Utilization of different parts of Moringa oleifera Lam. seeds as biosorbents to remove Acid Blue 9 synthetic dye

Abstract

In this work, Moringa oleifera seed husk (MOSH) and Moringa oleifera seed pulp (MOSP) were converted via a green route into efficient biosorbents for biosorption of Acid Blue 9 (AB9) synthetic dye from the wastewater. The textural properties, morphologies, and structures of both biosorbents were analyzed using Fourier infrared spectroscopy (FTIR), N2 adsorption/desorption isotherms, pH of point-zero-charge (pHPZC), and scanning electron microscope (SEM). The characterization results showed that the biosorbents have heterogeneous surfaces with a diversity of functional groups. The experimental data of biosorption kinetics were best described by the nonlinear Avrami fractional. The isothermal empirical data were supported by the nonlinear Liu equation, and the maximum biosorption capacities of MOSH and MOSP at 55 °C for AB9 synthetic dye are 329.5 mg g–1 and 694.2 mg g–1, respectively. The evaluation of thermodynamic parameters showed that the biosorption processes of both biosorbents were spontaneous, endothermic, and occurred by physisorption. The availability, low-cost, high adsorption capacity, and fast adsorption kinetics of MOSH and MOSP make them alternative, promising, and attractive green biosorbents for removal AB9 synthetic dye from aqueous solutions.