Rapid Preparation of g-C3N4/GO Composites via Electron Beam Irradiation for Enhanced Ofloxacin Removal

In this study, a highly efficient graphitic carbon nitride/graphene oxide (X kGy-g-C3N4/GO, X: mean different irradiation dose of 200, 300, 400, and 500 kGy) adsorbent was successfully prepared by electron beam irradiation method (EBR) and used for the adsorption of ofloxacin (OFL). Structure and morphology characterization results confirmed the successful composite of g-C3N4 and GO through EBR. The effects of various conditions on the adsorption capacity, including irradiation dose, pH, adsorbent dosage, and initial OFL concentration were analyzed in detail through experiments. Results indicated that 400 kGy-g-C3N4/GO exhibited the maximum adsorption capacity for OFL (222.0 mg·g−1), and the adsorption performance was affected by pH through electrostatic interactions, reaching optimum at pH = 7.0. Coexisting ion experiments revealed that CO32− reduced OFL adsorption capacity. The adsorption isotherm and kinetics were best described by the Langmuir model (R2 = 0.984) and pseudo-second-order model (R2 = 0.995), respectively. Thermodynamic studies of adsorption indicated a spontaneous and exothermic in adsorption process (∆G0 = −25.21, ∆S0 = 0.050, and ∆H0 = −10.25). This research provides a fresh approach to the reasonable design of g-C3N4/GO composites as adsorbent with potential applications in OFL wastewater treatment.