Removal of dye from aqueous solution via an adsorption-high temperature gas flow regeneration method on Co-Fe/sepiolite

Abstract

A new adsorbent/catalyst Co-Fe/sepiolite was prepared and tested for its potential application in dye wastewater. CoFe/sepiolite acted as an adsorbent at adsorption stage, then was used as a catalyst, which accelerated regeneration speed and increased the regeneration rate during regeneration. The efficiency of this adsorbent/catalyst was investigated using crystal violet (CV) as a model pollutant. Through the sorption capacity of the Co-Fe/sepiolite, the dye was removed from wastewater, the adsorbent was regenerated subsequently by high temperature gas flow catalytic oxidation, accompanied by the decomposition of CV. CV was oxidized into CO 2 , CO, NO, and CH compounds during regeneration, the formation of these compounds as final products made it possible to regenerate the Co-Fe/sepiolite by high temperature gas flow. The effect of heat treatment on Co-Fe/sepiolite structure was studied. In addition, the effects of temperature, space velocity, and time on regeneration rate were investigated. The results suggested high temperature gas flow regeneration as an efficient regeneration process. The Co-Fe/sepiolite can be potentially applied for combined dye adsorption and degradation processes.

Synthesis of Ce–Ni/sepiolite with excellent adsorption and catalytic oxidation performance toward dyes

“…There are many regeneration methods, including the hot gas stream, wet oxidation, electrochemical, Co 2+ /oxone, dielectric barrier discharge, electro-peroxone, thermal, and others. [12][13][14][15][16][17][18][19][20][21] Most of these regeneration methods require significant periods of time, ranging from 3 to 24 hours, while others, like wet oxidation, require specific tools. 22 Our previous work has highlighted the efficiency of the adsorption and hot gas stream regeneration process for dye wastewater treatment.…”

“…22 Our previous work has highlighted the efficiency of the adsorption and hot gas stream regeneration process for dye wastewater treatment. 12,23,24 This gas–solid catalytic reaction refers to a cycle of dye adsorption from aqueous solutions and hot O 2 gas stream regeneration. The regeneration rate of Co–Fe/sepiolite can reach 85.7% at 650 °C within 10 minutes.…”