Construction of macroporous salecan polysaccharide-based adsorbents for wastewater remediation

Adsorbents fabricated with biopolymer are extremely fascinating from the material design aspect, with numerous advantages like excellent biocompatibility, good biodegradability and availability at low cost. In this paper, a novel salecan polysaccharide-based biosorbent was designed for removal of Cd²⁺ ions from aqueous solutions. The resulting adsorbent was characterized by FTIR, XRD, TGA, SEM, rheology and swelling measurements. Adsorption of Cd²⁺ onto the salecan biosorbent was evaluated taking into account salecan amount, sorbent dosage, solution pH, initial Cd²⁺ concentration and contact time. Pseudo-second-order kinetic model and Weber-Morris intra-particle diffusion model well fitted the kinetic results, suggesting chemisorption and intra-particle diffusion as the most probable adsorption mechanism. Meanwhile, the equilibrium adsorption data was nicely described by Langmuir isotherm model with a maximum adsorption capacity of 170.1 mg Cd²⁺ per gram of sample. Finally, the salecan biosorbent exhibited an excellent reusability and 89.2% of the original sorption ability remained after 6 cycles. The present findings suggest that salecan-based biosorbents have potential for application as a wastewater remediation device.