RESUMO
In this study, CuFe2O4 ferrite was supported on biochar produced from malt biomass residues as a photocatalyst for degradation of methylene blue (MB), methyl orange (MO), and tartrazine (TZ) dyes. XRD, FT-IR, and FE-SEM were used to characterize the crystallinity and morphology of the samples. The characterization showed that the ferrite was uniformly supported on the surface of the biochar, confirming the formation of the composite. Degradation tests showed that CuFe2O4 degraded approximately 50, 47, and 62% of MB, MO, and TZ dyes, respectively, after 60 min of reaction. On the other hand, the CuFe2O4/biochar composite showed a significant increase in dye degradation, ~ 100%, for all three dyes. This increase in degradation efficiency may be due to less agglomeration of supported particles and due to decreased recombination of electron/hole pairs. Thus, results showed that the photocatalyst composite produced in this study is an effective alternative for removing dyes from wastewater.
Assuntos
Azul de Metileno , Poluentes Químicos da Água , Compostos Azo , Carvão Vegetal , Corantes/química , Monitoramento Ambiental , Compostos Férricos , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tartrazina , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
This is the first record on literature to use biochar as support for CoFe2O4 to applicate and evaluate it as photocatalyst for degradation of organic pollutants. The support was verified by XRD, FT-IR, SEM, EDS and band gap. Composites CFO1BQ3, CFO1BQ1, and CFO3BQ1 showed 100% degradation in 60â min. This outstanding performance can be related to the drop in band gap energy and recombination rate of e¯/h + . The composites showed better efficiency when compared to pure CoFe2O4 (â¼78%). This might be associate to the fact that biochar has a high concentration of phenolic, hydroxyl and carboxylic functional groups on its surface. In this reaction h+, O2â¢-, and â¢OH were the reactive species involved in the degradation. The toxicity of ponceau was tested before and after the treatment, through biochemical biomarkers in Danio rerio fish. In general, the treatment proved to be efficient in reducing ponceau toxicity in D. rerio fish.
RESUMO
This study is a pioneer in the use of hydrochar as a support for photocatalytic oxide and its application and evaluation as a catalyst in degradation reactions of ramipril. Novel composites were easily prepared by the support TiO2 or ZnO nanoparticles on the malt bagasse hydrochar. The preparation of the hydrochar requires low synthesis temperature (250 °C), generating the energy savings of the process. The production of the new composites was well supported by different analytical techniques XRD, FTIR, SSA, SEM, EDS, and reflectance diffuse. The effect of different proportions of TiO2 or ZnO on the composites was investigated on the degradation efficiency of the pharmaceutical ramipril, without pH adjustment. Composites with a 5:1 hydrochar/TiO2 or ZnO ratio (MH5T and MH5Z, respectively) showed degradations of 72 and 98% of ramipril at 120 min. This remarkable performance may be associated with the decrease in band gap energy and the electron-hole recombination rate. In addition, the composites were more efficient than metal oxides pristine, and this may be related to the fact that hydrochar have a high concentration of phenolic, hydroxyl, and carboxylic functional groups on their surface. Radical identification tests indicated that h+, O2â¢-, and â¢OH were the reactive species involved in the degradation. The proposed mechanism was studied via LC-MS/MS indicated that the ramipril molecule degrades into low m/z intermediates in the first 60 min of reaction using the MH5Z.
Assuntos
Ramipril , Espectrometria de Massas em Tandem , Carbono , Catálise , Cromatografia LíquidaRESUMO
Real hospital wastewater was effectively treated by a promising technology based on degradation reaction catalyzed by Fe0 under microwave irradiation in this work. Fe0 powders were synthesized and characterized by different techniques, resulting in a single-phase sample with spherical particles. Optimum experimental conditions were determined by a central composite rotatable design combined with a response surface methodology, resulting in 96.8% of chemical oxygen demand reduction and 100% organic carbon removal, after applying MW power of 780 W and Fe0 dosage of 0.36 g L-1 for 60 min. Amongst the several organic compounds identified in the wastewater sample, diclofenac and ibuprofen were present in higher concentrations; therefore, they were set as target pollutants. Both compounds were completely degraded in 35 min of reaction time. Their plausible degradation pathways were investigated and proposed. Overall, the method developed in this work effectively removed high concentrations of pharmaceuticals in hospital wastewater.