Photocatalytic Degradation Studies of Actual Wastewater with Dilution by ZnO and MgO Nanoparticles

Abstract

The present research was selected to evaluate the feasibility of treating pharmaceutical wastewater by photocatalytic degradation and using nanoparticles. The trends of degradation were found to be same as that of Photocatalytic degradation of wastewater without dilution. However, higher removal efficiencies were observed with diluted wastewater compared to wastewater without dilution. Even these higher removal efficiencies were recorded at much lower catalyst dosage and irradiation time as compared to removal efficiencies achieved in case of wastewater without dilution. Same trends were observed for other constituents of wastewater studied. Maximum colour removal of 99.2% and 92.0% by ZnO and MgO respectively were recorded at catalyst dosage of 0.6 g/l and irradiation time of 90 min. These values at catalyst dosage of 1.6 g/l and 150 min were found to be 78.0 and 66.7% respectively by ZnO and MgO nanoparticles. Potential of ZnO was found to be higher followed by MgO. The COD removal was maximum at catalyst dosage of 1.6 g/l and irradiation time of 150 min, values being 88.5% (ZnO) and 71.6% (MgO). Accordingly, the minimum removal values recorded at catalyst dosage of 0.6 g/l and irradiation time of 90 min were 45.8%, 42.7% and 29%. Again, higher removal efficiencies of other constituents of wastewater were recorded at catalytic dosage of 1.6 g/l and irradiation time of 150 min. In nut shell it can be said that the removal all constituents of wastewater tried by ZnO is higher compared to MgO. Finally, to treat the actual wastewater with dilution of 1:3 by Photocatalytic degradation adopting catalyst dosage of 0.6 g/l and irradiation time of 90 min employing ZnO preferably. Further, treatment of wastewater to achieve disposal standards specified for constituents of wastewater, as found feasible could be considered. However, author also opine to work out the techno economic feasibility of dilution of wastewater, selection of particular nanoparticles etc, before recommending to treat the wastewater.