Synthesis and application of modified chitosan beads for iron removal: kinetic and isotherm models

Abstract

Chitosan beads (CBs) and glutaraldehyde cross-linked chitosan beads (CGLBs) were used to investigate adsorption behavior of Fe (II/III) ions. Optimal adsorption conditions were determined by analyzing the solution pH, adsorption time, and adsorbent dosage. Kinetic studies were analyzed by using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The equilibrium data were modeled by Langmuir, Redlich-Peterson, and Freundlich. The kinetic data were found to follow the pseudo-first-order and pseudo-second-order models. The equilibrium data were best modeled by Langmuir and Freundlich isotherms. The maximum adsorption capacities estimated from the Langmuir model were 90.49 mg Fe (III)/g CGLBs, 59.85 mg Fe (II)/g CBs, and 56.99 mg Fe (II)/g CGLBs. These last two results allow concluding that the cross-linking slightly affected the adsorption capacity of pure chitosan, but the resulting beads are resistant to acidic medium using a small amount of glutaraldehyde and are a friendly alternative for the treatment of wastewater.

Adsorption of As(V) from Aqueous Solution on Chitosan-Modified Diatomite

“…Due to the presence of active functional groups such as hydroxyl, amino groups, and glycosidic bond, CS displays a powerful adsorption performance toward heavy metal ions from aqueous solutions [14][15][16][17][18]. However, pure CS as an adsorbent has several disadvantages, including high cost and low chemical stability, which limits the further application of CS in wastewater treatment [19]. Immobilizing CS on a low-cost clay such as montmorillonite [20], bentonite [21], sand [22], perlite [23], and ceramic alumina [24] could reduce the required amount of CS without affecting the overall adsorption capacity.…”

Chitosan microspheres modified with poly(ethylenimine) enhance the adsorption of methyl orange from aqueous solutions

“…Especially, CS shows a powerful adsorption performance toward dyes from aqueous solutions . However, CS has poor chemical stability and mechanical strength in acidic environments, which limits its application in adsorption processes . Crosslinking is an effective method to improve the stability of CS in acid solutions .…”