Developing polyetherimide/graphitic carbon nitride floating photocatalyst with good photodegradation performance of methyl orange under light irradiation

Polyetherimide-graphitic carbon nitride (PEI-g-C3N4) floating photocatalyst has been synthesized by using polyetherimide (PEI) as linker to bind graphitic carbon nitride (g-C3N4) together. XRD and XPS analysis for PEI-g-C3N4 show that the interaction between PEI and g-C3N4 does not disturb the structure of g-C3N4. FTIR, TEM and theoretical results suggest that the long chain PEI binds g-C3N4 particles together to form PEI-g-C3N4 via hydrogen bonding interaction. Based on photodegradation results of methyl orange (MO), PEI can not photodegrade MO and just works as linker in PEI-g-C3N4, while the photodegradation performance of PEI-g-C3N4 is from the contribution of g-C3N4. Total organic carbon (TOC) analysis show that nearly 47% organic carbon has been converted into inorganic carbon after photodegradation, suggesting that PEI-g-C3N4 can destroy both NN bond and aromatic rings in MO under light irradiation. The photodegradation efficiency (91%) of MO by g-C3N4 is higher than that (80%) by PEI-g-C3N4 with stirring. But, the photodegradation efficiency (37%) of MO by g-C3N4 is lower than that (55%) by PEI-g-C3N4 without stirring. This is the advantage of floating photocatalyst with respect to the powder photocatalyst since the former can utilize more solar energy than the latter when stirring is not available.