Electrochemical Hydrogen Peroxide Generation through Circular Valorization of Waste Biomass: Co-processing Sludge Digestate and Phytomass Residues

The increasing production of digestate, a byproduct of anaerobic digestion, requires sustainable valorization strategies for avoiding landfill disposal and constraints in the development of biogas industry. This study explores the synthesis of hydrochars derived from sludge digestate and Phragmites...

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Detalles Bibliográficos
Autores: Ramírez Vidal, Álvaro, Parodi, Nadia Agustina, Martín Ruiz, Fátima, Muñoz Morales, Martín, Llanos López, Javier
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad de Castilla-La Mancha
Repositorio:RUIdeRA. Repositorio Institucional de la UCLM
OAI Identifier:oai:ruidera.uclm.es:10578/42990
Acceso en línea:https://doi.org/10.1016/j.electacta.2025.146194
https://hdl.handle.net/10578/42990
Access Level:acceso abierto
Palabra clave:2e-ORR
Circular economy
Digestate
Hydrogen peroxide
Phytomass
Waste valorization
Descripción
Sumario:The increasing production of digestate, a byproduct of anaerobic digestion, requires sustainable valorization strategies for avoiding landfill disposal and constraints in the development of biogas industry. This study explores the synthesis of hydrochars derived from sludge digestate and Phragmites australis biomass, as well as their 1:1 (w/w) mixture (H1:1) via hydrothermal carbonization (HTC). Furthermore, their subsequent pyrolysis or chemical activation with KOH was also carried out. The primary goal was to investigate the electrocatalytic performance of these materials in the electrochemical H2O2 generation through the two-electron oxygen reduction reaction (2e?ORR). All the synthesized materials underwent comprehensive physicochemical characterization, including ultimate and proximate analysis, N2 adsorption isotherms, TGA, Raman spectroscopy, FTIR spectroscopy and SEM, in order to correlate the properties of novel carbonaceous materials with their electrocatalytic performance.The characterization revealed that the H1:1 sample exhibits an interesting combination of properties, including stability, porosity, the presence of functional groups, and structural defects. Moreover, a significant reduction in functional groups was observed upon hydrochar posttreatments. Electrochemical analysis using linear sweep voltammetry (LSV) demonstrated high current density and a low onset potential for H1:1, correlating with its superior H2O2 production efficiency (100 mg L?¹ at 2 hours), surpassing thermally activated samples (64 and 36 mg L?¹). This performance was attributed to its synergistic composition, carboxylic functional groups, and structural defects, which promote oxygen adsorption and activation. These discoveries showcase the potential of transforming sludge digestate into high-performance cathode materials for sustainable H2O2 production through the cost-effective and scalable HTC technology.