Highly effective remediation of high arsenic-bearing wastewater using aluminum-containing waste residue

Wastewater from non-ferrous metal smelting is known as one of the most dangerous sources of arsenic (As) due to its high acidity and high arsenic content. Herein, we propose a new environmental protection process for the efficient purification and removal of arsenic from wastewater by the formation of an AlAsO4@silicate core-shell structure based on the characteristics of aluminum-containing waste residue (AWR). At room temperature, the investigation with AWR almost achieved 100% As removal efficiency from wastewater, reducing the arsenic concentration from 5500 mg/L to 52 μg/L. With Al/As molar ratio of 3.5, the structural properties of AWR provided good adsorption sites for arsenic adsorption, leading to the formation of arsenate and insoluble aluminum arsenate with As. As-containing AWR silicate shells were produced under alkaline conditions, resulting in an arsenic leaching concentration of 1.32 mg/L in the TCLP test. AWR, as an efficient As removal and fixation agent, shows great potential in the treatment of copper smelting wastewater, and is expected to achieve large-scale industrial As removal.