A study on the fractionation of organic matter in natural water by ultrafiltration techniques

Diaflo ultrafilters have been studied for the fractionation of organic matter in natural water. One method for their use, including pretreatment, is described. The filter retention is not only depending on the weight of the molecule but also on the charge as shown by experiments with dyestuffs and inorganic ions. For pure solutions of phosphate and nitrate the retentions were 77 and 27% respectively. Filter UM 2, with a nominal molecular weight cutoff at 1,000, retained coloured and total organic matter to 94 and 91% respectively. UM 10 (10,000) retained coloured matter to 88%. Through filtrations the binding of calcium to organic in water was found to be 1 to 10%.