Adsorption mechanism of cationic surfactants onto acid- and heat-activated sepiolites

Sabah, Eyüp; Turan, Mustafa; Çelik, M.S.

doi:10.1016/s0043-1354(02)00110-0

Cited by 153 publications

(72 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The first method was derived from a two-phase titration technique originally applied to anionic surfactants [25][26][27], consisting of measuring the conductivity of the cationic polymer charges on neutralisation, which occurs on addition of sodium dodecylsulphate (SDS), a tensioactive molecule consisting of a long, hydrophobic carbon chain and an associated sulphate group. The formation of a water insoluble complex indicates the neutralisation of all the charges, and this neutralisation is marked by the discontinuity in the slope of the associated titration curve.…”

Section: Determining Charge On Polymersmentioning

confidence: 99%

Understanding Cationic Polymer Adsorption on Mineral Surfaces: Kaolinite in Cement Aggregates

Jacquet¹,

Geatches

Clark

et al. 2018

Minerals

View full text Add to dashboard Cite

Abstract:We present a joint experimental and theoretical investigation into the adsorption of polycationic quaternary ammonium polymers on the clay mineral kaolinite. Within the cement and concrete manufacturing industries such polymers are used to improve the final product by inerting the adsorption capacity of the clay minerals for more expensive additives. The adsorption of the presently used polymer (FL22) was compared with both a similar variant, but without a hydroxyl group (Fl22mod) and uncharged polyvinyl alcohol (PVA). Experimental results show that adsorption of FL22 is higher than that of FL22mod at both pH 6 and at pH > 10 and that the adsorption of PVA is the highest. Theoretical density functional theory (DFT) results and simplified models consisting of the basal surfaces of kaolinite, with monomers of FL22, FL22mod and PVA gave monomer coverage per unit surface area of kaolinite, a comparison of the configurations of the relaxed models, formation energies and Mulliken charges. These results show that the polycationic polymers interact with the basal surfaces of kaolinite electrostatically, explaining the high affinity of these polymers for kaolinite surfaces in the experimental results. The hydroxyl groups of FL22 and PVA form hydrogen bonds with the basal surfaces of kaolinite in conditions of pH 6. The joint experimental and theoretical results suggest that, due to the presence of the hydroxyl group, the conformation of FL22 changes under pH, where at neutral pH it lies relatively flat to the kaolinite surfaces, but at higher pH, conformational changes of the polymer occur, thereby increasing the adsorbed quantity of FL22.

show abstract

Section: Determining Charge On Polymersmentioning

confidence: 99%

Understanding Cationic Polymer Adsorption on Mineral Surfaces: Kaolinite in Cement Aggregates

Jacquet¹,

Geatches

Clark

et al. 2018

Minerals

View full text Add to dashboard Cite

show abstract

“…Sepiolite has a common industrial application due to its molecular sized channels and large specific surface (more than 200 m 2 g). It is an effective sorbent in the removal of compounds, such as aromatic amines, diquat, paraquat and methyl green from aqueous solutions (Sabah et al, 2002;Rytwo et al, 2002). Fly ash was extensively used as an adsorbent material for removing various heavy metals and colours of organic compounds (Mott and Weber, 1992;Viraghavan and Alfaro, 1998).…”

Section: Introductionmentioning

confidence: 99%

Removal of Phenolic and Lignin Compounds from Bleached Kraft Mill Effluent by Fly Ash and Sepiolite

et al. 2005

View full text Add to dashboard Cite

This study aimed to remove phenolic and lignin compounds from paper mill industry (4500 m 3 /h) wastewaters, which is discharged to sea from a plant located in the western Turkey. As adsorbent, fly ash, raw sepiolite and heat-activated sepiolite were used. The effect of factors such as, particle size, temperature and pH on adsorption process was investigated. From kinetic studies, equilibrium time was found as 1 h for both. The kinetic data supports pseudo-second order model but shows very poor fit for pseudo-first order model. Intraparticle model also shows that there are two separate stages in sorption process, namely, external diffusion and pore diffusion. Adsorption isotherms for fly ash and activated sepiolite were obtained at two different temperatures. From experiments carried out at different pHs, it was observed that pH plays an important role in the adsorption process in removing of both lignin and phenolic compounds, providing both ionizating the compounds and modifying sorbent surfaces. It was also observed that heat-activated sepiolite is more effective than raw sepiolite and fly ash to remove these compounds. Adsorption of lignin and phenolic compounds increases with decreasing particle size. In addition, the efficiency of adsorption decreases with increasing adsorption temperature for both fly ash and untreated sepiolite.

show abstract

“…Although Balci [17] supposed that the acid pretreatment can remove half of the bound water and structural water, subsequent heat treatment remains necessary. Sepiolite activation with acid solution followed by heat treatment limited the possible formation of crystal decomposition and produced higher surface area than acid and heat pretreatment alone [19]. Nevertheless, dehydration at 150°C or higher provoked structural folding, and sepiolite shape became irreversible with higher temperature than 400°C [20].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pretreatment on Ammonium Adsorption Properties of Sepiolite: Equilibrium, Kinetics and Thermodynamic Studies

Duc

Koga

Wei

et al. 2016

J. of Wat. & Envir. Tech.

View full text Add to dashboard Cite

Sepiolite is considered as a selective adsorbent to remove ammonium from wastewater. However, ammonium adsorption capacity under different pretreatment conditions has not been well documented. In this study, batch experiments were performed to investigate the ammonium adsorption capacity of low-strength wastewater by modified sepiolite. Sepiolite was conditioned with an acid, HCl, HNO 3 or H 2 SO 4 , then thermally treated. Results showed that the modification process enhanced ammonium adsorption and sepiolite treated with 1N HNO 3 followed by calcination at 400°C exhibited superior adsorption property. Adsorption capacity increased with contact time and initial concentration but decreased with increasing temperature and sepiolite dosage. A maximum adsorption capacity of 143 mg/g was achieved at pH 8 and a dosage of 1/70 g sepiolite/mL solution. In contrast, an increase of dosage from 1/70 to 1/10 improved the ammonium adsorption efficiency from 45 to 75%. Overall, the ammonium adsorption followed the pseudo-second-order kinetics. The equilibrium data were best fitted with Redlich Peterson isotherm. Through thermodynamic analysis, the ammonium adsorption was not spontaneous with sepiolite dosage of 1/70. However, the spontaneity of adsorption was feasible with ΔG° of −2.5 kJ/mol at 25°C and a dosage of 1/10. This study provided a potential pathway for ammonium removal during wastewater treatment.

show abstract

Adsorption mechanism of cationic surfactants onto acid- and heat-activated sepiolites

Cited by 153 publications

References 23 publications

Understanding Cationic Polymer Adsorption on Mineral Surfaces: Kaolinite in Cement Aggregates

Understanding Cationic Polymer Adsorption on Mineral Surfaces: Kaolinite in Cement Aggregates

Removal of Phenolic and Lignin Compounds from Bleached Kraft Mill Effluent by Fly Ash and Sepiolite

Effect of Pretreatment on Ammonium Adsorption Properties of Sepiolite: Equilibrium, Kinetics and Thermodynamic Studies

Contact Info

Product

Resources

About