A novel method for the degradation of tributyl phosphate was investigated through the use of nanopowders of iron and iron-nickel. A combination of magnetic field and sonication was used to induce degradation. Using a tributyl phosphate concentration of 300 ppm at pH 4, the Fenton reaction was initiated in the presence of sonication and a reduction in organic carbon content of up to 50% could be created under an induced magnetic field of 0.7 T. The magnetic properties of powders after sonication treatment, in the presence and absence of a magnetic field, were observed to be different. Different degradation mechanisms were proposed under the influence of varying induced magnetic field for iron and iron-nickel.