Recycling of nitrogen-containing waste diapers for catalytic contaminant oxidation: Occurrence of radical and non-radical pathways

The transformation of waste biomass into nitrogen-doped carbon-based functional materials is recognized as an economical route for energy production and conversion. Waste diapers contain urea that could be used as a nitrogen source, were considered renewable biomass. BPA, a widely used environmental endocrine disruptor, produces estrogen effects in the human body and is characterized by low concentrations and high toxicity in the environment. Here, a simple method of obtaining cobalt embedded waste diaper carbon (Co-WDC) using abandoned diapers is reported and used for an advanced oxidation process. Co-WDC completely removed 20 mg L −1 BPA from a solution within 6 min with a degradation rate constant of 0.68 min −1 . The LC–MS test revealed that BPA is decomposed into small molecules, and TOC was greatly reduced. Electron paramagnetic resonance and quenching experiments demonstrated the Co-WDC degradation system acted through two pathways, radical and non-radical pathway where 1 O 2 was the dominant species. Material characterization and discussion of the mechanism revealed that the introduction of Co mainly formed a metal-nitrogen structure that induced peroxymonosulfate to produce 1 O 2 , which participated in BPA degradation in the Co-WDC system. This work should generate interest in the recycling of waste biomass for peroxymonosulfate activation and environmental modification.