Effect of co-existent Al(III) in As-rich Acid Mine Drainage (AMD) on As removal during Fe(II) and As(III) abiotic oxidation process. (December 2021)

• Record Type: Journal Article
• Authors: Yuan, Zidan; Ma, Xu; Wang, Shaofeng; Yu, Le; Zhang, Peiwen; Lin, Jinru; Jia, Yongfeng
• Is Part Of: Journal of water process engineering. Volume 44(2021)
• Publication Date: 2021-12
• Subjects: As(III)-rich AMD -- Fenton-like reaction -- Co-existent Al(III) -- Removal -- Oxidation; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2021.102395
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: The effect of co-existent Al(III) in As-rich AMD on As removal via oxygen-induced abiotic oxidation caused concern due to weak affinity between Al(III) hydroxide and As(III). The removal of As from As-rich AMD with and without Al(III) at various pH and Fe/(Al)/As molar ratios was investigated. The results showed that 92.3–99.8% of As in Al(III)-containing systems was removed by 70–100% of Fe(II) and 40.2–67.8% of As(III) oxidation in 1–4 h at pH 3–9 and Fe/Al/As molar ratios of 2–8:1:1. Arsenic removal efficiencies generally increased with increasing the pH and Fe/Al/As molar ratio. Arsenic oxidation efficiencies first increased from pH 3 to 5 and then decreased from pH 5 to 9, while an opposite trend occurred with increasing the Fe/Al/As molar ratio. As(III) oxidation was controlled by ROS contents involving the Fenton-like reaction between Fe(II) and O2 . Ferric arsenite hydroxysulfate, ferric arsenate and As-bearing ferrihydrite+schwertannite were the main As sinks. Co-existent Al(III) promoted As(III) oxidation. The proposed method for aqueous As removal with the total As (As(T)) leaching solid product at pH 5 and Fe/Al/As molar ratio of 8:1:1 can bring the As level to the required limit as emphasized in regulatory frameworks. Highlights: Effect of co-existent Al(III) in As-rich AMD on abiotic As removal is studied. 92.3–99.8% of As is removed in 4 h at pH 3–9 and Fe/Al/As molar ratios of 2–8:1:1. 40.2–67.8% of As(III) is oxidized to As(V) by Fenton-like reaction of Fe(II) and O2. Fe(III)-As(III + V) co-precipitate is the major solid product for As immobilization. Co-existent Al(III) facilitates the As(III) oxidation without affecting As removal.