Membrane-based oxidation processes for the remediation of polluted groundwaters with As(III)
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P1
Keywords: arsenic, groundwater, membrane contactor, oxidation, ozone
Eugenio Bringas a*, Alessandra Criscuoli b, Mª Fresnedo San Román a, Inmaculada Ortiz a, Enrico Drioli b
aDept. Chemical Engineering and Inorganic Chemistry, ETSII y T, University of Cantabria, 39005, Santander, Spain
bInstitute on Membrane Technology, CNR – ITM, c/o University of Calabria, 87036, Rende (CS), Italy
The presence of arsenic in groundwater reservoirs is an environmental problem of big concern; the situation has special relevance in those developing countries with slender hydrological resources. It is generally caused by the filtration of polluted waters that incorporated dissolved natural arsenic initially contained in minerals and sediments. When present in surface waters arsenic is mainly present as As(V) while in groundwaters this pollutant is mainly present as As(III) due to the absence of oxygen.
Reverse osmosis and nanofiltration can be considered promising alternatives to reduce the level of arsenic in groundwaters. Research efforts show that the rejection percentage of As(V) using membrane technologies is greater than the one for the reduced species. Therefore, it is convenient to oxidise As(III) to As(V) to improve the removal process efficiency.
Traditionally, the oxidation of As(III) to As (V) has been performed with different oxidants using stirred tanks, scrubbers or fixed bed reactors. This work analyses the viability of replacing traditional oxidation processes by membrane based–oxidation technologies. In particular, it is focused on the viability of integrating oxidation of As(III) with ozone using hollow fiber contactors as pre–treatment step to the reverse osmosis process used in the removal of arsenic. A mathematical model that describes the process behaviour has been developed to simulate the kinetics of the oxidation of As(III) to As(V). The influence of the operation variables in the oxidation kinetics has been analyzed by means of process simulation.
The work aims at the development of process intensification and integration strategies analysing the replacement of traditional processes by innovative alternatives able to bring substantially decrease of equipment size, energy consumption, or waste generation increasing at the same time the process flexibility and modularity.
Acknowledgements
Financial support from project CTQ2005 – 02583/PPQ (MEC, Spain) and the SOCRATES –ERASMUS program is gratefully acknowledged.
Presented Wednesday 19, 13:30 to 14:40, in session EPIC-1 Poster Session (EPIC - Poster) - P1.
