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Stefanos Giannakis

Cette personne a quitté l’EPFL

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Publications associées (61)

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Solar disinfection modeling and post-irradiation response of Escherichia coil in wastewater

César Pulgarin, Stefanos Giannakis

In this work, an intensive assessment of solar disinfection of secondary wastewater was elaborated in controlled laboratory conditions. Batch tests of Escherichia coil-spiked synthetic secondary effluent, at nine different constant intensity levels, were f ...

Elsevier2015

Effective removal of the rotifer Brachionus calyciflorus from a Chlorella vulgaris microalgal culture by homogeneous solar photo-Fenton at neutral pH

Christian Ludwig, Stefanos Giannakis, Horst Pick, Adrian Pulgarin

In this study, a citrate-modified photo-Fenton process was successfully applied to decontaminate a Chlorella vulgaris microalgae culture spiked with the rotifer Brachionus calyciflorus (5 individuals mL−1). The applied treatment (1 mg L−1 Fe2+, 20 mg L−1 H ...

2022

Insights into the Photocatalytic Bacterial Inactivation by Flower-Like Bi2WO6 under Solar or Visible Light, Through in Situ Monitoring and Determination of Reactive Oxygen Species (ROS)

César Pulgarin, Juan Kiwi, Sami Rtimi, Stefanos Giannakis

This study addresses the visible light-induced bacterial inactivation kinetics over a Bi2WO6 synthesized catalyst. The systematic investigation was undertaken with Bi2WO6 prepared by the complexation of Bi with acetic acid (carboxylate) leading to a flower ...

2020

Effect of μM Fe addition, mild heat and solar UV on sulfate radical-mediated inactivation of bacteria, viruses, and micropollutant degradation in water

César Pulgarin, Luiz Felippe De Alencastro, Stefanos Giannakis, Dominique Grandjean

In this work, solar disinfection (SODIS) was enhanced by moderate addition of Fe and sodium perox- ydisulfate (PDS), under solar light. A systematic assessment of the activating factors was performed, firstly isolated, then in pairs and concluded in the co ...

2018

Modeling and treatment optimization of pharmaceutically active compounds by the photo-Fenton process: The case of the antidepressant Venlafaxine

César Pulgarin, Sami Rtimi, Stefanos Giannakis, Idriss Hendaoui

In this study, the anti-depressant Venlafaxine, a new emerging contaminant of interest for the Swiss legislation, was subjected to systematic degradation. In order to develop an efficient framework for the treatment of emerging contaminants at industrial s ...

Elsevier Sci Ltd2017

Detrimental vs. beneficial influence of ions during solar (SODIS) and photo-Fenton disinfection of E. coli in water: (Bi)carbonate, chloride, nitrate and nitrite effects

César Pulgarin, Stefanos Giannakis

In this work, we studied the effect of inorganic ions occurring in natural waters on E. coli inactivation by solar and photo-Fenton processes, two crucial methods for drinking water treatment in sunny or developing countries. HCO3-, Cl-, SO42-, NO3-, NO2- ...

2020

Identifying the mediators of intracellular E. coli inactivation under UVA light: The (photo) Fenton process and singlet oxygen

César Pulgarin, Stefanos Giannakis

Solar disinfection (SODIS) was probed for its underlying mechanism. When Escherichia coli was exposed to UVA irradiation, the dominant solar fraction acting in SODIS process, cells exhibited a shoulder before death ensued. This profile resembles cell killi ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Improving visible light photocatalytic inactivation of E. coli by inducing highly efficient radical pathways through peroxymonosulfate activation using 3-D, surface-enhanced, reduced graphene oxide (rGO) aerogels

César Pulgarin, Stefanos Giannakis

In this work, we synthesized highly porous reduced graphene oxide foams, presenting augmented antibacterial activity in presence/absence of peroxymonosulfate (PMS). To date, this is the first investigation of photocatalytic PMS disinfection by 3D-rGO mater ...

ELSEVIER SCIENCE SA2020

Mechanistic modelling of solar disinfection (SODIS) kinetics of Escherichia coli, enhanced with H2O2 - Part 2: Shine on you, crazy peroxide

César Pulgarin, Stefanos Giannakis

In this second part of the development of a mechanistic kinetic model of the solar inactivation of E. coli enhanced with hydrogen peroxide, we evaluate the mechanisms based on photonic inactivation and integrate them into the kinetic model of the dark proc ...

ELSEVIER SCIENCE SA2022

A novel proposition for a citrate-modified photo-Fenton process against bacterial contamination of microalgae cultures

César Pulgarin, Christian Ludwig, Stefanos Giannakis, Adrian Pulgarin

This study reports the first attempt of a citrate-modified photo-Fenton (PF) application at near-neutral pH (7.5–8.5, tap water) to disinfect Escherichia coli (as model bacterium), in Chlorella vulgaris cultures. The conditions are aimed towards bacterial ...

2020

Solar disinfection is an augmentable, in situ-generated photo-Fenton reaction-Part 1: A review of the mechanisms and the fundamental aspects of the process

César Pulgarin, Stefanos Giannakis

The present manuscript is a conceptual review concerning the photo-Fenton reaction at near-neutral pH, used for bacterial inactivation. In this first Part, an overview of the mechanisms involved, as well as the fundamental concepts governing the near-neutr ...

Elsevier Science Bv2016

Effect of reactor material and its reuse on photo-Fenton process efficiency at near-neutral pH: Alterations in E-coli inactivation and resorcinol degradation kinetics in water

Stefanos Giannakis

The effect of reactor material (borosilicate and polyethylene terephthalate-PET) and its reuse on the microbiological and chemical decontamination of water by the photo-Fenton reaction at near-neutral pH was assessed. Escherichia coli was used as an indica ...

Elsevier2017

Light-Assisted Advanced Oxidation Processes for the Elimination of Chemical and Microbiological Pollution of Wastewaters in Developed and Developing Countries

César Pulgarin, Sami Rtimi, Stefanos Giannakis

In this work, the issue of hospital and urban wastewater treatment is studied in two different contexts, in Switzerland and in developing countries (Ivory Coast and Colombia). For this purpose, the treatment of municipal wastewater effluents is studied, si ...

Molecular Diversity Preservation International2017

Elucidating bacterial regrowth: Effect of disinfection conditions in dark storage of solar treated secondary effluent

César Pulgarin, Stefanos Giannakis

In this study, we systematically investigate solar disinfection of synthetic secondary wastewater, with the effort to decrypt the effects disinfection conditions have on post-irradiation bacterial regrowth in the dark. A full factorial design of 240 experi ...

Elsevier2014

Iohexol degradation in wastewater and urine by UV-based Advanced Oxidation Processes (AOPs): Process modeling and by-products identification

Hubert Girault, César Pulgarin, Stefanos Giannakis, Natalia Gasilova, Milica Jovic

In this work, an Iodinated Contrast Medium (ICM), Iohexol, was subjected to treatment by 3 Advanced Oxidation Processes (AOPs) (UV, UV/H2O2, UV/H2O2/Fe2+). Water, wastewater and urine were spiked with Iohexol, in order to investigate the treatment efficien ...

Elsevier2017

Micropollutant degradation, bacterial inactivation and regrowth risk in wastewater effluents: Influence of the secondary (pre)treatment on the efficiency of Advanced Oxidation Processes

César Pulgarin, Luiz Felippe De Alencastro, Stefanos Giannakis, Dominique Grandjean

In this work, disinfection by 5 Advanced Oxidation Processes was preceded by 3 different secondary treatment systems present in the wastewater treatment plant of Vidy, Lausanne (Switzerland). 5 AOPs after two biological treatment methods (conventional acti ...

Elsevier2016

A green solar photo-Fenton process for the elimination of bacteria and micropollutants in municipal wastewater treatment using mineral iron and natural organic acids

César Pulgarin, Luiz Felippe De Alencastro, Sami Rtimi, Michaël Bensimon, Dominique Grandjean, Stefanos Giannakis

In this investigation, a new, green photo-Fenton process for wastewater treatment is proposed, involving the use of a natural iron source and natural additives, deriving from wastes, acting as iron chelators. The use of mineral iron as precursor in the pho ...

Elsevier Science Bv2017

Environmental considerations on solar disinfection of wastewater and the subsequent bacterial (re)growth

César Pulgarin, Stefanos Giannakis

In this work, solar disinfection of wastewater was studied, focusing on the effect of selected environmental variables, namely light intensity, continuous/intermittent light delivery, and post-irradiation storage as well as dilution in lake water. These va ...

Royal Society of Chemistry2015

Iron oxide-mediated semiconductor photocatalysis vs. heterogeneous photo-Fenton treatment of viruses in wastewater. Impact of the oxide particle size

César Pulgarin, Sami Rtimi, Michaël Bensimon, Stefanos Giannakis, Anna Carratala Ripolles, Masoud Talebi Amiri

The photo-Fenton process is recognized as a promising technique towards microorganism disinfection in wastewater, but its efficiency is hampered at near-neutral pH operating values. In this work, we overcome these obstacles by using the heterogeneous photo ...

Elsevier2017

Comparative effect of growth media on the monitoring of E. coli inactivation and regrowth after solar and photo-Fenton treatment

César Pulgarin, Stefanos Giannakis

This study intends to assess the cultivability of photo-treated Escherichia coil K-12 on media With different selectivity (PCA, LBA, T-7, T-7 + TTC, VRBA and MAC) and to establish optimal conditions for bacterial recuperation. For these purposes, immediate ...

Elsevier2017