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

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. 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. 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. 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.