New Ulva lactuca Algae Based Chitosan Bio-composites for Bioremediation of Cd(II) Ions

Abstract

The current article covers the production of chitosan (CS) from shells of shrimp waste and its utilization in the preparation of eco-friendly imprinting and non-imprinting composites with Ulva lactuca algae (Alg). These bio-composites namely (Imp-Alg-25wt% CS) and (NImp-Alg-25wt% CS) were used for removal of Cd(II) ions. Fourier transform infrared (FT-IR) spectra, scanning electron microscope (SEM) equipped with electron dispersive X-ray (EDX), X-ray diffraction (XRD), and elemental analysis measurements were performed to characterize these bio-composites sorbents. The highest adsorption of these sorbents towards Cd(II) ions was determined as a function of solutions pH, contact time, Cd(II) ion concentration, beads dose, and temperature. The equilibrium experimental data were treated using various mathematical isotherm and kinetic models to approve the maximum bio-sorption capacities of NImp-Alg-25wt% CS and Imp-Alg-25wt% CS (in mg/g). The results exhibited that Imp-Alg-25wt% CS gave higher removal capacity than NImp-Alg-25wt% CS at the same optimum parameters. Pseudo-2nd order dynamic and Langmuir isotherm models were well described in these biosorption processes. Thermodynamically, the removal behavior of Cd(II) using both bio-composites was spontaneous at room temperature. The reusability of the sorbents, NImp-Alg-25wt% CS and Imp-Alg-25wt% CS, showed three cycles. In addition, comparative study was also conducted for Cd(II) removal onto some reported sorbents.