Biogenic synthesis of zinc oxide-impregnated Musa acuminata peel composite as an efficient lignocellulosic macromolecular sieve for enhanced eradication of Congo red dye from wastewater

Abstract

Uncontrolled urbanization and industrialization, coupled with population growth, have increased water pollution in the world. Banana peel powder was used as biosorbent in two forms, through artificial dyeing in the industry and other coloring agents in industrial discharge. This study examines the efficiency of zinc oxide-mediated agro-waste material made of Musa acuminata (banana) peels for the adsorption of Congo red (CR) dye in industrial effluents. Banana peel powder was use as biosorbent in two forms, namely, in their natural state (UMP) and ZnO-treated form (TMP). The optimal conditions for the removal of dye in the batch process were determined for UMP at pH 6 and TMP at pH 5.8. The optimal dosage for the adsorbents was 1.2 g UMP and 1.2 g TMP. The Temkin model provided the most acceptable alignment to the experimental equilibrium results among the other isothermal models, with R² values of 0.9922 for UMP, and Langmuir was the best model with an R² value of 0.9482 for TMP. Although the isothermal studies also showed good correlation coefficients, the Temkin model provided the best fit. The biosorption behavior was best described by pseudo second order kinetics, with R² = 0.999 for UMP and R² = 0.9994 for TMP. The values of the thermodynamic parameters ΔG°, ΔS° and ΔH° are −17.175 kJ mol⁻¹ at 303 K, −3.798 kJ mol⁻¹ and -20.628 kJ mol⁻¹ for TMP and −16.964 kJ mol⁻¹ at 303 K, −20.026 J mol⁻¹ K⁻¹, and −25.943 kJ mol⁻¹ for UMP, respectively, indicating their exothermic and spontaneous nature.