Preparation and Characterization of Iminated Polyacrylonitrile for the Removal of Methylene Blue from Aqueous Solutions

Abstract

Acrylonitrile (AN) was homopolymerized to polyacrylonitrile (PAN) using potassium persulphate as an initiator. The cyano groups of AN chains were iminated through treating AN with polyethyleneimine (PEI) in an aqueous solution. Iminated polyacrylonitrile (IPAN), characterized by chemical analysis, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) studies, was used as an adsorbent for the removal of Methylene Blue (MB) dye from its aqueous solutions. All factors affecting the adsorption of MB onto the adsorbent IPAN, like agitation duration, temperature, adsorbent dose and the initial concentration of dye solution were extensively studied. Two adsorption isotherm models, namely Langmuir model and Freundlich model were applied to the adsorption data. The adsorption data fitted well to both models. The Langmuir adsorption capacity (Q_o) was found to be 54 mg/g. Freundlish constants, K_F and n, were found to be 1.459 and 1.7, respectively. The results of the desorption study show that 92% of the adsorbed dye could be desorbed when shaking the dye-loaded adsorbent with distilled water for three hours at 40°C.