Optimization of ciprofloxacin adsorption onto CoFe-MOF aerogel cylinders based on response surface methodology: Adsorption kinetics, isotherm models

In materials technology, composites are considered as one of the potential materials due to their stable structure, ability to contain functional groups that are essential for adsorption, porosity and large specific surface area, and processing process. Metal-organic framework materials based on carboxymethyl cellulose (CMC) substrates were synthesized through a solvothermal method to recover the antibiotic ciprofloxacin in an aqueous medium. Several experimental parameters that affect the adsorption process were investigated, including adsorption time, solution pH, ionic strength, and initial concentration. The langmuir isotherm and pseudo-second-order are in close agreement with the ciprofloxacin adsorption assay data. The CoFe-MOF aerogel material at the ratio of 1 CMC has a relatively high CIP adsorption capacity with an adsorption capacity of 226.8 mg/g at pH 8, an initial CIP concentration of 80 ppm for 90 min. The Box-Behnken design was used to optimize the adsorption process through 15 runs of experiments based on the response surface method (RSM). The analysis of variance (ANOVA) showed that the correlation between the test and the prediction followed the quadratic polynomial model with the regression parameter R2 = 0.9984. The optimal conditions for removal of 64.85% CIP were predicted to be 0.013 g/L CoFe-MOF aerogel, a CIP concentration of 92.42 mg/L, and a pH 7.26 within 90 min. In addition, the electrostatic interaction between the adsorbent and the adsorbent surface is significantly affected by the competition of Na ions in the salt and the solution pH value. In summary, CoFe-MOF aerogel is considered a suitable material that can have significant effects on wastewater treatment and a potential candidate for extended advanced research.