A STUDY ON THE CR(VI) REMOVAL FROM AQUEOUS-SOLUTIONS BY STEEL WOOL

The reduction of Cr(VI) by steel wool and the precipitation of reduced chromium by CaCO3 powder and NaOH solution were investigated in conti nuous and batch systems, respectively. The effects of acid and initial Cr(VI) concentrations, volumetric sate and temperature of solution on Cr(VI) reduction were studied. The results showed that the reduction of Cr(VI), to a large extent, depended on, and increased with, acid co ncentration. The Cr(III) and iron ions in the reduced solution were co mpletely precipitated by using NaOH solution at appropriate alkaline c onditions. If was concluded that CaCO3 powder could be used as a cheap precipitant for Cr(III) ions. But the iron ions in the reduced soluti on could not be fully removed by using this precipitant. (C) 1997 Else vier Science Ltd.