Removal of Cr(VI) ions from wastewater using nanosized ferric oxyhydroxide loaded anion exchanger on a fixedbed column

Abstract

Continuous fixed-bed studies were carried out in columns packed with nanosized ferric oxyhydroxide loaded anion exchanger (FOAE) to determine the breakthrough curves for different bed heights (5, 10, 15, and 20 cm), contact times (1.6, 0.8, and 0.5 min) and initial concentrations (25, 50, and 75 mg/L) of Cr(VI). Higher bed capacity and longer breakthrough time were obtained by increasing the bed height and contact time. The fixed-bed columns reached breakthrough point at 19, 8, and 4 h for contact times 1.6, 0.8, and 0.5 min, respectively. Correspondingly, the adsorption capacity decreased from 39.84 to 35.16 mg/g due to the shorter contact time. Whereas an increase in initial Cr(VI) concentration resulted in a decrease in breakthrough time and an increase in adsorption capacity. Bed depth service time (BDST) model fitted well with the experimental data, which assumed a linear relationship between bed height and service time.