One-step methodology for preparing physically activated biocarbons from agricultural biomass waste

Abstract

Activated biocarbons (ABs) with high specific surface area were prepared by the one-step methodology using three different agricultural biomass wastes: sugarcane bagasse (SB), coconut shell (CS) and endocarp of babassu coconut (EB). These lignocellulosic precursors are generated in large quantities in Brazil (among other countries) and, due to inappropriate disposal, they can cause several damages to the environment. From these precursors, ABs samples were prepared by a single step carbonization/physical activation (with steam) heat treatment and free of chemicals. This methodology was conducted inside a horizontal furnace under a rigorous argon flow, controlled heating program and water injection rate. The results of textural analysis revealed that the ABs products were mostly microporous with some mesopores, with BET specific surface area values of 547, 991 and 1068 m2 g−1 for the products derived from SB, CS and EB, respectively. These values were superior when compared with a number of commercial ABs and to other materials prepared using similar precursors and activation methodology reported in the literature. Among the samples investigated in this work, EB was the precursor that originated the best AB in terms of porosity (BET), pointing out to promising applications of this material as a cheap precursor of highly porous adsorbents.