Kinetics of Adsorption

Faust, Samuel D.; Aly, Osman M.

doi:10.1016/b978-0-409-90000-2.50006-6

Cited by 29 publications

(18 citation statements)

References 24 publications

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“…As observed, the values of Q m are slightly higher than those obtained from the Langmuir equation and follow a similar trend with temperature, i.e., Q m decreases slightly as the temperature increases. The E values are always below 83 kJ mol -1 , confirming the physical nature of the adsorption . Similar results have been reported for the adsorption of other herbicides onto ACs…”

Section: Resultssupporting

confidence: 88%

Removal of the Herbicide MCPA by Commercial Activated Carbons: Equilibrium, Kinetics, and Reversibility

Gimeno¹,

Pluciński²,

Kolaczkowski³

et al. 2003

Ind. Eng. Chem. Res.

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The adsorption of the herbicide 4-chloro-2-methylphenoxyacetic acid (CAS 94-74-6) has been studied using four commercial activated carbons (Norit 0.8, Aquacarb 207C, Aquacarb 208A, and Aquacarb 208EA). Adsorption equilibrium isotherms were obtained in the 293-358 K temperature range. The trend of adsorption for MCPA onto the four activated carbon was in the order Norit 0.8 > Aquacarb 207C > Aquacarb 208A > Aquacarb 208EA. Among various adsorption isotherm models, the Freundlich equation best fit the experimental data. Experiments conducted at different temperatures allowed for the calculation of the isosteric heat of adsorption, revealing that the adsorption process was exothermic for three of the four adsorbents studied. The distribution of the herbicide into the pores of activated carbon Norit 0.8 was studied by considering the Dubinin-Radushkevich isotherm. Also, the adsorption kinetics were assessed by means of a simplistic mechanism based on the shrinking-core mass-transfer model. Finally, as a preliminary step in the study of the potential use of wet air oxidation (WAO) for the regeneration of exhausted activated carbon, the reversibility of the adsorption process was tested. Only partial desorption of MCPA was achieved under WAO conditions, which involves a likely double route of activated carbon regeneration, i.e., liquid and surface contaminant oxidation.

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Section: Resultssupporting

confidence: 88%

Removal of the Herbicide MCPA by Commercial Activated Carbons: Equilibrium, Kinetics, and Reversibility

Gimeno¹,

Pluciński²,

Kolaczkowski³

et al. 2003

Ind. Eng. Chem. Res.

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“…Figure 1 shows that the ZPC of GAC tested was 5.3. Faust and Aly [ 25 ] reported a ZPC range between 4.75 and 7.10 for five types of activated carbons tested. At pH less than the ZPC, GAC had a net positive surface charge and at pH above the ZPC, it had a net negative charge.…”

Section: Resultsmentioning

confidence: 99%

Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon

Sounthararajah

Loganathan

Kandasamy

et al. 2015

IJERPH

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Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC) and suspended solids (SS) are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA) (DOC representative), they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal) was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS) had no effect on Pb and Cu, but it did on the other metals.

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“…The plot of ln(1 À F 2 ) vs. time is shown in Fig. [20] This table indicates that adsorption process is predominantly particle diffusion control. The numerical values of rate constant k and diffusion constant D D are listed in Table 3, which are in the range of the reported values.…”

Section: Rate Lawmentioning

confidence: 98%

Kinetics, Thermodynamics, and Sorption Profile of Eu(III) and Tm(III) on 4‐(2‐Pyridylazo) Resorcinol (PAR) Imbedded Polyurethane Foam

Saeed

Ahmed

Chaudary

et al. 2003

Solvent Extraction and Ion Exchange

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The adsorption studies of Eu(III) and Tm(III) was investigated on 4-(2pyridylazo) resorcinol (PAR) loaded polyurethane foam (PUF). The sorption conditions were optimized with respect to pH, shaking time, and loading capacity. Kinetic of sorption of Eu(III) and Tm(III) were evaluated at different intervals of time. The diffusion coefficient of Eu(III) and Tm(III) are found to be 4.48 Â 10 À5 cm 2 sec À1 and 7.81 Â 10 À5 cm 2 sec À1 . The Freundlich constant (1=n) are estimated to be 0.56 and 0.47 for Eu(III) and Tm(III), respectively, reflects a surface heterogeneity of the PUF. Langmuir isotherm gives a saturated capacity of 1.95 Â 10 À5 mol g À1 for Eu(III) and 1.01 Â 10 À4 mol g À1 for Tm(III), suggest a monolayer coverage of the surface. The Dubinin-Radushkevich (D-R) isotherm is applied and the sorption mean free energy (E) was calculated and was in the range 11-12 kJ mol À1 suggesting chemisorption involving chemical bonding is responsible for the adsorption process. The thermodynamics parameters such as enthalpy (DH), entropy (DS) and Gibbs free energy (DG) were calculated and interpreted. The large negative values of DH indicates that the adsorption of metal ions on PAR-loaded PUF is an exothermic process. A possible explanation of this exothermicity related to bonding has been given. The sorption is greatly affected in the presence of oxalate, citrate, tartrate, and phosphate.

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Kinetics of Adsorption

Cited by 29 publications

References 24 publications

Removal of the Herbicide MCPA by Commercial Activated Carbons: Equilibrium, Kinetics, and Reversibility

Removal of the Herbicide MCPA by Commercial Activated Carbons: Equilibrium, Kinetics, and Reversibility

Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon

Kinetics, Thermodynamics, and Sorption Profile of Eu(III) and Tm(III) on 4‐(2‐Pyridylazo) Resorcinol (PAR) Imbedded Polyurethane Foam

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