A novel process for preparation of active carbon from sapropelitic coals

Abstract

The aim of this work is the preparation of active carbons starting from sapropelitic coals. Firstly, a traditional route of manufacturing, coking and activation (820°C) was carried out. The specific area (BET) of the activated semicokes of six sapropelitic coal samples varied from a few square meters to about five hundred (for Taimylir coal). Secondly, using Taimylir coal, a novel way of active carbon preparation was attempted combining low temperature modification and chemical activation. The modification was carried out using nitric acid-acetic anhydride mixture at room temperature and tested by swelling and weight uptake measurements. The modified coal samples were analyzed by Thermogravimetry (TGA) and FT-IR spectroscopy. The chemical activation route included impregnation by an activant (KOH) and a subsequent heating (2 hr under argon) at selected temperatures ranging from 300 to 900°C. Surface areas were determined by BET and SAXS methods. The chemical modification resulted in new functional group formation and organic framework reorganization, which strongly affected the activation, as a value of 1200 m 2 g −1 was obtained after chemical activation.