Fabrication of rGO/g‐C 3 N 4 /TiO 2 Composite and Its UV‐Photocatalytic Performance for Removal of 2‐Methylisoborneol and Geosmin in Water

ABSTRACT Efficient techniques for removing off‐flavor substances are urgently needed. This study prepared the rGO/g‐C 3 N 4 /TiO 2 composite to investigate its photocatalysis performance for removing geosmin (GSM) and 2‐methylisoborneol (2‐MIB) in water under ultraviolet (UV) light irradiation. The effects of different factors on the removal efficiency of GSM and 2‐MIB were deeply discussed. The results indicated that the introduction of rGO effectively promoted the separation of photogenerated charge carriers while the heterojunction formed by g‐C 3 N 4 and TiO 2 broadened the spectral response range. Over 90% of 2‐MIB and GSM were removed within 60 min under the optimal conditions. Co‐existing HCO 3 − , CO 3 2 − , and NO 2 − in water inhibited the removal of off‐flavor substances by photocatalysis. The removal of GSM did not depend on pH, whereas 2‐MIB showed improved removal at neutral conditions. The catalytic activity of rGO/g‐C 3 N 4 /TiO 2 remained stable after three cycles of use. The UV photocatalysis of rGO/g‐C 3 N 4 /TiO 2 relied on the synergistic effect of the Type‐II heterojunction and rGO to generate more active species such as ·OH, 1 O 2 , O 2 · − , and h⁺. The removal of GSM was dominated by ·OH, whereas 2‐MIB removal was controlled by 1 O 2 . This study provided a feasible approach for the efficient removal of off‐flavor substances in water.