Rapid small-scale column tests for Cr(VI) removal by granular magnetite

This study evaluates the possibility of using magnetite as an adsorbent for the removal of Cr(VI) in a bed column setup under continuous flow conditions. For this purpose, granular magnetite was synthesized on a large scale and tested in both batch and rapid small-scale column experiments using reliable conditions of drinking water treatment. Column tests, which were designed to scale-down larger adsorption systems in terms of size, time and water flow, indicate a higher removal capacity compared to that observed during batch experiments with magnetite powder, reaching 9.2 mg/g at pH 6.4 before residual Cr(VI) exceeds 10 μg/L. The main parameters of this process, including pH, contact time and granular size, were also examined under similar column tests suggesting the improvement of the overall effectiveness and operation time at lower water pH, higher empty bed contact times and larger particle dimensions.