In situ photoelectrochemical measurement of phthalic acid on titania

An in situ photoelectrochemical method is proposed to determine adsorbed phthalic acid (PA) on the TiO2 surface in a sensitive, reproducible and accurate manner. The pre-adsorbed PA in the dark and the diffused PA from organic solution can be mineralized simultaneously under UV illumination due to the strong UV-induced oxidation power of TiO2. By controlling the UV illumination, the amount of adsorbed PA on TiO2 surface was determined in the presence of PA in a small time scale (e.g., seconds), eliminating the washing step after the adsorption reaction. This provides a convenient and effective alternative to study adsorption behaviour in low concentrations on TiO2. The proposed method was applied to determine the adsorption equilibrium constant of PA.