Production and characterization of humic acids from Pakistan's lignitic lakhra coal

The results of the study are aimed at evaluating the effect of nitric acid oxidation using different concentrations and oxidation time on humic acids production from Pakistan's lignitic lakhra coal. Humic acids was extracted from the oxidized samples of coal by sodium hydroxide. The yield of humic acids increased at first with increase nitric acid concentration and oxidation time. The yield reaches a maximum point and then starts decreasing. Using FT-IR spectra, the structure of humic acids is discussed in terms of the structure possessed by the lignite.