Nanomanganese cobaltate-decorated halloysite nanotubes for the complete degradation of ornidazole via peroxymonosulfate activation

Peroxymonosulfate (PMS) driven by halloysite nanotubes (HNTs) modified with nanomanganese cobaltate (MnCo2O4) generates reactive oxygen species (ROS) that offer high degradation efficiency and mineralization rates for many typical antibiotic pollutants, such as ornidazole (ONZ). The experimental results show that halloysite nanotubes (HNTs) modified with nanomanganese cobaltate (MnCo2O4@HNTs denoted as MCO@HNTs) can degrade ONZ completely over a wide pH range (6.08- 11.00) with little influence of the pH value. MCO@HNTs + PMS exhibited higher catalytic activity and lower Co- and Mn-ion leaching rates. It also showed a strong anti-interference effect on natural lake water and anions. Additionally, PMS can be quickly activated and consumed in natural lakes to avoid secondary pollution. The roasting of MCO@HNTs showed good catalytic activity and stability after degrading ONZ. The combination of ion quenching and electron paramagnetic resonance (EPR) analysis illustrated that the MCO@HNTs + PMS system had a strong oxidation capacity, and the produced singlet oxygen (1O2) was the main ROS for ONZ degradation. The degradation pathway of ONZ via the MCO@HNTs + PMS system was proposed based on the types of intermediates determined via liquid chromatography-mass spectrometry (LC-MS). This comprehensive study shows the preparation of a simple, environmentally friendly, and cheap PMS activation catalyst that has practical application value in the treatment of antibiotic wastewater and provides a focus on actual water testing with residual amount of PMS.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Halloysite nanotubes (HNTs) modified with nanomanganese cobaltate (MnCo2O4) can drive peroxymonosulfate (PMS) to generate reactive oxygen species (ROS) for the high degradation efficiency and mineralization rates of antibiotic pollutants such as ornidazole (ONZ). The MCO@HNTs + PMS system exhibits excellent catalytic activity, stability, and anti-interference effect in the wide pH range. Singlet oxygen (1O2) is identified as the main ROS for ONZ degradation. The study provides a simple, environmentally friendly, and cost-effective PMS activation catalyst for the treatment of antibiotic wastewater.