removal of cd^2+ from aqueous solution by nickel oxide/cnt nanocomposites

The present work investigates the efficiency of the nickel oxide/carbon nanotube (nio/cnt) nanocomposite for the removal of cd^2+ metal ions from an aqueous. the nio/cnt nanocomposite was synthesized by the direct co-precipitation method in an aqueous media in presence of cnts. the resulting materials were characterized by ftir, xrd, sem, n2 adsorption–desorption analysis. in order to optimize the adsorption of cd^2+ ions on nio/cnt nanocomposite, the effects of the different parameters—namely ph, contact time, initial concentration of cd^2+, and adsorbent dosage—were also studied. experimental data revealed that the cd^2+ ions adsorption of the nio/cnt nanocomposite was through langmuir and temkin isotherm models rather than the freundlich model. the kinetic data of adsorption of cd^2+ ions on the adsorbent was best described by a pseudo-second-order equation, indicating their chemical adsorption. thermodynamic parameters such as δg°, δh°, and δs° were calculated. the obtained values showed that the adsorption was spontaneous and exothermic in nature. the reusability test showed that the cd^2+ could be easily removed from the surface site of nio/cnt nanocomposite by a 0.1 m nitric acid solution as the adsorption capacity was maintained after 5 cycles of the adsorption/desorption process. this suggests that nio/cnt nanocomposite can be reused through many cycles of water treatment and regeneration.