The adsorption of methylene blue on montmorillonite from acid solutions

Abstract

AB ST R ACT : The adsorption of methylene blue (MB) on montmorillonite from acid solutions has not yet been studied in detail. In this paper the adsorption of this dye on Ca/SAz montmorillonite from 0.32, 0.80 and 1.60 M HCl solutions at ambient temperature and after 2 hours leaching was carefully studied and evaluated. Under the above conditions the MB/SAz intercalates formed are practically insoluble. In contrast to the adsorption of methylene blue on montmorillonite from aqueous solutions, the adsorption from acid solutions consists of two adsorption waves. The intercalated samples from the first and second waves were studied using X-ray powder diffraction (XRD), FTIR, Vis spectroscopy, and scanning electron microscopy (SEM) equipped with a microprobe system. The adsorption of MB in the first wave is attributed to ion exchange of the dye cationic species (MB + , MB 2 2+ , H-aggregates, MBH 2+ and H + ) for the original interlayer cations of montmorillonite. The percentages of MBH 2+ and H + based on total adsorbed MB were estimated for varying HCl concentrations. The second adsorption wave is linked to the precipitation of MB species on the outer MB/SAz surface.

Enhanced swelling and methylene blue adsorption of polyacrylamide‐based superabsorbents using alginate modified montmorillonite

“…The incorporation of MMT to SAPs not only reduces production costs but also improves the swelling properties of SAPs . In addition, MMT has often been used in the removal of organic dyes due to its high surface area, high cation exchange capacity, and low cost . The introduction of MMT should improve the dye adsorption ability of SAPs.…”

Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix

“…On the other hand, sorption of polar or ionic pollutants is dominated by electrostatic interactions and ion exchange phenomena. Materials with such characteristics can be found among several types of clays [36,[121][122][123][124][125]. The large majority of organic xenobiotic pollutants are non-polar, although some particular classes like most pharmaceuticals are polar or ionizable [119].…”

“…Electrostatic interactions with the surface and mechanisms such as cation exchange, cation bridging with the surface, surface complexation, and hydrogen bonding seem to be involved in the capture of ionic and polar species from aqueous media [121][122][123][124][125]176]. In addition, the interlayer expandability of many of these minerals and the presence of water molecules associated with exchangeable cations in these interlayers allows the exchange of these hydrated ions with much larger organic molecules and their intercalation between the aluminosilicate layers [123,177,178].…”

Uptake of Ce(III) and Ce(IV) on montmorillonite

“…Pb, Cd, Zn), cationic pollutants (e.g. dyes) from various wastes as well as for retention of RE, clay minerals were also used (Torstenfelt et al, 1982;Weiss et al, 1998;Kraus et al, 2006;Bergaya et al, 2006aBergaya et al, , 2006bKlika et al, 2007Klika et al, , 2011Vopálka et al, 2015). Uptake and factors influencing retention of La, Ce, Sm, Gd, Er, and Y on montmorillonite were investigated and it was found that montmorillonite in aqueous dispersion modifies their pH and therefore the precipitation of RE(III) hydroxides begins already at pH 5 (Bruque et al, 1980).…”