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oxidation processes » operational processes (Expander búsqueda), production processes (Expander búsqueda)
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1
artículo
Publicado 2010
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Advanced Oxidation Processes (AOX) are based on the in situ generation of hydroxyradicals (·OH), which have a high oxidation potential. In the case of Fenton processes !he generation of hydroxy radicals takes place by the combination of an oxidation agent (H202) with a catalyst (Fe(II)). These radicals are not selective and they react very fast with the organic matter,being able to oxidize a high variety of organic compounds. This property allows the degradation of pollutants into more biodegradable compounds, and,in some cases, their complete mineralization into C02 and mineral acids. Under optimal conditions, (pH=3, (Fe 2+] = 200 mg/L, [H2O2] = 3612 mg/L) the Fenton processes are able to reduce !he concentration of the organic matter present in the textile effiuent, up lo 97%.
2
artículo
Publicado 2010
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Advanced Oxidation Processes (AOX) are based on the in situ generation of hydroxyradicals (·OH), which have a high oxidation potential. In the case of Fenton processes !he generation of hydroxy radicals takes place by the combination of an oxidation agent (H202) with a catalyst (Fe(II)). These radicals are not selective and they react very fast with the organic matter,being able to oxidize a high variety of organic compounds. This property allows the degradation of pollutants into more biodegradable compounds, and,in some cases, their complete mineralization into C02 and mineral acids. Under optimal conditions, (pH=3, (Fe 2+] = 200 mg/L, [H2O2] = 3612 mg/L) the Fenton processes are able to reduce !he concentration of the organic matter present in the textile effiuent, up lo 97%.
3
artículo
Publicado 2017
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Phenol can be degraded to almost 100 % within a few minutes via Fenton and photo-Fenton processes. Its degradation and the ratio of initial molar concentrations of oxidant and catalyst increase in inverse senses, and a ratio of 38.4 was optimal for aqueous solutions contaminated with 20 ppm of phenol. In addition to this, the use of ultraviolet-A light enhanced degradation when compared to shorter wavelengths.
4
artículo
Publicado 1998
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Thermodynamic simulation models have been developed to observe the behavior of the minor elements Zn, Pb, As, Sb and Bi; as well as the major elements Cu, Fe, Si, 0 and S in the conversion and fusion processes: NORANDA and ISASMELT for the production of copper-rich mattes. The Noranda process shows a steady state model for obtaining a high-grade matte in metallic copper. The lsasmelt process is based on the concept of the two independent reaction sites in the bath (slag-killing interface): rapid oxidation and slow reduction. The heat balance of the process and the distribution thermodynamics of the minor elements are united and expressed in terms of the process variables such as temperature, enriched 02, composition of the charge, degree of matte and content of the magnetite in the Slag and other variables are incorporated into the modeling, which can predict the operating effects of che...
5
artículo
Publicado 1998
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Thermodynamic simulation models have been developed to observe the behavior of the minor elements Zn, Pb, As, Sb and Bi; as well as the major elements Cu, Fe, Si, 0 and S in the conversion and fusion processes: NORANDA and ISASMELT for the production of copper-rich mattes. The Noranda process shows a steady state model for obtaining a high-grade matte in metallic copper. The lsasmelt process is based on the concept of the two independent reaction sites in the bath (slag-killing interface): rapid oxidation and slow reduction. The heat balance of the process and the distribution thermodynamics of the minor elements are united and expressed in terms of the process variables such as temperature, enriched 02, composition of the charge, degree of matte and content of the magnetite in the Slag and other variables are incorporated into the modeling, which can predict the operating effects of che...
6
artículo
Publicado 2002
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The work of leaching is developed in Fewer, Concentrated and Refractory Material (sulfured), in pulp or particles (agitation or piles) to ambient temperature in advance of maximum leaching of twelve hours, using like half lixiviante the acid sulfuric concentrate added salts oxidizers like the chlorides and nitrate of sodium or ammonium nitrate in different proportions. The results obtained regarding the recovery of gold reach 98%. If the gold is encapsulated in the quartz or auriferous sand, fluoride of sodium will be added (never to use the calcium, because it forms plaster that hinders the process) with the purpose of dissolving the quartz, it doesn’t dissolve neither complex form with the gold, it is also good to leave in you liberate noble metals as the titanium, platinum, talio, germanium, etc., those which then are recovered with the means lixiviante to which I have denominated S...
7
artículo
Publicado 2002
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The work of leaching is developed in Fewer, Concentrated and Refractory Material (sulfured), in pulp or particles (agitation or piles) to ambient temperature in advance of maximum leaching of twelve hours, using like half lixiviante the acid sulfuric concentrate added salts oxidizers like the chlorides and nitrate of sodium or ammonium nitrate in different proportions. The results obtained regarding the recovery of gold reach 98%. If the gold is encapsulated in the quartz or auriferous sand, fluoride of sodium will be added (never to use the calcium, because it forms plaster that hinders the process) with the purpose of dissolving the quartz, it doesn’t dissolve neither complex form with the gold, it is also good to leave in you liberate noble metals as the titanium, platinum, talio, germanium, etc., those which then are recovered with the means lixiviante to which I have denominated S...
8
artículo
Publicado 2021
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The intensive use of agrochemicals for food production in developing countries has generated a problem of environmental concern since many of these substances, which are usually difficult to biodegrade, can reach natural sources, generating their contamination. That is why the search for new technologies for the elimination of these pollutants has arisen with great interest. Advanced oxidation processes (AOP), whose main characteristic is the generation of highly oxidizing species such as the hydroxyl radical, can achieve the chemical modification of the pollutant, generating by-products that can be less harmful to the environment. In this work, the degradation of methomyl, a highly used insecticide in the Arequipa region, Peru, was evaluated using different PAOs such as ozonation in alkaline medium, UV-C/H2O2 and photo-Fenton processes at acid pH in natural surface waters. The effect of...
9
artículo
Publicado 2014
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In Peru only treat 29.1% of urban domestic wastewater is performed. This treatment is carried out at 143 industries, pouring the rest into rivers, lakes and the sea, so it is necessary to give more importance to the management of water resources. The textile industry, which uses large amounts of dye pigments not properly treat their effluents, being part of the problem. The Fenton process is an alternative for the treatment of effluents from the dyeing process, the most important pollutant azo compounds. The Fenton process provides the ability to reuse and / or recycle water with high efficiency (86%) in a few minutes.
10
artículo
Publicado 2017
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A study of the kinetics of discoloration of a 20 ppm solution of Sunfix Yellow S4GL (RAS) reactive dye has been carried out using the H2O2/UV advanced oxidation process (AOP). To optimize the process, the effects on the discoloration of the initial concentration of hydrogen peroxide, the initial pH of the solution, the dye concentration and the intensity of the UV‐ C radiation were evaluated. The optimum values were the following: initial concentration of H2O2 a 3.8 x 10‐2 mol/L, pH3; initial dye concentration: 20 mg/L; UV radiation: 3 bulbs with 15 W of UV‐C power each. The discoloration reaction followed a pseudo first order kinetic model. Under optimum conditions, a one hour treatment yielded 100% discoloration.
11
artículo
Publicado 2017
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A study of the kinetics of discoloration of a 20 ppm solution of Sunfix Yellow S4GL (RAS) reactive dye has been carried out using the H2O2/UV advanced oxidation process (AOP). To optimize the process, the effects on the discoloration of the initial concentration of hydrogen peroxide, the initial pH of the solution, the dye concentration and the intensity of the UV‐ C radiation were evaluated. The optimum values were the following: initial concentration of H2O2 a 3.8 x 10‐2 mol/L, pH3; initial dye concentration: 20 mg/L; UV radiation: 3 bulbs with 15 W of UV‐C power each. The discoloration reaction followed a pseudo first order kinetic model. Under optimum conditions, a one hour treatment yielded 100% discoloration.
12
artículo
Publicado 2015
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For aerobic organisms it is essential atmospheric oxygen use. Though, it is also known that about 2-5% of that oxygen is reduced to form free radicals (ROS) such as superoxide, hydroxyl radical and hydrogen peroxide molecule in addition to organic peroxides produced by propagation reactions that can damage cellular biomolecules and starting at the best apoptosis and necrosis. As part of our evolution and adaptation to this gas toxicity we have developed a complex antioxidant defense system with endogenous components (superoxide dismutase-SOD, catalase, glutathione peroxidase, glutathione, uric acid, bilirubin, lipoic acid) and exogenous (Vitamins A, C and E, as well as polyphenols) that are included in our daily diet. This paradox of oxygen throughout life leads to a state of oxidative stress and contributes to the process of senescence, however not uniform for all our body systems. In...
13
artículo
Publicado 2015
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For aerobic organisms it is essential atmospheric oxygen use. Though, it is also known that about 2-5% of that oxygen is reduced to form free radicals (ROS) such as superoxide, hydroxyl radical and hydrogen peroxide molecule in addition to organic peroxides produced by propagation reactions that can damage cellular biomolecules and starting at the best apoptosis and necrosis. As part of our evolution and adaptation to this gas toxicity we have developed a complex antioxidant defense system with endogenous components (superoxide dismutase-SOD, catalase, glutathione peroxidase, glutathione, uric acid, bilirubin, lipoic acid) and exogenous (Vitamins A, C and E, as well as polyphenols) that are included in our daily diet. This paradox of oxygen throughout life leads to a state of oxidative stress and contributes to the process of senescence, however not uniform for all our body systems. In...
14
artículo
Publicado 2020
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The various industrial sectors, as well as livestock and agricultural activities, are increasing the production of inputs to meet the demand of the worldwide demographic explosion, making a challenge the clean maintenance of water, soil, and air. Therefore, the search for solutions for a pollutant-free environment without compromising economic development has become extremely important. Thereby, biotechnological studies in order to solve environmental issues have been gaining extensive attention through the coupling of technology procedures to biological systems as sustainable solutions to remediate contaminated areas. In this sense, this review covers topics such as the role of Omics era in microbial environmental biotechnology for pollution control as well as the microbial fuel cell use in energy production. Moreover, phytoremediation and the perspective of applying chemical methods ar...
15
artículo
Publicado 2020
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The various industrial sectors, as well as livestock and agricultural activities, are increasing the production of inputs to meet the demand of the worldwide demographic explosion, making a challenge the clean maintenance of water, soil, and air. Therefore, the search for solutions for a pollutant-free environment without compromising economic development has become extremely important. Thereby, biotechnological studies in order to solve environmental issues have been gaining extensive attention through the coupling of technology procedures to biological systems as sustainable solutions to remediate contaminated areas. In this sense, this review covers topics such as the role of Omics era in microbial environmental biotechnology for pollution control as well as the microbial fuel cell use in energy production. Moreover, phytoremediation and the perspective of applying chemical methods ar...
16
artículo
Publicado 2008
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In this paper we evaluate the technical feasibility of advanced oxidation process (AOX) using the reagent Fenton H2O2/Fe^(2+) in the treatment of wastewater generated by the caustic washing of an oil refinery. These waters contain a chemical oxygen demand (DQO), 20 160 mg / L and total phenols 1 800 mg / L. The results show the treatment efficiency of removal of 90% for DQO, and 99% for total phenol at pH 4.
17
artículo
Publicado 2017
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La arsenopirita, FeAsS, es un mineral que se encuentra frecuentemente en asociación con oro. En este tipo de mineral, el oro se suele encontrar en forma sub-microscópica, encapsulado en la matriz del mismo mineral, o bien constituyendo una solución sólida, lo cual dificulta o impide la recuperación del oro mediante las técnicas disponibles de lixiviación. Inclusive, una molienda muy fina no logra romper la matriz en la que se encuentra el oro, inhabilitando el acceso a las soluciones de lixiviación. Algunas alternativas conducentes a la recuperación de oro a partir de aquellos minerales, consisten en oxidación química, oxidación a presión, oxidación bacteriana y tostación oxidante (muy contaminante por generación de gases de As2O3 y SO2). El presente estudio pretende identificar las condiciones para ruptura de la matriz de la arsenopirita para con ello continuar con el pr...
18
artículo
Publicado 2020
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In this work we study the effects on the porosity and microhardness properties when using different ZrO2 + 8% Y2O3 diameters powders (less than 40 μm, between 40 to 60 μm and greater than 80 μm) to deposit in the upper layer of a TBC system (thermal barrier coating) of double layer formed by NiCrCoAlY and ZrO2 + 8% Y2O3 using the plasma spray process, in order to find the suitable powder and feasible to use as top layer. To this end, instruments such as TESCAN Vega SB scanning electron microscope with INCA Energy dispersive microanalyzer were used, with which it was possible to detect the porosity in different areas of evaluation of the upper layer and the Vickers durometer to measure the microhardness. Verifying that with particle diameters smaller than 40 μm, the aforementioned properties are adequate for the conformation of the ZrO2 + 8% Y2O3 top layer.
19
artículo
Publicado 2008
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En el presente trabajo, se evalúa la factibilidad técnica del proceso de oxidación avanzada (AOX) usando el reactivo Fenton H2O2/Fe^(2+) en el tratamiento de las aguas residuales generadas por el lavado cáustico de una refinería de petróleo. Estas aguas contienen una demanda química de oxígeno (DQO), de 20 160 mg/L y fenoles totales 1800 mg/L. Los resultados del tratamiento muestran eficiencia de remoción del 90% para DQO, y 99% para fenoles totales a pH de 4.
20
artículo
The arsenopyrite, FeAsS, it is a mineral that is commonly found associated with gold. In this kind of mineral, Gold is presented in sub-microscopic size particles, encapsulated in a matrix of the same mineral or forming a solid solution, this does not allow the recovery of gold with the available lixiviation techniques. Moreover, a fine grinding does not a chive to break the matrix in which the gold is located, not allowing the lixiviation solutions to come in. Some alternatives that lead to the recovery of gold from those minerals include chemical oxidation, oxidation under pressure, bacterial oxidation and roasting oxidation (which is very polluting due to the emission of As2O3 y SO2 gases. The aim of the following study is to identify the conditions to break the arsenopyrite matrix for continuing the usual process of cianuration. For doing so, experiments were carried out containing a...
