High-efficient degradation of sulfadiazine by a novel boron-induced Fe/CaO2 system

Abstract

Abstract

Adding cocatalyst is a common strategy to increase the rate and degree of Fenton reaction. Inorganic cocatalyst has the ability to provide electrons, reduce the risk of secondary pollution, and effectively improve the utilization efficiency of ROS. However, how inorganic cocatalyst boron improves the utilization efficiency of ROS needs to be further explored. This study investigated the enhancement of sulfadiazine (SDZ) degradation in a Fe(II)/CaO2 system by incorporating boron as inorganic cocatalyst. The results demonstrated that the Boron/Fe(II)/CaO2system achieved 96.1 % SDZ removal efficiency within 10 min, compared to only 69.2 % for the Fe(II)/CaO2 system. Boron accelerated the Fe(II) to Fe(III) cycle, maintaining a roughly 1:1 ratio, and increased the concentration of reactive oxygen species (·OH, 1O2, and ·O2–, FeⅣ=O) in the system. Active sites of SDZ vulnerable to free radical attack have been analyzed using frontier orbital density function, and the degradation paths of SDZ produced by Boron/Fe(II)/CaO2 system has been verified. The incorporation of boron notably enhanced the degradation capacity of the Fe(II)/CaO2 system for SDZ and other organics. This enhancement was particularly pronounced in real river water, which is rich in natural organic matter, with the degradation rate constant being increased by a factor of 6.5.