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Papers by sara bilmes

Chemical Physics Letters, Jul 1, 1990

SERS for pyridine adsorbed on a Rh electrode is presented. SERS-active Rh electrodes were electro... more SERS for pyridine adsorbed on a Rh electrode is presented. SERS-active Rh electrodes were electrochemically obtained in 1 M KOH after the growing of a thick layer of rhodium oxide, Raman spectra for adsorbed pyridine are potential dependent. Results are compared with those for pyridine adsorbed on Rh-covered SERS-active silver electrodes.

Journal of electroanalytical chemistry, Jan 10, 1983

The electrooxidation of CO adsorbed on Rh in 1 M HC104 at room temperature exhibits a complex pot... more The electrooxidation of CO adsorbed on Rh in 1 M HC104 at room temperature exhibits a complex potentiodynamic E/I profile which depends on the oxygen-containing species present on the electrode. The electrochemical behaviour of the system is explained through the participation of two CO-adsorbed states and the interaction of the latter with electrosorbed oxygen. The electro-oxidation of CO adsorbed on Rh can be correlated with the reaction occurring on Pt.

Electrochimica Acta, Aug 1, 1989

ABSTRACT Reflectivity spectra of polycrystalline Ag electrodes “activated” for surface enhanced R... more ABSTRACT Reflectivity spectra of polycrystalline Ag electrodes “activated” for surface enhanced Raman scattering (SERS) by oxidation reduction cycles were measured as a function of potential in 0.1 M KCl and 0.1 M KCl + 50 mM pyridine. They exhibit a broad absorption at ca 3.2 eV due to surface plasmon excitation. No charge transfer absorption in the 300–800 nm wavelength range is found for adsorbed pyridine.

Journal of Porous Materials, 2020

Functionalized mesoporous SiO 2 are common supports for some enzymes of industrial interest, such... more Functionalized mesoporous SiO 2 are common supports for some enzymes of industrial interest, such as laccases. However, the incorporation of specific functionalities and the loading of enzymes with dimensions close to the diameters of the pores obstructs the porous system. For biotechnological applications, tailored porous supports are still needed to enhance the laccase loading. The hierarchical meso/macroporous system in wrinkled-SiO 2 spheres (w-SiO 2) is a suitable option to overcome this issue. Herein, (3-aminopropyl) triethoxysilane and glutaraldehyde were use as functionalizing agents for the immobilization of laccase on w-SiO 2. The functionalization occurs in the mesopores of the wrinkled walls and the preservation of the macroporous entries facilitates the diffusion of the laccase inside the particle. The enzyme performance was evaluated by means of the crystal violet bleaching. The enzyme is stabilized through the imine groups provided by glutaraldehyde, allowing the retention of the activity after several reaction cycles. The bleaching can be boosted by acetosyringone, highlighting the possibility of using redox mediators to expand the range of oxidizable substrates. Understanding the effect of w-SiO 2 functionalization on laccases loading and performance could be extrapolated to other enzymes with biotechnological interest that requires this type of hierarchical porous silica.

Microporous and Mesoporous Materials, 2021

Abstract The increment of environmental pollution from heavy metals released by industrial or urb... more Abstract The increment of environmental pollution from heavy metals released by industrial or urban sources drives the development of new smart adsorbents. In particular, copper pollution is a rising concern due to its presence in industrial streams and electronic wastes. Mesoporous silica is a useful adsorbent for copper uptake but it requires the incorporation of specific functionalities to enhance the uptake and selectivity. Branched polyethylenimine (PEI) is a specific copper chelate agent but its bulky structure hinders the loading on mesoporous supports. In this work, the incorporation of PEI on a hierarchical porous silica with wrinkled meso/macroporosity (w-SiO2) resulted in a smart adsorbent with higher copper adsorption capacity. After the uptake, the annealing of the adsorbed PEI-copper complex leads to a w-SiO2/CuO nanocomposite with outstanding antimicrobial properties and catalytic activity due to the enhanced copper bioavailability. The minimum inhibitory concentration of supported copper oxide on silica for E. coli in LB broth medium was 825.5 μg Cu/ml. Oxidation of the electron donor molecule ABTS in the presence of this nanocomposite and H2O2 is a first demonstrator of the potential application as a peroxidase-like nanozyme. The use of adsorbents with hierarchical porosity to support bulky functionalities with high selectivity is a novel strategy for heavy metals upcycling.

Analytical Methods, 2019

Pesticides represent a significant source of contamination for urban and suburban surface, ground... more Pesticides represent a significant source of contamination for urban and suburban surface, ground and seawaters.

Concepts of Semiconductor Photocatalysis, 2019

Supporting a photocatalyst, such as titania nanoparticles (TiO 2 NPs), is a good strategy to impr... more Supporting a photocatalyst, such as titania nanoparticles (TiO 2 NPs), is a good strategy to improve its performance since it can facilitate the photocatalyst recovery from the aqueous media and provides a high surface area for pollutant adsorption. Among the several advanced functional materials used as TiO 2 NP support, the hierarchical meso/macroporous SiO 2 spheres not only show the advantages associated to its chemical nature but also the dendritic fibrous structure provides a porous network that offers many benefits to be exploited in optical and catalytic devices. In this chapter, different synthetic approaches to design hierarchical meso/macroporous silica and the strategies to support TiO 2 NPs regarding the photocatalytic performance of these materials are shown.

Arabian Journal of Chemistry, 2018

Journal of Photochemistry and Photobiology A: Chemistry, 2019

Heterogeneous photo-Fenton process mediated by Sn-substituted goethites with altered OH-surface d... more Heterogeneous photo-Fenton process mediated by Sn-substituted goethites with altered OH-surface density,

Journal of Sol-Gel Science and Technology, 2018

Journal of Electroanalytical Chemistry, 1983

Ciencia Hoy, 2011

La quimica tradicional se ha venido ocupando de las moleculas, que estan formadas por los atomos ... more La quimica tradicional se ha venido ocupando de las moleculas, que estan formadas por los atomos de los elementos de la tabla periodica vinculados entre ellos por fuertes enlaces. En las ultimas decadas, los quimicos se han puesto a considerar sistemas formados por grupos de moleculas vinculados por interacciones mas debiles. Los han llamado supermoleculas y su estudio ha dado lugar a la quimica supramolecular.

The Science of the total environment, Jan 15, 2016

Cadmium contained in soil and water can be taken up by certain crops and aquatic organisms and ac... more Cadmium contained in soil and water can be taken up by certain crops and aquatic organisms and accumulate in the food-chain, thus removal of Cd from mining or industrial effluents - i.e. Ni-Cd batteries, electroplating, pigments, fertilizers - becomes mandatory for human health. In parallel, there is an increased interest in the production of luminescent Q-dots for applications in bioimaging, sensors and electronic devices, even the present synthesis methods are economic and environmentally costly. An alternative green pathway for producing Metal chalcogenides (MC: CdS, CdSe, CdTe) nanocrystals is based on the metabolic activity of living organisms. Intracellular and extracellular biosynthesis of can be achieved within a biomimetic approach feeding living organisms with Cd precursors providing new routes for combining bioremediation with green routes for producing MC nanoparticles. In this mini-review we present the state-of-the-art of biosynthesis of MC nanoparticles with a critica...

Journal of Sol-Gel Science and Technology

Titania nanoparticles and gels are synthesized in reverse micelles with either an ionic (AOT) or ... more Titania nanoparticles and gels are synthesized in reverse micelles with either an ionic (AOT) or a non-ionic (Triton X-100) surfactant in alkanes with low water contents. Acids were in some cases dissolved in the aqueous phase. Whereas the size of the sol nanoparticles is independent of the micellar composition, the kinetics of the sol-gel transition are not. The gelation time is shorter for the non-ionic surfactant and becomes longer as the acid content in the water increases, and for smaller anions of equal charge.

Open Material Sciences, 2015

The encapsulation of living cells within inorganic silica hydrogels is a promising strategy for t... more The encapsulation of living cells within inorganic silica hydrogels is a promising strategy for the design of biosensors, modular bioreactors, and bioremediation devices, among other interesting applications, attracting scientific and technological interest. These hostguest multifunctional materials (HGFM) combine synergistically specific biologic functions of their guest with those of the host matrix enhancing their performance. Although inorganic immobilization hosts present several advantages over their (bio)polymer-based counterparts in terms of chemical and physical stability, the direct contact of cells with silica precursors during synthesis and the constraints imposed by the inorganic host during operating conditions have proved to influence their biological response. Recently, we proposed an alternative two-step procedure including a pre-encapsulation in biocompatible polymers such as alginates in order to confer protection to the biological guest during the inorganic and more cytotoxic synthesis. By means of this procedure, whole cultures of microorganisms remain confined in small liquid volumes generated inside the inorganic host, providing near conventional liquid culture conditions. Moreover, the fact of protecting the biological guest during the synthesis of the host, allows extending the synthesis parameters beyond biocompatible conditions, tuning the microstructure of the matrix. In turn, the microstructure (porosity at the nanoscale, radius of gyration of particles composing the structure, and fractal dimension of particle clusters) is determinant of macroscopic parameters, such as optical quality and transport properties that govern the encapsulation material's performance. Here, we review the most interesting applications of the two-step procedure, making special emphasis on the optimization of optical, transport and mechanical properties of the host as well as in the interaction with the guest during operation conditions.

Short Summary In this work we have been able to synthesize Silica nanoparticles containing PFD de... more Short Summary In this work we have been able to synthesize Silica nanoparticles containing PFD designed as Oxygen carriers to the skin, who could act as effective vectors to introduce the molecule into stable cosmetic formulations.

Environmental Science and Pollution Research, 2015

Anthropic activities generate contaminants, as pesticides and other pollutants, in the aquatic en... more Anthropic activities generate contaminants, as pesticides and other pollutants, in the aquatic environment which present a real threat to ecosystems and human health. Thus, monitoring tools become essential for water managers to detect these chemicals before the occurrence of adverse effects. In this aim, algal cell biosensors, based on photosystem II activity measurement, have been designed for several years in previous studies. In this work, we study a new immobilization technique of algal cells in the aim of improving the performance of these biosensors. Immobilization was here achieved by encapsulation in a hybrid alginate/silica translucid hydrogel. The feasibility of this process was here assessed, and the biosensor designed was tested on the detection of chemicals in urban rainwaters.

Surface and Colloid Science, 2004

... Buenos Aires, Argentina. Sara A. Bilmes INQUIMAE, Facultad de Ciencias Exactas y Naturales,... more ... Buenos Aires, Argentina. Sara A. Bilmes INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabell6n II. 1428 Buenos Aires, Argentina 83 E. Matijević et al. (eds.), Surface ...

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1984

... 40, avenue du Recteur Pineau, 86022 Poitiers (France) SARA BILMES Uninersidad Nacional de La ... more ... 40, avenue du Recteur Pineau, 86022 Poitiers (France) SARA BILMES Uninersidad Nacional de La Plata, Instituto de Inoestigaciones Fisecoquitnicas Teoricas y Applicadas, Sucursal 4, Casilla de Correa 16, 1900 La Plata ... 0.6 0.8 0 0.2 0.4 0.6 0.8 E /V(RHE) E , , /VIR.H_E.1 Fig ...

Journal of the Chemical Society, Faraday Transactions, 1996

Page 1. Roughening of thin silver films in aqueous electrolytes Sara A. Bilmes INQ UIMAE, Faculta... more Page 1. Roughening of thin silver films in aqueous electrolytes Sara A. Bilmes INQ UIMAE, Facultad de Ciencias Exactas, Universidad de Buenos Aires. Ciudad Universitaria Pab II . (1428) Buenos Aires, Argentina The reactivity ...