Simulated Sunlight Enhanced X3B Degradation by Persulfate Activated with Steel Slag

Abstract

The degradation of reactive brilliant red X-3B (X3B) in a simulated sunlight/S2O82−/steel slag system at near neutral pH has been studied. The influence of initial pH value, persulfate concentration, quantity of steel slag, and temperature on the degradation of X3B in aqueous solution were investigated. Up to 79.2% of X3B was removed in the simulated sunlight/S2O82−/steel slag system within 5 min at a pH of 6.0. Simulated sunlight played a catalytic role in the S2O82−/steel slag system and resulted in an enhancement of X3B degradation of approximately 11%. The degradation of X3B decreased with an increasing pH in the solution, whereas high temperature facilitated the activation of persulfate. The cycling of Fe2+/Fe3+ facilitated the reuse of steel slag under simulated sunlight irradiation. The steel slag was passivated after coming into contact with the oxidant within 1 min. The sequential addition of steel slag promoted X3B degradation, yielding a removal efficiency of 91%.