Engineering of Activated Biochar Derived from Pine Needle Waste Biomass as Ozonation Catalyst in Water

Abstract

Valorization of biomass wastes into carbon-based catalysts for water treatment is a clear paradigm of sustainability.Herein, we investigate an unprecedented transformation of pine needle waste biomass into activated biochars (PNCs) as ozonation catalysts for aqueous oxalic acid degradation. The physico-chemical and textural properties of PNCs are tailored by combining pyrolysis temperatures up to 1200 °C and the use or not of KOH or K₂CO₃ as activating agents. The physico-chemical and structural properties of these carbocatalysts are correlated with their catalytic activities. The PNC catalyst pyrolized at 1200 °C for 4 h using K₂CO₃ (PNC1200-4K₂CO₃) provides a complete pollutant degradation after 150 min, while PNC catalyst pyrolized at 1200 °C for 4 h without activation requires 300 min. PNC1200-4K₂CO₃ performance compares favorably with previous reports. The superior catalytic activity of this reusable catalyst is attributed to its highest population of π-extended aromatic domains as active sites together with high porosity. The catalytic formation of ¹O₂, HO^. and HOO^. radicals are supported by electron paramagnetic resonance measurements and selective quenching experiments. Unlike most of the previous analogous reports, herein, we demonstrate that ¹O₂ in the presence of PNC1200-4K₂CO₃ can degrade oxalic acid even in the presence of common radical scavengers.