Effect of variation in band gap via carbon doping in ZnO NPs on its photocatalytic activity in Pb ion removal from water

In the current scenario, heavy metal contamination in water bodies is a recurrent environmental problem. Among various known heavy metals lead (Pb) is of particular concern due to its persistent and recalcitrant nature in the water bodies causing serious health disorders and is even carcinogenic. This study is based on the photocatalytic way of removing Pb ions from the water sample by using undoped and carbon-doped Zinc oxide nanoparticles (ZnO NPs) synthesized by the sol-gel method. Carbon-doped ZnO NPs show smaller crystallite sizes as compared to undoped ones. Undoped ZnO shows flake-like and carbon-doped ZnO shows pyramid-like structures. Carbon doping reduces the optical band gap of ZnO by 120meV. In the photocatalytic experiment, the removal of Pb ions from wastewater is found to be 99.34% using the ZnO sample and 98.25% using the ZnO: C sample.