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

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.

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

Western Indian Ocean Journal of Marine Science ◽

10.4314/wiojms.v19i1.7 ◽

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.

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The balancing of NO concentration fluctuations by adsorption/desorption process on activated carbon

Separation and Purification Technology ◽

10.1016/j.seppur.2011.01.035 ◽

2011 ◽

Vol 78 (2) ◽

pp. 245-248 ◽

Cited By ~ 3

Author(s):

I. Potyková ◽

L. Obalová ◽

L. Kuboňová ◽

K. Obroučka

Keyword(s):

Activated Carbon ◽

Concentration Fluctuations ◽

Desorption Process ◽

Adsorption Desorption

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Comparison of association theory and Freundlich isotherm for describing granular activated carbon adsorption of secondary sewage effluent

Journal of Environmental Engineering and Science ◽

10.1139/s03-010 ◽

2003 ◽

Vol 2 (2) ◽

pp. 111-118 ◽

Cited By ~ 5

Author(s):

D S Chaudhary ◽

S Vigneswaran ◽

H H Ngo ◽

S H Kim ◽

H Moon

Keyword(s):

Activated Carbon ◽

Granular Activated Carbon ◽

Freundlich Isotherm ◽

Sewage Effluent ◽

Activated Carbon Adsorption ◽

Carbon Adsorption

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Potential demonstrations of “hot spots” presence by adsorption-desorption of toluene vapor onto granular activated carbon under microwave radiation

Chemical Engineering Journal ◽

10.1016/j.cej.2017.02.157 ◽

2017 ◽

Vol 319 ◽

pp. 191-199 ◽

Cited By ~ 20

Author(s):

Zhongyu Yang ◽

Honghong Yi ◽

Xiaolong Tang ◽

Shunzheng Zhao ◽

Qingjun Yu ◽

...

Keyword(s):

Activated Carbon ◽

Microwave Radiation ◽

Hot Spots ◽

Granular Activated Carbon ◽

Toluene Vapor ◽

Adsorption Desorption

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

Clay Minerals ◽

10.1180/claymin.2014.049.5.10 ◽

2014 ◽

Vol 49 (5) ◽

pp. 747-763 ◽

Cited By ~ 8

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.

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Interpretation of Isotherm Models for Adsorption of Ammonium onto Granular Activated Carbon

Biointerface Research in Applied Chemistry ◽

10.33263/briac112.92279241 ◽

2020 ◽

Vol 11 (2) ◽

pp. 9227-9241

Keyword(s):

Activated Carbon ◽

Granular Activated Carbon ◽

Freundlich Isotherm ◽

Solute Concentration ◽

Isotherm Model ◽

Isotherm Models ◽

Order Kinetic ◽

Order Kinetic Model ◽

Synthetic Solution ◽

Engineering Practices

High amounts of ammonium (NH4+) discharged in receiving water can lead to eutrophication. The adsorption of NH4+ from synthetic solution onto granular activated carbon (GAC) was scrutinized with respect to initial solute concentration (10 mg L−1), solution volume (0.2 L), adsorbent dosage (4 – 20 g), and contact time. Experimental data can be well described by the pseudo-second-order kinetic model (R2 > 0.994) and Freundlich isotherm model (R2 = 0.936), suggesting that chemisorption and multilayer adsorption occurred. Furthermore, this study explored the feasibility of using the Freundlich isotherm model to estimate the removal efficiency or required amount of adsorbent. The result findings indicated that GAC has a good potential to adsorb NH4+ from water and thus giving new insights into environmental engineering practices.

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