A novel approach in adsorption of heavy metal ions from aqueous solution using synthesized MCM-41 from coal bottom ash

摘要

In this study, mesoporous molecular sieve (MCM-41) was successfully synthesized from coal bottom ash (CBA). Different ratios of sodium hydroxide and CBA, as well as various calcination temperatures in alkali synthesis, were studied carefully to determine the optimum conditions for extracting silica from CBA powder. The synthesized products were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance (NMR), adsorption-desorption N-2, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The results show that the best CBA -synthesized MCM-41 has a specific surface area of 932 m(2)/g, a pore volume of 0.93 cm(3)/g and a pore diameter of 3.14 nm. Finally, the effect of removing heavy metals (Pb2+, Cu2+, and Cd2+) from the aqueous solution of the best CBA -synthesized MCM-41 was also determined at the optimum conditions obtained as 25 degrees C, pH = 5 and reaction time of 12 hours. The MCM-41 required to achieve maximum heavy metal removal was found to be 1.67 g/l with the removal efficiencies of 99.4%, 41.66%, and 43.98% for Pb2+, Cu2+ and Cd2+, respectively. Moreover, the intrinsic parameters of Langmuir and Freundlich adsorption isotherms were obtained by fitting experimental data. The experimental results revealed that the MCM-41 could be used as an executable and inexpensive adsorbent for the removal of heavy metal ions from aqueous solution