Synthesis and Evaluation of Fe(III) Embedded Silane Grafted Layered Double Hydroxide with Reduced Graphene Oxide Support as an Efficient Adsorbent for V(V) and Se(IV) from Aqueous Systems

Abstract

The objectives of present work emphasize the successful usage of Fe(III) modified layered double hydroxide clays with reduced graphene support (Si-rGO/LDH-Fe) for the removal of V(V) and Se(IV) from aqueous systems. The precursors along with the modified and sorbent loaded materials were successfully characterized by BET surface area analyzer, SEM-EDS mapping, FTIR, potentiometric titrations and XPS analysis. Sorption performance of Si-rGO/LDH-Fe towards V(V) and Se(IV) under optimized conditions such as pH, temperature and concentration were investigated. The equilibrium and kinetic investigations revealed that the adsorption of V(V) and Se(IV) onto Si-rGO/LDH-Fe follows non-linear Langmuir isotherm and pseudo-second-order model, respectively. The equilibrium reached within 120 min and the Langmuir isotherm fit well with the experimental data. The adsorption mechanism was proposed to be ligand exchange with electrostatic interactions. Such results indicated that V(V) and Se(IV) species interact by the protonated hydroxyl moieties on the surface of Si-rGO/LDH-Fe. The practical efficacy and effectiveness of Si-rGO/LDH-Fe was also compared with some of the related works reported so far. The regeneration capacity and reusability of Si-rGO/LDH-Fe were also tested by employing four cycles of desorption experiments.