Photocatalytic efficiency of molybdenum-doped zinc oxide nanoparticles in treating landfill leachate

Among various techniques available for leachate treatment, nano-photocatalytic-based techniques have been considered as efficient. The photocatalytic leachate treatment using nanoparticles of zinc oxide doped with molybdenum oxide was performed in the presence of sunlight at a laboratory scale. The molybdenum oxide doped ZnO nanoparticles were synthesized. The properties of nanoparticle were analyzed by using FTIR, SEM, and XRD. Then the parameters such as pH (3, 5, 7, 9, & 11), concentration of nanoparticles (0.5, 1, 2 and 3 g/l), concentration of leachate with dilution (1:10, 1:25, 1:50 and 1:100), and contact time (15, 30, 45, 60, 90, & 120 min) were measured to determine the removal of COD and turbidity. The analysis indicated that nanoparticle size was appropriate and acceptable. Electron microscope images also showed that the nanoparticle shape was hexagonal. The optimum value of pH was 5.  It was found that increasing the concentration of nanoparticles enhances the efficiency of the process, the concentration of nanoparticles from 0.5 to 2 g/l at 60 min of contact time, and the efficiency from 34.8 to 55.6%, and increasing in contact time decreases the COD and turbidity leachate. Enhancing the initial concentration of leachate reduces the treatment efficiency of landfill leachate.