Adsorption-desorption processes of azo dye on natural bentonite: batch experiments and modelling

Clay Minerals ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 747-763 ◽  
Author(s):  
A. Berez ◽  
F. Ayari ◽  
N. Abidi ◽  
G. Schäfer ◽  
M. Trabelsi-Ayadi
Keyword(s):  
Azo Dye ◽  
Physical Adsorption ◽  
Raw Material ◽  
Coefficient Of Determination ◽  
Batch Adsorption ◽  
Desorption Kinetics ◽  
Desorption Process ◽  
Non Linear ◽  
Desorption Isotherms ◽  
Adsorption Desorption

AbstractThe purpose of this study was to determine whether a bentonite from the Gafsa deposit (western Tunisia) could be used to remove the Foron Blue 291 (FB) azo dye from wastewater. Batch adsorption and desorption experiments were conducted using untreated and purified bentonite and the influence of contact time, pH, adsorbent mass and temperature of the dye solution on the adsorption of FB was evaluated. Kinetic and isotherm data were fitted using two non-linear kinetic and two non-linear isotherm equations. In addition, the fits were evaluated using the coefficient of determination (R2) and the RMSE. The percentage of dye removal increased with increasing amount of adsorbent until total discolouration was achieved. The adsorption isotherms followed the Langmuir model, with the purified bentonite having a higher adsorption capacity than the raw material due to its higher specific surface area. In addition, the FB molecules were removed from the liquid medium by physical adsorption. Batch desorption experiments were conducted to study the desorption kinetics and the characteristics of the desorption isotherms as well as to quantify the portion of the FB (by mass) that was irreversibly fixed on the solid. Overall, the desorption kinetics were similar to the adsorption kinetics, which indicated that the adsorption-desorption process of azo dye is non-singular; irreversibility occurred that was underlined by an observed thermodynamic index of irreversibility (TII) of 0.69–0.94. The desorption isotherms of the FB depended on the mass of the FB that was initially adsorbed on the bentonite sample, suggesting hysteresis. The amount of irreversibly retained FB was between 46 and 68% of the initial adsorbed mass.

Removal of Cd(II) from Water System Using Novel Biosorbent Derived from Persimmon Fallen Leaves

2015 ◽  
Vol 1130 ◽  
pp. 685-688
Author(s):  
Rui Yi Fan ◽  
Qing Ping Yi ◽  
Qing Lin Zhang ◽  
Zheng Rong Luo
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Water System ◽  
Raw Material ◽  
Batch Adsorption ◽  
Diospyros Kaki ◽  
Cadmium Metal ◽  
Fallen Leaves ◽  
Adsorption Desorption

A biosorbent was prepared by treating the persimmon (Diospyros kaki Thunb.) fallen leaves with sodium hydroxide (NaOH). The NaOH concentration and stirring period for the preparation of the biosorbent were adjusted to optimise the Cd(I) adsorption capacity of the biosorbents. Removal of highly toxic Cadmium metal ions from water system using the optimal biosorbent named ‘NPFL’ was investigated using a mimic industrial column. The result showed that NPFL could remove Cd(II) in large quantities from aqueous solution with coexisting metal ions. The raw material, NPFL and Cd(II) loaded NPFL were characterized by SEM-EDS. The reusability of NPFL was also studied by batch adsorption-desorption test.

Adsorption and desorption of perchloroethylene in soils, peat moss, and granular activated carbon

1989 ◽  
Vol 16 (6) ◽  
pp. 798-806 ◽  
Author(s):  
Richard Zytner ◽  
Nihar Biswas ◽  
Jatinder K. Bewtra
Keyword(s):  
Activated Carbon ◽  
Granular Activated Carbon ◽  
Freundlich Isotherm ◽  
Peat Moss ◽  
Organic Carbon Content ◽  
Dry Cleaning ◽  
Desorption Process ◽  
The Media ◽  
Desorption Isotherms ◽  
Adsorption Desorption

Studies were conducted to evaluate the adsorption–desorption isotherms of a common dry cleaning solvent, perchloroethylene (PCE), in soils, peat moss, and granular activated carbon. The results obtained followed the Freundlich Isotherm, and the organic carbon content of the media was the most significant controlling factor in the adsorption–desorption process. The peat moss exhibited the highest residual saturation concentration for pure PCE amongst all the media tested. The desorption studies indicated that PCE had medium mobility in soil and was not significantly affected by moderate changes in pH. Key words: adsorption, desorption, Freundlich Isotherm, granular activated carbon, peat moss, perchloroethylene, soils.

Desorption rate of glyphosate from goethite as affected by different entering ligands: hints on the desorption mechanism

2017 ◽  
Vol 14 (5) ◽  
pp. 288 ◽  
Author(s):  
Jeison M. Arroyave ◽  
Carolina C. Waiman ◽  
Graciela P. Zanini ◽  
Wenfeng Tan ◽  
Marcelo J. Avena
Keyword(s):  
Desorption Kinetics ◽  
Desorption Rate ◽  
Mineral Surfaces ◽  
Desorption Process ◽  
Ligand Exchange Reaction ◽  
Mineral Particles ◽  
Desorption Rate Constant ◽  
Desorption Mechanism ◽  
Adsorption Desorption ◽  
Kinetics Of

Environmental contextGlyphosate is a heavily used herbicide that is mobilised in soil and sediments through adsorption–desorption processes from the surface of mineral particles. We demonstrate that the desorption rate of glyphosate from goethite, a ubiquitous mineral, is nearly independent of the concentration and nature of the substance that is used to desorb it. The results elucidate the desorption mechanism and are relevant to understand and predict the environmental mobility of glyphosate. AbstractThe desorption kinetics of glyphosate (Gly) from goethite was studied in a flow cell using attenuated total reflectance Fourier-transform infrared spectroscopy. Because Gly forms an inner-sphere surface complex by coordinating to Fe atoms at the goethite surface, the desorption process is actually a ligand-exchange reaction, where Gly is the leaving ligand and water molecules or dissolved substances are the entering ligands. A series of possible entering ligands that can be found in nature was tested to evaluate their effect on the desorption kinetics of Gly. Contrarily to expectations, the desorption rate was quite independent of the entering ligand concentration. Moreover, the identity of this ligand (phosphate, citrate, sulfate, oxalate, EDTA, thiocyanate, humic acid, water) had only a small effect on the value of the desorption rate constant. By analogy with the reactivity of transition metal complexes in solution, it is concluded that the rate is mainly controlled by the breaking of the Fe–Gly bond, through a dissociative or a dissociative interchange mechanism. The results are relevant in understanding and predicting the environmental mobility of Gly: irrespective of the identity of the entering ligand, Gly will always desorb from iron (hydr)oxides in nature at nearly the same rate, simplifying calculations and predictions enormously. The importance of studying desorption kinetics using mineral surfaces and environmentally relevant molecules is also highlighted.

scholarly journals Adsorption-desorption of chlorpyrifos in soils and sediments from the Rufiji Delta, Tanzania

2020 ◽  
Vol 19 (1) ◽  
pp. 77-97
Author(s):  
Haji Mwevura ◽  
Peter Nkedi-Kizza ◽  
Michael Kishimba ◽  
Henrik Kylin
Keyword(s):  
Freundlich Isotherm ◽  
Trapping Efficiency ◽  
Batch Adsorption ◽  
Organic Carbon Content ◽  
Adsorption Coefficient ◽  
Adsorption And Desorption ◽  
Soils And Sediments ◽  
Desorption Isotherms ◽  
The Difference ◽  
Adsorption Desorption

Batch adsorption-desorption equilibrium techniques were used to investigate the adsorption capacity and influence of salinity on partitioning of the insecticide chlorpyrifos between water and soil or water and sediments from the Rufiji Delta. The data were fitted to different adsorption-desorption models and the hysteresis index was calculated using the ratio between the Freundlich exponents for desorption and adsorption, and secondly, the difference in area under the normalized adsorption and desorption isotherms using the maximum adsorbed and solution concentrations. The data showed non-linear adsorption and that chlorpyrifos was strongly adsorbed to soil and sediments from the Rufiji Delta. The linearized adsorption coefficient (KD) and Freundlich adsorption coefficient (Kf) correlated significantly with organic carbon content. Chlorpyrifos adsorption as well as hysteresis calculated by both methods decreased with salinity (i.e. the sediment adsorbs increasing amounts of chlorpyrifos with decreasing salinity). This indicates that settling of freshwater sediments is among the major removal pathways of the chemical from the water column, but increased turbulence during high tides may resuspend settled sediment simultaneously increasing salinity and re-dissolve chlorpyrifos. However, discharge of fresh water, particularly during heavy rains, increases the trapping efficiency of the sediments. The theoretical approach developed showed that the Langmuir model describes the desorption data better than the Freundlich model, and that a better index of hysteresis is one that considers areas under the adsorption and desorption isotherms, provided the desorption isotherm is described by the normalized Langmuir isotherm and the adsorption isotherm by the normalized Freundlich isotherm.

scholarly journals Desorption of β-carotene from bentonite adsorbent under microwave irradiation

2015 ◽  
Vol 34 (2) ◽  
pp. 363
Author(s):  
Tatjana Novaković ◽  
Ljiljana Rožić ◽  
Srdjan Petrović ◽  
Dragomir Stanisavljev
Keyword(s):  
Free Energy ◽  
Microwave Irradiation ◽  
Coefficient Of Determination ◽  
Desorption Kinetics ◽  
Desorption Process ◽  
First Order ◽  
Two Component ◽  
Equilibrium Data ◽  
Desorption Equilibrium ◽  
Β Carotene

<p>The desorption behavior of <em>β</em>-carotene from a bentonite adsorbent under microwave irradiation in isopropanol was studied as a function of temperature and different initial loading concentrations. A first-order, two-component, three-parameter model described the desorption kinetics with a coefficient of determination <em>R</em><sup>2</sup> &gt; 0.9932, and the <em>β</em>-carotene desorption process under microwave irradiation was controlled by both rapid and slow desorption. The activation energies of <em>β</em>-carotene desorption for the rapid and slow desorption processes were 19.61 and 53.04 kJ mol<sup>–1</sup>, respectively. It was observed that the desorption equilibrium data fitted well to both the Freundlich and Langmuir isotherms. The data obtained from the desorption-isotherm model were used to determine the thermodynamic parameters. The positive value of free energy indicates the non-spontaneity of <em>β</em>-carotene desorption. The change in entropy relative to the enthalpy of desorption reveals that the reaction is physical in nature.</p>

Elaboration of novel adsorbent from Moroccan oil shale using Plackett–Burman design

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methylene Blue ◽  
Oil Shale ◽  
Screening Method ◽  
Raw Material ◽  
Coefficient Of Determination ◽  
Processing Temperature ◽  
Acid Pretreatment ◽  
Experimental Data Processing ◽  
Experimental Values ◽  
Maximal Capacity

The new adsorbents were prepared from Moroccan oil shale by chemical and physical process .In this study, experimental Plackett-Burman has been used as a screening method to study six factors for the development of materials to adsorbent basis of oil shale Moroccan. The factors have been identified by two levels, To Know temperature (°C), Processing time (min), mass ratio (m precursor/m acid), Pretreatment mixture the precursor with acid, origin of the raw material and type of the activating agent (H2SO4, H3PO4).And it was chosen as a response The maximum quantity of adsorption of the molecule of Methylene blue (Qads in mg/g) and the specific surface measure by the method bet (Sbet in m2/g), The predicted values were in agreement with the experimental values with a coefficient of determination (R2) of 0.98. The model has been validated by experiments subsequent to optimized conditions. The experimental data processing by software JMP 7 showed that the processing temperature The report of oil shale on the acid and activation time were the important effect on the maximal capacity of adsorption of methylene blue. The sample prepared at 237 °C during 215 min with pre-processing has a maximal capacity of adsorption equal to 54mg/g according to model of adsorption of Langmuir and SBET equal to 143 m2/g.

scholarly journals Release of toxic methylene blue from water by mesoporous silicalite-1: characterization, kinetics and isotherm studies

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin
Keyword(s):  
Electron Microscopy ◽  
Contact Time ◽  
Dye Removal ◽  
Batch Adsorption ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Adsorption Method ◽  
X Ray ◽  
Ft Ir ◽  
Adsorption Desorption

AbstractIn the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.

scholarly journals Study on Adsorption Properties of Modified Corn Cob Activated Carbon for Mercury Ion

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Physical Adsorption ◽  
Raw Material ◽  
Order Kinetic ◽  
Mercury Ions ◽  
Corn Cob ◽  
Adsorption Time ◽  
X Ray

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.

scholarly journals Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO2: Promising Waste-Derived Adsorbents for Balofloxacin

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2295
Author(s):  
Marwa El-Azazy ◽  
Ahmed S. El-Shafie ◽  
Hagar Morsy
Keyword(s):  
Adsorption Capacity ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Spent Coffee Grounds ◽  
Thermal Stabilities ◽  
Coffee Grounds ◽  
Bet Analysis ◽  
Pseudo Second Order ◽  
Set Up ◽  
Adsorption Desorption

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.

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