Preparation of floating porous g-C3N4 photocatalyst via a facile one-pot method for efficient photocatalytic elimination of tetracycline under visible light irradiation

[Display omitted] •Floating porous g-C3N4 composite (FPCN) was successfully fabricated by a facile one-pot method.•FPCN exhibited a good photocatalytic performance under visible light without any stirring.•FPCN showed a good stability and reusability.•Possible degradation pathway of tetracycline and mechanism of the photocatalytic process were proposed. Powder catalysts are difficult to recycle, which may induce secondary pollution and may limit their practical application. Herein, we successfully synthesized floating porous g-C3N4 (FPCN) using a melamine sponge and urea via a facile one-pot method, which can solve the recycling problem of powder catalysts. The highest elimination efficiency of 5 mg/L tetracycline (TC) reached 70% by 2 g/L FPCN without any stirring under visible light after 4 h. However, the elimination efficiency of 5 mg/L TC by 2 g/L powder g-C3N4 was only 36.9% under the same conditions. The good photocatalytic performance of FPCN is attributed to its 3D interconnected network and enhanced light absorption. The effects of inorganic ions and organic matters on the photocatalytic performance of FPCN were studied. Finally, we proposed a possible mechanism and pathway for degradation of TC.