Removal of high-concentration of arsenic in acidic wastewater through zero-valent aluminium powder and characterisation of products

Untreated arsenic in acidic wastewater causes serious environmental pollution. Zero-valent aluminium (ZVAl), without pretreatment, was used in this study to remove arsenic from acidic wastewater. We demonstrated that ZVAl could remove arsenic from acidic wastewater in 30 min with over 99% efficiency. Inductively coupled plasma mass spectrometry (ICP-MS) and hydride-generation atomic fluorescence spectrometry (HG-AFS) were employed to determine the change in ion concentration in acidic wastewater before and after the experiment. The success of using ZVAl for removing arsenic from acidic wastewater was investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG). Characterisation of the precipitate after the reaction revealed that arsenic removal took place through a complex process which included reduction, surface corrosion, adsorption, co-precipitation, and chemical reactions to form precipitates. These results indicated that ZVAl is a promising material to efficiently remove arsenic from acidic wastewater in an environment friendly manner. The findings of this study will help to develop ZVAl as a method for treating arsenic-contaminated acidic wastewater. © 2021 Elsevier B.V.