Multivariate Optimization and Adsorption Characterization of As(III) by Using Fraxinus Tree Leaves

Abstract

This study introduces Fraxinus tree leaves as a new, efficient biosorbent of As(III). A suitable response surface was achieved by running a central composite design. Simultaneous optimization of both responses (R% and q) was carried out and 67% of the goal of desirability function was attained. The results obtained for simultaneous optimization are R = 70% and q = 80.6 mg g⁻¹ with 67% desirability in m = 600 mg L⁻¹ where s = 0.10 g and pH = 3.9. Langmuir and Freundlich isotherms model were applied in explaining the sorbent–sorbate equilibrium study, and maximum capacity uptake equals 99.97 mg g⁻¹ and K_L = 0.05 L mg⁻¹ has been obtained. Fourier Transfer Infra-Red (FT-IR) and kinetic results were considered to examine the functional groups involved and the adsorption mechanism.

Keywords:

• As(III)
• Central composite design
• Desirability function
• Fraxinus tree leaves