MEMBRANE FILTRATION STUDIES OF AQUATIC HUMIC SUBSTANCES AND THEIR METAL SPECIES - A CONCISE OVERVIEW PART-1 - ANALYTICAL FRACTIONATION BY MEANS OF SEQUENTIAL-STAGE ULTRAFILTRATION

A concise overview (75 references) of the analytical fractionation of aquatic humic substances using sequential-stage ultrafiltration is pre sented. First, humic substances in aquatic environments and actual pro blems connected with their fractionation and analysis are briefly cons idered. The molecular size classification of dissolved humic substance s by means of multistage ultrafiltration, with special emphasis on on- line techniques, is the focal point of the discussion. In particular, the capabilities of ultrafiltration for the size fractionation and cha racterization of species formed between colloidal humic substances and pollutants (e.g. metals) are stressed. (C) 1998 Elsevier Science B.V.