TiO2-active carbon composites for wastewater photocatalysis

Titanium oxide-active carbon composites (TiO2-AC) with photocatalytic activity were prepared by sol-gel method at low temperature. Titanium isopropoxide and active carbon were used as precursors, ethanol as solvent and HNO3 as catalyst. The composition of the studied composites was accomplished by means of X-ray diffraction, and Fourier Transform-Infrared spectrometry. The rutile crystalline phase was present in all samples. In scanning electron microscopy images the TiO2 aggregates existed either on the surface of the active carbon or heterogeneously dispersed over the whole catalyst matrix. The contact angle and point of zero charge measurements were applied to characterise the surface energy and surface charge. The photocatalytic activities of the TiO2-AC composites were evaluated in the bleaching of methyl orange and methylene blue solution from ternary mixture of methyl orange, methylene blue and Triton X100. The double divisor ratio spectra derivative method (as a multivariable calibration method) was developed to overcome the spectral overlapping, for the simultaneous analysis of ternary mixture.