Multiaperture g-C3N4@SiO2 to activate peroxydisulfate via visible light for efficient Rhodamine B removal

The sulfate radical-based advanced oxidation process (SR-AOPs) has been verified as a promising method to handle the persistent organic compounds in water using peroxydisulfate (PDS) as oxidant. A Fenton-like process was constructed and showed great potential to remove organic pollutants using visible-light-assisted PDS activation. The g-C3N4@SiO2 was synthesized via thermo-polymerization, and characterized using powder X-ray diffraction (XRD), scanning electron microscope equipped with an energy-dispersive X-ray (SEM-EDX), X-ray photoelectron spectroscopy (XPS), N-2 adsorption-desorption, Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) method, photoluminescence (PL), transient photocurrent, and electrochemical impedance. Photocatalytic performance was demonstrated using the removal rate of Rhodamine B (RhB), and 96.08% RhB was removed from the solution within 50 min (10 mg/L in 200 mL, g-C3N4@SiO2 = 0.25 g/L, pH = 6.3, PDS = 1 mmol/L). The free radical capture experiment proved that HO center dot, h(+), O-2(center dot-) and SO4 center dot- were generated and removed RhB. The cyclic stability of g-C3N4@SiO2 has also been studied, and the result shows no noticeable difference in the six cycles. The system of visible-light-assisted PDS activation might provide a novel strategy for wastewater treatment and must be an environment-friendly catalyst.

Automated summary

The sulfate radical-based advanced oxidation process (SR-AOPs) using peroxydisulfate (PDS) as oxidant has shown great potential in removing persistent organic compounds in water. A Fenton-like process with PDS activation under visible light has been successfully constructed for the efficient removal of organic pollutants. The synthesized g-C3N4@SiO2 photocatalyst exhibited excellent performance in removing Rhodamine B, achieving a removal rate of 96.08% within 50 minutes.