Synthesis and characterisation of LDH‐type anionic nanomaterials for the effective removal of doxycycline from aqueous media

In this work, the removal of a model antibiotic named ‘doxycycline’ by three‐layered double hydroxides (LDHs) such as Mg–Fe LDH, Mg–Al LDH and Mg–Al/MWCNT LDH was investigated. Almost full characterisation of the prepared LDHs before and after adsorption was conducted using X‐ray diffraction, Fourier‐transform infrared spectroscopy, zeta potential, Brunauer–Emmett–Teller used for detecting the surface area, high‐resolution transmission electron microscope (HRTEM) and field emission scanning electron microscope. The effect of different factors on doxycycline adsorption capacity was investigated. The removal percentages of doxycycline were 80, 82 and 92% by Mg–Fe LDH, Mg–Al LDH and Mg–Al/MWCNT LDH, respectively. These results were attributed to the difference in the pore volume and geometry between the different LDHs. The isothermal and kinetic models of adsorption were also studied. The kinetics of adsorption were described by the second‐order equation with a better fit showed by a high R 2 value. Mathematically, the Langmuir and Freundlich models best fitted the equilibrium data.