Structure, magnetism and heating ability of pyrrole-functionalized magnetic biochar (PFMB) for magnetic hyperthermia.

This work reports the synthesis, characterization, and magnetic hyperthermia performance of pyrrole-functionalized magnetic biochar (PFMB) nanocomposites prepared a hydrothermal method. The PFMB system comprises FeO nanoparticles embedded in a biochar matrix and coated with pyrrole to improve colloidal stability and heating efficiency. Structural and morphological analyses (XRD, FTIR, SEM/EDAX) confirmed the formation of a magnetite phase and successful surface functionalization. Magnetic measurements reveal a transition from ferrimagnetic behavior in bare MB to superparamagnetism in PFMB, with saturation magnetization reduced significantly from 58.8 to 20.8 emu g. Magnetic hyperthermia experiments under alternating magnetic fields (AMF) manifest enhanced heating efficiency for PFMB, with sample absorption rate (SAR) values varying considerably from 24.27 to 53.77 W g, compared to 12.34-31.80 W g for MB. The results indicate that at higher frequencies (332 kHz and 469 kHz), both MNPs reach the therapeutic hyperthermia threshold of 42 °C in a relatively short time. The heating performance correlates well with both frequency and field amplitude. Intrinsic loss power (ILP) values for PFMB reach 0.70 nH m kg, aligning with the values reported for established polymer-coated MNPs. These results demonstrate the potential of PFMB nanocomposites as efficient and stable candidates for magnetic hyperthermia applications.