Zeolite-templated microporous carbon as a superior adsorbent for removal of monoaromatic compounds from aqueous solution.

A microporous carbon with very high specific surface area and narrow pore size distribution was synthesized using Y zeolite as a template. The structural, porosity, and surface characteristics of the material were investigated by elemental analysis, N2 adsorption, powder X-ray diffraction, and Raman spectroscopy. The batch adsorption technique was performed to assess adsorption of three monoaromatic compounds, phenol, 1,3-dichlorobenzene, and 1,3-dinitrobenzene, on the synthesized carbon. Nonporous graphite, single-walled carbon nanotubes, and two commercial microporous activated carbons were also included as comparative adsorbents. The synthesized microporous carbon showed extraordinarily high adsorption affinity (comparable or higher than activated carbons and carbon nanotubes) for the three adsorbates, and very fast adsorption/ desorption kinetics (equilibrium reached less than 3 h) and complete adsorption reversibility for phenol. These adsorption properties were attributed to the large hydrophobic surface area and the regular-shaped, open and interconnected three-dimensional pore structure of the synthesized microporous carbon. Additionally, with normalization of adsorbent surface area adsorption of a bulky solute, 1,2,4,5-tetrachlorobenzene, was prominently higher on the synthesized carbon than on the activated carbons, due to alleviated size exclusion effect. Findings of the present work highlight the potential of using zeolite-templated carbons as effective adsorbents for removal of hydrophobic organic contaminants in water treatment.