Preparation of MnO2–Al2O3 adsorbent with large specific surface area for fluoride removal--颗粒学报PARTICUOLOGY

Xu, N., Liu, Z., Bian, S., Dong, Y., & Li, W. (2016). Preparation of MnO2–Al2O3 adsorbent with large specific surface area for fluoride removal. Particuology, 27, 66-71. https://doi.org/10.1016/j.partic.2016.01.005

Preparation of MnO₂–Al₂O₃ adsorbent with large specific surface area for fluoride removal

Naicai Xu ^{a b c}, Zhong Liu ^a *, Shaoju Bian ^a, Yaping Dong ^a, Wu Li ^a *

a Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
b Department of Chemistry, Qinghai Normal University, Xining 810008, China
c University of the Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2016.01.005

Volume 27, August 2016, Pages 66-71

Received 17 November 2015, Revised 4 January 2016, Accepted 14 January 2016, Available online 16 April 2016, Version of Record 14 June 2016.

E-mail: liuzhong@isl.ac.cn; liwu@isl.ac.cn

Highlights

• MnO₂–Al₂O₃ (MOAO) nanocomposite was synthesized by an impregnation technique.

• The prepared MOAO showed good adsorption performance toward fluoride ions in water.

• MOAO exhibited promising ability to remove fluorides from water in pH range of 4–10.

Abstract

MnO₂–Al₂O₃ (MOAO) binary nanocomposite with a 1:3 MnO₂ to Al₂O₃ molar ratio was synthesized by impregnation technique using mesoporous alumina (MA) precursor. The MOAO product consisted of MA and amorphous MnO₂. The manganese valence in MOAO was +4, indicative of MnO₂ being coated on the surface of MA during the impregnation process. MOAO had a large specific surface area (385.266 m²/g) and wormhole-like mesoporous structure. The average pore size, which could be precisely controlled over the range of 3.4–4.1 nm. The optimum removal of fluoride was obtained when the initial pH was in the range of 4–10. The defluorination efficiency of MOAO was far superior to that of MA when the initial fluoride concentration exceeded 40 mg/L. The large surface area and bimodal porous structure of MOAO after coating MnO₂ may be responsible for the high removal efficiency in the defluorination process.

Graphical abstract

Keywords

Alumina; MnO₂–Al₂O₃; Mesoporous structure; Structure properties; Adsorption

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