Improvement of phenol photodegradation efficiency by a combined g-C3N4/Fe(III)/persulfate system

• Unmodified g-C3N4 was employed to degrade refractory pollutant for the first time.
• The synergistic interaction of g-C3N4/Fe(III)/persulfate can improve the reactivity.
• An integrated radical and light Fenton mechanism was experimentally verified.

Graphite-like C3N4 (g-C3N4) is an efficient visible-light-driven photocatalyst commonly used in dye decolorization with very poor photocatalytic efficiency for degrading recalcitrant organic pollutants, such as phenol. In this study, we designed a g-C3N4/Fe(III)/persulfate system to significantly improve the phenol photodegradation efficacy by combining photocatalysis and light Fenton interaction. The phenol removal ratio and degradation rate of the g-C3N4/Fe(III)/persulfate system are 16.5- and 240-fold higher than those of individual g-C3N4 system. Sulfate radicals (SO4
• −)(SO4
• −) and H2O2 are detected in the g-C3N4/Fe(III)/persulfate system, suggesting that both radical decomposition and light Fenton interaction play important roles in phenol degradation. The efficient coupled photocatalytic system of g-C3N4 combined with Fe(III) and persulfate shows significant potential for application in large-scale degradation of environmental pollutants.