Self-sufficient Fenton-Like Degradation by Cu-TA Encapsulated Melamine Sponge

Water contamination is a severe and urgent issue, and advanced oxidation processes (AOPs) offer promising solutions for water purification. Among these, copper-based Fenton-like reaction demonstrate advantages such as rapid reaction kinetics and low reduction potential. However, a major limitation of most Fenton-like reactions is their reliance on externally added H 2 O 2 , which poses risks in transportation, storage, and management. To address this, developing self-sufficient Fenton-like systems with in-situ H 2 O 2 generation is critical. In this study, we conjugated copper ions (Cu 2+ ) and tannic acid (TA) on a melamine sponge (MS) substrate to fabricate a self-sufficient Fenton-like catalyst (MS-Cu-TA). MS exhibits high porosity and absorbency, which facilitate efficient liquid absorption for the degradation process. The H 2 O 2 content generated by a single MS-Cu-TA sponge was determined as ∼0.19 mmol, which was sufficient to sustain the Fenton-like reaction. Methylene Blue (MB) degradation results showed that MS-Cu-TA achieved comparable degradation efficiency (∼60% within 0.5 h) without exogenous H 2 O 2 . Notably, in this specific dye degradation process, adsorption and degradation occurred simultaneously. Results from reactive oxygen species (ROS) quenching tests and electron paramagnetic resonance (EPR) spectroscopic analysis revealed that the dominant ROS generated is •OH, which originates from in-situ formed H 2 O 2 . The in-situ H 2 O 2 generation is likely attributed to the auto-oxidation of TA, which acts as both reducing agent and H 2 O 2 precursor. Concurrently, TA reduces Cu 2+ to Cu + , which catalyzes H 2 O 2 to generate hydroxyl radicals (•OH) via a Fenton-like reaction. This work provides valuable insights for developing self-sufficient Fenton-like systems in wastewater treatment. In this study, we conjugated copper ions (Cu 2+ ) and tannic acid (TA) on a melamine sponge (MS) substrate to fabricate a self-sufficient Fenton-like catalyst (MS-Cu-TA). The in-situ H 2 O 2 generation is likely attributed to the auto-oxidation of TA, which acts as both a reducing agent and H 2 O 2 precursor. Concurrently, TA reduces Cu 2+ to Cu + , which catalyzes H 2 O 2 to generate hydroxyl radicals (•OH) via a Fenton-like reaction.