Piezo-Fenton catalysis in Fe3O4-BaTiO3 nanocomposites: A low-cost and highly efficient degradation method without the additive of H2O2 or Fe(II) ions

The Fenton reaction, an effective advanced oxidation process (AOP) for degrading organic pollutants, requires the addition of H2O2 that is expensive and not environmentally friendly to some extent. It has been reported that piezocatalysis can generate H2O2 under mechanical excitation. Therefore, it is promising to carry out the Fenton catalysis utilizing in situ H2O2 generated by piezocatalysis. However, the current piezocatalysis-assisted Fenton (Piezo-Fenton) reaction was realized by adding piezoelectric nanoparticles and Fe(II) ions to pollutant solutions, which would induce more iron-based chemicals that are not easy to recycle. Herein, Fe3O4-BaTiO3 nanocomposites were prepared to demonstrate the feasibility of piezo-Fenton catalysis without the addition of H2O2 or Fe(II) ions. The organic dye degradation efficiency of 98.2% is obtained using Fe3O4-BaTiO3 nanocomposites in the acidic solution, one-third and two-thrid greater than that of pure piezocatalysis and that of iron-based Fenton reaction, respectively. Moreover, since the piezocatalysis process is the rate-determining step of the whole piezo-Fenton reaction, all the H2O2 generated can be consumed. Considering that the solid nanocomposites can be magnetically recycled, piezo-Fenton catalysis leaves no additional chemicals in clean water and thus provides an environmentally friendly and low-cost approach for organic dye degradation.