Application of modified polysulfone membranes to the treatment of water solutions containing humic substances and metal ions

The results of ultrafiltration removal of humic substances and metal ion admixtures from aqueous solutions have been presented. The membranes applied were made of sulfonated polysulfone. Transport and separation properties of the membranes in relation to model solutions have been investigated. In the experiments two types of modified polysulfone membranes (of a different amount of sulfonated groups) were applied. Removal of iron and manganese ions as well as co-removal of these ions in the case of solutions containing both metal ions and humic substances were tested. It was found that ultrafiltration membranes made of sulfonated polysulfone can be useful in a highly effective (up to 98%) removal of humic substances from water. It was noticed that the increase of sulfone group content in polymeric matrix limited the occurrence of membrane fouling, which contributed to the increase of effectiveness of the process. Applied membranes allowed an effective removal of iron ions (up to 95%) from solutions also containing humic substances by retention of their metal-organic complexes or co-precipitating metal hydroxides. Manganese ions, which form complexes with humic substances in a very limited amount, were removed in a limited extent (up to 45%).