Adsorption kinetic and isotherm of methylene blue, safranin T and rhodamine B onto electrospun ethylenediamine-grafted-polyacrylonitrile nanofibers membrane

Abstract

EDA-g-PAN NFs membrane was prepared via electrospinning and chemical grafting techniques. Grafting (64%) with no change in the physical nature and colour was confirmed by FT-IR spectra. Adsorption kinetics of methylene blue (MB), rhodamine B (RB) and safranin T (ST) dyes onto PAN and EDA-g-PAN NFs membranes showed equilibrium time of around ~60 min. The adsorption kinetic followed pseudo-second-order model and intraparticle diffusion was not the only rate-limiting step. The adsorption data for the dyes fitted well to Langmuir and Freundlich equations. The order of adsorption capacity (qmax) obtained from Langmuir plot was: MB (94.07 mg/g) < ST (110.62 mg/g) < RB (138.69 mg/g). These values are more than most of the values reported in literature.