RESUMO
Iron oxide with a high degree of purity was recovered from waste and used as an environmentally friendly, low-cost catalyst in the application of the photo-Fenton process to simulated petrochemical wastewater (SPW). Iron oxide nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, N2 adsorption/desorption isotherms, zeta potential, toxicity and atomic absorption spectrometry. The experiments were performed in a batch photochemical reactor, at 20 ± 2.0°C and pH 3.0. The SPW was efficiently mineralized and oxidized using a low catalyst dosage. The results showed that the organic compounds present in the wastewater were not adsorbed onto the solid surface. The solid was found to be stable with negligible leaching and low toxicity. The kTOC/kCOD ratios were calculated and varied according to the process: for a homogeneous reaction, the ratio obtained was 0.31 and for the heterogenous photo-Fenton process, it was closer to 1. The chemical oxygen demand and total organic carbon removal values were very close, indicating that the SPW is immediately mineralized, without producing partially oxidized compounds. The residue-based goethite studied represents a good alternative to commercially available catalysts in terms of sources and availability.
Assuntos
Ferro , Águas Residuárias , Compostos Férricos , Peróxido de HidrogênioRESUMO
In this study, methylene blue (MB) removal from an aqueous phase by electrical discharge non-thermal plasma (NTP) over water was investigated using three different feed gases: N(2), Ar, and O(2). The results showed that the dye removal rate was not strongly dependent on the feed gas when the electrical current was kept the same for all gases. The hydrogen peroxide generation in the water varied according to the feed gas (N(2)Assuntos
Corantes/química
, Ferro/química
, Azul de Metileno/química
, Sulfetos/química
, Poluentes Químicos da Água/química
, Animais
, Argônio/química
, Artemia/efeitos dos fármacos
, Catálise
, Corantes/toxicidade
, Peróxido de Hidrogênio/química
, Dose Letal Mediana
, Azul de Metileno/toxicidade
, Nitrogênio/química
, Oxigênio/química
, Eliminação de Resíduos Líquidos/métodos
, Poluentes Químicos da Água/toxicidade
, Purificação da Água/métodos