The effect of acid activation and calcination of halloysite on the efficiency and selectivity of Pb(II), Cd(II), Zn(II) and As(V) uptake

Abstract

The present study investigated the efficiency and mechanisms of aqueous Pb(II), Cd(II), Zn(II) and As(V) adsorption on natural (H), calcined (HC), and acid-activated halloysite (HA). The XRD and FTIR measurements indicated that the aluminosilicate framework was not affected by high-temperature treatment, in contrast to acid activation, which led to structural changes mainly in the tetrahedral sheet. The sorption of cations on H sample was low, though it was most effective for As(V). The X-ray photoelectron spectroscopy results suggested that removal of As(V) might be related to its reduction to As(III) involving oxidation of Fe(II) present in the mineral structure and/or iron minerals. The calcination enhanced halloysite sorption capacity for cations, while the As(V) sorption decreased. This was due to partial dehydroxylation and the subsequent formation of additional active sites. The acid treatment induced selective adsorption of Pb(II).

Halloysite Composites with Fe3O4Particles: The Effect of Impregnation on the Removal of Aqueous Cd(II) And Pb(II)

“…8). These result were in agreement with previously reported studies (Maziarz, Matusik 2016). After coating the halloysite surface with Fe 3 O 4 and applying heat treatment, the desorption decreased.…”

“…Literature on Cd(II) and Pb(II) ionic species distribution versus pH reports that the dominant forms at pH < 6.0 are Cd 2+ and Pb 2+ , Pb(OH) + , respectively which is strictly connected with the metals' hydrolysis constants (Smičiklas et al 2000;Xu et al 2008). Previous studies indicated that the adsorption of Cd(II) by the H sample occurs mainly through ion exchange, while in the case of Pb(II) removal both ion exchange and surface complexation can take place (Matusik 2016;Maziarz, Matusik 2016). This may be evidence for lower adsorption in the case of Cd(II).…”

“…Thus, environmental remediation has recently become one of the most common subjects of scientific discussion and research. Several methods are known for water treatment including ion exchange, adsorption, coagulation and filtration, chemical precipitation, membrane processes, and reverse osmosis (Matlock et al 2002;Ozaki et al 2002;Blöcher et al 2003;Dąbrowski et al 2004;Unuabonah et al 2008;Zhang and Hou 2008;Jiang et al 2010;Motsi et al 2011;Matusik, Wścisło 2014;Bajda et al 2015;Koteja, Matusik 2015;Maziarz, Matusik 2016). Since among the various technologies developed for the removal of contaminants, the adsorption processes are the most effective, economical and commonly used, methods for adsorbent separation from the working medium need to be constantly developed.…”

Nanorobots Constructed from Nanoclay: Using Nature to Create Self‐Propelled Autonomous Nanomachines

“…Similar observations were made for Zn 2+ where the average velocity decreased to ≈133 µm (Figure B). The decrease in the velocities of nanomotors in the presence of Zn 2+ and Cd 2+ can be attributed to the adsorption of heavy metals onto the Halloysite nanoclay surface . The ions get attached onto the active sites of the Halloysite nanoclay which subsequently blocks the platinum layer on the outer surface of the nanoclay.…”

Thermodynamics and kinetics of the removal of methylene blue from aqueous solution by raw kaolin

“…The HNTs find several applications such as ceramic, support for catalysts and other functional materials [27,28]. Recently, raw halloysite was successfully tested as adsorbents for removal of dyes, heavy metals and pollutants from aqueous solutions [e.g., [29][30][31].…”