Imogolite is a nanomineral, with the general formula (OH)3Al2O3SiOH and tubular shape, that can be obtained from glassy volcanic ash soils or be synthesized at mild conditions in aqueous solutions. In nature, imogolite can be found as hollow nanotubes with an outer diameter of ~2.5 nm, an inner diameter of less than 1 nm and lengths between several hundred nanometers to one micrometer. It also has amphoteric groups of aluminol and silanol inducing very interesting acid-base properties. All these properties make this nanomineral a highly attractive adsorbents for emerging contaminants in aqueous solutions. In this study the adsorption capacity of Imogolite was tested using different concentrations of the hormone 17β-estradiol in aqueous solution. The presence of this pollutant was detected and quantify by spectrofluorimetry. Solid phase microextraction studies were performed and a chemometric approach was used to adjust the most relevant variables (rotation time, pH and imogolite mass). A maximum adsorption of 95.5% was obtained, using purified imogolite under the following experimental condition: pH 7, 17β-estradiol concentration of 350 µg/L, adsorbent dose of 0.017g per 5.0 mL of solution and an agitation at 1250 rpm for 10.0 minutes. To the best of our knowledge, this is the second time that the imogolite's adsorption capacity has been confirmed using an emerging organic pollutant. Our study also opens very promising applications of imogolite as green ecosorbent in analytical chemistry as well as other applications in the remediation of water organic pollution.

Using imogolite to adsorb emerging organic pollutants from water samples

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.