
Keywords: 4-HB; 4-Hydroxybenzoic acid; 3,4-DHB; 3,4-Dihydroxybenzoic acid; NH4OH; Ammonia solution; BET; Brunauer, Emmet and Teller; FTIR; Fourier transform infrared spectroscopy; G-Fe3O4; Graphene-magnetite; HPLC-UV/Vis; High performance liquid chromatography with