Biotechnological Interventions in India Coal Benefication by Microbial Coal Desulfurization and Flotation of Ash Materials

Abstract

Coal is a naturally occurring fossilized carbon mineral. It has been used as a source of newlineenergy for many centuries. India stands at the 2nd position for the production of coal in newlinethe world after China. It is a sedimentary rock comprised of numerous mineral matters newlinesuch as pyrite, silica, alumina, kaolinite, quartz etc. Coal has a huge application newlinethroughout the world starting from domestic heating to cement production, paper newlineproduction, electricity generation, alkali battery production. But the quality of coal is newlinecompromised due to the presence of sulfur as the major contaminant. Since sulfur gas newlineemissions from coal burning activities are directly associated with the natural newlineenvironment, they cause numerous environmental hazards like acid rain, metal corrosion, newlinehuman health issues like lungs disfunction, breathing problems etc. Moreover, the ash newlineforming materials have been associated with various negative impacts such as heavy newlinemetal contamination, shortening of plant height, reduction of soil quality and water newlinequality. Therefore, coal desulfurization and the reduction of ash forming materials are newlineurgent need for the clean environment. Biotechnological approach for coal newlinedesulfurization and removal of ash forming material gaining momentum over the newlineconventional physiochemical processes. newlineIn the first phase, the present work deals with the use of iron/sulfur-oxidizing bacterium newlineAcidithiobacillus ferrooxidans for the desulfurization of a coal sample from Assam, newlineIndia. The coal sample contains 3.87% w/w of organic sulfur, 1.4% w/w pyritic sulfur, newlineand 1.29% w/w of sulfate sulfur which altogether are contributing to its total sulfur newlinecontent of 6.56% w/w. The microbial process followed the oxidative-desulfurization newlinemechanism for the removal of sulfur from the coal sample. The bacterium performed newlinecleavage of the sulfide bonds in pyrite to release the inorganic sulfur. Mass spectroscopic newlineanalysis revealed that the bacterial strain A. ferrooxidans performed oxidative newlinedesulfurization of a model sulfur-containing organic compou