Synthesis and phosphate adsorption performance of elephant dung biochar modified with magnesium and iron

The large production volume combined with the high lignocellulose content makes elephant dung an attractive and underutilized biomass resource, but also presents waste management problems for orphanages. This study explored conversion of into biochars by slow pyrolysis at 500°C recovery phosphate. unmodified biochar (BC500) had a specific surface area (SBET) 62.5 m2×g-1 point zero charge (pHPZC) 7.7. Biochar modification MgCl2 (MgBC500) FeCl3 (FeBC500) pre-pyrolysis treatment affected SBET (48.7 259.4 m2×g-1, respectively) pHPZC (8.7 3.3, respectively). In FeBC500, Fe was present as magnetite (Fe3O4) hematite (α-Fe2O3) confirmed X-ray diffraction. Instead adsorption, both BC500 MgBC500 released phosphate pH 3-6. Phosphate adsorption onto FeBC500 reached equilibrium within 24 h followed pseudo-second order kinetics. isotherm best described Langmuir equation maximum capacity 0.744 mg-P×g-1. behavior related to metal biochar. Conversion environmentally friendly solution that may find further applications in other nutrients or pollutants.