CuO nanorods: a potential and efficient adsorbent in water purification

The present work deals with a simple in situ soft chemical synthesis of nanoscale copper(II) oxide, together with its characterization and a study of the adsorption and desorption behaviors of Pb(II) on nanoscale CuO. The nanoparticles are characterized by XRD, FESEM, TEM and BET surface area analyses. Electron microscopy clearly reveals a rod-like morphology of rhombohedral CuO, with an average diameter of similar to 5 nm and a length extending up to 50 nm. BET shows the average surface area of the nanorods to be similar to 52.57 m(2) g(-1). In an adsorption study, the influence of operational conditions, such as the contact time, the initial concentration of Pb(II), the initial pH of the solution and the temperature, on the adsorption of Pb(II) has also been examined. Studies also reveal that the uptake of Pb(II) onto CuO is a fast process; >70% of the uptake occurred within the first 10 min of contact time and uptake reached >92% within 60 min. The maximum sorption capacity of Pb(II) is 3.31 mg g(-1) at 298 K. The +ve Delta S degrees value and the +ve Delta H degrees value of 37.77 kJ mol(-1) indicate the endothermic nature of the adsorption process, whereas a decrease of Gibbs free energy (Delta G degrees) with increasing temperature indicates the spontaneous nature of the adsorption process. The adsorbent can be up to 84.1% regenerated using dilute acid and shows potential for the removal of lead from contaminated water.