Optimization of methylene blue photodegradation by Cr-PTC–HIna/TiO₂ composite using box-behnken design application

The Cr-PTC–HIna/TiO₂ composite synthesized using an isonicotinic acid modulated chromium and perylene-based metal-organic framework (Cr-PTC–HIna MOF) and titanium oxide (TiO₂) showed promising results for the photodegradation of methylene blue. The composite was synthesized through the solvothermal method with a molar ratio of Cr and Ti of 1:1 mmol. The XRD diffraction patterns of Cr-PTC–HIna/TiO₂ composite showed sharp peaks at 2θ = 12°, 25°, 27°, 37°, 48°, 54°, 55°, and 62° with crystal sizes of 14.144 nm. The Cr-PTC–HIna/TiO₂ composite has a band gap energy of 2.02 eV and a rod-shaped morphology with a particle size of 239.16 nm. The Box-Behnken Design (BBD) demonstrated that the composite can achieve an optimum degradation efficiency of methylene blue of 88.55 % under methylene blue initial concentration of 35.7 ppm, pH 6.6, and photocatalyst mass of 0.13 % under 250-watt Mercury lamp irradiation for 2 h.