Mild Conditions Method to Remediate Hazardous Jarosite and Its Application as Adsorbent of Arsenic(V) and Water

Abstract

The environmental risks of industrial jarosite (JAR) were mainly attributed to its average particle size (8.6 µm) and its content of leachable heavy metals such as cadmium (Cd, 64.2 mg L−1), lead (Pb, 4.16 mg L−1), and arsenic (As, 0.27 mg L−1). In this study, various methods were reported to eliminate the leachable elements contained in JAR without collapsing the crystalline structure: acid leaching, ionic exchange, and extended remediation. The effect of pH (2–10), temperature (20–175 °C), and time (<30 min) on the leaching of Cd, Pb, and As were studied. The ultrasound-assisted leaching process (at <60 °C and for 12 min) using a 0.19 M H2SO4 solution allowed to obtain a reduction of leachable Cd (99.2 wt. %), Pb (94.2 wt. %), and As (98.1 wt. %). Although the H2SO4 remediated jarosite, for example, still had a content of Pb, Cd, As, and Mn of 9.25, 0.91, 3.89, and 2.41 g kg−1, respectively, these metallic compounds were insoluble in the pH interval of 2 to 10. The jarosite obtained using acid leaching, JAR2L, had the highest adsorption capacity of As(V) (Qmax = 7.55 g kg−1), while the jarosite obtained using extended remediation had the highest water adsorption capacity (165 mL kg−1). The JAR can be remediated using acid ultrasound-assisted leaching and it can be applied in formulating strategic materials for the chemical industry.