Heterogeneous catalytic ozonation by amorphous boron for degradation of atrazine in water

Abstract

As one of the most promising and practical advanced oxidation processes (AOPs), the catalytic ozonation is triggered by the active components of catalyst, which are usually derived from metals or metal oxides. To avoid the metal pollution from catalyst, here the amorphous boron (A-boron) is used as a metal-free catalyst for catalytic ozonation to produce free radicals for effective degradation of atrazine (ATZ), the world-widely used herbicide and also a widespread pollutant in environment. A-boron exhibits an outstanding performance for catalytic ozonation to remove ATZ from water. As A-boron is introduced into ozonation, the degradation efficiency in 10 min is promoted to 97.1%, much higher than that of 15.1% under ozonation. The mechanism is that the B–B bonds and internal suboxide B in A-boron serve as the main active sites to donate electrons to accelerate ozone decomposition to produce reactive oxygen species (ROS), including •O2− and 1O2, and further enhance ATZ degradation via ROS reactions. Moreover, the A-boron is still highly active with a degradation efficiency of ATZ over 95% in 10 min even after four successive cycles. This work shows A-boron could be an alternative for the active components of metal or metal oxide in catalytic ozonation.