Engineering Iron–Microbe Interfaces on Biochar to Regulate Phosphate Fixation and Ibuprofen Retention across Soil–Water Continua

Biochar is a carbon material that can be produced from renewable biomass and has been primarily used in soil remediation and regarded as a functional carbon material due to its cost-effective and environmentally friendly characteristics. Aside from the primary aim of pollution remediation, biochar in this study was prepared using the invasive plant Leucaena leucocephala to achieve the forest conservation goal. Biochar was sequentially modified by acid washing followed by iron loading. The textural properties were enhanced, raising the BET surface area from 68 to 102 m²/g and improving pore volume 266%. Magnetically iron-modified biochar (Fe-ATB) achieved efficient phosphate recovery, exhibiting a 17-fold increase in binding affinity over pristine biochar. Magnetite formation (∼31% Fe oxide) enabled high magnetic recovery efficiencies in both aqueous (96.0%) and soil (91.2%) systems, supporting its economic viability for reusable adsorption cycles. Further research will be conducted on an emerging contaminant, Ibuprofen (IBP), using green waste from mixed wood as the source of biochar, adopting a more sustainable approach. To enhance IBP adsorption and degradation, additional modification of microbe loading will be applied to Fe-ATB. Out of 27 bacterial strains tested, six strains including Cellulosimicrobium funkei, Promicromonospora thailandica, Serratia marcescens, Bacillus aryabhattai, Sphingorhabdus buctiana, and Gordonia terrae exhibited high IBP tolerance up to 500 mg kg^-1. Therefore, applying iron-modified and microbe-loaded biochar is expected to improve IBP degradation, adsorption, and overall removal efficiency in IBP-contaminated soil and water, while facilitating magnetic separation and circular utilization, thereby contributing to sustainable remediation strategies.