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Minerals 2017, 7(1), 9; doi:10.3390/min7010009

Heating Changes Bio-Schwertmannite Microstructure and Arsenic(III) Removal Efficiency

1
Environmental Engineering Laboratory, College of Resource and Environment, Shanxi Agricultural University, Taigu 030801, China
2
Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
3
Analytical Instrumentation Center, Institute of Coal Chemistry, Chinese Academy of Sciences, 27 South Taoyuan Road, Taiyuan 030001, China
These authors contributed equally to this work.
*
Author to whom correspondence should be addressed.
Academic Editor: Karen Hudson-Edwards
Received: 21 November 2016 / Revised: 26 December 2016 / Accepted: 11 January 2017 / Published: 18 January 2017
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Abstract

Schwertmannite (Sch) is an efficient adsorbent for arsenic(III) removal from arsenic(III)-contaminated groundwater. In this study, bio-schertmannite was synthesized in the presence of dissolved ferrous ions and Acidithiobacillus ferrooxidans LX5 in a culture media. Bio-synthesized Sch characteristics, such as total organic carbon (TOC), morphology, chemical functional groups, mineral phase, specific surface area, and pore volume were systematically studied after it was dried at 105 °C and then heated at 250–550 °C. Differences in arsenic(III) removal efficiency between 105 °C dried-sch and 250–550 °C heated-sch also were investigated. The results showed that total organic carbon content in Sch and Sch weight gradually decreased when temperature increased from 105 °C to 350 °C. Sch partly transformed to another nanocrystalline or amorphous phase above 350 °C. The specific surface area of 250 °C heated-sch was 110.06 m2/g compared to 5.14 m2/g for the 105 °C dried-sch. Total pore volume of 105 °C dried-sch was 0.025 cm3/g with 32.0% mesopore and 68.0% macropore. However, total pore volume of 250 °C heated-mineral was 0.106 cm3/g with 23.6% micropore, 33.0% mesopore, and 43.4% macropore. The arsenic(III) removal efficiency from an initial 1 mg/L arsenic(III) solution (pH 7.5) was 25.1% when 0.25 g/L of 105 °C dried-sch was used as adsorbent. However, this efficiency increased to 93.0% when using 250 °C heated-sch as adsorbent. Finally, the highest efficiency for arsenic(III) removal was obtained with sch-250 °C due to high amounts of sorption sites in agreement with the high specific surface area (SSA) obtained for this sample. View Full-Text
Keywords: bio-schwertmannite; specific surface area; pore volume; arsenic(III); adsorption bio-schwertmannite; specific surface area; pore volume; arsenic(III); adsorption
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Qiao, X.; Liu, L.; Shi, J.; Zhou, L.; Guo, Y.; Ge, Y.; Fan, W.; Liu, F. Heating Changes Bio-Schwertmannite Microstructure and Arsenic(III) Removal Efficiency. Minerals 2017, 7, 9.

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