Adsorption for perfluorooctanoic acid with graphitic‐phase carbon nitride and its HPLC fluorescence determination

Abstract In this paper, graphitic‐phase carbon nitride (g‐C 3 N 4 ) was prepared from urea and detected by FTIR, XRD, SEM, TEM, Boehm titration, zeta potential, and N 2 adsorption‐desorption analyzes, demonstrating that g‐C 3 N 4 possesses a thin sheet structure, negative surface, and strong alkalinity. Considering the alkaline groups and huge areas, g‐C 3 N 4 was employed to adsorb perfluorooctanoic acid (PFOA). The adsorption capacity of g‐C 3 N 4 towards PFOA was evaluated by batch adsorption experiments, indicating the considerable adsorption capacity of 120.879 mg g −1 . The isothermal models and kinetic models were also performed in order to study the adsorption process, proving that PFOA adsorption was fitted by the Langmuir isothermal model and pseudo second‐order model. In addition, residual PFOA concentration after adsorption was determined by high performance liquid chromatography (HPLC) with a fluorescence detector after being derived with 3‐(2‐bromoacetyl) coumarin (3‐BrAC). The HPLC fluorescent detection showed satisfied linearity from 0.5 to 20.0 ug mL −1 with a sound R 2 of 0.9992. This is the first time that g‐C 3 N 4 was applied to PFOA adsorption from aqueous solutions with outstanding adsorption capacity.