Removal of Remazol Blue 19 from wastewater by zinc–aluminium–chloride-layered double hydroxides

Abstract

Layered double hydroxides (LDHs), also called anionic clays, consist of cationic brucite-like layers and exchangeable interlayer anions. These hydrotalcite-like compounds, with Zn and Al in the layers and chloride in the interlayer space, were prepared following the coprecipitation method at constant pH. The affinity of this material for Remazol Blue 19, RB19 [2-(3-(4-Amino-9,10-dihydro-3-sulpho-9,10-dioxoanthracen-4-yl) aminobenzenesulphonyl) vinyl) disodiumsulphate], was studied as a function of contact time, pH of the solutions LDH dose and the RB19/[Zn-Al-Cl] mass ratio. It was found that 48 h is enough time for the equilibrium state to be reached with maximum RB19 retention at pH of 9 for an LDH dose equal to 100 mg and with an RB19/[Zn-Al-Cl] mass ratio higher than 3. The adsorption isotherm, described by the Langmuir model, is of L-type. The results demonstrate that RB19 retention on LDHs occurs by adsorption on external surface when RB19/[Zn-Al-Cl] mass ratio is equal or \3 and by both adsorption and interlayer ion exchange for ratios higher than 3. A mechanism for removal of RB19 anion has been confirmed by X-ray diffraction, IR spectroscopy and TG analysis (TG and DTG curves).

Acid Green 1 removal from wastewater by layered double hydroxides

“…The experimental patterns are comparable with those of the pseudo-second order and the corresponding correlation coefficients are close to 1. The same result was obtained in a previous work (Elkhattabi et al 2013).…”

“…This residence time was applied for the following retention experiments. A similar behaviour was obtained for other adsorbate with LDH materials (Elkhattabi et al 2013;Legrouri et al 2005;El Gaini et al 2008a).…”

“…It is shown that the AG1 retention is at its maximum in the pH value around 8. The low retention observed at lower pH values (< 7) may be attributed to a partial dissolution of the basic mineral matrix by acidic hydrolysis, which becomes more pronounced when the pH decreases (El Gaini et al 2008b;Elkhattabi et al 2013). The low adsorption observed at pH 9 may be explained by a competition with the carbonate ions for which the LDH is known to have a great affinity.…”

“…Layered double hydroxides (LDHs) have proven to be good candidates for removing anionic dyes from aqueous solutions. These materials, which are endowed with high anionic exchange capacity and good adsorptive ability, have been able to retain and host several large organic anions (Lakraimi et al 2000;Li et al 2005) including dyestuffs (Dos Santos et al 2013;Elkhattabi et al 2013;Guo et al 2013;Pereira et al 2013;Alexandrica et al 2015).…”

Zn-M-CO3 Layered Double Hydroxides (M=Fe, Cr, or Al): Synthesis, Characterization, and Removal of Aqueous Indigo Carmine

“…The vibration bands associated with the organic anion, as well as the adsorption bands characteristic for our samples after IC adsorption are evidenced in the spectrum (d), (e) and (f), the asymmetric stretching vibration related to the S=O bond appears between 1000-1125 cm -1 . The adsorption bands at around 1360 and 1620 cm -1 are assigned to the stretching vibration of the C=C bond belonging to an aromatic ring, while the bands at 1635 and 1065 cm -1 are assigned to those of C=O and C-N bond respectively [40], the band characteristic to the carbonate anion is evidenced with a considerable decrease in intensity shown in spectrum (e) compared with spectrum (b), confirms the fact that the interlayer carbonate anions have been displaced [41]. In the light of these results, we can deduce that the structural differences between the obtained products were thus confirmed from the results of FTIR meas-urements, and these results were consistent with those of powder XRD analyses.…”