Sulfate radicals from Fe³⁺/persulfate system for Rhodamine B degradation

The Fe³⁺/persulfate system for Rhodamine B (RhB) oxidative degradation has been investigated. The catalytic mechanism in the Fe³⁺/persulfate system was proposed as follows: Fe³⁺ was restored to Fe²⁺ by the generated intermediate products during the degradation process. The influence parameters were examined in batch experiments, including Fe³⁺ and persulfate concentration and initial pH. The results indicated that the Fe³⁺/persulfate system exhibited good performance for RhB degradation and followed first-order kinetics. 95.91% of the RhB was removed within 30 min under the following conditions: [Fe³⁺]₀ = 1 mM, [persulfate]₀ = 1 mM and pH 3.0. The RhB degradation efficiencies increased as the Fe³⁺ and persulfate concentrations increased. In addition, the RhB degradation was inhibited in the presence of inorganic anions, which was primarily due to a complex reaction between Fe³⁺ and various anions except for .