v-doped starch/graphitic-carbon nitride composite for enhanced pollution degradation through response surface methodology: the study of photocatalytic and adsorption process

The v-doped starch/graphitic carbon nitride was synthesized for the degradation of organic pollutants. this novel photocatalyst was characterized by various techniques including fourier transform infrared (ft-ir) spectroscopy, field emission scanning electron microscopy (fesem), x-ray diffractometer (xrd), photoluminescence (pl) spectroscopy, energy dispersive x-ray (edx), transmission electron microscopy (tem), and brunauer-emmett-teller (bet) analysis. based on the central composite designs-response surface methodology (ccd-rsm) design, 50 full experiments were done including ph (7.8-9.8), adsorbent dose (0.01-0.1 g), mb concentration (2-12 ppm), time (30-240 min), and temperature (15-45 °c) for the methylene blue removal by v-doped starch/graphitic carbon nitride, and the best removal yield (90.8 %) was obtained at ph=8.33, 0.08 g adsorbent dose, 12 ppm of mb concentration, 215 min, and 15 °c. further, the interaction of adsorption parameters was considered, and the freundlich and pseudo-second-order were shown as the best adsorption models. after the adsorption process, the photocatalytic degradation of mb was conducted under uv irradiation with high yield (92 %), and the trapping experiments confirmed the photocatalytic degradation. as a result, the v-doped starch/graphitic carbon nitride can be employed for the adsorption and photocatalytic activities for the removal of organic pollutants from aqueous solution.