Experimental design optimization and isotherm modeling for removal of copper(II) by calcium-terephthalate MOF synthesized from recycled PET waste

In this research, a calcium-terephthalate metal-organic framework ([Ca(BDC)(H2O)(3)]) was synthesized by a new high yield solvothermal method as an efficient adsorbent. Terephthalate ligand recovered from polyethylene terephthalate (PET) waste was used as a precursor in the synthesis process. The adsorption ability of this compound to remove copper(II) from aqueous solutions was investigated. Experimental designs involving Plackett-Burman and Doehlert designs were used for the optimization of the adsorption process. Plackett-Burman design was used for screening the effective factors such as pH, adsorbent dosage, and initial concentration of Cu(II). Running Doehlert design (DD) as an optimization approach led to find a model for relation between response and effective factors and maximized uptake capacity (q) of Cu(II) (q = 351.3 mgg(-1)) under optimum conditions (pH = 5, adsorbent dosage = 1.50 mg and initial concentration of Cu(II) = 150 mgL(-1)). Infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and field-emission scanning electron microscopy (FESEM) analyses were applied to investigate the chemical and crystal structure of [Ca(BDC)(H2O)(3)]. Furthermore, kinetics, isotherms, thermodynamics, and desorption studies are complementary divisions of this research.

Automated summary

In this research, a new high yield solvothermal method was used to synthesize a calcium-terephthalate metal-organic framework as an efficient adsorbent for copper(II) removal from aqueous solutions. Experimental designs and optimization approaches were applied to investigate the adsorption process, and the maximum uptake capacity of copper(II) was achieved under the optimum conditions. Additionally, various analyses were conducted to study the chemical and crystal structure of the synthesized compound, as well as the kinetics, isotherms, thermodynamics, and desorption properties.