Adsorption of hexavalent chromium from aqueous solution by modified corn stalk: A fixed-bed column study

Continuous fixed-bed column studies were carried out by using modified corn stalk (MCS) as an adsorbent for the removal of Cr(VI) from aqueous solution. The effect of various parameters like bed depths (1.4, 2.2 and 2.9 cm), flow rate (5, 10 and 15 mL/min), influent Cr(VI) concentrations (100, 200 and 300 mg/L) and influent solution pH (2.66, 4.91 and 5.66) was investigated. The exhaustion time increased with increase of bed depth, decrease of flow rate and influent concentration. The Adams–Bohart, Thomas and Yoon–Nelson models were applied to the adsorption under varying experimental conditions to predict the breakthrough curves and to evaluate the model parameters of the fixed-bed column that are useful for process design. The Thomas and Yoon–Nelson models were in good agreement with the experimental data. The MCS column study states the value of the excellent adsorption capacity for the removal of Cr(VI) from aqueous solution.

► The modified corn stalk column exhibits an excellent sorption capacity for the removal of Cr(VI).
► The exhaustion time increased with increasing bed depth.
► But it decreased both with increasing flow rate and influent Cr(VI) concentration.
► The Thomas and Yoon–Nelson models were in good agreement with the experimental data.