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Stefanos Giannakis

Cette personne a quitté l’EPFL

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Publications associées (61)

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Phototransformation of Acesulfame K in surface waters: Comparison of two techniques for the measurement of the second-order rate constants of indirect photodegradation, and modelling of photoreaction kinetics

Stefanos Giannakis

By use of photochemical modelling we show that acesulfame K (ACE) can undergo photodegradation in surface waters, mainly by reaction with (OH)-O-center dot and possibly (CDOM)-C-3* (the triplet states of chromophoric dissolved organic matter). With the pos ...

Elsevier2017

Impact of different light intermittence regimes on bacteria during simulated solar treatment of secondary effluent: Implications of the inserted dark periods

César Pulgarin, Stefanos Giannakis

In this study, the effect of light intermittence on solar disinfection of secondary treated wastewater was investigated. Synthetic secondary effluent was spiked with Escherichia coli and submitted to 3 different light intermittence regimes by circulating t ...

Pergamon-Elsevier Science Ltd2013

Photo-Fenton inactivation of MS2 bacteriophage at alkaline pH by Fe salts or nm to μm-sized oxides, and the Janus-faced effects of natural organic matter in surface waters

César Pulgarin, Stefanos Giannakis

In this study, MS2 bacteriophage was inactivated by homogeneous and heterogeneous photo-Fenton processes in an alkaline matrix (pH 8) using low concentrations of H2O2 and iron forms (1 mg/L), including Fe(II), Fe(III), and Fe (hydr)oxides. As a reference, ...

Elsevier2024

Effect of advanced oxidation processes on the micropollutants and the effluent organic matter contained in municipal wastewater previously treated by three different secondary methods

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

In this study, wastewater from the output of three different secondary treatment facilities (Activated Sludge, Moving Bed Bioreactor and Coagulation-Flocculation) present in the municipal wastewater treatment plant of Vidy, Lausanne (Switzerland), was furt ...

Elsevier2015

Bacterial inactivation in sunlit surface waters is dominated by reactive species that emanate from the synergy between light, iron, and natural organic matter

César Pulgarin, Stefanos Giannakis, Jun Ma

In this study, the synergistic and antagonistic effects of Fe species and coexisting natural organic matter (NOM) on the efficacy of solar light disinfection of water are investigated. Different initial iron species (Fe2+/Fe3+) and naturalorganic matter ty ...

Elsevier2023

Effect of Fe(II)/Fe(III) species, pH, irradiance and bacterial presence on viral inactivation in wastewater by the photo-Fenton process: Kinetic modeling and mechanistic interpretation

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

Advanced Oxidation Processes and in particular photo-Fenton, represent promising strategies of pathogen inactivation in wastewater effluents. Nevertheless, its full potential is not yet unlocked, as the efficacy of photo-Fenton against viruses has not been ...

Elsevier2017

Employing bacterial mutations for the elucidation of photo-Fenton disinfection: Focus on the intracellular and extracellular inactivation mechanisms induced by UVA and H2O2

César Pulgarin, Stefanos Giannakis

The bacterial inactivation mechanisms by solar light and the photo-Fenton process is still a matter of debate. In this study, we bring evidence towards the elucidation of the mechanisms that govern photo-Fenton disinfection at near-neutral pH. With the use ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Acids from fruits generate photoactive Fe-complexes, enhancing solar disinfection of water (SODIS): A systematic study of the novel " fruto-Fenton " process, effective over a wide pH range (4-9)

César Pulgarin, Stefanos Giannakis, Aline Laetitia Schaub

This study aimed to enhance solar disinfection (SODIS) by the photo-Fenton process, operated at natural pH, through the re-utilization of fruit wastes. For this purpose, pure organic acids present in fruits and alimentary wastes were tested and compared wi ...

Pergamon-Elsevier Science Ltd2024

Superior visible light-mediated catalytic activity of a novel N-doped, Fe3O4-incorporating MgO nanosheet in presence of PMS: Imidacloprid degradation and implications on simultaneous bacterial inactivation

Stefanos Giannakis

Impressive Imidacloprid (IMD) degradation and bacterial inactivation were attained through the photocatalytic activation of peroxymonosulfate (PMS) via a novel, N-doped MgO@Fe3O4, under visible light. After complete characterization (XPS, XRD, FT-IR, FE-SE ...

ELSEVIER2022

Sunshine and a pinch of tropical soils: A natural, low-cost photo-Fenton variation for safer water, assisted by H2O2 or percabonate

César Pulgarin, Michaël Bensimon, Stefanos Giannakis, Thomas Guillaume

Clean water is essential for human survival, but access to safe drinking water remains a challenge in resource -limited regions. Herein, we explored a low-cost but effective solution for water potabilization using natural iron sources from soils along with ...

ELSEVIER2023

Monitoring the post-irradiation E. coli survival patterns in environmental water matrices: Implications in handling solar disinfected wastewater

César Pulgarin, Stefanos Giannakis

In this study, simulated solar disinfection of secondary effluent was followed by dark storage at different temperatures or different receiving water matrices. Escherichia coli illumination was followed by 3-day monitoring of the bacterial population and i ...

Elsevier2014

FeOx magnetization enhancing E-coli inactivation by orders of magnitude on Ag-TiO2 nanotubes under sunlight

César Pulgarin, Juan Kiwi, Arnaud Magrez, Sami Rtimi, Ivica Zivkovic, Stefanos Giannakis

Drastic bacterial enhancement was observed when the Ag(3%)-TiO2 nanotubes were modified with FeOx (3%) magnetic oxide. On bare TiO2- nanotubes a reduction of 0.21og(10)CFU was observed within one hour under simulated low intensity solar light. Under simila ...

Elsevier2017

Natural iron ligands promote a metal-based oxidation mechanism for the Fenton reaction in water environments

César Pulgarin, Stefanos Giannakis

The Fenton reaction is an effective advanced oxidation process occurring in nature and applied in engineering processes toward the degradation of harmful substances, including contaminants of emerging concern. The traditional Fenton application can be rema ...

ELSEVIER2020

Supported PtxPd1-x bimetallic nanoparticles on ionic liquid-functionalized SiO2@graphene oxide nanocomposite and its application as an effective multiphasic catalyst

Stefanos Giannakis

In this work, PtxPd1-x (x = 0, 0.5, and 1) nanoparticles (NPs) were synthesized on the surface of SiO2@graphene oxide which covered by 1-butyl-3-methylimidazolium hexafluorophosphate ([bmitn] PF6) ionic liquid (IL) layer. FT-IR spectroscopy, zeta potential ...

ELSEVIER SCIENCE BV2019

Unfolding the action mode of light and homogeneous vs. heterogeneous photo-Fenton in bacteria disinfection and concurrent elimination of micropollutants in urban wastewater, mediated by iron oxides in Raceway Pond Reactors

César Pulgarin, Florian Frédéric Vincent Breider, Dominique Grandjean, Stefanos Giannakis

In this work, iron oxides have been proposed as low-cost heterogeneous photo-Fenton catalysts for the simultaneous disinfection and reduction of microcontaminant load from urban wastewater in raceway pond reactors at near-neutral pH. The objective was not ...

2020

Visible light plays a significant role during bacterial inactivation by the photo-fenton process, even at sub-critical light intensities

César Pulgarin, Stefanos Giannakis, Cristina del Socorro Lonfat

The aim of this research is to clarify the contribution of sunlight wavelengths, irradiance and Fe2+/H2O2 during bacterial disinfection by the photo-Fenton process in clear surface waters. We considered different solar spectrum distributions (visible, UVA- ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Solar photo-Fenton disinfection of 11 antibiotic-resistant bacteria (ARB) and elimination of representative AR genes. Evidence that antibiotic resistance does not imply resistance to oxidative treatment

César Pulgarin, Stefanos Giannakis

The emergence of antibiotic resistance represents a major threat to human health. In this work we investigated the elimination of antibiotic resistant bacteria (ARB) by solar light and solar photo-Fenton processes. As such, we have designed an experimental ...

PERGAMON-ELSEVIER SCIENCE LTD2018

Kinetic modeling of lag times during photo-induced inactivation of E. coli in sunlit surface waters: Unraveling the pathways of exogenous action

César Pulgarin, Stefanos Giannakis

This work presents a kinetic analysis of the exogenous photo-induced disinfection of E. coli in natural waters. Herein, the inactivation of bacteria by light and photo-generated transient species, i.e., hydroxyl radical (HO center dot), excited triplet sta ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Homogeneous vs. heterogeneous photo-Fenton elimination of antibiotic-resistant bacteria bearing intracellular or extracellular resistance: Do resistance mechanisms interfere with disinfection pathways?

César Pulgarin, Stefanos Giannakis

The present study aimed to fill the knowledge gap between the implications of intracellular and extracellular antibiotic resistance mechanisms may inflict on the inactivation pathways of the photo-Fenton process under mild conditions. It was thus designed ...

Elsevier Sci Ltd2024

Solar-assisted bacterial disinfection and removal of contaminants of emerging concern by Fe2+-activated HSO5- vs. S2O82- in drinking water

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

2019