Characterization of Colombian Clay and Its Potential Use as Adsorbent

Abstract

This paper presents a mineralogical and physicochemical characterization of a Colombian clay found in an area with the greatest exploitation potential of smectites and possible use as an adsorbent for the removal of chromium. The clay was characterized by using X-ray diffraction (XRD), cation exchange capacity (CEC), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA/DSC), and nitrogen adsorption at 77 K. The homoionized clay was used as an adsorbent for the removal of Cr(III) in an aqueous solution. The homoionized clay was modified with hexadecyltrimethylammonium bromide (HDTMA-Br), and the organoclay obtained was evaluated for the adsorption of Cr(VI) in aqueous solution. The XRD analysis showed that the clay from Armero-Guayabal is primarily constituted by smectite (48 wt%) followed by quartz mineral (21 wt%). The chemical analysis of bulk clay showed that the predominant oxides are SiO2 (55.81 wt%), Al2O3 (16.25 wt%), and Fe2O3 (7.51 wt%), and the nitrogen adsorption indicated that the bulk clay has a specific surface area of 45.1 m2/g. Homoionized clay and organoclay achieved Cr(III) and Cr(VI) removals greater than 85.05 ± 2.04% (pH between 3 and 4) and 82.93 ± 1.03% (pH between 3 and 5), respectively, proving the potential of these materials for the removal of heavy metals in an aqueous solution.

Adsorption of Cr(VI) in Aqueous Solution Using a Surfactant-Modified Bentonite

“…e modification of the bentonite with the quaternary ammonium salt caused an increase in the basal spacing (d 001 ) of the layers from 1.6 nm to 2.1 nm brought about by HDTMA + cation intercalation. Macías-Quiroga et al [16] and Otavo-Loaiza et al [19] have reported similar basal spacing values for this bentonite and the bentonite modified with HDTMA-Br. e increase in the interlayer spacing indicates that the HDTMA + cations intercalated in the interlamellar space were arranged in the form of a pseudo-trimolecular layer [20].…”

“…e large band at 1030 cm −1 corresponds to the Si-O stretching vibration. e above signals can be considered characteristic of dioctahedral smectite [16,23]. Broad bands centered near 3421-3427 cm −1 and 1636-1639 cm −1 are due to the-OH stretching mode of the interlayer water [24].…”

“…e clay used was a Colombian bentonite sample from Armero-Guayabal (Tolima). e main clay mineral of the bentonite used in this study is the montmorillonite (48 wt%), and its mineralogical and chemical composition has been previously reported [16].…”

Tartrazine Removal from Aqueous Solution by HDTMA-Br-Modified Colombian Bentonite

“…Studies on the removal of tartrazine from a solution using a modified bentonite are limited [41]. In Colombia, it has been estimated that smectite clay deposits for exploitation are 1.1 × 10 9 metric tons [42], which could be used as an adsorbent material. This study evaluates the effect of variables pH, ionic strength, agitation speed, adsorbent mass, and contact time on the adsorption of a tartrazine dye in an aqueous medium, using a Colombian bentonite modified with hexadecyltrimethylammonium bromide (HDTMA-Br) as the material adsorbent.…”

Colombian clays binary mixtures: physical changes due to thermal treatments

“…For instance, thermal stability and swelling behavior showed a strong relationship with the differences in the electrical charge of the layers, the origin of the charge deficiency, and interlayer cations [11]. Moreover, these features have motivated the study of Colombian clays in different fields such as environmental remediation, catalysts, and waste treatments [7,8,10,12]. Currently, commercial exploitation is mainly concentrated in animal feeding additives and cat litters.…”