Synthesis, characterization, and application of nickel oxide/CNT nanocomposites to remove Pb^2+ from aqueous solution

In this study, the efficiency of nickel oxide/carbon nanotube (nio/cnt) nanocomposite to remove pb^2+ from aqueous solution is investigated. nio/cnt nanocomposite was prepared using the direct coprecipitation method in an aqueous media in the presence of cnts. samples were characterized using simultaneous thermal analysis (sta), x-ray diffraction (xrd), filed emission scanning electron microscopy (fesem), and brunauer– emmett–teller (bet). to optimize the adsorption of pb^2+ ions on nio/cnt nanocomposite, the effects of different parameters including ph, contact time, initial concentration of pb^2+, and adsorbent mass—were also investigated. the optimum pb^2+ removal efficiency on nio/cnt nanocomposite is achieved under experimental conditions of ph 7, contact time of 10 min, initial pb^2+ concentration of 20 ppm, and adsorbent mass of 0.1 g. the experimental data showed that the pb^2+ ions adsorption of nio/cnt nanocomposite was through a freundlich isotherm model rather than a langmuir model. the kinetic data of adsorption of pb^2+ ions on the adsorbent was perfectly shown by a pseudo-second-order equation, to indicate their chemical adsorption. thermodynamic parameters such as δg°, δh°, and δs° were also measured; the obtained values showed that the adsorption was basically spontaneous and endothermic.