Research on the Chloramphenicol Removal Performance of Co-Doped Porous Carbon Materials Derived from Co-Zn Bimetallic ZIFs

Chloramphenicol antibiotics (CAPs) are broad-spectrum antibiotics, and excessive consumption has led to increasingly dangerous residues in the environment. The accumulation of these highly toxic and difficult-to-biodegrade CAPs and their long-term exposure in ecological environments can pose insidious and long-term hazards to human health and aquatic organisms. In this study, co-carbon composite nanocatalysts (CoxZn10−x-NC) with many carbon nanotubes on the surface were prepared via the one-step pyrolysis of bimetallic CoxZn10−x-ZIF with different Co/Zn ratios and used for the degradation of trace amounts of CAPs in a water column. The microstructure and chemical composition of the prepared catalysts were fully characterized using SEM, TEM, and XPS. The CAP degradation experiments demonstrated that Co6Zn4-NC in CoxZn10−x-NC possessed the highest catalytic activity level, removing 100% of the CAPs in 60 min. The CAPs had a corresponding reaction rate constant of 0.22 min−1, and Co6Zn4-NC was able to completely mineralize 44.57% of them. Doping moderate amounts of Zn can effectively improve the carbon nanotube structure on the catalyst surface and promote the generation of monoatomic Co, thus improving catalytic activity. The results of the free-radical burst experiments and electron paramagnetic resonance (EPR) showed that the free-radical pathway mainly dominated within the Co6Zn4-NC+PMS system, in which SO4•− was the main ROS for CAP degradation.