Toxicologia Ambiental e Analítica

Nanoadsorbent of Organic Compounds Based on Two- and Three-Dimensional Mesocylinder Monoliths

Abstract

Sherif A. EL-Safty*,M. Khairy ,M. Ismael

The considerable contamination of the aqueous environment by organic pollutants still requires the development of effective adsorbents for removal of these compounds. The current work reports the applicability of hexagonal and cubic aluminosilica monoliths with macro-and meso-cylinder pore structures and aluminium contents with 19 ≤ Si/Al ≥ 1 as effective adsorbents for removal of organic pollutants such as aniline compounds from an aqueous solution. A simple, reproducible, and one-pot synthesis strategy was used to achieve a realistic control over a wide range of mesophase geometries, cylindrical-like pores, and relatively high surface area, yet maintains the long-range structural ordering of aluminosilica monoliths. To better understand the role of the geometry and nanoscale pore orientation of mesostructures, theoretical models have been developed. In addition, the atomic charge distribution in the interior structures was investigated to give insight about the effect of active site surfaces in the enhancement of the adsorption process. The coordination and location of aluminium sites in the frameworks play a key role in the generation of the surface acidity of aluminosilica monoliths, which enhanced the adsorption capacity of the organic pollutants. Our experimental results suggest that the acidity of the adsorbents significantly increased with increasing amounts of aluminium species in the pore framework walls. The natural surfaces of acidic active sites of monoliths strongly induced the removal and adsorption of toxic aromatic amines from wastewater. The relative adsorption affinity of the mesocylinder adsorbent for organic pollutants was decreased in the order of p-nitroaniline < o-aminophenol < p-chloroaniline < aniline. In addition, the thermodynamic studies indicated that these adsorbent monoliths with macroand meso-cylinder pore cavities show promise for the spontaneous removal of organic containments from aqueous water. Finally, we believe our adsorption model will open a new avenue in the development of simple and effective strategy for removal of pollutants and wastewater treatment.