Masoud Samandari; Afshin Tagva Manesh; Seyed Ali Hosseini; Sakineh Mansouri
Abstract
The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed ...
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The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed to the mixed oxide. The SEM images approved Mg-Al LDH comprised of flakes and the calcined LDH comprised of spherical nanoparticles. BET results indicated the specific surface area of 100.2 and 86.3 m2.g-1 for pure LDH and calcined LDH, respectively. The process was optimized by one factor at a time method and considering four process factors i.e. reaction temperature, peroxide dosage, initial phenol concentration, and reaction time. The optimum conditions resulted at initial phenol concentration of 100 ppm, reaction temperature of 60 ºC, with peroxide volume of 3 mL and time on stream of 45 min over calcined LDH with maximum 85% removal of phenol. On the pure LDH, the maximum phenol removal (79%) resulted at peroxide volume of 2.5 mL at 55 min. The study concluded that the calcined Mg-Al LDH due to synergistic effect of MgO and Mg-Al mixed oxide showed higher catalytic activity despite a relatively low surface area.
Bahram Bagheri; Seyed Ali Hosseini; Habib Mehrizadeh
Abstract
The catalytic wet peroxide oxidation of phenol from aqueous wastewater and COD reduction over Cu-Mn2 and Cu-Co2 nano mixed oxides are reported. The effects of process variables of pH, reaction time and hydrogen peroxide dosage were investigated in the process over both catalysts. The catalysts were characterized ...
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The catalytic wet peroxide oxidation of phenol from aqueous wastewater and COD reduction over Cu-Mn2 and Cu-Co2 nano mixed oxides are reported. The effects of process variables of pH, reaction time and hydrogen peroxide dosage were investigated in the process over both catalysts. The catalysts were characterized by X-ray diffraction (XRD) and it was concluded that the mixed oxides are in the form of the spinel structure. However, a little bit CuO was found in the mixed oxides. The morphology and particles size of the catalysts were investigated by scanning electron microscope (SEM). The morphologies and particle size of the catalyst were approximately the same with an average range of 40-60 nm. The catalytic results indicated the higher activity of CuCo2O4 spinel. The phenol oxidation on Cu-Co2 oxide was 82% after 40 min, whereas on the Cu-Mn2 oxide was 78% even after 50 min. The COD reduction The higher activity and reusability of the Cu-Co2 catalyst is attributed to the high synergistic effect between CuO particles and Cu–Co2 spinel, promoting phenol degradation.