UiO-67 metal-organic framework loaded on hardwood biochar for sustainable management of environmental boron contaminations

Boron contamination in water poses significant potential risks to human health and the environment, necessitating the development of efficient, cost-effective, and sustainable remediation technologies. This study introduces a novel composite material combining a zirconium-based metal-organic framework (UiO-67) and a low-cost carbonaceous material (hardwood biochar, BC) with synergetic efficiency to address boron-polluted waters. The UiO-67-biochar (UBC) composite exhibits effective surface chemistry and a remarkably high specific surface area of approximately 881.9 m²/g, substantially increasing from the 19.7 m²/g of biochar. Our experimental results demonstrate that UBC removed up to 88.5 % of boron from 20 ppm polluted water, achieving levels compliant with the WHO standards. The composite also showed excellent reusability, maintaining 95 % efficiency over multiple cycles without loss of crystallinity. Life cycle assessment and cost analysis indicate that an optimal MOF to biochar ratio of approximately 60 wt% minimises CO 2 emissions and costs while maximising the boron removal efficiency. The UiO-67-biochar composites proposed here offers a promising scalable solution for boron contamination and potentially other environmental pollutants, combining the high functionality of UiO-67 with the practical and economic advantages of biochar. • Synthesised UBC composites showed strongly improved morphology and surface functionality. • UBC2 with optimum mass ratio of MOF effectively adsorbed boron from water to a safe level. • Electrostatic attractions, coordination bonds, π-π stacking, and hydrogen bonding are main adsorption mechanisms. • Reusability and stability of UBC via regeneration tests indicated promising prospect.