TY - JOUR
T1 - Mechanism of arsenate coprecipitation at the solid/liquid interface of ferrihydrite
T2 - A perspective review
AU - Tokoro, Chiharu
AU - Kadokura, Masakazu
AU - Kato, Tatsuya
N1 - Funding Information:
We thank Gabrielle David, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript. The synchrotron radiation experiments were performed using BL9A and BL12C beamline courtesy of Photon Factory Program Advisory Committee (Proposal No. 2010G054), and BL5S1 beamline courtesy of Aichi Synchrotron Radiation Center, Aichi Science & Technology Foundation, Aichi, Japan (Proposal No. 201503015 and 201602024).
PY - 2020/2
Y1 - 2020/2
N2 - Arsenate (As(V)) is a toxic element in acid mine drainage and has to be removed during the neutralization process. Coprecipitation with ferrihydrite is the main mechanism for As(V) removal from acid mine drainage. To improve treatment efficiency, a quantitative understanding of the coprecipitation mechanism is required. Coprecipitation can incorporate more As(V) into ferrihydrite than adsorption. The results of XRD (X-ray Diffraction) and XANES (X-ray Adsorption Near Edge Structure) analysis confirmed that the formation of poorly crystalline ferric arsenate increased when the initial As/Fe molar ratio increased in the coprecipitation with ferrihydrite. EXAFS (Extended X-ray Adsorption Fine Structure) analysis at the iron K-edge showed that the proportion of octahedral structures in ferrihydrite increased when the initial As/Fe molar ratio increased. Moreover, EXAFS analysis at the arsenic K-edge, assuming three kinds of surface complexes for the As–Fe bond, revealed that the coordination number for As–Fe with an atomic distance of 2.85 × 10−10 m increased and that for As-Fe with an atomic distance of 3.24 × 10−10 m decreased as the initial As/Fe molar ratio increased. Thus, for more efficient wastewater treatment, active control of coprecipitation phenomena according to mechanistic details is essential.
AB - Arsenate (As(V)) is a toxic element in acid mine drainage and has to be removed during the neutralization process. Coprecipitation with ferrihydrite is the main mechanism for As(V) removal from acid mine drainage. To improve treatment efficiency, a quantitative understanding of the coprecipitation mechanism is required. Coprecipitation can incorporate more As(V) into ferrihydrite than adsorption. The results of XRD (X-ray Diffraction) and XANES (X-ray Adsorption Near Edge Structure) analysis confirmed that the formation of poorly crystalline ferric arsenate increased when the initial As/Fe molar ratio increased in the coprecipitation with ferrihydrite. EXAFS (Extended X-ray Adsorption Fine Structure) analysis at the iron K-edge showed that the proportion of octahedral structures in ferrihydrite increased when the initial As/Fe molar ratio increased. Moreover, EXAFS analysis at the arsenic K-edge, assuming three kinds of surface complexes for the As–Fe bond, revealed that the coordination number for As–Fe with an atomic distance of 2.85 × 10−10 m increased and that for As-Fe with an atomic distance of 3.24 × 10−10 m decreased as the initial As/Fe molar ratio increased. Thus, for more efficient wastewater treatment, active control of coprecipitation phenomena according to mechanistic details is essential.
KW - EXAFS
KW - Local structure
KW - Octahedral structure
KW - Tetrahedral structure
KW - XAFS
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U2 - 10.1016/j.apt.2019.12.004
DO - 10.1016/j.apt.2019.12.004
M3 - Article
AN - SCOPUS:85077141838
VL - 31
SP - 859
EP - 866
JO - Advanced Powder Technology
JF - Advanced Powder Technology
SN - 0921-8831
IS - 2
ER -