Evaluation of the ultraviolet and visible light photocatalytic activity of undoped and nitrogen-doped titanium dioxide nanoparticles (N-TNPs) against low-density polyethylene (LDPE)

CYRA MARIE P. AGNO, PAULINE YSABELLE A. GILONGOS, YANI ANGELINE D. JALANDONI, and RAMON ANGELO N. SINCO

Philippine Science High School – Western Visayas Campus, Brgy. Bito-on, Jaro, Iloilo City 5000, Department of Science and Technology, Philippines

Abstract

Plastics have become a major environmental concern due to its persistence in ecosystems. Plastic degradation processes nowadays are centered on photocatalysis because of its potential as a clean energy source. This study used undoped and nitrogen-doped titanium dioxide nanoparticles (TNPs/N-TNPs) as photocatalysts. TNPs were reported effective in polyethylene degradation due to its high surface-area-to-volume ratio, and nitrogen doping can shift its absorption spectrum to the visible region. To test photocatalytic activity, LDPE films were irradiated in aqueous nanoparticle suspensions under ultraviolet and visible light. FTIR and microscope characterization were conducted before and after irradiation. Photodegradation was then quantified by solving for carbonyl and vinyl indices. N-TNP treated films under visible light showed the most observable difference in the number of spots and scratches and the greatest increase in carbonyl index. This confirms that nitrogen doping extended the photocatalytic activity of TNPs into the visible spectrum for more efficient photodegradation.

Keywords: carbonyl index, irradiation, nitrogen-doping, photocatalysis, vinyl index