Adsorptive removal of Cr(VI) from aqueous solution using blackberry leaves - column study

Abstract

The present study represents the blackberry leaves as the bio-sorbent for the removal of Cr(VI) ion from aqueous solution in continuous process. The effect of process parameters like, pH (1-8), influent metal ion concentration (10, 20 and 30 mg.L−1), flow rate (10, 30 and 40 ml.min−1), bed depth (4, 6 and 10 cm) were investigated to determine the breakthrough time. The result demonstrates that breakthrough time increases with the increase of bed depth and influent metal ion concentration but decreases with the increase of flow rate as at the lower flow rate the adsorbent gets less time to saturate. The empirical or semi-empirical models like Thomas, Bohart-Admas, Yoon-Nelson, Wolborska models were used to analyse the experimental data. FTIR studies were carried out to find out the functional groups, like Surface O-H, Aliphatic C-H, Aldehyde C-H, Carboxylate anion C=O, -SO3, Sulphonic acid S=O are responsible for the adsorption of the Cr(VI) ions onto the blackberry leaves. Desorption studies indicate that elution by dilute HNO3 through the fixed bed of the adsorbent columns could be regenerated and reuse for several times.