Cyanide-Isolated Cobalt Catalyst for Ultraefficient Advanced Oxidation Treatment

Area of Science:

• Advanced oxidation processes
• Materials science
• Environmental engineering

Background:

• Atomically designed "Co-N-C" catalysts show promise for peroxymonosulfate (PMS) activation in water treatment.
• Developing efficient and stable catalysts is crucial for advanced oxidation processes.

Purpose of the Study:

• To synthesize cobalt hexacyanocobaltate (Co-HCC) with abundant atomically isolated Co^II-NC sites for ultraefficient PMS activation.
• To develop a catalytic membrane for confined oxidation of organic pollutants using Co-HCC.
• To investigate the fundamental insights into the high catalytic performance and application in wastewater treatment.

Main Methods:

• Synthesis of cobalt hexacyanocobaltate (Co-HCC) with atomically isolated Co^II-NC sites.
• Characterization of the catalyst's structure and properties.
• PMS activation experiments to evaluate radical generation and catalytic activity.
• Fabrication of a Co-HCC-based catalytic membrane.
• Testing the catalytic membrane for micropollutant removal and mineralization in wastewater under high flux.

Main Results:

• Co-HCC exhibits ultrahigh PMS activation with a high turnover frequency, surpassing homogeneous Co²⁺ catalysis.
• The Co-HCC catalytic membrane achieves complete disruption of micropollutants at 10,000 LMH (0.2 s retention time).
• The membrane demonstrates >90% mineralization of organic pollutants in complex wastewater within 100 s, with operational simplicity and 2-week longevity.

Conclusions:

• Atomically isolated Co^II-NC sites in Co-HCC provide unprecedented catalytic performance for PMS activation.
• Co-HCC catalytic membranes offer an efficient, confined oxidation environment for rapid and complete removal of organic pollutants.
• This work establishes a new benchmark for "Co-N-C" catalyst design and catalytic membranes in advanced water treatment.