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Juan Kiwi

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Publications associées (117)

Photocatalysis/catalysis by innovative TiN and TiN-Ag surfaces inactivate bacteria under visible light

Juan Kiwi, César Pulgarin, Rosendo Sanjines, Oualid Baghriche, Sami Rtimi

This study presents the design, preparation, testing and characterization of TiN and TiN-Ag nanoparticulate films leading to photocatalytic and catalytic inactivation of Escherichia coli. When Ti was sputtered in N2 atmosphere, the TiN films unexpectedly r ...

Elsevier2012

Advantages of highly ionized pulse plasma magnetron sputtering (HIPIMS) of silver for improved E-coli inactivation

Juan Kiwi, César Pulgarin, Rosendo Sanjines, Oualid Baghriche

This study addresses the DC-magnetron sputtering (DCMS) of Ag-films on polyester and compares the results found for the E. coli inactivation with the inactivation obtained when applying highly ionized pulse plasma power magnetron sputtering (HIPIMS). The a ...

Elsevier2012

High power impulse magnetron sputtering (HIPIMS) and traditional pulsed sputtering (DCMSP) Ag-surfaces leading to E. coli inactivation

Juan Kiwi, César Pulgarin, Rosendo Sanjines, Oualid Baghriche

This study addresses the high power impulse magnetron sputtering (HIPIMS) deposition of Ag-nanoparticle films on polyester and the comparison with films deposited by direct current pulsed magnetron sputtering (DCMSP). The first evidence is presented for th ...

2012

TiO2 nanoparticles suppress Escherichia coli cell division in the absence of UV irradiation in acidic conditions

Juan Kiwi

TiO2 nanoparticles (NPs) activated by UV irradiation are known to have a bactericidal effect. In this study we report the details of TiO2 NPs influence on the colony-forming capacity of E. coli in the dark at pH 4.0-4.5. At this pH the bacterial cells are ...

2012

Ag-surfaces sputtered by DC and pulsed DC-magnetron sputtering effective in bacterial inactivation: Testing and characterization

Juan Kiwi, César Pulgarin, Rosendo Sanjines, Cristina del Socorro Lonfat, Oualid Baghriche

This study addresses the deposition of active, uniform nanoparticulate Ag-thin films on polyester textiles by DC-magnetron sputtering (DC) and pulsed DC-magnetron sputtering (DCP). The deposition of Ag on the polyester fiber was observed to be the function ...

2012

Photocatalytic evaluation of TiO2/nylon systems prepared at different impregnation times

Juan Kiwi, César Pulgarin

TiO2/nylon fabrics were investigated for methanol degradation under UV light irradiation. TiO2 Degussa P-25 was supported on nylon by immersing the nylon in sol-gel TiO2 and silicone. The TiO2 layers on the nylon were explored as a function of the time of ...

Elsevier2011

E. coli Inactivation by High-Power Impulse Magnetron Sputtered (HIPIMS) Cu Surfaces

Juan Kiwi, Andrzej Kulik, César Pulgarin, Oualid Baghriche

This study reports HIPIMS-sputtered samples of Cu-particulate films with currents at 6 and 60 amps leading to E. coil inactivation. The Cu coverage and nanoparticle structure of the fibers is reported by TEM. Evidence is presented of redox processes in the ...

2011

Antimicrobial Cu-functionalized surfaces prepared by bipolar asymmetric DC-pulsed magnetron sputtering (DCP)

Juan Kiwi, César Pulgarin, Rosendo Sanjines, Cristina del Socorro Lonfat

Cu-cotton fabrics were functionalized by bipolar asymmetric DC-pulse magnetron sputtering (DCP). The DCP of Cu-particles on cotton proceeds at a higher energy than DC-magnetron sputtering (DC). The different sputtering mode showed effects on the structure ...

2011

Preparation, testing and performance of a TiO2/polyester photocatalyst for the degradation of gaseous methanol

Juan Kiwi, César Pulgarin

TiO2 modified polyester photocatalysts were prepared by immersion. drying and curing of the polyester in TiO2 containing suspensions under different experimental conditions. The structure of TiO2 layers on the polyester varied according to the time of imme ...

2010

Structure-reactivity relations for DC-magnetron sputtered Cu-layers during E. coli inactivation in the dark and under light

Juan Kiwi, Lioubov Kiwi, César Pulgarin, Rosendo Sanjines

This study addresses unreported features for Cu DC-magnetron sputtering on cotton mediating inactivation of Escherichia coil K12 (from now on E. coil). In-depth profile for the different Cu-species inside the cotton fibers was determined by 5 key Ar+ etchi ...

2010

Magnetron-Sputtered Ag Surfaces. New Evidence for the Nature of the Ag Ions Intervening in Bacterial Inactivation

Juan Kiwi, César Pulgarin, Rosendo Sanjines

DC-magnetron sputtering with an Ag target on textile surfaces produced Ag particles with sizes similar to 4.7 nm (+/- 15%). Sputtering for 15 s led to Ag layers of 15-20 nm. The threshold sputtering time precluding airborne bacterial growth was about 60 s. ...

2010

Synthesis, Characterization, and Photocatalytic Activities of Nanoparticulate N, S-Codoped TiO2 Having Different Surface-to-Volume Ratios

László Forró, Juan Kiwi, Jacques-Edouard Moser, César Pulgarin, Andrzej Sienkiewicz, Julian Andrés Rengifo Herrera, Katarzyna Pierzchala

An efficient, visible light active, N, S-codoped TiO2-based photocatalyst was prepared by reacting thiourea with nanoparticulate anatase TiO2. Commercial anatase powders were manually ground with thiourea and annealed at 400 degrees C in two crucibles with ...

American Chemical Society2010

Nanoparticles of TiO2 cause aggregation of Escherichia coli cells and suppress their division at pH 4.0-4.5 in the absence of UV irradiation

Juan Kiwi

2010

N, S co-doped and N-doped Degussa P-25 powders with visible light response prepared by mechanical mixing of thiourea and urea. Reactivity towards Escherichia coli inactivation and phenol oxidation

Juan Kiwi, César Pulgarin, Julian Andrés Rengifo Herrera

2009

Abatement of organics and Escherichia coli by N, S co-doped TiO2 under UV and visible light. Implications of the formation of singlet oxygen (1O2) under visible light

László Forró, Juan Kiwi, César Pulgarin, Andrzej Sienkiewicz, Julian Andrés Rengifo Herrera

2009

Self-cleaning modified TiO2-cotton pretreated by UVC-light (185 nm) and RF-plasma in vacuum and also under atmospheric pressure

Juan Kiwi, César Pulgarin

Two new innovative findings presented in this study are: (a) TiO2-cotton fabrics obtained by pretreatment with UVC-light (185nm) at atmospheric pressure introduced functionalities into the cotton surface enabling the chelation/binding of TiO2. This was pos ...

2009

Innovative UVC Light (185 nm) and Radio-Frequency-Plasma Pretreatment of Nylon Surfaces at Atmospheric Pressure and Their Implications in Photocatalytic Processes

Juan Kiwi, César Pulgarin

Innovative pretreatment by UVC light (185 nm) and by radio-frequency (RF) plasma at atmospheric pressure to functionalize the Nylon surface, increasing its bondability toward TiO2, is reported in this study In the case of UVC light pretreatment in air, the ...

2009

Optimization of the solution parameters during the degradation of Orange II in a photo-reactor mediated by Fe-Nafion membranes

Juan Kiwi

The Fenton and photo-Fenton mediated degradation process of Orange II was investigated in a flow photo-reactor. The degradation was monitored as a function of the wavelength of the applied light, recirculation flow rate, amount of H2O2 and the initial conc ...

2009

Photocatalytic discoloration of Methyl Orange on innovative parylene–TiO2 flexible thin films under simulated sunlight

Juan Kiwi, Lioubov Kiwi, Albert Renken, Danièle Laub

Parylene films loaded with TiO2 are reported as hotocatalysts in azo dye discoloration processes. The TiO2 loading of the parylene film was 0.32% (w/w) and the amount of TiO2 on the film was about two orders of magnitude below the TiO2 added in suspension ...

2008

Flexible polymer TiO2 modified film photocatalysts active in the photodegradation of azo-dyes in solution

Michaël Bensimon, Juan Kiwi, Lioubov Kiwi, Danièle Laub

2008

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