Photocatalytic removal of polychlorinated biphenyls (PCBs) using carbon-modified titanium oxide nanoparticles

Abstract

In this work, the sonicated sol-gel method was used for synthesizing carbon-modified titanium oxide nanoparticles. Carbon incorporation was achieved by using titanium (IV) isopropoxide as a titanium and carbon-containing precursor. The photocatalytic efficiency of the synthesized photocatalyst was assessed by examining the photocatalytic removal of polychlorinated biphenyls (PCBs) from aqueous solution. For comparison, unmodified (regular) titanium dioxide (n-TiO 2 ) was used as a reference catalyst. To confirm the carbon incorporation in CM-n-TiO 2 nanoparticles, energy dispersive spectroscopy (EDS) analysis was used. Significantly, the bandgap energy was found to be reduced from 2.99 eV for n-TiO 2 to 1.8 eV for CM-n-TiO 2 , which in turn improved the performance of CM-n-TiO 2 toward the photocatalytic removal of PCBs. The effects of CM-n-TiO 2 loading, PCBs concentration, and pH of the solution on the photodegradation rate of PCBs were investigated. The highest removal rate was found to be at pH 5 and CM-n-TiO 2 loading of 0.5 g L -1 . According to Langmuir-Hinshelwood model, the photodegradation of PCBs using CM-n-TiO 2 followed a pseudo-first order reaction kinetics.