Facile fabrication of mesoporous iron modified Al2O3nanoparticles pillared montmorillonite nanocomposite: a smart photo-Fenton catalyst for quick removal of organic dyes

Abstract

A mesoporous iron modified Al₂O₃ nanoparticle pillared montmorillonite nanocomposite (mesoporous Fe/APM nanocomposite) was synthesized by using sodium exchanged montmorillonite by cation-exchange, gallery-templated synthesis and impregnation method. Formation of Al₂O₃ nanoparticles (Al₂O₃ NPs) having average particle size 5.20–6.50 nm within montmorillonite, formation of mesoporous Al₂O₃ NPs pillared montmorillonite (mesoporous APM) from montmorillonite and formation of a mesoporous Fe/APM nanocomposite signifies the present investigation. The roles of ammonia, CTAB, octyl amine and calcination temperature for fabrication of mesoporous Fe/APM nanocomposite were highly significant. Ammonia was used for post-synthesis treatment, which helped in the formation of micellar assemblies in the interlayer space. The materials were characterized by different techniques such as N₂ adsorption–desorption study, which demonstrated the mesoporosity of the material. A transmission electron microscopy (TEM) image proves the morphology and size of the Al₂O₃ NPs and mesoporous Fe/APM nanocomposites. X-ray diffraction technique (XRD) describes the formation of the pillaring of the Al₂O₃ NPs within montmorillonite (APM). It has been noted that pure montmorillonite is a micro/mesoporous material. But after pillaring of Al₂O₃ NPs within the montmorillonite, mesoporosity developed, which is the vital aspect of present investigation. It was observed that the mesoporous Fe/APM nanocomposite has high photo-Fenton activity towards degradation of organic dyes such as acid blue (AB) and reactive blue (RB). Nearly 100% degradation took place within 30 minutes with high concentration of dye (500 mg L⁻¹) by mesoporous 5 Fe/APM nanocomposite under ambient conditions. Small particle sizes of nanocomposite, quick reduction of Fe(III) and mesoporosity are the key points for proficient degradation of AB and RB.