Novel nanogels based on hydroxypropyl cellulose–poly(itaconic acid) for adsorption of methylene blue from aqueous solution: process modeling and optimization using response surface methodology

Abstract

The present work studies the adsorptive removal of methylene blue (MB) dye from aqueous solution using a novel biocompatible adsorbent based on hydroxypropyl cellulose (HPC) and itaconic acid nanogels. The biocompatible adsorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering analyses. Response surface methodology was used to modeling and optimization of the adsorption process. A second-order empirical relationship between adsorption capacity and independent variables (pH of the solution, contact time and dye concentration) was obtained. The results of design of experiments demonstrated that the predicted values were well fitted with the experimental data where coefficient of determination (R2) equaled 0.9861. Pareto analysis for identification of the factors effect on the system revealed that the initial concentration of MB was the most effective parameter. Maximum removal efficiency (99.9%) was achieved at optimum parameters where pH, MB concentration, and contact time were 5.6, 130 mg L−1, and 5 min, respectively. Furthermore, the adsorption experimental data were well fitted to the Temkin isotherm and pseudo-second-order kinetic model. Consequently, it was found out that the HPC–PIA nanogels with high adsorption capacity (nearly 761 mg g−1) can be a suitable adsorbent for removal of cationic dyes from textile colored wastewaters.