Manufacture and physical characterization of wood-derived activated carbon from South Texas mesquite for environmental applications

Abstract

Activated carbons are widely used to remove contaminants from waste streams. Desirable properties of activated carbon include large surface area, porosity, high degree of selectivity between contaminant and carrier medium, rapid transport of the contaminant from bulk stream to the internal porous structure of the adsorbent, high adsorption capacity at low contaminant concentration, and available commercially at competitive prices. This research focuses on the production and physical characterization of carbonaceous adsorbents from low cost mesquite woodchips available in the South Texas region. Activated carbons were prepared from mesquite woodchips in a bench-scale tubular reactor. Steam and a potassium carbonate solution were used for the physical and chemical activation methods to manufacture activated carbons. The activated carbons were then characterized in terms of their physical and adsorption capacities for nitrogen at 77 K and methanol and water vapor at ambient temperature. The surface areas of the samples were determined using the N2-Brunauer-Emmett-Teller method. The percent yield, bulk density, pore size distribution, average pore width, and total pore volume were evaluated. Equilibrium adsorption capacities of methanol and water vapor were determined by a gravimetric method. Experimental adsorption capacity data were in agreement with the Freundlich and Langmuir adsorption models.