Highly efficient and selective adsorption of In3+ on pristine Zn/Al layered double hydroxide (Zn/Al-LDH) from aqueous solutions

Abstract A pristine Zn/Al-layered double hydroxide (Zn/Al-LDH) showed excellent adsorption ability and selectivity towards In 3+ ions from aqueous solutions. The adsorption behaviour as a function of the contact time, solution pH, ionic strength, and amount of adsorbent under ambient conditions revealed a strong dependency on the pH and ionic strength over In 3+ intake. The structure and properties of Zn/Al-LDH and In 3+ adsorbed Zn/Al-LDH (In–Zn/Al-LDH) were examined carefully by X-ray diffraction, Fourier transform infrared spectroscopy, N 2 -sorption/desorption, UV–vis spectroscopy, and X-ray photoelectron spectroscopy. The adsorbent had a sufficient number of active sites that were responsible for the In 3+ adsorption and quite stable even after the adsorption process. The selective adsorption of In 3+ on Zn/Al-LDH was also observed even from a mixture containing competing ions, such as Mn 2+ , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , and Cu 2+ . The adsorption experiments showed that Zn/Al-LDH is a promising material for the pre-concentration and selective removal of In 3+ from large volumes of aqueous solutions.