Production of activated carbon derived from waste hemp (Cannabis sativa) fibers and its performance in pesticide adsorption

Abstract

The main objective of this work was to find optimal production parameters for the preparation of activated hemp fibers (ACh) with good adsorption properties toward pesticides. In order to examine the role of manufacturing parameters on ACh surface characteristics, activation process of carbonized hemp fibers was investigated by temperature programmed reaction and evolved gaseous products of activation were monitored by mass spectrometry. ACh samples were characterized by BET surface area, scanning electron microscopy and temperature-programmed desorption. KOH activation induces the reduction of oxygen groups existing on the carbonized hemp fiber surface and the formation of the more stable, predominantly anhydride groups, while porosity development correlates with both H-2 and CO, evolved during the activation, and increases with carbonization and activation temperature. Finally, the highest efficiency in pesticides removal was achieved by carbonization of waste hemp fibers and activation at 900 degrees C with KOH/carbonized material ratio of 2/1. High efficiency in pesticides removal indicates that activated hemp fibers could be successfully used as a sorbent in water purification. (C) 2015 Elsevier Inc. All rights reserved.