General to specific
Carbon-based materials and engineered nanostructures have become essential in modern water
purification technologies due to their versatility and tunable properties. Among them, biochar
produced from the thermal conversion of biomass has attracted considerable interest for
environmental applications because it is inexpensive, stable, and easily modified. When combined
with metal oxides, biochar can serve as an effective support for designing high-performance
adsorbents with enhanced surface reactivity and improved contaminant removal capabilities. Iron
oxide nanostructures, in particular, are widely utilized because of their strong affinity for oxyanion
pollutants and their suitability for incorporation into fixed-bed treatment systems.
Within this rapidly expanding field, enhancing the exposure and utilization of the active iron
species remains a key focus for researchers aiming to improve adsorption efficiency. Immobilizing
nanostructured iron oxides onto high-surface-area carbon supports is one promising direction,
especially when the support architecture can overcome diffusion limitations commonly observed
in porous granular adsorbents. Biochar fibers, because of their interconnected framework and large
external surface, represent a compelling platform for hosting iron-oxide-based nanostructures.
In this context, the present work introduces biochar fibers decorated with vertically aligned iron
oxide nano-needle arrays (Fe-NN/BFs) synthesized through a simple hydrothermal method. This
architecture is designed to optimize iron exposure, reduce diffusion limitations, and achieve rapid
arsenic removal from groundwater. Comprehensive batch and column studies were performed to
assess the adsorption kinetics, capacity, regeneration potential, and practicality of Fe-NN/BFs,
demonstrating their promise as an efficient and scalable solution for arsenic remediation