Eosin Removal by Cetyl Trimethylammonium-Cloisites: Influence of the Surfactant Solution Type and Regeneration Properties

Abstract

The effect of the counteranion of hexadecyltrimethylammonium salts on the physico-chemical properties of organoclays was investigated, using a selected natural clay mineral with a cation exchange capacity of 95 meq/100 g. The uptake amount of C16 cations was dependent on the hexadecyltrimethylammonium (C16) salt solution used, the organoclay prepared from C16Br salt solution exhibited a value of 1. 05 mmole/g higher than those prepared from C16Cl and C16OH salt solutions. The basal spacing of these organoclays was in the range of 1.81 nm to 2.10 nm, indicating a similar orientation of the intercalated surfactants, and could indicated that the excess amount of surfactants, above the cation exchange capacity of 0.95 meq/g could be adsorbed on the external surface of the clay mineral sheets. These organoclays were found to be stable in neutral, acidic, and basic media. The thermal stability of these organoclays was carried out using thermogravimetric analysis and in-situ X-ray diffraction (XRD) techniques. The decomposition of the surfactant occurred at a maximum temperature of 240 °C, accompanied with a decrease of the basal spacing value close to 1.42 nm. The application of these organoclays was investigated to remove an acidic dye, eosin. The removal amount was related to the initial used concentrations, the amount of the surfactants contents, and to the preheated temperatures of the organoclays. The removal was found to be endothermic process with a maximum amount of 55 mg of eosin/g of organoclay. The value decreased to 25 mg/g, when the intercalated surfactants were decomposed. The reuse of these organoclays was limited to four regeneration recycles with a reduction of 20 to 30%. However, noticeable reduction between 35% to 50% of the initial efficiency, was achieved after the fifth cycle, depending of the used organoclays.

organo acid-activated clays for water treatment as removal agent of Eosin-Y: Properties, regeneration, and single batch design absorber

“…Thus, the C16TMA intercalation did not alter the structure of the layers. The mild pH of the C16TMABr solution did not effectively alter the host layers of AACs structure, as reported for other OCs from different sources [ 8 ].…”

“…The expansion value of 3.80 nm was maintained for concentrations higher than 1.64 mmol. However, when using a clay mineral from a different source, an expansion of 1.90 nm was achieved regardless of the C16TMABr concentrations being higher than the CEC values [ 8 ]. It is mentioned that the alkyl chain length and the layer charge of the clay mineral affected the prearrangement of inserted surfactants [ 42 , 43 ].…”

“…The procedure was followed as reported in a recent work [ 8 ]. A stock solution of EY dye (1000 mg/L) was prepared and used for further preparation of other diluted solutions.…”

Adsorption behavior of Crys tal Violet dye in aqueous solution using Co+2 hectorite composite as adsorbent surface

“…Although synthetic dyes are widely utilized in the textile sector, 20 to 40 % of these pigments s till end up in effluents [1][2][3]. The majority of pigments contain hazardous and cancer-causing subs tances.…”

Novel Mechanistic Insights on the Photoredox Degradation of CECs Using Organic Photocatalysts

“…[59,66] For this reason, in literature a lot of studies focus their attention on the degradation of EOY and dyes in general. [66,67] In this thesis, we used EOY as a photocatalyst, combined with green light: this is an innovating technique, which wants to prove the possibility of degrading two or more contaminants at the same time under the same working condition.…”