Cu2O@β-cyclodextrin as a synergistic catalyst for hydroxyl radical generation and molecular recognitive destruction of aromatic pollutants at neutral pH

Wastewater systems contain a large number of compounds, such as anthropogenic aromatic pollutants and natural organic matter (NOM), and usually have pH higher than 4. Fenton-like reaction is the most widespread method for removal of organic pollutants, but their reactivity with H 2 O 2 may be inhibited by NOM due to the competition of hydroxyl radicals and chelating agents. In this work, Cu 2 O@β-cyclodextrin was developed to achieve the collaboration between molecular recognition and Fenton-like catalysis to destruct aromatic pollutants at neutral pH. In Cu 2 O@β-CD, covalent Cu O C bond was topotaxially converted from CuCl assisted by β-CD at room temperature. Covalently linked β-CD could keep humic acid from interfering catalytic performance of Cu 2 O surfaces and inhibit the leaching of copper. A higher catalytic ability was observed for Cu 2 O@β-CD with rate constant 0.0331 min −1 than Cu 2 O (0.0064 min −1 ) at neutral pH. A mechanism of synergistic catalysis was proposed on the basis of Cu + , β-CD and phenoxo-Cu 2+ complexes in the Cu 2 O@β-CD/BPA/H 2 O 2 system. The strategy of coupling molecular recognition into Fenton-like reaction provides an efficient and promising approach to the destruction of aromatic pollutants at neutral pH.