Morphology controlled synthesis of α-FeOOH crystals and their shape-dependent adsorption for decontamination of Congo red dye

Abstract

The α-FeOOH nanorods with superb adsorption properties have been synthesised by a facile and scaled-up method. In this approach, KOH solution concentration plays a crucial role in controlling the morphology of α-FeOOH nanaocrystals. It has been demonstrated that the synthesised α-FeOOH nanorods are about 10 nm in diameter and 100 nm in length. The α-FeOOH nanorods have a high specific surface area (333 m2 g− 1), and exhibited super adsorption properties, with maximum adsorption capacity of 104.2 mg g− 1 for Congo red (CR). The as-prepared nanorods show a larger specific surface area than the nanoparticles do, which enhance their adsorption capacity and increase their potential for application in wastewater treatment. The adsorption process of CR on α-FeOOH nanorods was systematically investigated, which was found to obey the pseudo-second-order rate equation and Langmuir adsorption model.