Rapid removal of sulfamethoxazole from simulated water matrix by visible-light responsive iodine and potassium co-doped graphitic carbon nitride photocatalysts.

An environment-friendly iodine and potassium co-doped g-C3 N4 (IKC3 N4 ) photocatalyst was synthesized via the co-pyrolysis of urea and potassium iodate. Various characterization techniques were employed to evaluate the physical, thermal and chemical characteristics of the as-synthesized photocatalyst. Sulfamethoxazole (SMX) was used as a representative antibiotic pollutant. SMX removal by IK-C3 N4 photocatalysts exceeded 99% (∼23 times higher than that of pure g-C3 N4 ) within 45 min of visible light irradiation. The kinetics of SMX removal was analyzed with respect to solution pH, photocatalyst dosage and initial SMX concentration. Experimental data was found to fit the pseudo-first order kinetics and the Langmuir-Hinshelwood kinetics. The reuse of the photocatalyst up to 3 consecutive photodegradation cycles gave a minimal decline in SMX removal while the structure and the crystallinity of the nanomaterials remained unchanged. Overall, morphology engineering of conventional bulk graphitic carbon nitride can produce highly efficient photocatalysts for the decontamination of antibiotics in the aqueous environment.