Removal of protein from artificial and natural wastewater was performed using Fe-doped TiO2 film under visible light in an in-house made photoreactor. The Fe(III) dopant improved TiO2 absorption in the visible region. Fe(III) dopant at 2.5%wt. in TiO2 gave the highest yield of protein photodegradation. Further increase in the dopant concentration decreased photoefficiency due to a higher electron-hole recombination rate and a reduced light harvesting capability. The conditions were optimal for protein remediation in an alkaline medium with 10%v/v H2O2. The degradation of protein started with oxidation of amino acids, which were further broken down to carbon skeletons and ammonium ions. The carbon skeletons and ammonium ions were oxidized to carbon dioxide and nitrates, respectively. The results obtained may help understand the phytotoxicity of nanomaterials interacting in the environment, prior to their use in agriculture.
