Magnetically Separable Mesoporous Fe3O4@g-C3N4 as a Multifunctional Material for Metallic Ion Adsorption, Oil Removal from the Aqueous Phase, Photocatalysis, and Efficient Synergistic Photoactivated Fenton Reaction

Water pollution is a global problem. Therefore, efficient methods for oil/water separation, degradation of organic dyes, and adsorption of metal ions from wastewater are urgently needed for environmental protection. Herein, mesoporous g-C3N4, nanosized Fe3O4, and aminopropyl triethoxysilane were used as raw materials to assemble a multifunctional magnetic water purification material (MPG-C3N4/Fe3O4/NH2). The homogeneously dispersed Fe3O4 particles and hydrophobic hydrocarbon chain on the surface endows it with excellent magnetic oil/water separation properties even after 10 cycles. MPG-C3N4/Fe3O4/NH2 possesses prominent adsorption capacity of as high as 93.45 mg/g for metallic ions Cu2+. The adsorption of Cu2+ on MPG-C3N4/Fe3O4/NH2 is in accordance with the second-order kinetic model and the Langmuir monolayer adsorption model. Notably, MPG-C3N4/Fe3O4/NH2 can degrade organic pollutants because of its photocatalytic ability due to the heterojunction formation between MPG-C3N4 and Fe3O4 nanoparticles. The hydrophobic surface allows more oxygen to enter the heterogeneous degradation system, improving the efficiency of O2 to receive photogenerated electrons to convert into O2•–. Surprisingly, MPG-C3N4/Fe3O4/NH2 can be used as a heterogeneous photoactivated Fenton catalyst with brilliant degradation rates and efficiency (as high as 95% within 40 min) toward complicated organic pollutants, for example, RhB, phenol, and BPA with favorable reusability.