Influence of thermal treatment on bentonite used as adsorbent for Cd, Pb, Zn retention from mono-solute and poly-solute aqueous solutions

Abstract

The retentions of Zn, Cd and Pb cations by one treated bentonite up to 750 °C were analyzed. The retentions were evaluated by using mono-and poly-solute aqueous solutions of such cations. The adsorptions were carried out in batch system at room temperature. The solid/liquid ratio was 2% wt.v -1 . The solids were characterized by X-ray diffraction, thermal and chemical analyses. The Zn cation from mono-or polysolute-solutions was retained in higher amount than Cd and Pb cations in similar solution types by bentonite. The retentions were effective up to 450 °C calcined bentonite, after that, the retention capacity decreased in concordance with dehydroxylation of the structure of clay minerals.

Antioxidant Efficacy and “In Vivo” Safety of a Bentonite/Vitamin C Hybrid

“…For Bent, three weight loss peaks were observed (see DTG curve): the first main mass loss around 85 • C corresponds to the dehydration of interparticle water, adsorbed and interlayer water [51][52][53][54]. The second weight loss event from 380 to 580 • C with a maximum at 484 • C, as can be seen in the DTG curve, is due to the removing of the hydroxyl groups from the laminar structure in water form (structural dehydroxylation) [55][56][57]. The last smaller weight loss about 671 • C is associated with another stage of dehydroxylation [58] that can lead to the total structure collapse [55,57].…”