Significant effect of ph on photocatalytic degradation of organic pollutants using semiconductor catalysts

Photocatalytic is one of the inexpensive and non-toxic techniques for degradation of organic pollutants into harmless substances such as water and carbon dioxide. in this study,simple electrolysis method was used in preparation of ag/tio2 and α-fe2o3/hy catalysts. the physicochemical properties of the catalysts were studied using xrd,ftir,fesem-edx and surface area analysis. the ph of solution plays an important role in the photocatalytic degradation of organic pollutants which influences the surface-charge properties of the catalysts. ag/tio2 and α-fe2o3/hy were used as catalyst on degradation of 2-chlorophenol (2-cp) and methyl orange (mo),respectively. the effect of ph on degradation of 2-cp and mo were investigated over a ph range from 2 to 9. higher degradation of 2-cp and mo were obtained at ph 5 (74%) and ph 2 (80%),respectively. this finding might be explained by the amphoteric performance of the catalyst using point zero charge (phzpc). the phzpc for ag/tio2 and α-fe2o3/hy was found to be at ph 6.3 and ph 7.2,respectively. hence,the activities of the catalysts may have been affected by the existence of a strong electrostatic field between the positively charged catalysts surface and negatively charged 2-cp and mo caused a ph value lower than their phzpc give greater degradation. © 2016 penerbit utm press. all rights reserved.