Study of the Adsorption Efficacy of Cr(III) on a Metal Oxide-Based Material Derived from the Quartz Sand Enrichment Process

Abstract

In the present study, the efficacy of chromium removal from water media was studied. For this purpose, a metal oxide based material, derived from the enrichment process of quartz coastal sand was used as possible adsorbent of chromium (III) ions. Following additional modification of the adsorbent, the effect of operational parameters including pH, contact time and Cr(III) concentration were studied according to one-factor-at-a-time procedure. Adsorption efficacy was assessed by the measurement of the remaining chromium concentration in solution, after adsorption. Atomic absorption spectroscopy technique, with flame atomization was used for the determination of chromium concentration in solution. Obtained results revealed that selected material exhibited higher adsorption efficacy in alkaline solution (pH = 6-9). The maximum removal efficacy (>93%) was achieved after 180 minutes of contact time, with an adsorbent dosage of 5 g/L and initial chromium concentration 20 mg/L. The adsorption process for Cr(III) follow the Freundlich isotherm and gives high correlation coefficient R². Calculations performed based on the Langmuir isotherm showed that the maximum adsorption efficiency of Cr³⁺ in the natural metal-oxide material has resulted 10 mg/g or 10000 μg/g. Pseudo second order reaction kinetics has provided a realistic description for removal of Cr(III) from solution with high correlation coefficient R² of (0.999). The adsorption isotherms were better described by the Freundlich equation (R² = 0.934). Adsorption of trivalent chromium ions onto selected material followed the pseudo second order model (R² = 0.996). Hence, the residual materials derived from the enrichment processes of quartz sand can be used as alternative adsorbent for the removal of trivalent chromium ions from aqueous solutions.