Lignocellulosic-based hydrochars: Synthesis, characterization and application in water decontamination

The utilization of lignocellulosic biomass for the production of carbonaceous materials has become increasingly prominent in the fields of environmental engineering and the circular economy. With the establishment of new material sources, waste management has improved, and novel materials are being synthesized with a reduced environmental impact. Consequently, hydrothermal carbonization (HTC) emerges as a sustainable and environmentally friendly thermochemical technique for the treatment of lignocellulosic biomass, particularly agro-industrial waste. HTC produces a carbonaceous material called hydrochar, which has extensive applications in environmental water decontamination processes. Hydrochars derived from agro-industrial waste serve as a sustainable alternative for the reclamation of agro-industrial byproducts and exhibit desirable properties for use in water treatment processes. The abundance of oxygenated functional groups (OFGs) and the presence of persistent free radicals (PFRs) make hydrochar a carbonaceous material suitable for diverse water decontamination applications. This review offers a thorough analysis of the synthesis, characterization, properties, and applications of hydrochars in water decontamination via adsorption and advanced oxidation processes, including heterogeneous photocatalysis and persulfate activation.