The accelerated growth of cyanobacteria in water bodies is a global critical environmental issue caused by continuous discharges of effluents into the environment that are rich in phosphorus and nitrogen. So, cyanobacteria have found propitious conditions for proliferation, provoking significant ecological imbalances. Cyanobacteria produce cyanotoxins, which are harmful to life, and compounds like 2-methylisoborneol and geosmin that affect water's taste and odor.
View Article and Find Full Text PDFJ Environ Sci Health A Tox Hazard Subst Environ Eng
May 2023
Diclofenac (DCF) can cause several adverse effects in the environment and it should be removed from industrial pharmaceutical wastewaters. Advanced oxidation processes (AOPs) are promising methods for the DCF degradation. But, in many cases, AOPs require acidic pH.
View Article and Find Full Text PDFEnviron Technol
November 2023
ABSTARCTThe antibiotic amoxicillin (AMX) is a semisynthetic aminopenicillin, classified as an β-lactam antibiotic. This work aims to evaluate the AMX degradation (190 mg L), in aqueous medium, applying photo-Fenton ([TOC] = 100 mgC L; F = 3.27 mmol min; [Fe] = 0.
View Article and Find Full Text PDFThe treatment of pharmaceutical industrial wastewaters, containing the antibiotic amoxicillin (218.29 mg L), via some advanced oxidation processes (POA), was studied. The HO photolysis process presented the highest percentage of mineralization (97%), after the total reaction time (180 min).
View Article and Find Full Text PDFIn this work, a saline aqueous solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a falling-film solar reactor. The influence of the parameters such as initial pH (5-7), initial concentration of Fe2+ (1-2.5mM) and rate of H202 addition (1.
View Article and Find Full Text PDFAn artificial neural network (ANN) was implemented for modeling phenol mineralization in aqueous solution using the photo-Fenton process. The experiments were conducted in a photochemical multi-lamp reactor equipped with twelve fluorescent black light lamps (40 W each) irradiating UV light. A three-layer neural network was optimized in order to model the behavior of the process.
View Article and Find Full Text PDFA highly concentrated aqueous saline-containing solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a system composed of an annular reactor with a quartz immersion well and a medium-pressure mercury lamp (450 W). The study was conducted under special conditions to minimize the costs of acidification and neutralization, which are usual steps in this type of process. Photochemical reactions were carried out to investigate the influence of some process variables such as the initial concentration of Fe(2+) ([Fe(2+)](0)) from 1.
View Article and Find Full Text PDFThe objective of this paper is to develop and validate a mechanistic model for the degradation of phenol by the Fenton process. Experiments were performed in semi-batch operation, in which phenol, catechol and hydroquinone concentrations were measured. Using the methodology described in Pontes and Pinto [R.
View Article and Find Full Text PDFThe photo-Fenton process (Fe(2+)/Fe(3+), H(2)O(2), UV light) is one of the most efficient and advanced oxidation processes for the mineralization of the organic pollutants of industrial effluents and wastewater. The overall rate of the photo-Fenton process is controlled by the rate of the photolytic step that converts Fe(3+) back to Fe(2+). In this paper, the effect of sulfate or chloride ions on the net yield of Fe(2+) during the photolysis of Fe(3+) has been investigated in aqueous solution at pH 3.
View Article and Find Full Text PDFThe inhibition of the photo-Fenton (Fe2+/Fe3+, H2O2, UV light) degradation of synthetic phenol wastewater solutions by chloride ions is shown to affect primarily the photochemical step of the process, having only a slight effect on the thermal or Fenton step. Kinetic studies of the reactions of oxoiron (IV) (FeO2+) with phenol indicate that, if FeO2+ is formed in the photo-Fenton degradation, its role is probably minor. Finally, it is shown that, for both a synthetic phenol wastewater and an aqueous extract of Brazilian gasoline, the inhibition of the photo-Fenton degradation of the organic material in the presence of chloride ion can be circumvented by maintaining the pH of the medium at or slightly above 3 throughout the process, even in the presence of significant amounts of added chloride ion (0.
View Article and Find Full Text PDFThe application of the photo-Fenton process for the treatment of wastewaters contaminated with diesel oil was investigated. This particular process has been widely studied for the photochemical degradation of highly toxic organic pollutants. Experiments were performed according to a factorial experimental design at two levels and two variables: H(2)O(2) concentration (5-200 mM) and Fe(2+) concentration (0.
View Article and Find Full Text PDFThe photo-Fenton reaction (Fe2+/Fe3+, H2O2, UV light) is strongly inhibited by high concentrations of added chloride ion. In this work, the effect of added chloride ion on the photocatalytic step that converts Fe(III) back to Fe(II) is studied by nanosecond laser flash photolysis over a wide range of pH (1.0-3.
View Article and Find Full Text PDFThe photo-Fenton process utilizes ferrous ions (Fe2+), hydrogen peroxide (H2O2), and ultraviolet (UV) irradiation as a source of hydroxyl radicals for the oxidation of organic matter present in aqueous effluents. The cost associated with the use of artificial irradiation sources has hindered industrial application of this process. In this work, the applicability of solar radiation for the photodegradation of raw gasoline in water has been studied.
View Article and Find Full Text PDFThe application of the photo-Fenton process to the treatment of saline wastewater contaminated with hydrocarbons is investigated. Aqueous saline solutions containing raw gasoline were used as a model oil-field-produced water. The dependence on concentrations of the following reagents has been appropriately evaluated: hydrogen peroxide (100-200 mM), iron ions (0.
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