Agentes fotosensibilizadores derivados de Ftalocianinas con aplicaciones en la inactivación fotodinámica de microorganismos

El uso indiscriminado de fármacos frente a infecciones microbianas ha generado el advenimiento de la resistencia a múltiples medicamentos en los microorganismos. La inactivación fotodinámica (PDI) ha sido propuesta como una terapia alternativa para la erradicación de microbios. En este sentido, diferentes estudios han mostrado que derivados de ftalocianinas presentan utilización potencial como agentes fototerapéuticos. Así, en este trabajo de tesis, se sintetizaron diferentes derivados de ftalocianinas con el fin de utilizarlos en tratamientos de PDI. Inicialmente, se obtuvieron tres ftalocianinas catiónicas (CF3(NM3)3-ZnPc3+, A(NM3)3-ZnPc3+ y (NM3)4-ZnPc4+) con el objetivo de utilizarlas como fotosensibilizadores. Los estudios espectroscópicos mostraron las bandas de absorción y emisión de fluorescencia características de esta familia de compuestos. La molécula A(NM3)3-ZnPc3+ generó especies reactivas de oxígeno (ROS) con alta eficiencia. Los experimentos de PDI se realizaron en Candida albicans, Staphylococcus aureus y Escherichia coli. Los resultaron indicaron que A(NM3)3-ZnPc3+ fue muy efectiva para la erradicación de microorganismos. Por otra parte, se sintetizaron conjugados de ftalocianinas con polímeros precursores catiónicos, tales como quitosano (Q-ZnPc) y polietilenimina (PA-ZnPc). Estos polímeros pueden adquirir cargas positivas en el medio biológico debido a la disponibilidad de grupos amino libres que presentan. Las características espectroscópicas de absorción, fluorescencia e IR indicaron la funcionalización de los conjugados ftalocianinas-polímeros. Además, presentaron considerables rendimientos cuánticos de generación de oxígeno singlete () tanto en DMF como en medio acuoso. Los estudios de PDI indicaron que PA-ZnPc presentó una mayor eficiencia en la erradicación de C. albicans y S. aureus, comparado con Q-ZnPc. Debido a la baja inactivación de E. coli por parte de estos conjugados, la PDI se potenció con el agregado de quitosano. Por último, se llevó a cabo la síntesis de ftalocianinas con el objetivo de formar películas poliméricas con aplicación en PDI (EDOT-ZnPc y EDOT-CuPc). Mediante la voltametría cíclica de EDOT-Pcs se formaron electropolímeros con características espectroscópicas y fotoquímicas interesantes para su aplicación en PDI. EDOT-ZnPc/película presentó un mayor efecto en la erradicación de S. aureus en suspensiones celulares planctónicas y en biopelículas con el agregado de KI al medio. Estas películas fotoactivas pueden ser aplicadas en la inactivación de microorganismos evitando la acumulación del PS en el medio y permitiendo su reutilización en tratamientos posteriores.The inappropriate use of the drugs against microbial infections has generated the advent of multidrug resistance in microorganisms. The photodynamic inactivation (PDI) has been proposed as alternative therapy to eradicate microbial cells. Different studies have shown that phthalocyanine derivatives have the potential use as phototherapeutic agents. Thus, in this thesis work, different phthalocyanine derivatives were synthetized with the aim of using in PDI treatment. First, three cationic phthalocyanines (CF3(NM3)3-ZnPc3+, A(NM3)3-ZnPc3+ y (NM3)4-ZnPc4+) were obtained with the objective of being used as photosensitizers. The spectroscopic studies showed the absorptions bands and emission of the fluorescence bands characteristics of these compounds. The A(NM3)3-ZnPc3+ molecule generated reactive oxygen species (ROS) with high efficiency. The PDI experiments were accomplished in Candida albicans, Staphylococcus aureus and Escherichia coli. The results indicated that A(NM3)3-ZnPc3+ was more effective for the microbial eradications. Moreover, phthalocyanines conjugated with cationic precursors polymers were synthetized, such as chitosan (Q-ZnPc) and polyethylenimine (PA-ZnPc). These polymers can take positive charges in biological medium due to the availability of the free amine groups. The absorptions, fluorescence and IR spectroscopic bands are characteristic of these compounds indicated to the functionalization of the phthalocyanine-polymer conjugates. In addition, they presented considerable quantum yields of the oxygen singlet generation () in both DMF and aqueous medium. The PDI studies indicated that PA-ZnPc presented a high efficiency in the C. albicans and S. aureus eradication, compared to Q-ZnPc. Due to the low inactivation of the E. coli by the conjugates, the PDI was potentiated with the addition of chitosan. Finally, was carried out the synthesis of the phthalocyanines with the objective of form polymeric films with the PDI applications (EDOT-ZnPc y EDOT-CuPc). By cyclic voltammetries of the EDOT-Pcs were formed electropolymers with spectroscopies and photochemistry characteristics interesting for the PDI applications. EDOT-ZnPc/film presented a high effect in the S. aureus eradication in planktonic cellular suspensions and in biofilms with the KI added to the medium. These photoactive films can be applied in PDI avoiding the accumulation of photosensitizers in the medium and allowing reusing the films in later treatments.Fil: Baigorria, Estefanía. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Bentonite-composite polyvinyl alcohol/alginate hydrogel beads: Preparation, characterization and their use as arsenic removal devices

Arsenic (As) is a major source of water contamination that has both natural and anthropogenic origins, so that, to remove it from water is a relevant topic. Taking into account the ease of operation, the cost of processing and the required instrumentation, adsorption processes could be considered as very convenient alternative technologies for water remediation. The present research work is focused on the development and characterization of eco-friendly polyvinyl alcohol (PVA) and alginate (Alg) hydrogel beads containing natural bentonite (Bent) as potential useful devices for As removal from polluted water. Composite beads with different PVA/Alg proportions (75/25 and 50/50) with and without 30 wt.% Bent were prepared by ionic gelation. The obtained beads were thoroughly characterized by means of thermal analysis (differential scanning calorimetry and thermogravimetric analysis), crosslinking degree by evaluating the gel fraction (GF), the capacity of swelling, morphological aspects (by Scanning Electron Microscopy), functional groups and interactions (by FTIR) and finally, the performance of the beads as arsenic adsorbent was tested by treating batch aqueous solutions. Morphological investigations showed that wet beads were highly porous and spherical. Moreover, the beads with the highest PVA content absorbed higher amounts of water whereas the incorporation of clay to the hydrogels produced a reduction on the swelling degree and an increase of GF. The adsorption behavior of the pearls towards As was studied in terms of PVA/Alg ratio, clay loading and contact time. The results clearly demonstrated that the clay inclusion plays a key role in the As removal since unfilled PVA/Alg beads were not able to remove it. The FTIR spectra of beads after As removal show the partial migration of the components of the beads, which can be associated with the intermediate crosslinking degree and almost amorphous state within the matrix.Fil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Cano, Leonardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Sanchez, Laura Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ollier Primiano, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Amphiphilic tricationic Zn(II)phthalocyanine provides effective photodynamic action to eradicate broad-spectrum microorganisms

A novel tricationic Zn(II)phthalocyanine derivative, (NCH3)3ZnPc3+, was synthesized by ring expansion reaction of boron(III) [2,9(10),16(17)-trinitrosubphthalocyaninato]chloride. First, the reaction of this subphthalocyanine with 2,3-naphthalenedicarbonitrile and Zn(CH3COO)2 catalyzed by 8-diazabicyclo[5.4.0]undec-7-ene was used to obtain the A3B-type nitrophthalocyanine. After reduction of nitro groups with Na2S and exhaustive methylation of amino groups, (NCH3)3ZnPc3+ was formed in good yields. In addition, the tetracationic analog (NCH3)4ZnPc4+ was synthesized to compare their properties. The absorption and fluorescence spectra showed the Q-bands and the red emission, respectively, which are characteristic of the Zn(II)phthalocyanine derivatives in N,N-dimethylformamide. Furthermore, photodynamic activity sensitized by these compounds was studied in the presence of different molecular probes to sense the formation of reactive oxygen species. (NCH3)3ZnPc3+ efficiently produced singlet molecular oxygen and also it sensitized the formation of superoxide anion radical in the presence of NADH, while the photodynamic activity of (NCH3)4ZnPc4+ was very poor, possibly due to the partial formation of aggregates. Furthermore, the decomposition of L-tryptophan induced by (NCH3)3ZnPc3+ was mainly mediated by a type II mechanism. Antimicrobial photodynamic inactivation sensitized by these phthalocyanines was evaluated in Staphylococcus aureus, Escherichia coli, and Candida albicans, as representative microbial cells. In cell suspensions, (NCH3)3ZnPc3+ was rapidly bound to microbial cells, showing bioimages with red fluorescence emission. After 5 min of irradiation with visible light, (NCH3)3ZnPc3+ was able to completely eliminate S. aureus, E. coli and C. albicans, using 1.0, 2.5 and 5.0 μM phthalocyanine, respectively. In contrast, a low photoinactivation activity was found with (NCH3)4ZnPc4+ as a photosensitizer. Therefore, the amphiphilic tricationic phthalocyanine (NCH3)3ZnPc3+ is a promising photosensitizing structure for application as a broad-spectrum antimicrobial phototherapeutic agent.Fil: Baigorria, Estefanía. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durantini, Javier Esteban. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Di Palma, María Albana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Gsponer, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Milanesio, María Elisa. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durantini, Edgardo Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin

Environmental Impacts and Technologies for Remediation of Acid Mine Drainage: Current Situation and Perspectives

Mining and mineral processing produces large volumes of waste rock and mill tailings, which correspond to the main sources of acid mine drainage (AMD) generated through the oxidation of sulfide minerals. This acid effluent is characterized by high concentrations of sulfate, iron, aluminum, and trace elements, such as arsenic and manganese, representing a recalcitrant environmental problem around the world. For example, the AMD might flow into groundwater, streams, and rivers, giving rise to several environmental problems of high concern. Besides the parental rock material, seasonal variations can significantly affect the acid production and behavior along the environmental systems. Therefore, AMD requires a careful environmental and geochemical evaluation so that the most properly technology for the removal of pollutants can be applied. The main remediation systems for the removal of contaminants from AMD can be divided among preventive, passive, and active techniques. Treatment processes have been projected so that treated effluents and solid waste can be properly recycled and reused for industrial applications. Emerging technologies based on nanomaterial and environmental-friendly material are showing improved performance to remove complex analytes from AMD, allowing the recovery of metals as a potential alternative for sustainable mining. In this chapter, the main factors controlling the AMD generation and their environmental impacts are discussed, in addition to the various technologies applied for the remediation and removal of toxic metals from acidic drainages, highlighting the development of greener material for freshwater sustainability.Fil: Galhardi, Juliana A.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Baigorria, Estefanía. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Synthesis, spectroscopic properties and photodynamic activity of Zn(II) phthalocyanine-polymer conjugates as antimicrobial agents

Conjugates of Zn(II) phthalocyanine to chitosan (CS) and polyethylenimine (PEI) were synthetized through the following stages: first a phthalonitrile substituted by a (carbomethoxy)phenoxy group (Pn 1) was obtained by nucleophilic aromatic substitution reaction, then a AB3 Zn(II) phthalocyanines (ZnPc 2) was synthesized by the ring expansion reaction of boron(III) subphthalocyanine (SubPc) chloride with Pn 1. After hydrolysis of ZnPc 2, a Zn(II) phthalocyanine bearing a carboxylic acid group (ZnPc 3) was obtained, which was conjugated to CS (CH-ZnPc 4) and PEI (PEI-ZnPc 5) by amide bond. UV–visible absorption and fluorescence spectra presented the characteristic bands of the Zn(II) phthalocyanine in N,N-dimethylformamide (DMF), with appropriate fluorescence quantum yield. Also, the conjugation of Zn(II) phthalocyanine to polymers was confirmed by IR spectra. These conjugates were able to photosensitize singlet molecular oxygen in DMF and aqueous medium. Moreover, they induced the formation of superoxide anion radical in the presence of NADH. The results showed that type II pathway is involved in the photodecomposition of Trp sensitized by these conjugates, although there is also a contribution from the type I mechanism. Photoinactivation of microorganisms was investigated in Candida albicans, Staphylococcus aureus and Escherichia coli and, varying the concentration of CH-ZnPc 4 and PEI-ZnPc 5 and the irradiation times. Both conjugates were efficient in the eradication of S. aureus by PDI, while that PEI-ZnPc 5 was the most effective for photokilling C. albicans. These conjugates were little active to photoinactivation of E. coli. However, the addition of CS allowed to improve the photocytotoxicity towards this Gram-negative bacterium. These results indicate that PEI-ZnPc 5 is an efficient photosensitizer to inactivate S. aureus and C. albicans. In addition, it is capable of killing E. coli cells in the presence of CS.Fil: Baigorria, Estefanía. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Milanesio, María Elisa. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Eco-Friendly Nanostructured Materials for Arsenic Removal from Aqueous Basins

The contamination of water basins used as drinking water resources is a topic of major concern for public health. Arsenic is one of the major sources of aqueous contamination of broad global-level concern. This metalloid reaches aqueous basins by natural and anthropogenic activities causing countless problems in the environment, so its removal is of great importance. Numerous technologies are used to further reduce or eliminate arsenic from aqueous systems using various materials as active components. Nanostructured materials offer large contact surfaces and unique properties for efficient arsenic removal from contaminated water by different techniques. Many developments have been recently proposed as sustainable and environmentally friendly solutions for this purpose. In addition, there is promising evidence of the use of these nanomaterials for the removal of toxic metals from aqueous sources.The aim of this chapter is to present a holistic view of the most recent eco-friendly nanostructured materials used for arsenic removal from contaminated aqueous systems. Different aspects of each approach are discussed, such as the removal efficiency, the cost-effectiveness, the ease of manipulation, separation and regeneration, and the suitability for field application and the challenges that are involvedFil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ollier Primiano, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Fullerene C60-chitosan conjugate applied in the photoinactivation of Staphylococcus aureus

A novel fullerene/chitosan (C60-CS) conjugate was synthesized. The addition reaction of the amine groups of chitosan (CS) to fullerene (C60) was carried out in N,N-dimethylformamide (DMF), and triethylamine at room temperature. The conjugate C60-CS was purified by dialysis in water. C60-CS showed an absorption spectrum characteristic of modified fullerenes. The ability to produce O2(1Δg) was determined by the decomposition of 9,10-dimethylanthracene (DMA) in DMF, finding a quantum yield value of 0.07. Besides, to obtain information about the contributions of the photoreaction mechanisms, the L-tryptophan photodecomposition was studied in the presence of reactive oxygen species (ROS) scavengers, such as D-mannitol and sodium azide. The results indicated a significant contribution of the type II mechanism to the photooxidation of the amino acid. This effect was confirmed by studies of the kinetics of nitrotetrazolium blue photoreduction in the presence of nicotinamide adenine dinucleotide. This conjugate´s photodynamic inactivation (PDI) capacity was investigated in Staphylococcus aureus. The photodynamic effect induced a 4 log decrease in cell viability when the cells were treated with 10 μM C60-CS and 30 min of irradiation with white light. The photoreaction mechanisms involved in the photosensitized inactivation of S. aureus by C60-CS were studied with the addition of azide ions, deuterated saline water, D-mannitol, and potassium iodide. It was confirmed that the photodynamic action of C60-CS was mainly mediated by type II photoprocess. Photooxidation of DMA induced by C60-CS in S. aureus cells indicated the production of O2(1Δg) in this biological medium. Finally, PDI studies were performed on agar surfaces, treating the cells with C60-CS before deposition on the surface. The subsequent inactivation of S. aureus sensitized by C60-CS after 30 min of irradiation with white light produced a marked elimination of bacteria as a function of increasing concentration. Therefore, this conjugate is a promissory photosensitizing agent to inactivate S. aureus.Fil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Milanesio, María Elisa. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Recent trends in eco-friendly materials for agrochemical pollutants removal: polysaccharide-based nanocomposite materials

In this chapter, recent progress in the investigation of polysaccharide-based nanocom-posite materials for pesticide adsorption from wastewater is critically reviewed. The main properties and characteristics of the nanocomposites, as well as their adsorption performance toward several types of pesticides, are analyzed and discussed in terms of their efficiency and operability in sustainable agricultural practices.Fil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Sanchez, Laura Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ollier Primiano, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Removal efficiency of As(III) from aqueous solutions using natural and Fe(III) modified bentonites

Contamination of water with arsenic is a major global health problem. The use of adsorbent materials for the removal of As from aqueous systems is a plausible solution to this problem. In this work, the use of commercial bentonites (purified and modified with iron (III)) for the removal of As from water was studied. The samples were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier Transformed Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and nitrogen adsorption/desorption isotherms to determine their physicochemical properties. The arsenic removal capacities of adsorbent materials were studied from 1 mg/L solutions of As (III) using the colorimetric technique of molybdenum blue. High adsorption capacity (0.33 mg/g) of As (III) was obtained in aqueous systems after 1 h of treatment with unmodified bentonite. The incorporation of iron improved the removal performance in short times. The obtained results could be the starting point for the development of a low-cost filtration system that contributes to solve the problem of arsenic in water.Fil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Cano, Leonardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Silica nanoparticles embedded with water insoluble phthalocyanines for the photoinactivation of microorganisms

Silica nanoparticles (SiNPs) embedded with Zn(II) 2,9,16,23-tetrakis(methoxy)phthalocyanine (SiNPZnPcOCH3), Zn(II) 2,9,16,23-tetrakis(4-pyridyloxy) phthalocyanine (SiNPZnPcOPy) and Zn(II) 2,9,16,23-tetrakis(t-butyl) phthalocyanine (SiNPZnPctBu) were synthesized in the nonpolar core of AOT/1-butanol/water micelles using triethoxyvinylsilane and 3-aminopropyltriethoxysilane. These SiNPs-Pc presented an average diameter of about 20–25 nm. UV–vis absorption spectra presented the characteristic Soret and Q bands of phthalocyanines embedded into the nanoparticles. Moreover, red fluorescence emission of SiNPs bearing phthalocyanines was detected in water. The SiNPs-Pc produced the photodecomposition of 2,2′-(anthracene-9,10-diyl)bis(methylmalonic acid), which was used to sense the singlet molecular oxygen O2(1Δg) generation in aqueous medium. Also, the formation of superoxide anion radical was detected by nitro blue tetrazolium reduction in the presence of NADH. Photoinactivation of microorganisms was investigated in Staphylococcus aureus and Candida albicans. In vitro experiments showed that photosensitized inactivation induced by SiNPZnPcOCH3 and SiNPZnPctBu improved with an increase of irradiation times. After 30 min irradiation, over 7 log reduction was found for S. aureus. Also, these SiNPs-Pc produced a decrease of 2.5 log in C. albicans after 60 min irradiation. In both cases, a lower photoinactivation activity was found for SiNPZnPcOPy. Studies of photodynamic action mechanism showed that the photokilling of microbial cells was protected in the presence of sodium azide and diazabicyclo[2.2.2]octane. Also, a reduction on the cell photodamage was found with the addition of D-mannitol. Therefore, the photodynamic activity sensitized by SiNPZnPcOCH3 and SiNPZnPctBu in microbial cells was mediated by a contribution of both type I and type II photooxidative mechanisms. Thus, silica nanoparticles are interesting materials to vehicle ZnPcOCH3 and ZnPctBu in aqueous media to photoeradicate microorganisms.Fil: Baigorria, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Reynoso, Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Alvarez, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Milanesio, María Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Durantini, Edgardo Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin