Cu-ZnO/CuO porous heterostructures for adsorption of lead ion

[Display omitted] •The Cu-ZnO/CuO (CuZC) heterostructures had been synthesized by a green approach.•The XRD and TEM analyses confirmed the crystallinity and nanoscale size of CuZC.•The Pb (II) ion adsorption study was conducted using the ICP-OES techniques.•The isotherm and kinetics study confirmed the chemisorption type of CuZC and Pb (II) ion interaction. The pure ZnO and Cu-ZnO/CuO (CuZC) heterostructures had been successfully synthesized using an orange fruit peel extract-based solution combustion synthesis approach. The XRD result revealed the wurtizite phase structure of ZnO NPs with a crystallite size of 12 nm for the CuZC heterostructures. The indirect UV–vis-DRS analysis revealed the band gap energy of ZnO NPs and CuZC heterostructure to be 3.16 and 2.95 eV, respectively. Porous morphology and absence of impurities were confirmed from the FESEM-EDS and TEM/HRTEM analyses. The lead (Pb) ion adsorption potential of NPs was analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES) technique. The removal efficiency for CuZC heterostructure at an initial Pb ion concentration of 20 mg/L is 96.3 %. Based on the adsorption kinetics and isotherm models fitting value, dominance of the chemisorption adsorption process was confirmed. The doped NPs have the potential to be used as an effective and favorable adsorbent material for remediation of heavy metal ions from water solutions.