Mechanism and kinetics of ultrasound enhanced removal of arsenic from high alkali leaching solution for alkali recovery

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-06, Vol.489, p.151299, Article 151299
• Main Authors: Chen, Yuefeng, Xiang, Dawei, Zhu, Manying, Wang, Shixing, Zhu, Rong, Liu, Xiang, Fu, Likang
• Format: Article
• Language: English
• Subjects: Arsenic; High alkaline solution; Recovery; Removal; Ultrasound
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.151299

[Display omitted] •Ultrasound-enhanced Ba(OH)2 removes arsenic and recycles alkaline from high alkaline solution.•The arsenic precipitation rate was 93.30%, which is 77.51% higher than conventional.•Ultrasound reduces the apparent activation energy and promotes solid–liquid interfacial reaction.•The recycled alkaline solution achieved again a high arsenic leaching rate from the slag. Alkaline leaching has become one of the most commonly used methods to treat arsenic-containing waste. Efficient removal of arsenic from the high alkaline solution and reuse of alkali have become a crucial issue in its industrial application. In this study, ultrasound is used to strengthen the arsenic removal from high-alkali solutions by forming precipitation of barium arsenate and recover alkali. Under the optimal conditions, the arsenic in the alkaline solution is reduced from 3.78 to 0.25 g/L. The arsenic precipitation percentage under ultrasound is 93.30 %, which is 77.51 % higher compared to conventional arsenic precipitation. The kinetic experiments indicated that the introduction of ultrasound reduced the apparent activation energy by 23.62 kJ/mol. In addition, the precipitated phases were analyzed to investigate the removal mechanism of ultrasound-enhanced arsenic precipitation. Ultrasound can strip off the sediment wrap and promote solid–liquid interfacial reactions. After arsenic removal, alkaline solution was used to leach arsenic from zinc slag, and the arsenic leaching percentage reached 90.39 %, achieving the recycling of high alkaline solution. This work proved that ultrasonic strengthening technology is an effective green technology for removing arsenic and recovering alkali from high alkaline arsenic-containing solution.