Removal of Mo(VI), Pb(II), and Cu(II) from wastewater using electrospun cellulose acetate/chitosan biopolymer fibers

Abstract

Environmentally friendly polymers such as cellulose acetate (CA) and chitosan (CS) were used to obtain electrospun fibers for Cu²⁺, Pb²⁺, and Mo⁶⁺ capture. The solvents dichloromethane (DCM) and dimethylformamide (DMF) allowed the development of a surface area of 148 m² g^-1 for CA fibers and 113 m² g^-1 for cellulose acetate/chitosan (CA/CS) fibers. The fibers were characterized by IR-DRIFT, SEM, TEM, CO₂ sorption isotherms at 273 K, Hg porosimetry, TGA, stress-strain tests, and XPS. The CA/CS fibers had a higher adsorption capacity than CA fibers without affecting their physicochemical properties. The capture capacity reached 102 mg g^-1 for Cu²⁺, 49.3 mg g^-1 for Pb²⁺, and 13.1 mg g^-1 for Mo⁶⁺. Furthermore, optimal pH, adsorption times q_t, and C₀ were studied for the evaluation of kinetic models and adsorption isotherms. Finally, a proposal for adsorbate-adsorbent interactions is presented as a possible capture mechanism where, in the case of Mo⁶⁺, a computational study is presented. The results demonstrate the potential to evaluate the fibers in tailings wastewater from copper mining.

Keywords: Adsorption metal ions; Biopolymers; Electrospun fibers; Wastewater treatment.