Removal of reactive blue 19 from simulated wastewater using Solanum melongena stalk/MWCNTs: thermodynamics, kinetic, equilibrium and regeneration potentials

Abstract

In the present study, a nanocomposite was prepared for the removal of dye from the aqueous phase. In this regard, multi-walled carbon nanotubes (MWCNTs) were anchored on the stalk of Solanum melongena (SMB) to obtain a robust adsorbent with the capacity to eliminate reactive blue 19 (RB19) using the batch adsorptive processes. Solanum melongena stalk decorated with MWCNTs (SMC) and SMB were characterized using Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), Field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR) analysis. With the exception of solution pH, an increase in contact time, adsorbent dose, initial RB19 concentration, and solution temperature were noticed to elevate the uptake potential of SMB and SMC. Kinetic experimental data for SMB and SMC were consistent with the pseudo-second-order and Elovich model, respectively. The experimental isotherm data obtained for SMB and SMC were best expressed by Freundlich and Langmuir models, respectively. After the fifth adsorption–desorption cycle, SMC exhibited 52% of adsorption efficiency. Hence, SMC can be an auspicious candidate for the efficient adsorption of RB19.