Chromium speciation and removal of chromium(iii) by complexation in Nilufer stream, Turkey

Abstract

Nilufer stream (Bursa, Turkey) receives domestic and industrial discharges containing heavy metals as well as organic pollutants. The speciation profiles of discharge waters were built up for chromium(Ill) and chromium(VI) ions in samples those were collected on a monthly basis from two stations in September 1996-August 1998 period. They indicate that chromium(III) contents of samples from station I that was in leather tanneries region were higher than of samples from station 11 that was in automotive and textile industries region. In order to remove Cr(III) ion from discharge waters by complexometry, the removing tendencies of some ligands such as salicylic acid and salicylic acid derivatives were ordered by means of the speciation diagrams of Cr(III):ligand systems, the working pH values and reduced concentrations of Cr(III).