Synthesis, characterization, and photo-Fenton activity of Bi[Fe(CN)6]·4H2O

Abstract

The Fenton reaction has been widely used in wastewater treatment processes, and the reaction rate is improved by irradiation with light. In this work, Bi[Fe(CN)6]·4H2O was synthesized as a photo-Fenton catalyst by precipitation at room temperature without any stabilizer or capping agent. Two synthesis routes were used and compared; one using K3[FeIII(CN)6] solution and the other using K4[FeII(CN)6]. When Bi(NO3)3 solution was mixed with K3[FeIII(CN)6] solution, the Bi[Fe(CN)6]·4H2O was obtained. However, the KBi(H2O)2[Fe(CN)6]·H2O was first precipitated by the reaction of Bi3+ with [FeII(CN)6]4-, and this intermediate was transformed into Bi[Fe(CN)6]·4H2O. Compared with Bi[Fe(CN)6]·4H2O prepared with K3[FeIII(CN)6], the photo-Fenton degradation of Rhodamine B (RhB) with Bi[Fe(CN)6]·4H2O prepared with K4[FeII(CN)6] exhibited a higher activity. It attributed to a smaller particles size of Bi[Fe(CN)6]·4H2O prepared with K4[FeII(CN)6]. Although Bi[Fe(CN)6]·4H2O could degrade RhB in darkness, its activity increased under visible light irradiation. The prepared catalyst also degraded reactive orange 16 (RO) and tetracycline hydrochloride (TC) under visible light irradiation. The degradations of RhB, RO, and TC were confirmed by mass spectrometry. From experimental results, the Bi[Fe(CN)6]·4H2O prepared with K4[FeII(CN)6] showed high activity and promise as a catalyst for wastewater treatment.