Determination of hydroxyl radicals in TiO2/Ti photoelectrocatalytic oxidation system using Fe(phen)3(2+) spectrophotometry.

A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic (PEC) oxidation system was established by o-phenanthroline-Fe(II)(Fe(phen)3(2+)) spectrophotometry and using anion exchange membrane. Fe (phen)3(2+) can be oxidized to o-phenanthroline-Fe(III)(Fe(phen)3(3+)) by strong oxidization of hydroxyl radicals(*OH). Then the cumulate concentration of hydroxyl radicals can be calculated through determining the change of the Fe(phen)3(3+) absorbency at 509 nm. In addition, the research results showed the production rate of hydroxyl radicals was affected obviously by pH of solution, the cumulate concentration of hydroxyl radicals was the largest at nearby the initial pH 6.3 (isoelectric point), and the change direction of pH after illumination tended to nearby isoelectric point.