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

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 CuCl2 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 %.

Automated summary

In this study, ultrasonic-assisted removal of Congo red by MOF-5/Cu as a metal-organic framework was effective and efficient. The use of sonication played a crucial role in accelerating the adsorption process by enhancing the dispersion of the adsorbent in the solution. Optimal parameters obtained by Central composite design led to a rapid adsorption process with excellent adsorption capacity for Congo red.