Ternary nano-composites of polypyrrole/iron oxide/fly ash cenosphere (PPY/Fe3O4/FAC) were synthesized and used as magnetic photocatalyst. The synergistic effect of FAC, a buoyant carrier and polypyrrole, a conducting polymer enhanced the photocatalytic activity. Different composites were synthesized by varying the concentration of Fe3O4 and FAC to evaluate its effect on the photocatalytic properties of composites. The presence of Fe in Fe2+ and Fe3+ oxidation states at binding energies of 709.3 and 711.4 eV respectively was depicted by XPS curve. PPY/Fe3O4/FAC (1 : 3) composite showed the highest photocatalytic activity with rate constant (k) 0.0058 min–1. The removal efficiency of BPA was found to be around 75% and ~62% total organic content (TOC) was eliminated at optimized conditions from the solution. Transmission electron microscopy (TEM) showed the cluster morphology of the PPY/Fe3O4/FAC nano-composites with ~6–10 nm size of Fe3O4. X-ray diffraction studies elucidated the characteristic peaks of both PPY and Fe3O4 at 2θ ~ 20°–30°, and 26.04°, respectively in the composites which also confirmed the interaction of PPY with Fe3O4.