Hydroxyapatite nanoparticles on dendritic α-Fe2O3 hierarchical architectures for a heterogeneous photocatalyst and adsorption of Pb(ii) ions from industrial wastewater

Abstract

A facile surfactant free hydrothermal process was used to prepare dendritic α-Fe₂O₃ and hydroxyapatite (HAp) nanoparticles dispersed on dendritic α-Fe₂O₃ nanostructures. The dendrite consists of a 1 μm long central trunk with secondary branches of 80 nm. The prepared nanocomposite with a mesoporous structure exhibits a high specific surface area. A possible formation mechanism for the dendrite is proposed. These HAP/α-Fe₂O₃ nanocomposites were further used to degrade methyl violet (MV) dye using photodegradation and adsorb Pb(II) ions from industrial waste water through an adsorption process. These investigations clearly confirm the extremely fast degradation and adsorption of the dye and Pb(II) ions from the aqueous solution. The experimental adsorption data also very well fit with the pseudo-second-order model. The results confirm the new method has advantages of both a photodegradation and adsorption process for the removal of various wastewater pollutants. The present method is more energetic, cost effective, sustainable and also easily recycled after the adsorption process with a high recovery ratio due to the magnetic response of the nanocomposite.