MgAl-Layered double hydroxide for amoxicillin removal from aqueous media

Amoxicillin (AMX) removal from aqueous media by MgAl-Layered double hydroxide (LDH) was investigated. LDH material with Mg2+/Al(3+)molar ratio of 2 was synthesised by co-precipitation at pH 9. The resulting material was characterised by thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction and scanning electron micrograph (SEM). The surface charge of LDH was measured using zeta potential technique. AMX adsorption tests were achieved at different pHs, temperatures, contact time and initial AMX concentrations. The adsorption process turned out to be spontaneous and endothermic. AMX was found to adsorb according to pseudo-second-order kinetics, while adsorption isotherms agree with Sips model, suggesting that the adsorption of AMX onto MgAl-LDH occurs predominantly by chemisorption mechanism, showing a maximum monolayer adsorption capacity of 30.42 mg/g at 30 degrees C. Triplicate regeneration tests did not reduce the retention capacity.