Controlled synthesis of microsheets of ZnAl layered double hydroxides hexagonal nanoplates for efficient removal of Cr(VI) ions and anionic dye from water

Abstract

The removal of effluents from water is necessary for environmental concerns. The common approach to the development of methodologies for water purification is to search for excellent materials with optimised chemical compositions and unique structural dimension. Here a facile chemical approach has been developed for the synthesis of microsheets of chlorine interlayer ZnAl layered double hydroxides (Cl-ZnAl LDHs) hexagonal nanoplates by simply varying the molar ratio of salts precursors in the presence of hexamethylenetetramine (HMTA). The possible formation mechanism of microsheets of Cl-ZnAl LDHs hexagonal nanoplates has been described on the basis of different characterization. The prepared unique structural microsheets exhibited ultrafast adsorption rates and high adsorption capacities in the removal of anionic methyl orange (MO) dye and Cr(VI) ions from aqueous solution. The adsorption isotherms, kinetics models and mechanisms for Cr(VI) ions and MO onto Cl-ZnAl LDHs were also investigated in detail. The high uptake capability, reusability and ultrafast kinetics make Cl-ZnAl LDHs unique structural microsheets a potentially attractive low-cost adsorbent for the efficient removal of metal ions and toxic dye from contaminated water. Furthermore, the simple synthesis strategy might be envisaged for another type of LDHs, and consequently, a variety of applications can target due to their specific structural dimensions.