Carbon nitrides can form coordination compounds or metallic oxides in the presence of transition metals, depending on the reaction conditions. By adjusting the pH to basic levels for mild synthesis with metals, composites like g-C₃N₄-M(OH)_x (where M represents metals) were obtained for nickel (II) and manganese (II), while copper (II) yielded coordination compounds such as Cu-g-C₃N₄. These materials underwent spectroscopic and electrochemical characterization, revealing their photocatalytic potential to generate superoxide anion radicals—a feature consistent across all metals. Notably, the copper coordination compound also produced significant hydroxyl radicals. Leveraging this catalytic advantage, with band gap energy in the visible region, all compounds were activated to disinfect E. coli bacteria, achieving total disinfection with Cu-g-C₃N₄. The textural properties influence the catalytic performance, with copper’s stabilization as a coordination compound enabling more efficient activity compared to the other metals. Additionally, the determination of radicals generated under light in the presence of dicloxacillin supported the proposed mechanism and highlighted the potential for degrading organic molecules with this new material, alongside its disinfectant properties.

A carbon-based material was synthesized using potato peels (BPP) and banana pseudo-stems (BPS), both of which were modified with manganese to produce BPP-Mn and BPS-Mn, respectively. These materials were assessed for their ability to activate peroxymonosulfate (PMS) in the presence of MnCO₃ to degrade acetaminophen (ACE), an emerging water contaminant. The materials underwent characterization using spectroscopic, textural, and electrochemical techniques. Manganese served a dual function: enhancing adsorption properties and facilitating the breaking of peroxide bonds. Additionally, carbonate ions played a structural role in the materials, transforming into CO₂ at high temperatures and thereby increasing material porosity, which improved adsorption capabilities. This presents a notable advantage for materials that have not undergone de-lignification. Among the materials tested, BPS exhibited the highest efficiency in the carbocatalytic degradation of ACE, achieving a synergy index of 1.31 within just 5 min, with 42% ACE degradation in BPS compared to BPS-Mn, which achieved 100% ACE removal through adsorption. Reactive oxygen species such as sulfate, hydroxyl, and superoxide anion radicals were identified as the primary contributors to pollutant degradation. In contrast, no degradation was observed for BPP and BPP-Mn, which is likely linked to the lower lignin content in their precursor material. This work addressed the challenge of revalorizing lignocellulosic waste by highlighting its potential as an oxidant for emerging pollutants. Furthermore, the study demonstrated the coexistence of various reactive oxygen species, confirming the capacity of carbon-based matrices to activate PMS.