Engineered Ti/Fe-biochar derived from straw lignin supporting ZnAl-layered double hydroxide nanosheets for enhanced oxidant activation: Towards effective degradation of emerging contaminants and artificial photosynthesis-promoted tobacco growth

A heterostructured composite (BCLDH) was fabricated by in situ growth of ZnAl-layered double hydroxide nanosheets on engineered Ti/Fe-biochar derived from straw lignin. The material exhibits a hierarchical porous structure, a high surface area (312 m² g⁻¹), and uniformly dispersed active components. BCLDH0.2 acts as an efficient peroxymonosulfate activator and visible-light photocatalyst, enabling complete degradation of the neonicotinoid insecticide nitenpyram within 15 min with a 39% mineralization rate. The enhanced activity stems from improved charge separation via heterojunction engineering and synergistic radical generation (SO₄•⁻, ·OH, ¹O₂). The catalyst shows excellent stability and compatibility in various water matrices. Notably, foliar application of BCLDH0.2 significantly promoted tobacco growth, increasing fresh and dry weights by up to 56% and 49%, respectively. This effect is attributed to an “artificial photosynthesis” mechanism, where photogenerated electrons transfer to chloroplasts and enhance the photosynthetic electron transport rate. This work provides a dual-functional material strategy that integrates agricultural waste valorization, advanced oxidation processes, and photosynthesis enhancement for sustainable environmental and agricultural applications. • ZnAl-LDH/Ti/Fe-biochar enables atomic-level charge separation & electron transport. • PMS/Vis/composite: nitenpyram fully degraded in 15 min (39% min.), multi-radical. • Foliar composite boosts tobacco biomass (56%) via photoelectron-chloroplast transfer. • Waste-derived, stable in water & flow systems; LCA confirms eco-compatibility.