Development of nano-crosslinked polyacrylonitrile ions exchanger particles for dyes removal

Poly(acrylonitrile-co-divinylbenzene) nanoparticles (PAN) based adsorbents developed for the adsorption of methylene blue (MB) from contaminated water. Essential factors affecting the adsorption process such as MB concentration, adsorption time and adsorption temperatures have studied. A linear increment of the adsorption capacity recognized with the increase of the dye concentration up to 7 ppm, then leveling off was noticed. The adsorption capacity of both adsorbents increased linearly with adsorption time, and the equilibrium almost reached after 5 h. A negative impact of the adsorption temperature observed upon the adsorption capacity. Fitting the adsorption results with different kinetic models revealed that the adsorption of MB met with the pseudo-second-order kinetic model having higher R2 values; 0.9971 and 0.9945 for PAN and amidoxime modified polyacrylonitrile. Testing the diffusion mechanism of the MB adsorption process indicates that the film diffusion governs the rate-limiting process. The Freundlich isotherm model was found more favorable for the adsorption of MB. The thermodynamic parameters indicate the exothermic nature of the adsorption process. The best performance recognized at low temperatures.