Researchers have developed a cobalt manganese spinel catalyst, CoMn0.75/BC, regulated by biochar and derived from layered double hydroxides. When used to activate peroxymonosulfate, the catalyst achieved 96.9% removal of 5 mg L−1 imidacloprid from water within 40 minutes.
Key Findings
- The catalyst's degradation rate was substantially higher than systems using biochar or cobalt manganese oxide alone. Biochar served multiple functions: dispersing spinel nanoparticles, chelating metal ions via carbonyl groups, and generating singlet oxygen through persistent free radicals.
- The reaction mechanism shifted toward non-radical pathways, primarily high-valent metal oxo species and singlet oxygen, offering resistance to interference from background ions and natural organic matter.
- The catalyst maintained >85% imidacloprid removal across pH 3-11 and was minimally affected by chloride and sulfate ions.
- Performance remained strong in tap water and surface water samples.
- After five reuse cycles, removal decreased from 96.9% to 91.3%; crystal structure was retained and metal leaching was low.
- In a continuous-flow column test, removal remained above 80% after 420 minutes.
- The system also degraded other neonicotinoids: thiamethoxam, clothianidin, dinotefuran, and nitenpyram.
Statements from Authors
The study's corresponding authors stated:
"Biochar is not only a support material in this system. It actively changes how the catalyst works, steering the reaction toward more selective non-radical oxidation pathways. This provides a useful design strategy for next-generation catalysts used in pesticide wastewater treatment."
They also noted:
"By using biochar to regulate both catalyst structure and reaction pathway, we can move beyond simple pollutant adsorption and toward efficient catalytic detoxification."
Publication Details
The research was published in Biochar (2026) by Dong et al., available at https://doi.org/10.1007/s42773-026-00636-6.