DSpace Repository :: Browsing by Subject "TRATAMIENTO DEL AGUA"

Browsing by Subject "TRATAMIENTO DEL AGUA"

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Abatement of 2,4-D by H2O2 solar photolysis and solar photo-Fenton-like process with minute Fe(III) concentrations
(2018-11) Serra-Clusellas, Anna; De Angelis, Laura; Lin, Chung-Ho; Vo, Phuc; Bayati, Mohamed; Sumner, Lloyd; Lei, Zhentian; Amaral, Nathalia B.; Bertini, Liliana María; Mazza, José; Pizzio, Luis R.; Stripeikis, Jorge; Rengifo-Herrera, Julian A.; Fidalgo de Cortalezzi, María Marta
"The Photo-Fenton-like (PF-like) process with minute Fe(III) concentrations and the Hydrogen Peroxide Photolysis (HPP), using Xe-lamp or solar light as sources of irradiation, were efficiently applied to eliminate the herbicide 2,4-D from water. PF-like experiments concerning ferric and H2O2 concentrations of 0.6 mg L 1 and 20 mg L 1 respectively, using Xenon lamps (Xe-lamps) as a source of irradiation and 2,4-D concentrations of 10 mg L 1 at pH 3.6, exhibited complete 2,4-D egradation and 77% dissolved organic carbon (DOC) removal after 30 min and 6 h of irradiation respectively whereas HPP (in absence of ferric ions) experiments showed a 2,4-D reduction and DOC removal of 90% and 7% respectively after 6 h of irradiation. At pH 7.0, HPP process achieved a 2,4-D abatement of approximately 75% and a DOC removal of 4% after 6 h. PF-like exhibited slightly improved 2,4-D and DOC removals (80% and 12% respectively) after the same irradiation time probably due to the low pH reduction (from 7.0 to 5.6). Several chlorinated-aromatic intermediates were identified by HPLC-MS. These by-products were efficiently removed by PF at pH 3.6, whereas at neutral PF-like and acid or neutral HPP, they were not efficiently degraded. With natural solar light irradiation, 10 and 1 mg L 1 of 2,4-D were abated using minor H2O2 concentrations (3, 6, 10 and 20 mg L 1 ) and iron at 0.6 mg L 1 in Milli-Q water. Similar results to Xe-lamp experiments were obtained, where solar UV-B þ A light H2O2 photolysis (HPSP) and solar photo-Fenton-like (SPF-like) played an important role and even at low H2O2 and ferric concentrations of 3 and 0.6 mg L 1 respectively, 2,4-D was efficiently removed at pH 3.6. Simulated surface water at pH 3.6 containing 1 mg L 1 2,4-D, 20 mg L 1 H2O2 and 0.6 mg L 1 Fe(III) under natural sunlight irradiation efficiently removed the herbicide and its main metabolite 2,4-DCP after 30 min of treatment while at neutral pH, 40% of herbicide degradation was achieved. In the case of very low iron concentrations (0.05 mg L 1) at acid pH, 150 min of solar treatment was required to remove 2,4-D."
Análisis del posible tratamiento de aguas cloacales dulces para el reúso en zonas de Chaco con estrés hídrico: mejora en la eficiencia de resultados económicos y ambientales, a partir del aprovechamiento de la inversión tecnológica efectuada para la potabilización del agua arsenical y salina en Concepción del Bermejo
(2016) Theulé, Cecilia; Pelizzari, Daniel
"En un planeta con sólo el 0.9% del agua dulce disponible, el manejo del recurso está en el foco preferencial de la agenda de UN, conforma el punto 6 de los ODS, y se encuentra integrado a las medidas de mitigación y adaptación al cambio climático. En ese contexto, esta tesis presenta el estudio de prefactibilidad de reutilización de aguas residuales de baja conductividad y no arsenicales para actividades productivas y recreativas en zonas de estrés hídrico. La zona del Chaco elegida (Concepción del Bermejo) combina alto estrés hídrico, con aguas subterráneas arsenicales y salinas."
Carboxymethylated bacterial cellulose: an environmentally friendly adsorbent for lead removal from water
(2018-12) Rossi, Ezequiel; Montoya Rojo, Úrsula; Cerrutti, Patricia; Foresti, María Laura; Errea, María Inés
"Carboxymethylated bacterial cellulose (CMBC) was synthesized under controlled reaction condition to provide a material with a degree of substitution (DS) that guarantees that the characteristic water insolubility of cellulose is retained (DS = 0.17). The CMBC synthesized was fully characterized by conductometric titration, infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and solubility assays. The suitability of the produced CMBC for lead removal from water was evaluated. Experimental isotherm data were fitted to different models of sorption isotherms: Langmuir, Freundlich, Dubinin-Radushkevich, and Frumkin, with Langmuir equation resulting in the best fit. Kinetic data were also adjusted to pseudo-first-order and pseudo-second-order models and results undoubtedly showed that the pseudosecond-order kinetic equation was the one that most appropriately described the lead adsorption of CMBC, indicating that lead is adsorbed on CMBC predominantly by chemical interaction. The breakthrough curve was fitted to different models: Bohart-Adams, Clark and Modified Dose-Response, being the Bohart-Adams equation the one that gave the best fit. Desorption studies were carried out in order to know the technical feasibility of the reuse of CMBC. Almost 96% of the retained lead was eluted in just 20 mL, and the CMBC lifetime was over 50 adsorption/desorption cycles. Overall, results obtained suggest that the CMBC herein synthesized may result in an alternative economic and environmentally friendly lead adsorbent for water treatment."
Chitosan: from organic pollutants to high-value polymeric materials
(2017) Errea, María Inés; Rossi, Ezequiel; Goyanes, Silvia Nair; D'Accorso, Norma Beatriz
"...chitosan has proved to be versatile for so many industrial applications and its versatility is the main value of this polymer. However, the lability at acidic pH of chitosan is a limiting factor that affects mainly its industrial implementation for the removal of metallic anions from water. In addition, the physical and mechanical properties may vary between two manufacturing batches due to the characteristic polydispersity of chitosan with respect to molecular weight and degree of acetylation. This variation could affect the industrial process and in some cases, when strict specifications are requested (e.g., drug delivery), increase the final cost of the product because a purification step prior to use is required. Briefly, despite of the disadvantages mentioned before, due to its great versatility, its nontoxicity, its biodegradability, and the fact that it has a renewable resource, the industrial interest in chitosan and its application has been increasing remarkably in the last years."
Electrocoagulación para el tratamiento de efluentes
(2014) Persino, Federico; Rancan, Claudio
"El objetivo principal del presente proyecto es analizar la tecnología de la electrocoagulación como alternativa para el tratamiento de efluentes líquidos. Se analizará en comparación con otras tecnologías disponibles en el mercado y con las necesidades de los usuarios. El trabajo comienza describiendo el contexto desde un sentido más amplio, para luego sumergirse en el mercado local argentino y sus particularidades. La tecnología de la electrocoagulación desestabiliza los contaminantes, los separa en fases por medio de un proceso electrolítico, para luego ser removidos definitivamente por algún medio mecánico como la decantación y/o el filtrado. Para ello se hace circular corriente eléctrica de baja intensidad por medio de electrodos que se ubican dentro de una cuba electrolítica, donde se estaciona el agua temporalmente para su procesamiento."
Enhanced retention of bacteria by TiO2 nanoparticles in saturated porous media
(2016-08) Gentile, Guillermina José; Fidalgo de Cortalezzi, María Marta
"The simultaneous transport of TiO2 nanoparticles and bacteria Pseudomonas aeruginosa in saturated porous media was investigated. Nanoparticle and bacterium size and surface charge were measured as a function of electrolyte concentration. Sand column breakthrough curves were obtained for single and combined suspensions, at four different ionic strengths. DLVO and classical filtration theories were employed to model the interactions between particles and between particles and sand grains. Attachment of TiO2 to the sand was explained by electrostatic forces and these nanoparticles acted as bonds between the bacteria and the sand, leading to retention. Presence of TiO2 significantly increased the retention of bacteria in the sand bed, but microorganisms were released when nanomaterial influx ceased. The inclusion of nanomaterials in saturated porous media may have implications for the design and operation of sand filters in water treatment."
Glyphosate and AMPA removal from water by solar induced processes using low Fe(III) or Fe(II) concentrations
(2019-11) Serra-Clusellas, Anna; De Angelis, Laura; Beltramo, Mercedes; Bava, Melina Ailén; de Frankenberg, María Josefina; Vigliarolo, Julián; Di Giovanni, Nicolás; Stripeikis, Jorge; Rengifo-Herrera, Julián A.; Fidalgo de Cortalezzi, María Marta
"A solar photo-Fenton-like (SPF-like) process is explored for the removal of 1 mg L−1 glyphosate and its main degradation by-product, aminomethylphosphonic acid (AMPA), from Milli-Q water by means of low Fe(III) concentrations (0.6–2 mg L−1) at pH = 2.8 and variable H2O2 concentrations at the laboratory scale. The research is focused on glyphosate and AMPA oxidation, which present similar toxicity patterns. A 1 mg L−1 glyphosate solution requires 5–6 h of the SPF-like process to be degraded when a minute Fe(III) concentration (0.6 mg L−1) is used in acidic water. Glyphosate abatement time is diminished to 2 h when the Fe(III) concentration is increased to 2 mg L−1. At pH levels above 2.8, the herbicide is partially adsorbed onto the colloids of iron oxyĲhydroxide) compounds. AMPA requires a higher oxidative power than glyphosate to be degraded, and more than 6 h of solar treatment are needed, using 10 mg L−1 h−1 H2O2 and 2 mg L−1 Fe(III) at acidic pH. Solar photo-Fenton (SPF), using 4 mg L−1 Fe(II) and 10 mg L−1 h−1 H2O2 at pH = 2.8, must be applied to achieve practically total AMPA removal in 6 h of irradiation. SPF-like and SPF treatments led to 70% and 80% mineralization, respectively, under the best operational conditions. This work demonstrates that SPF-like and SPF at low Fe(III) or Fe(II) concentrations are effective treatments for the removal of glyphosate from water at acidic pH. Continuous addition of H2O2 is required for AMPA abatement."
Polímeros modificados químicamente como agentes de captura de metales en agua
(2020-04-21) Rossi, Ezequiel; Errea, María Inés; Fidalgo de Cortalezzi, María Marta
"En el marco del interés por el tratamiento de aguas contaminadas, el objetivo general de este Trabajo de Tesis fue obtener materiales para la remoción de metales pesados de sistemas acuosas, mediante la modificación química de polímeros. Específicamente, se presentan los productos obtenidos al modificar celulosa, quitosano y poli (cloruro de vinilbencilo) (PCVB), la caracterización de los nuevos materiales y los estudios de captura de metales a los que fueron sometidos."
Trielectrode plasma reactor for water treatment
(2020-04) Giuliani, Leandro; De Angelis, Laura; Díaz Bukvic, Gema; Zanini, Matías; Minotti, Fernando; Errea, María Inés; Grondona, Diana
"The water pollution due to emerging organic pollutants, such as agrochemicals, has become a topic of growing interest worldwide. The increase of pollutants in aquatic systems stimulated the development of new strategies for water remediation. Plasma technology is an advanced oxidation process which has proved to be an efficient method for organic matter degradation. In this work, a novel design of a trielectrode plasma reactor based on a a dielectric barrier discharge extended to a third electrode operated in ambient air is presented. The water to be treated flows through a gutter with low impedance and far from the electrodes connected to the voltage sources.The reactor operates in ambient air; it does not rely on the use of expensive inert gases. The design of the reactor is easily scalable. The performance of the reactor, in terms of the removal efficiency and the energy yield, was tested in an aqueous solution of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), one of the most widely used around the world. The reactor presents a good efficiency in the removal of the herbicide 2,4-D and values of energy yield of about 240 mg/kWh."
Virus removal by iron oxide ceramic membranes
(2014-09) Fidalgo de Cortalezzi, María Marta; Gallardo, María V.; Yrazu, Fernando M.; Gentile, Guillermina José; Opezzo, Oscar; Pizarro, Ramón A.; Poma, Hugo R.; Rajal, Verónica Beatriz
"Nanoporous iron oxide ceramics were studied for the removal of virus contamination from water. Supported and unsupported iron oxide nanostructured hematite was fabricated by a green chemistry route from ferroxane nanoparticles. The material had a surface area of approximately 30 m2/g and a mean pore size of 65 nm. Bacteriophage P22 was chosen as a model for human virus. The kinetics and equilibrium of the attachment process was investigated. P22 adsorption isotherms on iron oxide were described by the Freundlich equation. Batch experiments resulted in 1.5 LRVs. Removal proceeded rapidly for the first 7 h; next, a diffusion-limited stage occurred. Dynamic attachment experiments demanded extensive recirculation to achieve significant reduction levels. Up to 3 LRV were observed. The enhanced performance can be explained by the higher iron oxide area available and the facilitated access to inner porosity sites that were previously unavailable due to slow diffusion. The role of electrostatic interactions in the attachment mechanisms was confirmed by the dependence of the isotherm on the ionic strength of the suspension medium. P22 bacteriophage is expected to attach to the iron oxide by electrostatic forces up to a pH of 6.5. DLVO theory predicts moderately well the interaction energies between P22 particles themselves and between the phage and the ceramic. However, a slight underestimation of the P22–P22 repulsive forces was evident by comparison to the experimental data."

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