Value adding red mud waste: High performance iron oxide adsorbent for removal of fluoride. Issue 3 (June 2017)

• Record Type: Journal Article
• Authors: Pepper, Rachel A.; Couperthwaite, Sara J.; Millar, Graeme J.
• Is Part Of: Journal of environmental chemical engineering. Volume 5:Issue 3(2017:Sep.)
• Page Start: 2200
• Page End: 2206
• Publication Date: 2017-06
• Subjects: Akaganeite -- Bauxite residue -- Synthesis -- Fluoride -- Adsorption; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2017.04.031
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: A novel method for the synthesis of iron oxide based sorbents from bauxite residue (red mud) was developed by way of a sequential digestion and selective precipitation process. The red mud was consecutively digested with phosphoric acid and hydrochloric acid, precipitated by sodium hydroxide addition, and aged for 72 h at pH 3–3.5. This process allowed the production of a relatively pure crystalline material, akaganeite (β-FeOOH), comprised of high surface area (223 m 2 /g). The performance of the synthesised material as a fluoride sorbent was compared with a commercial adsorbent (granular ferric hydroxide). Equilibrium isotherms revealed that both sorbents reduced the amount of fluoride in solution to <1.5 mg/L. Significantly, the red mud derived akaganeite had a higher maximum adsorption capacity than the commercial granular ferric hydroxide (11.40 and 9.23 g/kg, respectively). Performance differences were suggested to relate to the presence of active sites which comprised of iron and aluminium and/or titanium species.