Sol-gel-cum-hydrothermal synthesis of mesoporous Co-Fe@Al<inf>2</inf>O<inf>3</inf>−MCM-41 for methylene blue remediation

A combined sol-gel-cum-hydrothermal method has been employed to synthesize novel monometallic (Mn, Fe, Co) and bimetallic (Co-Fe, Mn-Co, Fe-Mn) nanoparticles loaded onto Al 2O3−MCM-41. Powder XRD, N 2 sorption, field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) measurements show that the materials possess mesoporosity, high surface area and nanosize. Monometallic Fe, Co and Mn @Al 2O3−MCM-41 and bimetallic Co-Fe, Fe-Mn and Mn-Co @Al 2O3−MCM-41 materials were tested for methylene blue remediation from aqueous media. In the present study, Co-Fe@Al 2O3−MCM-41 was found to be an excellent adsorbent. The adsorption efficiency of Co-Fe@Al 2O3−MCM-41 has been studied as a function of adsorbent dose and pH of the solution. Maximum adsorption of methylene blue was obtained at high pH values of the solution. Framework mesoporosity, high surface area, and narrow pore distribution are the key factors for an efficient adsorption of methylene blue on Co-Fe@Al 2O3−MCM-41. [Figure not available: see fulltext.]