Optimization of Multilayer Adsorption of Methyl Orange Onto Metal‐Organic Framework 5: A Highly Effective Adsorbent Synthesized via a Faster and Greener Pathway

Metal–organic framework 5 (MOF‐5) was successfully synthesized via reflux method in 4 h at 150 °C and under ambient pressure. The XRD suggests a crystalline structure and the Raman spectrum is dominated by the vibration modes of the organic part. Based on SEM results, MOF‐5 is cubic in shape, with mono‐ and polycrystals ranging from 5 to 45 nm. The BET analysis revealed a microporous nature with a surface area of 533 m 2 /g. The equilibrium adsorption data showed a sigmoidal course, which is well fitted by the n‐layer BET model. While the maximum number of layers is 13.19, with an adsorption capacity of 94.2 mg/g for a single layer. The kinetic study revealed rapid MO adsorption, which is physisorption at high concentration and chemisorption at low concentrations. Response surface methodology (RSM), based on Box‐Behnken design (BBD), was used to systematically determine the optimal amounts of the three most effective Plackett‐Burman design (PBD) variables. The maximum MO removal adsorption rate of (84.5%) was obtained under optimal conditions (53 min, adsorbent dose of 0.486 g/L and MO concentration of 145 mg/L). The adsorption mechanism of MOF‐5 is based on its porosity, coordination interaction and π‐π stacking interactions.