Adsorption of humic acid on acid-activated Greek bentonite

Doulia, Danae; Leodopoulos, Ch.; Gimouhopoulos, K.; Rigas, Fotis

doi:10.1016/j.jcis.2009.07.028

Cited by 182 publications

(81 citation statements)

References 43 publications

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“…The amount of adsorption at equilibrium, q e (mg/g) was calculated by mass balance equation (Doulia et al, 2009): where C o and C e are the initial and equilibrium concentration of cadmium solutions (mg/L), V is the solution volume (ml), and m is the adsorbent weight (g). The adsorption percent (%) was calculated using the equation (Doulia et al, 2009)…”

Section: Adsorption Isothermsmentioning

confidence: 99%

“…5). Based on previous studies, the best pH for HA removal is 3 (Salman et al, 2007;Terdkiatburana et al, 2008;Wang et al, 2008;Doulia et al, 2009). At pH values below 3.0 the concentration of hydroxonium ions in the solution would be high and prevents any adsorption by the active sites on the substrate surface.…”

Section: Effect Of Experimental Parameters On CD and Ha Adsorption Efmentioning

confidence: 99%

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Removal of cadmium and humic acid from aqueous solutions using surface modified nanozeolite A

Tashauoei

Attar

Amin

et al. 2010

Int. J. Environ. Sci. Technol.

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ABSTRACT:The sorption of cadmium and humic acids from aqueous solutions using surface-modified nanozeolite A has been investigated under various examination conditions. The morphology of untreated and treated nanozeolite was studied under scanning electron microscope and transmission electron microscope. Isotherms of cadmium adsorption onto surfacemodified nanozeolite A were studied at different pH, solid to liquid ratio, adsorbate concentration and interaction time. Kinetic and equilibrium studies were conducted and the equilibrium data have been analyzed using Langmuir and Freundlich isotherm models. The study revealed that experimental results were in agreement with the Freundlich model. The Langmuir monolayer adsorption capacity was found to be 1666.67 g cadmium and 6.75 g humic acid per gram of modified nanozeolite A, which is higher than that of reported value for other zeolites. The sorption ability was enhanced by surface modification and reduction in size and enabled the zeolite to adsorb cadmium. The adsorption of cadmium and humic acid on nanozeolite was found to be the highest at pH 6 and 3, respectively. Results showed that solid to liquid ratio and pH are the most important factors for cadmium and humic acid removal, respectively. Effect of competitive ions was studied and results showed that there is no competition between cadmium and humic acid sorption and presence of these ions.

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Section: Adsorption Isothermsmentioning

confidence: 99%

Section: Effect Of Experimental Parameters On CD and Ha Adsorption Efmentioning

confidence: 99%

Removal of cadmium and humic acid from aqueous solutions using surface modified nanozeolite A

Tashauoei

Attar

Amin

et al. 2010

Int. J. Environ. Sci. Technol.

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“…The effect of pH on the adsorption of humic substances is due to the diffusion characteristic of humic substances caused by the differences of molecular size of humic acid. At lower pH values, humic acid tends to diffuse faster [27].…”

Section: Effects Of Ph On the Nom Adsorption By Lpcmentioning

confidence: 97%

Adsorption of Natural Organic Matter (Nom) in Peat Water by Local Indonesia Tropical Clay Soils

Notodarmojo¹

2017

GEOMATE

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A series of experiment on the adsorption of natural organic matter (NOM) originated from peat water in Central Kalimantan, Indonesia by local peat clay soils had been carried out. A selected local peat clay soil (LPC) and activated local peat clay soil (ALPC) had been used as adsorbents. The activation of the local peat clay soil was carried out by immersing it in 1 M HCl solution at 900 o C. The effects of pH on the adsorption capacities were investigated. It has been found that at lower pHs (3-5) the adsorption capacities increased significantly. A rotary shaker was set at 180 rpm as an agitator in performing the kinetically behaviour and adsorption isotherm of NOM onto the LPC and the ALPC. It was found that the equilibration time for the LPC and the ALPC were 180 and 150 minutes, respectively. The kinetics equation model that most fitted to the adsorption experimental data for the both adsorbents was pseudo-second order kinetics model (r 2 > 0.99). The Dubinin-Radushkevich depicted the data more accurately to describe the NOM-LPC and NOM-LAPC adsorption isotherms (r 2 > 0.99). Further analysis on the peat water NOM characteristics and local clay (LPC and ALPC) suggested that physical adsorption, mainly electrostatic interactions enhanced adsorption process and hydrophobic or solute driven adsorption dominated in the early stage of the process, followed by a chemical adsorption process.

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“…The nonzero intercept is a clear indication that some other mechanism along with intraparticle diffusion is also involved with the intraparticle diffusion. In other words the intraparticle diffusion is not the only rate-controlling step in the Co(II) ion diffusion [46,47]. Milosavljević et al [48] reported that if the data represent multi-linearity, then two or more steps influence the adsorption process.…”

Section: Kinetic Studymentioning

confidence: 99%

Removal of cobalt(II) from aqueous solution by local Saudi bentonite: Kinetic and equilibrium investigations

Al-Duaij

Attia

Khezami

et al. 2016

Maced. J. Chem. Chem. Eng.

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Natural bentonite clay from Saudi Arabia was used to remove cobalt from aqueous solution. The clay samples were first characterized for their chemical composition and structure. Batch sorption studies were then conducted to assess their capacity to remove cobalt. The effect of contact time, initial analyte concentration, bentonite dose and temperature on the adsorption was investigated. The results showed that equilibrium was attained in 60 minutes. The metal adsorption was fitted to a Langmuir isotherm model and the maximum monolayer adsorption capacity was found to be 19.85 mg g −1 at 333 K. The pseudosecond-order kinetic model provided the best correlation to the experimental data. The application of an intra-particle diffusion model revealed that the adsorption mechanism of the cobalt ions is a rather complex process and that diffusion is involved in the overall rate of the adsorption process, but it is not the only rate-controlling step. The activation energy, E a , ranged between 4.33 and 9.14 kJ mol −1 , indicating a physical adsorption process.Keywords: bentonite; cobalt; kinetics; equilibrium ОТСТРАНУВАЊЕ НА КОБАЛТ(II) ОД ВОДНИ РАСТВОРИ СО ЛОКАЛЕН САУДИСКИ БЕНТОНИТ: КИНЕТИЧКИ И РАМНОТЕЖНИ ИСТРАЖУВАЊАПриродната бентонитна глина од Саудиска Арабија беше употребена за отстранување на кобалт од водни растврори. Глинените примероци прво беа карактеризирани преку хемиска анализа и структура. Потоа беа спроведени сорпциски истражувања со цел да се процени нивниот капацитет за отстранување на кобалт. За атсорпцијата беа испитувани ефектот на времето на дејството, почетната концентрација на аналитот, бентонитната доза и температурата. Резултатите покажаа дека рамнотежата се постигнува за 60 минути. Атсорпцијата на металот беше усогласена со изотермен модел на Langmuir и беше определено дека максималниот монослоен капацитет изнесува 19,85 mg g −1 на 333 K. Најдобра корелација беше постигната со кинетички модел од псевдо-втор ред. Примената на дифузиски модел на интра-честички откри дека атсорпцискиот механизам на јоните на кобалт е доста сложен процес и дека вклучува дифузија во севкупната брзина на атсорпцискиот процес, но не е чекорот што ја контролира брзината. Активациската енергија, E a , се движи од 4,33 до 9,14 kJ mol −1 што укажува на физички атсорпционен процес.

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Adsorption of humic acid on acid-activated Greek bentonite

Cited by 182 publications

References 43 publications

Removal of cadmium and humic acid from aqueous solutions using surface modified nanozeolite A

Removal of cadmium and humic acid from aqueous solutions using surface modified nanozeolite A

Adsorption of Natural Organic Matter (Nom) in Peat Water by Local Indonesia Tropical Clay Soils

Removal of cobalt(II) from aqueous solution by local Saudi bentonite: Kinetic and equilibrium investigations

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