Pyrite/H2O2/hydroxylamine system for efficient decolorization of rhodamine B

Abstract

To improve the efficiency of the Fe(II)/Fe(III) cycle and continuous reactivity of pyrite, a pyrite/H2O2/hydroxylamine (HA) system was proposed to treat rhodamine B (RhB). The results showed that near-complete decolorization and 52.8% mineralization 50 mg L−1 RhB were achieved under its optimum conditions: HA 0.8 mM, H2O2 1.6 mM, pyrite 0.4 g L−1, and initial pH 4.0. The degradation reaction was dominated by an •OH radical produced by the reaction of Fe2+ with H2O2 in solution. HA primarily had two roles: in solution, HA could accelerate the Fe(II)/Fe(III) cycle through its strong reducibility to enhance RhB decolorization; on the pyrite surface, HA could improve the continuous reactivity of pyrite by inhibiting the oxidation of pyrite. In addition, the dosing manner of HA had a significant effect on RhB decolorization. In addition, the high decolorization and mineralization efficiency of other dye pollutants suggested that the pyrite/H2O2/HA system might be widely used in textile wastewater treatment. HIGHLIGHTS A pyrite/H2O2/HA system was proposed for efficient RhB decolorization in a wide-range pH of 3.0–10.0.; HA could not only promote the Fe(II)/Fe(III) cycle to enhance the decolorization of RhB, but also improve the continuous reactivity of pyrite.; The dosing manner of HA had a notable effect on RhB decolorization.; Complete decolorization and high mineralization of other dye pollutants were achieved by the proposed system.;

Keywords

• h2o2
• hydroxylamine
• hydroxyl radical
• pyrite (fes2)
• rhodamine b