Seaweed extract assisted CaO-NGO & CaO-BGO in removing pollutant- p-Nitrophenol and antibiotics- levofloxacin for wastewater treatment

• Synthesis of CaO-decorated N-GO and CaO-decorated B-GO. • Sunlight influenced catalytic degradation of antibiotics and nitrophenol . • Improved optical behavior with a refined band gap of 3.2 eV and 3.9 eV. • The active sites were anticipated by quantum computational studies. In this present work, Calcium oxide decorated nitrogen-doped graphene oxide (CaO-NGO) and Calcium oxide decorated boron-doped graphene oxide (CaO-BGO) were synthesized using seaweed extracts. The X-ray diffraction analysis proves the composites are equally distributed and have a well-defined crystalline nature. Further, Fourier-transform infrared spectroscopy analysis was employed to determine the functional groups and their mode of vibrations; these results confirm the successful incorporation of CaO, N, and B. The UV–Vis Diffuse Reflectance Spectroscopy analysis determined the band gap and optical properties of the synthesized composites. It was found that incorporating N and B leads to narrowing the band gap. The addition of doping elements leads to constrained band gaps compared to the pristine GO, with values of 3.2, 3.9, 4.6, and 4.9 eV. Photocatalytic degradation performance was evaluated for the degradation of p -Nitrophenol and levofloxacin. CaO-BGO shows higher degradation activity under natural sunlight at 50 mg of dosage with a time period of 120 min. Theoretical stimulated calculations were performed to determine the active species of the composites that photodegrade the pollutant and the antibiotic. This study shows that CaO-NGO and CaO-BGO exhibit enhanced photocatalytic degradation and possess visible light-active properties; it is also used as a photocatalyst to degrade pollutants from wastewater.