The present study aimed to evaluate the feasibility of developing low-cost N- and Fe-doped TiO photocatalysts for investigating the mineralization of 2,4-dimethylaniline (2,4-DMA). With a single anatase phase, the photocatalysts showed high thermal stability with mass losses of less than 2%. The predominant oxidative state is Ti, but there is presence of Ti associated with oxygen vacancies.
View Article and Find Full Text PDFZnO nanorods were grown on silicon (Si) substrates by two techniques: (i) Chemical Bath Deposition (CBD) and (ii) a CBD seed layer combined with Carbothermal Reduction Vapor Phase Transport (CTR-VPT). The structured ZnO nanorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle measurments. The photoelectrochemical property of ZnO nanorods were analyzed by linear voltammetry under UV-ABC light excitation.
View Article and Find Full Text PDFSci Total Environ
February 2019
CuO nanostructured thin films supported on silicon with 6.5 cm area (geometric area greater than the studies reported in the literature) were synthesized by a chemical bath deposition technique. The electrodes were characterized by MEV, XRD, XPS, contact angle, cyclic voltammetry and electrochemical impedance spectroscopy analyses.
View Article and Find Full Text PDFThe main objective of this work is to demonstrate the viability of solar photoelectro-Fenton (SPEF) process to degrade pesticides in urban wastewater matrix, selecting the herbicide bentazon as a model molecule. In order to provide a correct assessment of the role of the different oxidants and catalysts involved, bentazon was comparatively treated by anodic oxidation with electrogenerated HO (AO-HO), electro-Fenton (EF) and UVA-assisted EF (i.e.
View Article and Find Full Text PDFElectro-oxidation with electrogenerated HO (EO-HO) was applied to treat acidic aqueous solutions of 4-aminoantipyrine (4-AA), a persistent drug metabolite of dipyrone, in sulfate medium. Trials were made using a boron-doped diamond anode in the presence of HO electrogenerated on site. A 2 central composite design (CCD) was employed to evaluate the effect of four independent variables, namely current density (j), pH, 4-AA concentration and electrolysis time, on the percentages of degradation and mineralization, as well as on mineralization current efficiency (MCE).
View Article and Find Full Text PDFSolutions with 0.65 mM of the antituberculosis drug isoniazid (INH) in 0.050 M NaSO at pH 3.
View Article and Find Full Text PDFThe mineralization of bio-recalcitrant humic acids (HAs) by a solar photo-Fenton (SPF) process was investigated in aqueous system, in order to understand its abatement in real high-HA content matrices, such as sanitary landfill leachates. SPF reactions were performed in tubular photoreactors with CPCs at lab-scale (simulated solar light) and pilot-scale (natural sunlight). Considering the experimental conditions selected for this work, the formation of insoluble HA-Fe complexes was observed.
View Article and Find Full Text PDFThis study describes the performance of electro-Fenton (EF) and photoelectro-Fenton (PEF) processes to degrade the herbicide tebuthiuron (TBH) in 0.050 M NaSO at pH = 3.0.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
February 2019
This paper reports the degradation of 10 mg L Ametryn solution with different advanced oxidation processes and by ultraviolet (UV) irradiation alone with the main objective of reducing acute toxicity and increase biodegradability. The investigated factors included Fe and HO concentrations. The effectiveness of the UV and UV/HO processes were investigated using a low-pressure mercury UV lamp (254 nm).
View Article and Find Full Text PDFSci Total Environ
December 2016
This study employed direct UV-ABC photolysis and the UV-ABC/HO process to investigate the degradation of tolfenamic acid (TA), a common anti-inflammatory drug used in both human and veterinary medicine. A 2 factorial design with added center point was used to evaluate the effect of three independent variables-namely, HO concentration ([HO]), TA concentration ([TA]), and experiment time (time)-on TA degradation and HO photolysis during UV-ABC/HO treatment using a high-pressure mercury vapor lamp (photon flux of 2.6307 × 10 J s) as the UV irradiation source.
View Article and Find Full Text PDFA solution with 0.38 mM of the pesticide propoxur (PX) at pH 3.0 has been comparatively treated by electrochemical oxidation with electrogenerated HO (EO-HO), electro-Fenton (EF), and photoelectro-Fenton (PEF).
View Article and Find Full Text PDFBackground: Due to contamination of the environment by pesticides and their mishandling, there is the need for treatment of contaminated sites and correct disposal of materials containing them. Thus, studies with advanced oxidation processes are expanding and can determine the rate constant of the hydroxyl radical with organic compounds of great importance in environmental contamination. In this context, the use of laser flash photolysis has been shown to be viable for the determination of these constants.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2015
This paper reports the synthesis, characterization, and application of TiO2 and TiO2/Ag nanoparticles for use in photocatalysis, employing the herbicide methylviologen (MV) as a substrate for photocatalytic activity testing. At suitable metal to oxide ratios, increases in silver surface coating on TiO2 enhanced the efficiency of heterogeneous photocatalysis by increasing the electron transfer constant. The sol-gel method was used for TiO2 synthesis.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
April 2013
In the present study, selected advanced oxidation processes (AOPs)-namely, photo-Fenton (with Fe(2+), Fe(3+), and potassium ferrioxalate-FeOx-as iron sources), solar photo-Fenton, Fenton, and UV/H2O2-were investigated for degradation of the antineoplastic drug mitoxantrone (MTX), frequently used to treat metastatic breast cancer, skin cancer, and acute leukemia. The results showed that photo-Fenton processes employing Fe(III) and FeOx and the UV/H2O2 process were most efficient for mineralizing MTX, with 77, 82, and 90% of total organic carbon removal, respectively. MTX probably forms a complex with Fe(III), as demonstrated by voltammetric and spectrophotometric measurements.
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