Removal of Cr(VI) under flow conditions using a green nano-iron loaded resin

A new nanocomposite material, consisting of nanoiron incorporated in cationic resin beads, was evaluated for the removal of Cr(VI) under flow conditions, by conducting column experiments. An aqueous solution containing Cr(VI) 5 mg/L and NaCl 0.01 M as inert electrolyte was introduced in the column applying a continuous up-flow mode. The tests were carried out using a column with diameter 2.6 cm and the flowrate was stepwise increased, reducing the Empty Bed Contact Time (EBCT) from 38 to 2.3 minutes. The reduction of Cr(VI) was found to depend on the residence time of the solution inside the bed of R-nFe, and the pH of flowing solution. The column has treated an amount of solution equivalent to 640 bed volumes without appearance of the Cr(VI) breakthrough. Also, when the feeding solution was spiked with both Cr(VI) and Ni, the effluents were free from the two elements, indicating that the nanocomposite material can be equally efficient in the case of mixed contamination.