Rapid and Effective Ultrasonic‐Assisted Adsorptive Removal of Congo Red onto MOF‐5 Modified by CuCl2 in Ambient Conditions: Adsorption Isotherms and Kinetics Studies

Abstract In this study, ultrasonic‐assisted removed Congo red by MOF‐5/Cu as a metal‐organic framework, making the adsorption process very fast. Ultrasonic has proven to be a handy tool in accelerating dyes′ adsorption by enhancing the adsorbent‘s affinity and the adsorbent. MOF‐5 synthesized the solvothermal method and then modified it by CuCl 2 in ambient conditions. Scanning Electron Microscope (SEM), X‐ray Diffraction (XRD), Fourier Transform Infrared (FT‐IR), Brunauer‐Emmett‐Teller (BET), and Thermogravimetric analysis (TGA) were used for the identification structure and morphology of MOF‐5/Cu. Sonication had an essential role in shortening the adsorption time (2 min) of Congo red by enhancing the dispersion of adsorbent (MOF‐5) in solution. Congo red concentration was measured with a UV‐visible spectrometer apparatus. Optimal values of Congo red concentration, Dosage of MOF‐5/Cu, time, and pH were obtained by Central composite design. According to the optimal parameters, the adsorption process was very rapid. Removal of Congo red happened with excellent adsorption capacity (357.42 mg g −1 ). Also, the MOF‐5/Cu was regenerating by acetone five‐time and show good results. Repeatability of the adsorption process was carried out, and the Relative Standard Deviation (RSD) was obtained 1.85 %.