A noble method to immobilize titanium dioxide (TiO2) powder to expanded polypropylene (EPP) balls with controlled-temperature melting method was developed. Based on the comparison of degradation efficiency between uncoated and TiO2-embedded EPP balls under UV illumination, the degradation of methylene blue was significantly improved using TiO2-embedded EPP balls, and surface reactions in heterogeneous photocatalysis were found to be more dominant than photoinduced radical reactions in aqueous solutions. Also, the algal growth in river was suppressed after the buoyant TiO2-embedded EPP balls were applied. Thus, TiO2-embedded EPP balls were found to be an effective photocatalyst to suppress the algal growth in river.