Spherical ZVI/Mn-C Bimetallic Catalysts for Efficient Fenton-like Reaction under Mild Conditions

Abstract

The heterogeneous Fenton-like reaction has been receiving increasing attention for its inexpensiveness and high efficiency in water treatment. In this study, a novel strategy was proposed for preparing spherical ZVI/Mn-C bimetallic catalysts with a high activity for a Fenton-like reaction by using the ammonium alginate assisted sol–gel method coupled with a carbothermic reduction. The results showed that the obtained ZVI/Mn-C spheres had a uniform size, smooth surface and good sphericity, and the particle size of ZVI was limited to about 30 nm by the carbon layer. Among all catalysts, the ZVI/Mn-C-31 catalyst exhibited the highest phenol degradation efficiency in the Fenton-like process, and almost 100% phenol degradation efficiency was achieved under neutral pH at room temperature within 5 min. Moreover, the ZVI/Mn-C-31/H2O2 system showed a 100% degradation efficiency for removing a wide range of aromatic pollutants, including catechol, resorcinol and o-nitrophenol. Moreover, the radicals-scavenging experiment illustrated that the ·OH played a key factor in mineralizing the organic matters, and the ·O2− generated from the MnO-H2O2 system accelerated the conversion rate of ferric iron to ferrous iron. Due to the synergistic effects between ZVI and MnO, the ZVI/Mn-C-31 catalyst performed excellently in the Fenton-like reaction at an extended pH range.