Photocatalytic phenol degradation by immobilized nano ZnO: intermediates & key operating parameters.

Phenol is a toxic and refractory water pollutant that cannot be completely degraded through common wastewater treatment methods. In this study, the aqueous oxidation of phenol over ZnO was investigated as a potential method for abatement of this pollutant. Concrete was used as the immobilized surface, and activation energy was provided with 8W UV-A lamps. Scanning Electron Microscope (SEM) test results also confirmed an appropriate cover of ZnO on the concrete surface. The effects of operating parameters such as initial phenol concentration, light intensity, dosage of ZnO particles, and pH were studied. The photocatalytic system afforded the highest degradation efficiency at C0 = 50 mg L(-1), ZnO = 80 gr m(-2), pH = 11, light intensity = 32 W, and more than 90% of the initial phenol was degraded after five hours. The type of secondary products was also determined by GC-Mass test. The results showed that this method is successful in reducing the toxicity.