Mechanistic insights into simultaneous removal of copper, cadmium and arsenic from water by iron oxide-functionalized magnetic imogolite nanocomposites

Abstract

Imogolite and magnetic imogolite-Fe oxide nanocomposites at and 25% Fe loading (w/w), respectively) were synthesized and tested for the removal of aqueous copper (Cu), cadmium (Cd), and arsenic (As) pollutants. The materials were characterized by transmission electron microscopy, and specific surface area and isoelectric point measurements. The Fe-containing samples were additionally characterized by Mössbauer spectroscopy and vibrating-sample magnetometry. Significant differences were found in the morphological, electrophoretic, and magnetic characteristics between imogolite and the nanocomposites. The in-situ Fe-oxide precipitation process modified the active surface sites of the imogolite. The Fe-oxide, mainly magnetite, favored the contaminants' adsorption over the pristine imogolite. The adsorption kinetics of these pollutants were adequately described by the pseudo-second order and intraparticle diffusion models. The kinetic models showed that surface adsorption was more important than intraparticle diffusion in the removal of the pollutants by all the adsorbents. The Langmuir-Freundlich model described the experimental adsorption data, and both nanocomposites showed greater adsorption capacity than the imogolite. The adsorption of Cu and Cd was sensitive to cationic competition, showing a decrease of the adsorption capacity when the two cations coexisted, while their adsorption increased in the presence of arsenate.

Enhanced Removal of Mercury and Lead by a Novel and Efficient Surface-functionalized Imogolite with Nanoscale Zero-valent Iron Material

“…This model is used to describe the chemisorption processes on heterogeneous surfaces; it considers that adsorption takes place in two stages: a fast reaction, mainly associated with the movement of the adsorbate over outer active sites, and diffusion (slow) into and out of the adsorbent pores (Arancibia-Miranda et al 2020, Arancibia-Miranda et al 2015, Chien &Clayton 1980, Wu et al 2001. This model is expressed as:…”

“…Furthermore, the sorption capacity of nZVI can also be improved by synergistically combining it with other nanomaterials. In this sense, inorganic nanotubes based on aluminosilicates, called imogolite (Imo), have attracted much research attention due to their one-dimensional structure, mechanical resistance and reactive surfaces (Arancibia-Miranda et al 2020, Arancibia-Miranda et al 2015. Imogolite is a hydrated aluminosilicate with the chemical formula (OH)3Al2O3SiOH (Cradwick et al 1972).…”

“…Because of its high dispersibility in water and the amphoteric character of Imo, which is strongly influenced by the pH of the medium (Arancibia-Miranda et al 2015), cations should be able to interact with the inner surface and anions with the outer surface of the nanotubes (Bonelli 2016). Due to the special properties of imogolite, this nanomaterial has attracted substantial interest in the scientific community because of its potential application in the removal of cations and anions from polluted water (Arancibia-Miranda et al 2020, Bonelli 2016, Levard et al 2009. In this work, we propose the functionalization of imogolite with nZVI as a strategy to obtain a powerful and new sorbent nanomaterial with magnetic properties.…”

Ionic Liquid Agar–Alginate Beads as a Sustainable Phenol Adsorbent

“…However, PWW treatment at low concentrations using the abovementioned techniques is either resource-intensive, time consuming, demands delicate operations conditions or creates unwanted by-products [8]. Due to intrinsic limitations linked to these techniques, it is very important to develop alternative cheap and sustainable PWW treatment techniques [9]. Santonastaso et al and Weidner and Ciesielczyk highlighted the significance of adsorption technique for the treatment of aqueous streams [10,11].…”

Enhanced removal of mercury and lead by a novel and efficient surface-functionalized imogolite with nanoscale zero-valent iron material

“…Because of its high dispersibility in water and the amphoteric character of Imo, which is strongly influenced by the pH of the medium (Arancibia-Miranda et al 2015), cations should be able to interact with the inner surface and anions with the outer surface of the nanotubes (Bonelli 2016). Due to the special properties of imogolite, this nanomaterial has attracted substantial interest in the scientific community because of its potential application in the removal of cations and anions from polluted water (Arancibia-Miranda et al 2020, Bonelli 2016, Levard et al 2009.…”