Abstract

• Hexavalent chromium, Cr (VI), contamination of wastewater is a great threat to living organisms and environment. Hence, the innovative advancement in the removal of Cr(VI) from wastewater is urgently on demand. The current research studied the influence of morphological and structural properties of CoS nanoadsorbents on the adsorption efficiency of Cr(VI) removal. The prepared CoS nanoadsorbents were synthesized with one-pot solvothermal/hydrothermal route without using toxic and harmful chemical reagents. The morphological and structural properties of prepared CoS nanoadsorbents were investigated by using various analytical techniques including Scanning Electron Microscopy (SEM), X- ray Diffraction (XRD) and FT-IR spectroscopy. The inorganic-organic hybrid CoS/En-nanoflowers gave the highest Cr(VI) removal efficiency from aqueous liquid compared to that of its counterparts such as CoS-nanorods and CoS-nanoflowers within 40 min. The Cr(VI) adsorption capacity of CoS/En-nanoflowers was found to be 87.7 mg/g and the adsorption process followed the pseudo-second-order kinetic model. Based on the theory of hard and soft acid-base (HSAB) and zeta potential results, the mechanism of Cr(VI) removal was suggested as electrostatic attraction between CoS/En surface and Cr(VI).