Green synthesis of a multifunctional β-cyclodextrin modified polymer sorbent using agrarian wastes of Nelumbo nucifera for the efficient sequestration of toxic dyes from polluted water

Abstract

This study explores an eco-friendly strategy for the effective removal of toxic dyes Malachite Green, Methylene Blue, and Basic Magenta Dye, from water bodies, utilizing a novel β-Cyclodextrin modified Nelumbo nucifera (β-CDNN) sorbent. The sorbent was characterized using different analytical techniques, to assess its dye sorption capability. The analysis of sorption isotherm data revealed that the Freundlich model most accurately represented the equilibrium data. Kinetic studies indicated that the sorption process followed a pseudo-second-order model. At pH 5–8, the sorbent achieved maximum removal efficiencies of 96.7 %, 94.2 %, and 96.3 % for Malachite Green (402.7 mg/g), Methylene Blue (385.6 mg/g), and Basic Magenta Dye (401.03 mg/g), respectively, at equilibrium time 60 mins for MAG & MEB and 80 mins for MAD. The maximum swelling capacity of β-CDNN was recorded at 180.4 % and selectivity assay was performed via a MAG-AO7 dye mixture. The sorbent reusability was recorded for six consecutive cycles without much loss in efficiency. Additionally, β-CDNN exhibited a removal efficiency of 91.3 % in real dye samples. The findings highlight the rapid dye adsorption capabilities of β-CDNN, establishing it as a versatile, cost-effective, and environmentally friendly solution for water remediation, while also underscoring the beneficial use of bio-waste materials.