Optimization of bioscorodite crystallization for treatment of as(III)-bearing wastewaters

Masahito Tanaka, Tsuyoshi Hirajima, Keiko Sasaki, Naoko Okibe

研究成果: Chapter in Book/Report/Conference proceedingConference contribution

1 被引用数 (Scopus)

抄録

Arsenic (As) is a major impurity contaminating metal refinery wastewaters. To immobilize As ions, we have previously reported microbial scorodite (FeAsO4·2H2O) crystallization using the thermo-acidophilic iron-oxidizing archaeon, Acidianus brierleyi. In order to extend the applicable range of As(III)-bearing metal refinery wastewaters (especially for dilute As(III) concentrations of 250–1500 ppm), this study investigated the effect of several factors possibly affecting the bioscorodite crystallization efficiency; (i) [Fe(II)]ini/[As(III)]ini molar ratio at different target As(III) concentrations, (ii) initial pH, and (iii) seed scorodite with different morphologies. The [Fe(II)]ini/[As(III)]ini molar ratio strongly affected the bioscorodite crystallization efficiency at each target As(III) concentration. Whilst the [Fe(II)]ini/[As(III)]ini molar ratio of 1.4 was most effective at 500–1500 ppm As(III), the optimal molar ratios for treating more dilute concentrations (< 500 ppm) were shown to be relatively higher. However, further increasing the [Fe(II)]ini/[As(III)]ini molar ratio resulted in formation of unwanted potassium jarosite (KFe3(OH)6(SO4)2) together with scorodite. Lowering the initial pH from 1.5 to 1.2 resulted in earlier scorodite nucleation, but lower overall As immobilization. Feeding chemical- and bio-scorodite seed crystals differently affected the reaction speed and the stability of newly-precipitated bioscorodite. The TCLP test indicated that scorodite formed on bioscorodite seeds is more stable than that formed on chemically-synthesized scorodite seeds.

本文言語英語
ホスト出版物のタイトル22nd International Biohydrometallurgy Symposium
編集者Sabrina Hedrich, Axel Schippers, Kathrin Rubberdt, Franz Glombitza, Wolfgang Sand, Wolfgang Sand, Mario Vera Veliz, Sabine Willscher
出版社Trans Tech Publications Ltd
ページ555-558
ページ数4
ISBN(印刷版)9783035711806
DOI
出版ステータス出版済み - 2017
イベント22nd International Biohydrometallurgy Symposium, 2017 - Freiberg, ドイツ
継続期間: 9 24 20179 27 2017

出版物シリーズ

名前Solid State Phenomena
262 SSP
ISSN(印刷版)1012-0394
ISSN(電子版)1662-9779

その他

その他22nd International Biohydrometallurgy Symposium, 2017
Countryドイツ
CityFreiberg
Period9/24/179/27/17

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics

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