Dye-interleaved nanocomposite: Indigo carmine and methyl orange in the lamella of zinc-aluminium-layered double hydroxide

Abstract

Layered organic-inorganic hybrid nanocomposite, containing an organic dye in an inorganic interlayer was prepared using indigo carmine (IC) and methyl orange (OM) as a guest in Zn 2 -Al layered double hydroxide (LDH) inorganic host by a ion exchange , with [Zn 2 -Al-Cl] LDH in aqueous solution. The affinity of the LDH with the dyes was studied as a function of contact time, initial pH of the solutions and initial dye concentration. It was found that 8h is enough time for the equilibrium state to be reached in IC and OM adsorption. IC and OM retention was independent of the initial pH. The adsorption isotherm of IC and OM, described by the Langmuir model, is of L-type. Powder X-ray diffractogram shows that the basal spacing of the Zn 2 -Al layered double hydroxide with Chloride as intergallery anion [Zn 2 -Al-Cl] expanded from 0.78 nm to 2.22 nm for the Zn 2 -Al layered double hydroxide-IC layered organic-inorganic hybrid nanocomposite [Zn 2 -Al-IC] and 2.4 nm for the Zn 2 -Al layered double hydroxide-OM layered organic-inorganic hybrid nanocomposite [Zn 2 -Al-OM].