Invited Speaker
Prof. Marta I. Litter
Institute for Environmental Research and EngineeringIIA CONICET-UNSAM
Argentina
Speech Title: Mechanisms of removal of heavy metals and arsenic from water by TiO2-heterogeneous photocatalysis
Abstract: Presence of heavy metals and metalloids in water represents nowadays one of the most important environmental problems. These species have infinite lifetimes, and chemical or biological treatments present severe restrictions or are economically prohibitive. Chromium, mercury, uranium, arsenic or lead are in the list of priority pollutants of most environmental agencies, with more and more exigent limits of discharge or concentration in drinking water. From the beginning of the development of heterogeneous photocatalysis, transformation and deposition of metals was visualized as one of the potential applications of the process. Three types of mechanisms can be considered for these processes, all of them taking place through successive monoelectronic electron transfer steps: (a) direct reduction by photogenerated electrons; (b) indirect reduction by intermediates generated from electron donors (reducing radicals); (c) oxidative removal by holes or hydroxyl radicals.
This presentation is an overview of recent work performed in our laboratory with the cases of chromium and arsenic treated in profundity.
Keywords: TiO2-photocatalysis; metal ions, chromium, arsenic
Biography: Prof. Dr. Litter is Doctor in Chemistry from the Buenos Aires University, Argentina (1974) with Postdoctoral stage at the University of Arizona, USA (1983). She is Senior Researcher of the Research Council (CONICET) and Full Professor at the University of General San Martín, Argentina. She was Principal Researcher at the National Atomic Commission until her retirement where she was Head of the Environmental Chemistry Remediation Division.
She authored more than 200 scientific publications in international journals, books and chapters of books. She received the Mercosur Prize twice in 2006 and 2011. She was President of the Local
Organizing Committee of the 5th. International Congress on Arsenic in the Environment (As2014), Buenos Aires, Argentina, from 11 to 16 May 2014. She was designated pioneer on photocatalysis in Argentina (2016), Member of World Academy of Sciences (TWAS, 2019) and Member of the Latin American Academy of Sciences (2020). She received recently the 2021 Dr. Eduardo Charreau for the Regional Scientific-Technological Cooperation Prize