SOLUBILIZED COAL AS A SUBSTRATE FOR BIODESULFURIZATION

Problem areas in a multi-step coal desulfurization process were investigated. The process involves mild hot air oxidation, followed by alkaline extraction to separate the resultant humic acid molecules from the insoluble pyrite and ash, and microbial removal of organic sulfur from the solubilized coal molecules. A computer-controlled and -monitored solubilization reactor for humic acid production was constructed. Studies designed to evaluate the physical/chemical nature and solubility characteristics of the humic acids were undertaken, with the ultimate aim of ensuring accessibility of sulfur atoms buried in the interior of these large hydrocarbon macromolecules. One per cent Tween-80 enhanced the solubility of humic acids four-fold. Radiotracer labelled humic acids containing 10.8 x 10(-11) Bq mg-1 of I-125 were produced. These labelled humic acids will be used to develop an accurate and dependable assay for microbial organic desulfurization.