Treatment of phenol-contaminated water by heterogeneous Fenton process
Concern for the development check engine code for the treatment of industrial wastewater has grown significantly in recent years. Phenol has been established as the model compound for evaluating proposals for new treatment processes. The Fenton heterogeneous process presents the advantages of the conventional Fenton process or homogeneous, but causes less contamination check engine code of the effluent with iron used as catalyst.
Effective purification of industrial wastewater has become an increasing concern in recent decades. check engine code The legislation of developed countries, and increasingly in developing countries, has evolved to reflect this concern and environmental regulations leading to increasingly stringent standards.
Industrial effluents containing toxic pollutants and often resistant to conventional wastewater treatment, so there is the need to develop effective technologies for removing pollutants and effort in research and development has deepened. Phenol and phenolic compounds are raw materials or intermediates in numerous petrochemical, chemical and pharmaceutical industries, check engine code and are likewise oxidative degradation products of aromatic hydrocarbons of higher molecular weight. Therefore phenol check engine code is possibly the most widely used compound for the development of new processes for water purification model.
The oxidation of contaminants in water by wet oxidation (wet air oxidation, check engine code WAO) and by catalytic wet oxidation (catalytic wet air oxidation, check engine code CWAO) using air and pure oxygen is one of the most studied technologies for removing phenols. Allows very high removal efficiencies, but requires the use of pressure and high temperature (20-200 bar, 200-320ºC), which increases the treatment. An alternative to reducing the severity of the reaction conditions is the catalytic wet oxidation with hydrogen peroxide (peroxide catalytic wet oxidation, CWPO) which is different variants. Of these Fenton's reagent is one of the leading options. In this process hydrogen peroxide is decomposed catalytically in the presence of ferrous ion to produce hydroxyl radicals which has great oxidation capacity.
Application of Fenton process to the treatment of wastewater has attracted great interest due to the low cost of ferrous salts, its low toxicity and hydrogen peroxide is easy to handle and the excess is broken down into harmless products. Also, the equipment requirements are low and the reaction conditions are mild. However, the Fenton process has some drawbacks such as the high consumption of hydrogen peroxide and the need to remove the added iron, which adds additional processing steps and increases the cost.
Some of the drawbacks of Fenton process check engine code can be avoided by use of a heterogeneous catalyst (heterogeneous Fenton process). The active phase is formed check engine code by transition metals, although it is usually iron, supported on active carbon, alumina, silica, mesoporous molecular sieves, zeolites, pillared check engine code clays and ion exchange resins. The major drawbacks of the heterogeneous check engine code Fenton process are derived from the leaching of the active phase when the medium pH is reduced to values of about 3, which is indeed the optimum operating homogeneous Fenton process. The catalysts supported on activated carbon can be performed by treatment with a limited leaching of the active phase.
Figure 1 shows how a model waste water with 100 mg / L of phenol can be treated by a process based on heterogeneous Fenton iron catalyst supported on carbon (Fe / AC) active until the complete removal of contaminating starting. Though check engine code the disappearance of the phenol initially contained, the water is not completely decontaminated, since after treatment persist certain degradation products, mainly organic acids and their elimination is complex. Figure 2 shows the typical distribution of the organic acids formed by Fenton heterogeneous phenol treatment. check engine code The products formed in the oxidation are important when evaluating the process, with some of them, such as quinone, may be even more toxic than the starting phenol, but as shown in Figure 3 can be aromatics eliminated by applying an appropriate treatment time.
Tags:
I have a problem with an influent containing 180 ppm bisulfite, and have organic matter (probiene sulfitado a process of
Concern for the development check engine code for the treatment of industrial wastewater has grown significantly in recent years. Phenol has been established as the model compound for evaluating proposals for new treatment processes. The Fenton heterogeneous process presents the advantages of the conventional Fenton process or homogeneous, but causes less contamination check engine code of the effluent with iron used as catalyst.
Effective purification of industrial wastewater has become an increasing concern in recent decades. check engine code The legislation of developed countries, and increasingly in developing countries, has evolved to reflect this concern and environmental regulations leading to increasingly stringent standards.
Industrial effluents containing toxic pollutants and often resistant to conventional wastewater treatment, so there is the need to develop effective technologies for removing pollutants and effort in research and development has deepened. Phenol and phenolic compounds are raw materials or intermediates in numerous petrochemical, chemical and pharmaceutical industries, check engine code and are likewise oxidative degradation products of aromatic hydrocarbons of higher molecular weight. Therefore phenol check engine code is possibly the most widely used compound for the development of new processes for water purification model.
The oxidation of contaminants in water by wet oxidation (wet air oxidation, check engine code WAO) and by catalytic wet oxidation (catalytic wet air oxidation, check engine code CWAO) using air and pure oxygen is one of the most studied technologies for removing phenols. Allows very high removal efficiencies, but requires the use of pressure and high temperature (20-200 bar, 200-320ºC), which increases the treatment. An alternative to reducing the severity of the reaction conditions is the catalytic wet oxidation with hydrogen peroxide (peroxide catalytic wet oxidation, CWPO) which is different variants. Of these Fenton's reagent is one of the leading options. In this process hydrogen peroxide is decomposed catalytically in the presence of ferrous ion to produce hydroxyl radicals which has great oxidation capacity.
Application of Fenton process to the treatment of wastewater has attracted great interest due to the low cost of ferrous salts, its low toxicity and hydrogen peroxide is easy to handle and the excess is broken down into harmless products. Also, the equipment requirements are low and the reaction conditions are mild. However, the Fenton process has some drawbacks such as the high consumption of hydrogen peroxide and the need to remove the added iron, which adds additional processing steps and increases the cost.
Some of the drawbacks of Fenton process check engine code can be avoided by use of a heterogeneous catalyst (heterogeneous Fenton process). The active phase is formed check engine code by transition metals, although it is usually iron, supported on active carbon, alumina, silica, mesoporous molecular sieves, zeolites, pillared check engine code clays and ion exchange resins. The major drawbacks of the heterogeneous check engine code Fenton process are derived from the leaching of the active phase when the medium pH is reduced to values of about 3, which is indeed the optimum operating homogeneous Fenton process. The catalysts supported on activated carbon can be performed by treatment with a limited leaching of the active phase.
Figure 1 shows how a model waste water with 100 mg / L of phenol can be treated by a process based on heterogeneous Fenton iron catalyst supported on carbon (Fe / AC) active until the complete removal of contaminating starting. Though check engine code the disappearance of the phenol initially contained, the water is not completely decontaminated, since after treatment persist certain degradation products, mainly organic acids and their elimination is complex. Figure 2 shows the typical distribution of the organic acids formed by Fenton heterogeneous phenol treatment. check engine code The products formed in the oxidation are important when evaluating the process, with some of them, such as quinone, may be even more toxic than the starting phenol, but as shown in Figure 3 can be aromatics eliminated by applying an appropriate treatment time.
Tags:
I have a problem with an influent containing 180 ppm bisulfite, and have organic matter (probiene sulfitado a process of
No comments:
Post a Comment