Batch adsorption of 2,4-dichlorophenoxy-acetic acid (2,4-D) from aqueous solution by granular activated carbon

Aksu, Zümríye; Kabasakal, E.

doi:10.1016/s1383-5866(03)00144-8

Cited by 377 publications

(234 citation statements)

References 22 publications

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“…The authors attributed it to endothermic nature of the adsorption systems, confirmed by values of the thermodynamic parameters at different temperatures. Similarly, Aksu and Kabasakal (2004) noticed a positive temperature effect in the case of 2.4-D adsorption on granular activated carbon. They supposed, the trend can be a result of pores size developing, activation of the adsorbent surface or creation of new active sites on the carbon surface by breaking existing bonds.…”

Section: Introductionmentioning

confidence: 81%

“…This is confirmed in many studies of pesticide adsorption on carbon materials (Aksu and Kabasakal 2005;Fontecha-Camara et al 2006;Pastrana-Martinez et al 2009;Daneshvar et al 2007). However, the opposite effects (Fontecha-Camara et al 2006;Chingombe et al 2006;Aksu and Kabasakal 2004;Dos Santos et al 1998) or no relationship between temperature changes and the amount of adsorbed substance (FontechaCamara et al 2006;Hamadi et al 2004) were also found.…”

Section: Introductionmentioning

confidence: 99%

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Adsorption equilibrium and kinetics of selected phenoxyacid pesticides on activated carbon: effect of temperature

et al. 2016

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The temperature influence on equilibrium and kinetics of adsorption of 4-chlorophenoxyacetic and 3-bromophenoxypropionic acids from aqueous solutions on the Norit activated carbon was studied. The correlations between temperature and parameters characterizing adsorption process were found. Increase of rate of adsorption kinetics of phenoxy pesticides with temperature was observed. The rates of adsorption were best described and fitted by multi-exponential equation; simple approximate solution was obtained by using MOE equation (contribution of second order kinetics was always below 80 %). Intermediate quality of description and good correlation with temperature changes was attained for fractal-like MOE kinetics. Slightly worse results were obtained for rate coefficients estimated by MOE fitting. Model-independent adsorption half-times are proposed as the best single descriptor of the experimental kinetic data. Its temperature dependence is strongly correlated with rate coefficients.

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Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Adsorption equilibrium and kinetics of selected phenoxyacid pesticides on activated carbon: effect of temperature

et al. 2016

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“…If the plots do not pass through the origin, the intra-particle diffusion is not the only rate-limiting step, so some other kinetic models can also be simultaneously applied to the adsorption rate. The presence of two linear sections indicates that the first linear part of the plot (not presented here) corresponds to external mass transfer or film diffusion, whereas the second part of the plot indicates the diffusion into the adsorbent particles passing through the interlayer space (Aksu and Kabasakal 2004;Rida et al 2013). The intercept value C gives information about the thickness of the boundary layer.…”

Section: Kinetic Studiesmentioning

confidence: 99%

Adsorption of Ag+ ions on hydrolyzed lignocellulosic materials based on willow, paulownia, wheat straw and maize stalks

Vassileva

Radoykova

Detcheva

et al. 2016

Int. J. Environ. Sci. Technol.

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In the present work, the adsorption of Ag ? ions on hydrolyzed plant biomass (willow, paulownia, wheat straw and maize stalks) was investigated. Chemical analyses were performed to establish the composition of the obtained materials. Adsorption mechanism, adsorption sites and specific surface areas of these materials were examined by BET analysis, IR spectroscopy, XPS and EPR. The effects of contact time, acidity of initial solutions and Ag ? ion concentrations were followed. Pseudo-firstorder, pseudo-second-order and intra-particle diffusion models were used to analyze kinetic data. In all cases, the adsorption was significantly affected by the pH value. Different types of adsorption isotherms of Ag ? ions (either Langmuir or Freundlich) were registered depending on the adsorbing material. The adsorption mechanism is complex, and the process passes through different stages as clustering of Ag ? ions and formation of elemental Ag. The maximal adsorption capacities varied from 2.05 to 6.07 mg g -1 . The obtained results revealed that the examined waste lignocellulosic materials are promising adsorbents for Ag ? ions.

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“…Spośród wszystkich dostępnych technik oczyszczania wody adsorpcja, zwłaszcza na węglach aktywnych, wydaje się najbardziej skuteczna i wciąż najczęściej stosowana. Skuteczność węgli aktywnych w usuwaniu herbicydu z roztworów wodnych została udowodniona w wielu pracach [4][5][6][7][8][9][10][11][12][13][14][15]. W większości prac do adsorpcji zastosowano komercyjnie dostępne węgle aktywne lub też węgle przygotowane przez autorów z różnych prekursorów.…”

Section: Wstępunclassified

“…W przypadku węgla AC-NH 3 , który charakteryzuje się najwyższą wartością pH PZC (7,85), spadek adsorpcji wraz ze wzrostem pH przebiegał bardziej łagodnie. W każdym przypadku najsłabsze zdolności adsorpcyjne węgli aktywnych (na poziomie 10%) zaobserwowano w środowisku alkalicznym w pH = 10, co jest wynikiem odpychania elektrostatycznego ujemnych ładunków zlokalizowanych na powierzchni adsorbentów i anionów 2,4-D. Podobne zależności adsorpcji 2,4-D od pH (jej sukcesywny spadek wraz ze wzrostem pH) zaobserwowano na innych węglach aktywnych [4,11,12] czy też popiele z węgla brunatnego [24].…”

Section: Wyniki I Dyskusjaunclassified

The Influence of Surface Chemistry of the Activated Carbons on the Adsorption of 2,4-dichlorophenoxyacetic Acid

Kuśmierek

Świątkowski

2016

Eng. Prot. Environ.

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The aim of this study was to investigate the effect of surface chemistry of the activated carbons on the adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D). The 2,4-D was adsorbed on non-modified Norit R3-ex activated carbon (AC-NM) as well as on activated carbons modified by oxidation with concentrated nitric acid (AC-HNO3) and by heat treatment in ammonia at 900°C (AC-NH3). Adsorption isotherms of the 2,4-D on the activated carbons were analyzed using the Freundlich, Langmuir and Langmuir-Freundlich models. The Langmuir equation was slightly better fitted to the experimental data with the correlation coefficients better than 0.99. The values of the Langmuir maximum adsorption capacity (qm) were 2.945, 2.740 and 3.297 mmol/g for the AC-NM, AC-HNO3 and AC-NH3 activated carbons, respectively. The adsorption capacity of the activated carbons increased in the order: AC-HNO3 < AC-NM < AC-NH3. The best adsorbent was activated carbon with basic properties, while the worst adsorption properties were observed for the activated carbon with acidic properties. The acid treatment of activated carbon produced a large number of oxygen-containing functional groups on the carbon surface as it increases its acidic property and, in consequence, reduces the adsorption of the 2,4-D. The treatment of activated carbon with ammonia at high temperature leads to the formation of nitrogen-containing groups. The basic properties of the carbon surface enhance the interaction between activated carbon and acid molecules (dipole-dipole, H-bonding, covalent bonding) causing the increased adsorption of the 2,4-D from water. The effect of pH on the adsorption of 2,4-D onto activated carbons was also studied. The adsorption of the 2,4-D was almost constant at the pH range of 2.0-2.6 and decreased with the further increasing in the pH. The solution pH determines the adsorbent charge and the protonation or dissociation of the adsorbate. The pKa of 2,4-D is 2.8, and at a pH greater than the pKa value, the herbicide existed predominantly in anionic forms. As the pH increased, the degree of dissociation of 2,4-D increased, thereby making it more negatively charged. The values of the point of zero charge (pHPZC) were 6.10, 3.35 and 7.85 for the AC-NM, AC-HNO3 and AC-NH3 activated carbons, respectively. At pH of less than the pHPZC, the surface of the carbon had a net positive charge; at a pH greater than pHPZC, the surface had a net negative charge. The large reduction in the 2,4-dichlorophenoxyacetic acid adsorption at highly basic conditions can be attributed to the electrostatic repulsion between the negatively charged activated carbons and the dissociated 2,4-D molecules. The experimental results demonstrate that the surface chemistry of the activated carbons affects significantly the adsorption of the 2,4-D and should be taken into account when choosing an adsorbent for the removal of the herbicide from water.

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Batch adsorption of 2,4-dichlorophenoxy-acetic acid (2,4-D) from aqueous solution by granular activated carbon

Cited by 377 publications

References 22 publications

Adsorption equilibrium and kinetics of selected phenoxyacid pesticides on activated carbon: effect of temperature

Adsorption equilibrium and kinetics of selected phenoxyacid pesticides on activated carbon: effect of temperature

Adsorption of Ag+ ions on hydrolyzed lignocellulosic materials based on willow, paulownia, wheat straw and maize stalks

The Influence of Surface Chemistry of the Activated Carbons on the Adsorption of 2,4-dichlorophenoxyacetic Acid

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