Chitosan/MCM-48 nanocomposite as a potential adsorbent for removing phenol from aqueous solution

Abstract

A new hybrid mesoporous nanocomposite (CMCM-48) based on chitosan and silica MCM-48 was considered as a potential adsorbent for removing phenol from aqueous solutions (toxic liquid waste) in a batch process. The new composite adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and nitrogen adsorption-desorption isotherms. The adsorption isotherm studies were analyzed using linear and nonlinear Langmuir, Freundlich and Dubinin-Radushkevich models for the optimum conditions when the initial phenol concentration, pH, adsorption temperature and time were 10-500 mg L^-1, 3-10, 25.5 °C and 300 min, respectively. It was revealed that the experimental results agree well with the Dubinin-Radushkevich model, <i>i.e.</i> the correlation coefficient <i>R</i> ² was 0.983085. The adsorption kinetics was modeled with linear and nonlinear pseudo-first-order, pseudo-second-order and intra particle diffusion kinetic models. The pseudo-second-order model was the best for describing the adsorption process with a correlation coefficient <i>R</i> ² = 0.99925. The stability of the equilibrium data was studied for a phenol sorbent with a maximum adsorption capacity of 149.25 mg g^-1. The results verified that the synthesized CMCM-48 was an efficient adsorbent for removing phenol from aqueous solutions.