A green and reusable floatable bead-like core-shell photocatalyst with spinel ferrite core and shell consisting of graphitic carbon nitride nanosheet, enhanced by non-noble metal cocatalyst for anionic dye removal

Abstract

The practical utilization of powder photocatalysts is frequently obstructed by various drawbacks including rapid charge recombination, low photon utilization, post-treatment separation, photocorrosion, and the potential environmental risks associated with sedimentation. This study aims to mitigate these challenges through the fabrication of a novel spherical, floatable magnetic core-shell photocatalyst (NiFe₂O₄-Sodium Alginate@ SnO₂-g-C₃N₄), using spinel ferrite nanoparticles (NiFe₂O₄) as the core and SnO₂-g-C₃N₄ catalysts as the shell. The shell was synthesized hydrothermally, while a green synthesis approach was used for the core. The fabrication involved a gelation process to combine the shell with the core, resulting in transparent spheres with improved floating capabilities after freeze-drying. The successful synthesis was confirmed through characterization techniques such as XRD, FT-IR, EDX, XPS, and FESEM. The photocatalytic efficiency was assessed by degrading Acid Red 88 in a 200 mL batch reactor under UV-C lamp irradiation as light sources, using ambient temperature as the experimental condition. Various parameters were tested, including pH levels (3, 5, 7, 9, and 11), photocatalyst dosages (0.2, 0.4, 0.6, 0.8, and 1 g/L), and dye concentrations (10, 20, 30, 40, and 50 mg/L), in order to determine the optimal conditions. The results demonstrated a removal efficiency of 97.41 % under optimal conditions of pH 11, a photocatalyst dosage of 0.4 g/L, and an initial dye concentration of 20 mg/L. Stability and reusability tests conducted over five cycles showed a slight decrease in efficiency, from 97.41 % to 80.32 %. These findings underscore the potential of this photocatalyst for effectively treating dye-contaminated wastewater.