Extraction, purification and characterization of fulvic acid

The aim of this project was to extract and purify gram quantities of fulvic acid for distribution to the group members. Ideally the material should have come from groundwater in the Sellafield repository area but the total organic carbon content of water samples taken from boreholes in the area was found to be between 0.03 and 0.05 ppm. In order to extract sufficient fulvic for distribution to group members it would, therefore, be necessary to process more than 100 000 litres of groundwater. This was considered impractical and instead fulvic acid was extracted from four thousand litres of water taken from the Derwent Reservoir (Derbyshire, UK) using DEAE-cellulose. Several stages of purification included anion exchange on Amberlite XAD-8 resin and cation exchange on Amberlite AG50W-X8. The final purified fulvic acid concentrate, volume 1300 ml, contained 4.1 g/l TOC (total fulvic acid ∼11 g). It was characterised in terms of elemental analysis, molecular weight, proton-binding properties, UV absorbance. Uranium binding measurements were also made for comparison with previous work. (orig.)