Comparison of the efficiency of mesoporous silicas as absorbents for removing naphthalene from contaminated water

  • Ali Balati Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113, Iran
  • Afsaneh Shahbazi Department of Environmental Pollutants Research, Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113, Iran
  • Mostafa M. Amini Department of Chemistry, Shahid Beheshti University, G.C., Tehran 1983963113, Iran
  • Seyed Hossein Hashemi Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113, Iran
  • Khosro Jadidi Department of Chemistry, Shahid Beheshti University, G.C., Tehran 1983963113, Iran

Abstract

Mesoporous silicas MCM-48 and SBA-15 were synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Adsorption capacity of two mesoporous silica for removing naphthalene from waste water was determined. The results indicate that under similar conditions, SBA-15 had a better adsorption capacity than MCM-48. In this context, SBA-15 was modified using 3-aminopropyltrimethoxysilane and the effect of contact time, adsorbent dose, solution pH and concentration of naphthalene was investigated in batch adsorption systems. Solution pH appeared to be a key factor affecting the adsorption of naphthalene by NH2-SBA-15. The adsorption experiments revealed that a higher percentage of up to 79.3% of naphthalene was adsorbed in highly acidic media (pH of 2). The equilibrium data were analyzed using Langmuir and Freundlich isotherms and nonlinear regression analysis. This revealed that based on the correlation coefficient (R2 = 0.979) the Langmuir model provided the best fit to the results. The adsorption kinetic was determined using the pseudo-first order, pseudo-second order and Elovich kinetic models. Of the kinetics models tested, the pseudo-first-order equation provided the best fit to the results (R2 = 0.991) of the absorption of naphthalene by the adsorbent.

Published
2014-06-19
Section
Articles