Characterization of hydroxyl radical generation for aop’s treatment on graphite pencil and its np-modified surfaces

In this study, an electron paramagnetic resonance/spin trap (EPR/ST) technique was used to investigate hydroxyl radical generation on the surface of NP-modified and unmodified graphite pencil lead. A chemical process was used to modify the graphite flacks on the pencil surfaces with a photoactive titania-nanoparticles (TiOx). The morphology of the graphite surfaces, modified and unmodified, has been investigated by SEM, TEM, XRD spectroscopic techniques. Different types of UV-irradi-ation light sources indicated that UV-B light source of l_max = 310 nm is the best for the remediation of organic pollutants on the surface of the modified graphite pencil. Moreover, the use of H₂O₂/ UV-B/titania-GP combination removes 8 times better the organic contaminants namely, ethylene glycol (EG), than the use of H₂O₂/UV-B/GP system. These results correlate well with the observed oxygen active intermediate trapping experimental results on the modified graphite under the same conditions. It also supports a proposed homolytic fission mechanism of hydrogen peroxide (H₂O₂ ) that affects directly the advanced oxidation processes (AOPs). These optimum conditions resulted in a faster remediation with a minimal ever reported peroxides for the removal of organic pollutants from a model wastewater.