at room temperature, the optimum pH of adsorption is between 4 and 7. At lower pH values, a strong competition existed between cadmium ions and protons for sorption sites and the sorption efficiency was decreased. After 60 minutes the adsorption equilibrium can be achieved. Chitosan is very effective at removing cadmium with the maximum adsorption capacity is 112.05mg•g-1. The adsorption kinetic curves agree with the pseudo-second-order adsorption kinetic equations and the adsorption isotherms could be well described by Langmuir isotherm equations.


2008 ◽  
Vol 6 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Lyudmila Belyakova ◽  
Oleksandra Shvets ◽  
Diana Lyashenko

AbstractThe present work investigates the adsorptive interactions of Hg(II) ions in aqueous medium with hydroxylated silica, aminopropylsilica and silica chemically modified by β-cyclodextrin. Batch adsorption studies were carried out with various agitation times and mercury(II) concentrations. The maximum adsorption was observed within 15–30 min of agitation. The kinetics of the interactions, tested with the model of Lagergren for pseudo-first and pseudo-second order equations, showed better agreement with first order kinetics (k1 = 3.4 ± 0.2 to 5.9 ± 0.3 min−1). The adsorption data gave good fits with Langmuir isotherms. The results have shown that β-cyclodextrin-containing adsorbent has the largest adsorption specificity to Hg(II): K L = 4125 ± 205 mmol−1. “β-cyclodextrin-NO3-” inclusion complexes with ratio 1: 1 and super molecules with composition C42H70O35 ⊎ 3 Hg(NO3)2 are formed on the surface of β-cyclodextrin-containing silica.


2012 ◽  
Vol 1373 ◽  
Author(s):  
Teresa Ramírez-Rodríguez ◽  
Fray de Landa Castillo-Alvarado

ABSTRACTThe intra-particle diffusion model (IPD), proposed by Weber and Morris has been applied to the analysis of the kinetics of adsorption on activated carbon fibers with phosphate groups in the removal of cadmium ions in aqueous media. It is evident that the removal of cadmium ion kinetic model of pseudo-second order provides a better fit than the model of pseudo-first order and the intra-particle diffusion model provides the best to the sample compared activating solution: grams fibers of 1:3.


2019 ◽  
Vol 51 (1) ◽  
pp. 93-100
Author(s):  
Irena Ilic ◽  
Natasa Jovic-Jovicic ◽  
Predrag Bankovic ◽  
Zorica Mojovic ◽  
Davor Loncarevic ◽  
...  

Montmorillonite (Mt) and acid modified montmorillonite (MtA) were tested as nicotine adsorbents. The samples were characterized using FT-IR spectroscopy and low temperature nitrogen physisorption. Nicotine adsorption was performed with respect to contact time, pH and initial nicotine concentration. The kinetics of adsorption obeyed the pseudo-second-order kinetics. The optimal pH values for nicotine adsorption were 6 and 9 for Mt and MtA, respectively. The isotherms related to adsorption on Mt at pH = 6 and 9 as well as for MtA at pH=6 were best fitted with Sips isotherm model, while adsorption onto MtA at pH=9 obeyed Langmuir isotherm model.


2017 ◽  
Vol 49 (4) ◽  
pp. 419-429
Author(s):  
Natasa Jovic-Jovicic ◽  
Predrag Bankovic ◽  
Zorica Mojovic ◽  
Bojana Nedic-Vasiljevic ◽  
Sanja Marinovic ◽  
...  

The bio-nanocomposite of montmorillonite and natural biopolymer chitosan (C-MM) was synthesized. Intercalation of chitosan in form of monolayer into the interlamellar space of montmorillonite was confirmed by XRD and IR analysis. The adsorption of textile dyes: Acid Yellow 99 (AY99), Acid Orange 10 (AO10) and Reactive Black 5 (RB5) onto C-MM was investigated. The adsorption was performed with the respect to adsorption time, pH and initial dye concentration. The kinetics of adsorption obeyed pseudo-second-order of kinetics and was the most efficient in acidic pH. Langmuir model best described the adsorption of AY99 and AO10 , while RB5 adsorption isotherm was best fitted with Freundlich model.


2019 ◽  
Vol 14 (4) ◽  
pp. 808-824
Author(s):  
Sujitha Ravulapalli ◽  
Ravindhranath Kunta

Abstract Activated carbons were prepared from the stem parts of Achyranthes aspera and Allamanda blanchetii plants and were investigated as adsorbents for the removal of malachite green dye from contaminated water. Various extraction conditions such as pH, initial concentration of dye, adsorbent dosage, temperature, agitation time and presence of co-ions were optimized for the maximum possible extraction of the dye. For analyzing the combined effect of these parameters on the removal efficiency of the adsorbents, statistical optimization modelling was adopted. The adsorbents developed were characterized and the adsorption abilities were observed to be 40.0 mg/g and 53.0 mg/g for the active carbons of Achyranthes aspera and Allamanda blanchetii plants respectively. The mechanism of adsorption was studied using various isotherm models and it was found that the Freundlich model describes well the adsorption process. Thermodynamic studies revealed the endothermic and spontaneous nature of physisorption. The kinetics of adsorption were well defined by the pseudo-second-order model. Desorption and regeneration studies of the spent adsorbents indicated that the percentage of extraction has not come down below 80.0% even after five regenerations for both the adsorbents. The validity of the methods developed are tested with real dye-polluted industrial effluent samples.


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


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hamid Ziyat ◽  
Mohammed Naciri Bennani ◽  
Hassan Hajjaj ◽  
Omar Qabaqous ◽  
Said Arhzaf ◽  
...  

The present work aims to study the affinity of a component of the thyme essential oil “thymol” to natural Moroccan clay “Rhassoul” using the adsorption technique. The physicochemical characterizations of the purified and modified clay were carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), DTA/TGA, and SEM-EDX. Thymol adsorption tests on the purified Rhassoul (Rh-P) and the modified one by CTAB (Rh-CTAB) were followed by UV-visible spectroscopy. They show that the adsorption isotherms can be described by the Freundlich model and that the kinetics of adsorption is in accordance with the pseudo-second-order model for the two clays. Adsorption capacities obtained were of the order of 6 mg/g for the purified Rhassoul and 16 mg/g for the modified Rhassoul by cetyltrimethylammonium bromide (CTAB). These values show that the modified Rhassoul has a better adsorption capacity compared to the purified Rhassoul.


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