Biosorption and desorption of humic acid by microbial biomass

The adsorption of a humic acid by eight fungal species was studied, of which R. arrhizus was studied in detail. The effects of solution pH, fungal species, biosorbent particle size, and solution ionic strength on the amount of humic acid adsorbed were examined and implications discussed. Experimental results showed that low solution pH and high ionic strength generally favoured biosorption while fungal biosorbents with a high chitin/chitosan content and small particle size had a higher total adsorptive capacity. The regenerability of biosorbents was also studied with the finding that 0.1N NaOH was the most efficient among those under investigation.