Facile Provision of CuO-Kaolin nanocomposite for boosted Sonocatalytic removal of Cr(VI) from hydrous media.

Ayagh, Kobra; Farrokhi, Mehrdad; Yang, Jae-Kyu; Shirzad-Siboni, Mehdi

Nowadays, nanoscale materials have been widely applied in the removal of contaminants from water system. Reduction of Cr(VI) (as a poisonous species) to Cr(III) (as a slight toxic species) was performed using CuO-Kaolin with ultrasound (US) irradiation. The CuO-Kaolin nanocomposites were synthesized via a facile coprecipitation method. Then X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and Energy dispersive X-ray spectroscopy analyses were performed to identify the structural features of CuO-Kaolin. The role of influential parameters for the reduction of Cr(VI) was investigated in sonocatalytic advanced oxidation system. 89.35% of Cr(VI) was removed via US/CuO-Kaolin process after 90 min at optimum conditions (pH= 3, sonocatalyst dosage= 1 g L-1 and [Cr (VI)]0= 20 mg L-1). This outstanding result was due to the synergistic effect of the increased electron delivery to conduction band on CuO-Kaolin nanocomposite and the increased reactive surface region of nanoparticles by sonication. The presence of H2O2 as an amplifier improved the removal efficiency of Cr(VI) from 89.35 to 100% after 20 min. Kinetic experimental results were well described by a pseudo first-order kinetic model. Desorption experiments showed an excellent stability of sonocatalyst during the reaction and maintenance of the catalytic activity up to 10 sequential cycles.