Heterogeneous activation of persulfate for the degradation of bisphenol A with Ni2SnO4–RGO

Abstract

Spherical Ni₂SnO₄ nanoparticles were uniformly loaded on reduced graphene oxide (RGO) sheets via a hydrothermal process. The obtained nickel stannate–reduced graphene oxide (Ni₂SnO₄–RGO) composite was used as a catalyst for activating persulfate (PS). The heterostructure composed of Ni₂SnO₄ and RGO prevents both the agglomeration of Ni₂SnO₄ nanoparticles and the restacking of RGO sheets. The synergy between the two components affords enhanced Ni₂SnO₄–RGO catalytic activity. Using Ni₂SnO₄–RGO to activate PS can degrade bisphenol A (BPA) at a faster rate with less PS, in comparison with the most recently reported catalysts. BPA solution (50 mL, 0.10 mM) can be 100% degraded by PS (0.02 g) within 30 min at pH 8 using Ni₂SnO₄–RGO (0.02 g) as the catalyst. Moreover, the preparation of Ni₂SnO₄–RGO is simple, inexpensive and environment-friendly. The radical scavenging study indicates that sulfate radicals () and hydroxyl radicals (˙OH) are involved in the oxidation, in which plays a leading role. In addition, Ni₂SnO₄–RGO retains high catalytic activity after four consecutive cycles, exhibiting greatly enhanced stability in comparison with Ni₂SnO₄. Besides, the effect of different inorganic anions on the degradation was also explored.