A Pseudo-Second Order Kinetic Equation for Sorption Processes

Хамизов, Р. Х.

doi:10.1134/s0036024420010148

Cited by 71 publications

(25 citation statements)

References 18 publications

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“…This model postulates that the adsorption rate is limited by the interaction of adsorbate molecules with adsorption centers on the surface of the carbon material (Ho & McKay, 1999), and not by diffusion into the particles of the adsorbent. The prefix "pseudo" is used in the world scientific literature (Ho & McKay, 1999;Simonin, 2016;Moussout et al, 2018;Khamizov, 2020) in order to distinguish kinetic equations using adsorption capacities from ordinary first-and second-order equations using the concentration of adsorbate in aqueous solution.…”

Section: Resultsmentioning

confidence: 99%

“…At the same time, it is believed [Khamizov, 2020] that the applicability of the pseudo-second order model does not depend on the mechanisms determining the adsorption rate. In any case, the chemical reaction of CP with structural fragments of the AC spatial framework can affect the overall rate of the process.…”

Section: Resultsmentioning

confidence: 99%

“…In any case, the chemical reaction of CP with structural fragments of the AC spatial framework can affect the overall rate of the process. It is rather difficult to separate the contributions of the mass transfer and the chemical stage based on using only formal equations (Khamizov, 2020).…”

Section: Resultsmentioning

confidence: 99%

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Adsorption of 4-Chlorphenol by Brown Coal Activated by Potassium Hydroxide

Tamarkina¹,

Kucherenko²,

Frolova³

2021

WPT STN

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The purpose of work is to evaluate the 4-chlorophenol (CP) adsorption capacity of brown coal activated carbons (ACs) prepared at different temperature of KOH activation. ACs were obtained in three stages: 1) impregnation of coal with a KOH solution, 2) heating (4 deg/min) in argon to a given temperature t (400-800°C) and exposure for 1 h, 3) cooling, washing from KOH, drying. The samples are designated as AC(t). Based on the N2 adsorption-desorption isotherms, the ACs total pore volume (Vt, cm3/g) and specific surface area (S, m2/g) were determined. The ACs adsorption capacity were measured at 25°С, CP concentration ≤700 mg/L, АC dosage – 1 g/L. The alkaline activation temperature was found to be a key factor in forming porosity of ACs and ability to adsorb CP. The CP maximum capacity (ACP(m), mg/g) increases 6.6 times up to 307 mg/g for AC(800) having S=1142 m2/g. The specific adsorption capacity (ACP(S) = ACP(m)/S, mg/m2) sharply decreases in a sample range from AC(400) to AC(550) and weakly depends on temperature at 550-800°C. The kinetics of CP adsorption is best described by a pseudo-second order model. The rate determining stage is the interaction of CP molecules with AC surface. The CP adsorption isotherms are best described by the Langmuir model. The dependence of the ACP(m) from S can be approximated by three linear equations that probably correspond to the three regions of forming surface adsorbtion centers (AdCs). The first (S≤370 m2/g) is characterized by a small adsorption capacity increment (kS=0.103 mg/m2), but a significant (16.4 times) decrease in the specific capacity ACP(S). In the second region (S=370-770 m2/g, t=550-750°C), capacity increment is 10 times more (kS=0.985 mg/m2) and in the third region (S≥770 m2/g, t≥750°C) the increase in CP capacity is the smallest (kS=0.067 mg/m2). The thermoinitiated formation of AdCs is assumed to be not proportional to the increase in surface area, and their chemical structure and reactivity is determined by the alkaline activation temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Adsorption of 4-Chlorphenol by Brown Coal Activated by Potassium Hydroxide

Tamarkina¹,

Kucherenko²,

Frolova³

2021

WPT STN

View full text Add to dashboard Cite

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“…The pseudo‐second‐order kinetic model describes the adsorption process dominated by chemisorption at activated sites, [ 40,41 ] and expresses as follows:

t / q_{t} = 1 / k_{2} q_{e}^{2} + t / q_{e},

where q e (mg g −1 ) is the equilibrium amount of Nap on resin; q t (mg g −1 ) is the Nap amount adsorbed on per unit weight of resin at t min, k 1 (min −1 ) and k 2 (g mg −1 min −1 ) refer to the rate constant of pseudo‐first‐order equation and pseudo‐second‐order equation, respectively.…”

Section: Resultsmentioning

confidence: 99%

Enhancing the adsorption property of macroporous XAD‐2 resin by nanosecond‐pulsed discharge plasma modification

Yang

Wang

et al. 2020

Plasma Processes & Polymers

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In this study, a nanosecond‐pulsed discharge plasma is employed to modify the macroporous XAD‐2 resin to improve the adsorption performance of polycyclic aromatic hydrocarbons. After modification, XAD‐2‐20 resin shows great advantage on naphthalene (Nap) adsorption, whose adsorption capacity increased by 80.6% and 43.5% compared with the raw and XAD‐2‐30, respectively. The physiochemical properties of XAD‐2 resin are characterized by scanning electron microscope, N2 adsorption/desorption, X‐ray photoelectron spectroscopy, and Fourier‐transform infrared (FTIR) spectrum. The amount of micro‐mesoporous with a size of 2–3.5 nm are formed and many carbonyl groups (C═O) and ester or carboxylic groups (O–C═O) are introduced on the XAD‐2‐20 surface, and the value of O/C is increased from 14% to 53% compared with the raw resin.

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“…It is affirmed that the incorporation of Fe in C 4 (A,F)C̅ H 11 increases the adsorption rate of chloride ions. Since the adsorption mechanism proposed by the pseudosecond-order kinetic model is established on the physicochemical interaction between the adsorbate molecules and the adsorbent, 33,34 the doped iron seems to play an accelerating The intraparticle diffusion kinetic model is as follows 35 = + q k t c…”

Section: ■ Introductionmentioning

confidence: 99%

Chloride Adsorption Capacity of Monocarbonate: The Importance of Iron Doping

Huang

Tao

Yang

et al. 2022

ACS Sustainable Chem. Eng.

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Resistance to chloride penetration is a concerned durability issue to ordinary Portland cement (OPC) based materials used in the marine environment. Monocarbonate has become an increasingly common hydration product observed in OPC-based materials and plays an important role in chloride adsorption. The Portland cement used in ocean engineering has a notably higher C4AF content than C3A, and C4AF has become a particularly important aluminate phase in it. However, few studies have focused on the discrepancy in the chloride-binding capabilities of C3A hydrates and C4AF hydrates. The objective of this paper is to study the discrepancies in chloride adsorption between undoped and Fe-doped monocarbonates. The results suggest that the Fe-doped C4(A,F)C̅H11 exhibits superior chloride adsorption than undoped C4AC̅H11 because the doping of Fe weakens the restriction of the surrounding hydrogen bond connected to CO3 2– in its interlayer. A pseudo-second-order kinetic model is more suitable for the characterization of the chloride adsorption process on monocarbonates. Freundlich isotherm is favorable to fit the experimental data of chloride adsorption by the monocarbonate. This study holds great promise for improving the chloride penetration resistance of Portland cement.

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A Pseudo-Second Order Kinetic Equation for Sorption Processes

Cited by 71 publications

References 18 publications

Adsorption of 4-Chlorphenol by Brown Coal Activated by Potassium Hydroxide

Adsorption of 4-Chlorphenol by Brown Coal Activated by Potassium Hydroxide

Enhancing the adsorption property of macroporous XAD‐2 resin by nanosecond‐pulsed discharge plasma modification

Chloride Adsorption Capacity of Monocarbonate: The Importance of Iron Doping

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