An effective Fenton reaction by using waste ferric iron and red phosphorus

Abstract

Traditional Fenton reaction (Fe2+/H2O2) is limited by the instability and the sluggish regeneration of ferrous iron (Fe2+). Compared with Fe2+, ferric iron (Fe3+) is cheaper, easier to obtain and more stable. However, Fe3+-induced Fenton reaction activity is low. Here, a high-efficiency Fe3+-induced Fenton system is achieved by introduction of red phosphorus (P). The red P can donate electrons to Fe3+ for Fe2+ regeneration. As a result, the red P/H2O2/Fe3+ system exhibits three obvious advantages: i) The degradation rate of pollutant is 25.6 times and 18.3 times that of the Fe3+/H2O2 and red P/H2O2 systems. ii) The decomposition rate of H2O2 reaches an amazing value of 92.4%, which is much higher than that of the traditional Fenton system (51.6%). iii) Pollutants could be degraded efficiently with a wide initial pH range of 2.0–8.0, indicating that the red P/H2O2/Fe3+ system gets rid of pH constraints. Importantly, this study realizes the transformation of waste Fe3+ into treasure and resource reuse and further reduces the cost of Fenton reaction. Therefore, this study opens up a new strategy for utilization of widely-spread Fe3+ for environmental remediation and also provides a new application of red P.