Wheat Straw as a Bio-Sorbent for Arsenate, Chromate, Fluoride, and Nickel

Abstract

Abstract:Batch-type experiments were used to study As(V), Cr(VI), F − , and Ni 2+ sorption/desorption on wheat straw. For the lowest concentration added (0.5 mmol·L −1 ), the sorption sequence was F − > Ni 2+ > Cr(VI) >> As(V) (93%, 61%, 29%, 0.3%), but changed to Ni 2+ > F − > Cr(VI) >> As(V) when 3.0 and 6.0 mmol·L −1 were added (with 65%, 54%, 25%, 0%, and 68%, 52%, 27%, 0% sorption, respectively). Overall, As(V) showed the lowest sorption, whereas it was 25-37% for Cr(VI), 61-68% for Ni 2+ , and 52-93% for F − . For As(V), pH in the equilibrium solution was always above the pH of the point of zero charge (pH PZC ) for wheat straw, decreasing sorption efficiency. For Cr(VI), pH was below pH PZC , but not enough to reach high sorption. For F − , pH in the equilibrium was above pH PZC , which could reduce sorption. For Ni 2+ , pH in the equilibrium was always below pH PZC , which made sorption difficult. The satisfactory fitting of Cr(VI), F − , and Ni 2+ data to the Freundlich model suggests multilayer-type adsorption. Desorption was high for F − , whereas Ni 2+ showed the lowest desorption. This research could be especially relevant when focusing on the use of wheat straw as a bio-sorbent, and in cases where straw mulching is used.

Animal Biopolymer-Plant Biomass Composites: Synergism and Improved Sorption Efficiency

“…Wheat straw is a multicomponent biomass that contains cellulose, hemicellulose, and lignins; whereas chitosan is a single component polysaccharide comprised of β-(1→4)-2-amino-2-deoxy-D-glucopyranose units [3,4]. Studies have shown that valorization of straw [5] often requires energy intensive conversion to yield fuels, along with chemical modification strategies for enhanced utilization as an adsorbent [6,7]. Chitosan is a chitin-based material that has utility as an adsorbent for the controlled removal of diverse chemical species from water [8].…”

“…Bertolino et al reported that chitosan-based nanocomposites possess excellent thermal properties [13] for packaging, tissue engineering, and pharmaceutical applications [14], whereas Lissuzo et al reported on the utility of chitosan-based nanocomposites for drug delivery [15]. In the case of wheat straw biomass, Romar-Gasalla et al reported a low uptake of anion species due to its negative surface charge, whereas others report the effectiveness of modified wheat straw for the adsorption of cationic adsorbates [7].…”