Sorption of Organic Compounds by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite

Abstract

Abstraet~wing to their large and chemically active surface, hydroxy-intercalated and pillared clays can be potent sorbents for organic compounds. The sorption behavior of A1 and Zr-hydroxy-intercalated bentonite (HA1-, HZr-MX80), A1 and Zr-pillared bentonite (A1-MX80, Zr-MX80), and a commercial A1-pillared bentonite (EXM 534) for 3-chloroaniline (3-CA), atrazine (AT), and 3-chlorophenol (3-CP) was investigated. The results were compared with the sorption behavior of the untreated Na-rich bentonite (MX80) and granulated activated carbon (GAC). Also the influence of the salinity of the sorbate and the age of the sorbents was studied.A1 and Zr-hydroxy-intercalated and pillared bentonites sorbed higher amounts of 3-CA, AT, and 3-CP than the untreated bentonite. The quantities sorbed related to the electron-donating properties of the sorbate and the acidity of the sorbents. Sorbed quantities increased from the hydroxy-intercalated to the pillared species, and from the AI to the Zr forms. The organic bases, 3-CA and AT, were sorbed in higher quantities than the organic acid 3-CP. For AT, the sorbents exhibited a high affinity. Aging of the samples and a high ionic strength of the sorbate reduced the sorption of 3-CA, whereas the sorptioa of AT was not affected greatly. The sorption capacity of GAC for organic bases was generally higher than that of the hydroxy-intercalated and pillared bentonites.The data suggest that at initial concentrations at a ppm level, 3-CA and AT can be entirely removed from aqueous solutions by A1 and Zr-hydroxy-intercalated and pillared bentonites. These materials, especially Zr-pillared bentonites, represent potent alternative sorbents for atrazine, chloroanilines, and probably a wide range of other organic bases.

Sorption of atrazine, propazine, deethylatrazine, deisopropylatrazine and hydroxyatrazine onto organovermiculite

“…[15][16][17] Pillarization is one of the modifications often designated to environmental applications, 12,15,16,18 consisting in the intercalation of a polynuclear hydroxyl trivalent metal cation, for instance, Al Fe 3+ and Ti 3+ , between the layers, followed by heating. This process provides the development of interlayer metal oxide pillars.…”

Removal of Supranol Yellow 4GL by adsorption onto Cr-intercalated montmorillonite

“…Al, Zr and Ti hydroxy-intercalated and pillared have been recently used to remove anionic organic compounds. Matthes and Kahr [12] has found that the maximum sorption capacities of atrazine on Zr-intercalated bentonite and activated carbon GAC in ultrapure water were nearly identical. Cr-intercalated clay exhibits higher surface area than above materials.…”

Adsorption of 3-Chloroaniline on Potato Skin in Aqueous Solution

“…p of 3-chloroaniline is 3.52, indicating that this basic compound will primarily be present as nonionic organic base. It is therefore sensible to hypothesize that specific interactions such as hydrogen bonding or Van der Waals forces may play important role in the adsorption mechanism of neutral molecules and weak base compounds [6,15]. The adsorption process follows Freundlich isotherm indicating that adsorption of 3-CA on potato skin is favorable.…”

“…These aromatic amines compounds may be hazardous to plant, animals, and human for long duration even at very low concentration ( g/L) and are suspected to be carcinogenic and highly toxic to human beings and aquatic life [6]. Due to this anxiety, the US Environmental Protection Agency (EPA) included most of these substances in list of priority pollutants [7].…”

“…In reviewing the literature, adsorption studies of 3-chloroaniline have been investigated in aqueous solutions on various adsorbents such as soil [14], chelating resin [2], and clays [3,6,15,16].…”