Rapid reduction of Cr(VI) coupling with efficient removal of total chromium in the coexistence of Zn(0) and silica gel

► The conversion of Cr(VI) to Cr(III) by Zn(0) alone was slow owing to the formation of passivating film. ► A rapid reduction of Cr(VI) coupling with the efficient removal of total chromium in the coexistence of Zn(0) and silica gel was achieved. ► Silica gel, serving as buffer, adsorbent and dispersion, sustained the activity of Zn(0).