Silicate minerals control the potential uses of phosphorus-laden mineral-engineered biochar as phosphorus fertilizers

Abstract Silicate minerals constitute the main components in silicon (Si)-rich biomass, affecting phosphorus (P) adsorption and release competencies of mineral-engineered biochar; however, mechanisms underlying their differences remain largely unresolved. To examine these interactions, we investigated mineralogical compositions quantified P-adsorption capacities Al-, Fe-, Mn-, Zn-, Mg-engineered biochars from Si-rich rice husk material. The potential uses P-laden biochar for P fertilizers were assessed using citric acid extraction. results X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectrometry revealed that mixed metal (oxyhydr)oxides metal-silicate compounds precipitated structure acted as adsorbents. Micro-crystalline silicates derived biomass-induced precipitates all engineered biochars, which effectively retained aqueous with varying excellent (25.6–46.5 mg/g) but relatively slow kinetics (48 h). suitability Mg-, Fe-biochars P-recycled was confirmed by high amounts extractable (19–69% total P). Varying Zn, Mg, Mn (34–47% host metals) also released through ligand-promoted dissolution. Our data shed light on novel utilization Mg- Zn-biochars biomass retrieval use P, micronutrient (Mn Zn) fertilizers. Regarding removal capacity, needed a longer period than conventional metal-engineered biochar. Graphical