GdVO4 modified fluorine doped graphene nanosheets as dispersed photocatalyst for mitigation of phenolic compounds in aqueous environment and bacterial disinfection

The agglomeration of graphene based photocatalysts is major bottleneck for their applicability in slurry type photoreactors. In this work, we have prepared fluorine doped graphene (FG) as high dispersed adsorbent by sonochemical exfoliation method. GdVO4 nanoparticles were anchored on FG to fabricate GdVO4/FG photo catalyst. The high-dispersion of FG and GdVO4/FG was ascertained by zeta potential measurements and Tyndall effect. The atomic force microscope analysis depicted that thickness of FG and GdVO4/FG was less than 2.0 nm. The band gap of GdVO4/FG was 2.1 eV. The high surface area of GdVO4/FG was suited for adsorption coupled photocatalysis involving mineralization of phenol and 2, 4-dinitrophenol (DNP) in aqueous medium. The photodegradation process followed pseudo first order kinetics. The simultaneous adsorption and photocatalysis was most efficient process for degradation of selected phenolic compounds. Under visible light, both phenol and DNP mineralized in 7 and 9 h, respectively. The high performance liquid chromatography and mass spectrometry confirmed the formation of intermediate during degradation process which ultimately mineralized into CO2 and H2O. The photocatalytic activity of GdVO4/FG was also tested for bacterial disinfection of Pseudomonas fluorescence, Staphylococcus aureus, Streptococcus enterica, Bacillus subtilis and Escherichia coli bacteria. The oxidative radical species OH center dot and O-2(center dot-) played vital role in photodegradation and disinfection process. Due to high dispersion and recyclability, GdVO4/FG could be used as an efficient photocatalyst for removal of both biotic and abiotic pollutants present in water.