Evaluation of the Efficiency of Double Aluminum-Magnesium Layered Nano-Hydroxide in Removal of Pharmaceuticals from Aquatic Solutions and Determination of Optimal Adsorption

Background: Antibiotics and their metabolites are known as dangerous non-degradable substances that potentially remain after the wastewater treatment process. Therefore, it is necessary to remove these compounds from aqueous solutions. This study aimed to use layered double nano-hydroxides to remove carbamazepine, cephalexin, and ciprofloxacin.   Methods: In this experimental study the characteristics of double aluminum-magnesium layered nano-hydroxide were investigated by SEM, FTIR, XRD, and DLS. In order to determine the removal efficacy of this adsorbent; the effects of pH, adsorbent dose, contact time and initial concentration of antibiotics was investigated and the isotherms and kinetics of absorption were determined.   Results: According to the SEM and TEM analysis, the synthesized adsorbent had a hexagonal shape and its size ranged from 200 to 1000 nm. The analysis of XRD and FTIR showed that the adsorbent is a layered double hydroxide. The highest removal rate of antibiotics was observed at the contact time of 120 min, pH of 9, the adsorbent dose of 8 g/L and concentration of 30 mg/L for all three types of antibiotics which was 94%, 91% and 97% for carbamazepine, cefalexin, and ciprofloxacin respectively.  The study of isotherm and kinetics showed that absorption data were more consistent with the Freundlich model and pseudo-second-order kinetics.   Conclusion: The results of this study showed that layered double hydroxide that was synthesized by urea hydrolysis, had high efficacy in the treatment of carbamazepine, cephalexin, and ciprofloxacin.