Adsorption of azo dyes from water by new poly (3-acrylamidopropyl)-trimethylammonium chloride-co-N,N-dimethylacrylamide superabsorbent hydrogel—Equilibrium and kinetic studies

Abstract

The aim of this work is removal of azo dyes, Acid Red 18 (AR-18), Acid Yellow 36 (AY-36) and Acid Red 73 (AR-73) from water by adsorption method with the help of new poly (3-acrylamidopropyl)-trimethylammonium chloride-co-N,N-dimethylacrylamide, poly (APTAC-co-DMAAm) superabsorbent hydrogel. The superabsorbent hydrogel was synthesized by free radical polymerization of APTAC and DMAAm monomers in presence of N,N′-methylene bis acrylamide as a crosslinking agent. The SAH was characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analyzer (TGA) and scanning electron microscope (SEM). A batch adsorption method was used for removal of acid dyes from water. The parameters affecting on the adsorption of dyes such as initial concentration of dye, pH of the solution, SAH dose and contact time was investigated. The equilibrium adsorption data were interpreted in terms of the Langmuir and Freundlich isotherm models. The experimental data were reasonably described by Freundlich model. The adsorption kinetics was analyzed using pseudo first-order and pseudo second-order models and the adsorption data were well described by pseudo second-order model. The maximum adsorption capacity of SAH D7 for removal of AR-18, AY-36 and AR-73 dyes was 249.87mg/g, 199.96mg/g and 198.16mg/g, respectively, which provide strong evidence of potential of SAH D7 for the application of azo dyes removal from water.