Studies on Preparation of adsorbent Precursor From Coal; Using Oxidative Technique

Studies on converting a low rank high ash Lingaraj open cast project coal of Mahanadi Coalfield Limited, India to an adsorbent via its structural modification through partial oxidation have been carried. Oxidation studies on high ash low rank coal from this Mahanadi coalfield was carried out at 150 ± 5ºC for different time durations, namely 24 hr, 50 hr, 216 hr. similar studies using varying nitric acid concentration, namely 1N, 2n, 3n and 4N were also carried out. The oxidized coals thus obtained were characterized in terms of elemental composition, oxygenated functional groups, like COOH and OH, CO2 surface area, etc. it was found that consequent upon oxidation, the surface area decreased in both the cases, that is on air oxidation as well as on nitric acid oxidation. FTIR spectra of 24 hr, 50 hr, 216 hr air oxidized coals were recorded and compared. It was found that there has been a gradual decrease in aliphatic- CH groups with increase in duration of aerial oxidation along with formation of –COOH and > CO groups. The characterization of mineral matter constituents present in coal during heating was considered to be important because these may form a wide variety of newly formed phases. Hence FTIR spectra of mineral matter constituents of raw and oxidized coal sample were also recorded and compared. It was observed that there have been no significant changes in the kaolinite structure during aerial oxidation. A possible hypothesis has been forwarded to correlate the progressive decrease in surface area with the physic-chemical properties of the oxidized coals. The above studies have been carried out keeping in view of preparation of adsorbent precursor