Las Enfermedades Emergentes Desatendidas. Situación Nacional e Internacional

Las Enfermedades Desatendidas (ED) son un grupo de enfermedades infecciosas y parasitarias que secaracterizan por una inversión históricamente baja del sector farmacéutico y que afectan principalmente a laspoblaciones que viven en condiciones socioeconómicas de pobreza, con bajos ingresos y nivel educativo,vivienda precaria, carencia de acceso a servicios básicos como agua potable y saneamiento básico, en zonasde conflicto o en condiciones ambientales deterioradas, con escaso acceso a los servicios de salud. LaOrganización Mundial de la Salud (OMS) ha clasificado a 17 enfermedades infecciosas dentro de este grupo,donde cuatro de ellas, son consideradas, además, como Enfermedades Emergentes y Re-emergentes. Estasson: cisticercosis, rabia, enfermedad de Chagas y dengue. La OMS recomienda cinco estrategias de SaludPública para prevenir y controlar este grupo de enfermedades. Estos son: quimioterapia preventiva, manejointensificado de los casos, control de vectores, provisión de agua segura y estrategias de Salud Pública. Chileha logrado controlar algunas de estas enfermedades, a través de la implementación de algunas o varias deestas estrategias. Es así como, en el caso de la enfermedad de Chagas nuestro país ha logrado la interrupciónde la transmisión vectorial, a nivel domiciliario en el año 1999 y en el caso de la rabia, el último casoregistrado en humanos data del año 1996.  

ELECTROCHEMICAL MICROREACTORS FOR THE ABATEMENT OF ORGANIC POLLUTANTS IN WATER SOLUTION

Electrochemical methods can offer new sustainable routes for the abatement of organic pollutants resistant to biological processes. These methods use a clean reagent, the electron, and very mild operative conditions (ambient temperature and atmospheric pressure) with limited operative costs. However, electrochemical processes present some important disadvantages when performed in conventional reactors. In particular, to achieve reasonable cell voltages when the medium has not an adequate conductivity, one needs adding to the system a supporting electrolyte. This is certainly a main obstacle for a wide application of electrochemical tools. Indeed, adding chemicals is often a problematic issue, since this may lead to the formation of secondary products, makes more difficult the separation procedures and increases the operative costs. Recently it has been shown that the electrochemical processes can strongly benefit from the utilization of microfluidic electrochemical reactors (i.e. cells with a distance between the cathode and the anode of tens or hundreds of micrometers) allowing to minimize or even remove some of the above mentioned disadvantages. Thus, very small distances between electrodes lead from one side to a drastic reduction of the ohmic resistances, (allowing to operate with lower cell voltages and without supporting electrolyte), and on the other side to intensify the mass transport of the reagents towards electrodes surfaces. The utilization of micro devices may present the drawback of a more easy fouling but also other potential advantages such as an easier scale-up procedure through simple parallelization of many small units. In this work, the possible utilization of various electrochemical oxidation methods for the treatment of aqueous solutions of Acid Orange 7 (AO7) chosen as a model compound (namely, direct electrochemical oxidation, indirect oxidation with active chlorine and electro-Fenton) used alone or in a combined way was studied for the sake of comparison of various electrochemical approaches. The abatement of AO7 was performed successfully in the micro reactors under a single-pass mode without supporting electrolyte at low cell voltages. A very high conversion for passage can be achieved, allowing to operate the process under a continuous mode and to achieve a fast screening of the effect of operative parameters due to very short times of treatment. The utilization of three micro reactors in series open interesting new perspectives, including the opportunity to modulate the current density among the reactors, in order to optimize the figures of merit of the process. The effect of various operating parameters such as the initial concentration of the AO7, the electrode surface, the flow rate and the current density was also investigated in detail

Transesterification of rapeseed oil over acid resins promoted by supercritical carbon dioxide

The methanolysis of rapeseed oil catalyzed by commercial styrene-divinylbenzene macroporous acid resins was performed in a batch reactor at 100-140 \ub0C and 10-46 MPa to study the effect of supercritical carbon dioxide (scCO2) on the performances of the process. Reaction temperatures of 120-140 \ub0C were necessary to obtain high enough yields of fatty acid methyl esters. Upon addition of scCO2 faster transesterification kinetics was obtained also at the lowest investigated operating pressure (10-11 MPa), working in two fluid phase systems. Experiments performed changing the reaction time indicated that most of the esters were formed during the first 3 h. When the pressure was increased at 38-46 MPa, the fluid phases merged in a single one without significant modification of the performances of the process. The enhancement effect of scCO2 on the transesterification kinetics is tentatively discussed in terms of modification of the phase behaviour of the reaction system and swelling of the polymeric acid resin. \ua9 2010 Elsevier B.V. All rights reserved

Electrochemical remediation of phenol contaminated kaolin under low-strength electric fields

Soil degradation is a global concern. Electrochemical remediation (ER) technology is considered an appealing strategy for soil remediation because it is a low-cost, adaptable, and effective noninvasive in situ technology. Currently, the remediation of soil characterized by fine grains, low-hydraulic permeability, heterogeneous conditions, and mixtures of contaminants is still challenging since other conventional technologies are poorly effective. ER of soil is based on the application of low potentials between a couple of electrodes which induces an electric field (E) in the contaminated field. In this work, very low values of electric field (E ≤ 0.25 V cm−1) were used for the ER of contaminated kaolin. Phenol was selected as model hazardous organic compound and kaolin as model, reproducible and low buffering and low permeability clay. The effect of several factors, including the nature of the electrodes, treatment time, kind of current, the strength of the E and the nature of supporting electrolyte, on the performance of the process was investigated in detail and discussed in terms of the normalized phenol concentration and its total removal from the kaolin. Overall, the main finding is that the use of very low value of E (0.15 V cm−1) can allow to simultaneously desorb, mobilize and also in-situ degrade phenol. The highest removals of phenol up to approximately 80% and 90% from the kaolin under both direct and sinusoidal E, respectively, were reached using compact graphite as electrodes in presence of Na2SO4 into the kaolin

Investigation of electrode material - redox couple systems for reverse electrodialysis processes. Part II: experiments in a stack with 10-50 cell pairs

Abstract The performances of reverse electrodialysis depend on several factors, including the nature of the electrode material and of the redox processes adopted to make possible the conversion between chemical potential and electric power. In this paper the possible utilization of various redox processes (reduction/oxidation of iron species, oxidation and reduction of water, oxidation of chlorine and reduction of water) was studied in a stack equipped with 10-50 cell pairs and by focused electrolyses in a three compartment cell. The effect of selected redox processes on power density output and eventual contamination of saline solutions flowing in the stack was evaluated in detail. The effect of the number of cell pairs and of the concentration of saline solutions was also investigated

Electrochemical incineration of oxalic acid in the presence of NaCl

Recent researches have demonstrated that electrochemical methods offer an attractive alternative to traditional routes for treating wastewaters containing toxic or/and refractory organic pollutants. The effectiveness of the electrochemical treatment depends on many factors including the presence in solution of specie able to act as mediators. In particular, the effect of chloride ions on the performances of the process has been the object of numerous researches. However, up to now, many practical and theoretical aspects about this argument are not completely clear. In the present work, the anodic incineration of oxalic acid (OA) in the presence of NaCl has been investigated with the aim of studying in a systematic way the influence of numerous parameters, such as the current density, the flow rate, the OA, the NaCl concentrations and the pH on the performances of the process and to individuate the optimal operative conditions. Oxalic acid was chosen as model substrate for its low reactivity toward anodic oxidation, which also results in an incomplete mineralization of more complex organics. Furthermore, the oxidation of this simple molecule does not involve the formation of stable intermediates thus giving rise to a more easy rationalizing of experimental results. Since the effect of NaCl on the process is expected to depend on the nature of the electrodic material, two very different anodes were used: the Ti/IrO2-Ta2O5 which presents a quite low oxygen overpotential and boron doped diamond (BDD) which is probably one of the more promising materials for the electrochemical incineration

Electrochemical remediation of kaolin-soil contaminated by phenol: effect of several operative parameters

Electrochemical remediation technology is considered an appealing strategy for the remediation of fine- grained soils, characterized by a low hydraulic conductivity and large specific surface area, contaminated with inorganic, organic, and mixed pollutants. In both Electrokinetic (EK) and Electrochemical Geo-Oxidation (ECGO) technologies, an electric field is imposed on the contaminated soil to remove the pollutants by the combined mechanisms of electroosmosis, electromigration, and/or electrophoresis. Moreover, ECGO uses low voltage and both direct and alternating amperage (DC/AC) applied in a proprietary series to induce reduction-oxidation reactions on soil surfaces at the micro-scale. According to the literature, in this method, each soil particle acts as a micro-capacitor that charges and discharges in a cyclic fashion. The energy burst on discharge at the micro-scale is intense, theoretically allowing the conversion of most organic contaminants to carbon dioxide and water near the conducting particle surface [2-4]. However, the effectiveness of the technology strongly depends on the physical-chemical states of the soils and the contaminants, pH, sorption of contaminants on soil particle surfaces and different effects induced by the hydrogen ions and hydroxide ions generated at the electrodes. In this work, the effect of several factors, including the intensity and mode of the applied electric field, duration of treatment, nature of supporting electrolytes, on the electrochemical remediation of kaolin-soil contaminated by phenol (200 mgPhenol/kgsoil) was investigated. It was found that a proper selection of the operative parameters is the key- factor to improve the electrochemical remediation of the contaminated soil. High removal of phenol from the kaolin up to 88% was achieved after 93 hours of treatment using graphite electrodes and a gradient electric field of 0.15 V cm-1. [1] A. T. Yeung et al. J. Hazard. Mater. 2011, 195, 11 [2] D. Rahner et al. Electrochim. Acta 2002, 47, 1395 [3] J. Röhrs et al. Electrochim. Acta 2002, 47, 1405 [4] L.M. Zanko et al. Electrochim. Acta 2020, 354, 13669

HYDROTHERMAL LIQUEFACTION OF MICROALGAE IN THE PRESENCE OF HOMOGENEOUS AND HETEROGENEOUS CATALYSTS

The continuous raise in the prices of fossil fuels and the awareness of the society challenges related to their use has recently driven a strong growth of interest on the investigation of different biochemical or thermochemical processes for the production of liquid biofuels