SORPTION OF CHELATING-AGENTS (HEDP AND NTA) ONTO MINERAL PHASES AND SEDIMENTS IN AQUATIC MODEL SYSTEMS .2. SORPTION ONTO SEDIMENTS AND SEWAGE SLUDGES

For an ecological assessment of the introduction and fate of organic chelating agents in the aquatic environment, the previously (part I of the article [1]) reported studies on the adsorption of 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and nitrilotriacetic acid (NTA) onto clay minerals were completed with the investigation of the adsorption onto sewage sludges and sediments. The earlier stated results: "high adsorption strength of HEDP, low adsorption of NTA", were now confirmed again. The FREUNDLICH-adsorption constants "k" for HEDP were typically found in the range between one and two thousand (adsorption onto sediments), whereas the "k"-values of the NTA adsorption onto sediments did not exceed 35.