Highly efficient removal of congo red and methyl orange by using petal-like Fe-Mg layered double hydroxide

Abstract

ABSTRACT In this work, petal-like Fe-Mg layered double hydroxide (LDH) was fabricated by a simple solvothermal method. A well-defined petal-like shape was observed in SEM and TEM characterisations. The ability of petal-like Fe-Mg LDH for the removal of congo red (CR) and methyl orange (MO) in aqueous solution was investigated. The prepared LDH was characterised with XRD, FTIR, TGA and BET surface area analysis. Various parameters such as initial dye concentration, pH, temperature, and contact time were examined. Moreover, the reusability of adsorbent was investigated and promising results were obtained. The maximum adsorption capacity of Fe-Mg LDH was found to 894.71 mg/g and 370.36 mg/g for CR and MO, respectively. The experimental results showed the adsorption data on optimal conditions were found to follow the pseudo-second-order model with a high degree of correlation coefficient. These results demonstrate that the surface of LDH is homogeneous with the adsorption mechanism of monolayer uptake. The Fe-Mg LDH can be regenerated by calcination and can be efficiently reused up to 6 times after the adsorption of CR and MO.