TY - JOUR
T1 - Application of Mg–Al layered double hydroxide for treating acidic mine wastewater
T2 - a novel approach to sludge reduction
AU - Rahman, Mir Tamzid
AU - Kameda, Tomohito
AU - Miura, Takao
AU - Kumagai, Shogo
AU - Yoshioka, Toshiaki
N1 - Publisher Copyright:
© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/2/7
Y1 - 2019/2/7
N2 - To reduce sludge volume, Mg–Al layered double hydroxide (LDH) was used to remove pollutants from mine wastewater. Mg–Al LDH can remove both cations and anions from mine wastewater via co-precipitation and anion exchange mechanisms, respectively. We herein investigated the difference in removal efficiencies between Mg–Al LDH and Ca(OH) 2 . Initial As and Fe concentrations of 8.4 and 308.6 mg/L led to final concentrations of <0.001 and 15.4 mg/L, respectively, when 5 g/L LDH with an Mg/Al molar ratio of 2:1 was employed. This suggests that As was removed in the form of H 2 AsO 4 − , which exchanged with intercalated NO 3 − in the Mg–Al LDH structure, while Fe was removed by the formation of Fe–Al LDH via co-precipitation. In contrast, treatment with 5 g/L Ca(OH) 2 gave As and Fe concentrations of 0.1 and <0.01 mg/L, respectively. Thus, under Ca(OH) 2 treatment, As is removed by the co-precipitation of arsenate with the formation of ferric oxyhydroxide (FeO(OH)), while Fe is removed by co-precipitation of the formed Fe(OH) 3 . The sludge volume obtained using Mg–Al LDH was approximately ten times lower than that obtained when using Ca(OH) 2 .
AB - To reduce sludge volume, Mg–Al layered double hydroxide (LDH) was used to remove pollutants from mine wastewater. Mg–Al LDH can remove both cations and anions from mine wastewater via co-precipitation and anion exchange mechanisms, respectively. We herein investigated the difference in removal efficiencies between Mg–Al LDH and Ca(OH) 2 . Initial As and Fe concentrations of 8.4 and 308.6 mg/L led to final concentrations of <0.001 and 15.4 mg/L, respectively, when 5 g/L LDH with an Mg/Al molar ratio of 2:1 was employed. This suggests that As was removed in the form of H 2 AsO 4 − , which exchanged with intercalated NO 3 − in the Mg–Al LDH structure, while Fe was removed by the formation of Fe–Al LDH via co-precipitation. In contrast, treatment with 5 g/L Ca(OH) 2 gave As and Fe concentrations of 0.1 and <0.01 mg/L, respectively. Thus, under Ca(OH) 2 treatment, As is removed by the co-precipitation of arsenate with the formation of ferric oxyhydroxide (FeO(OH)), while Fe is removed by co-precipitation of the formed Fe(OH) 3 . The sludge volume obtained using Mg–Al LDH was approximately ten times lower than that obtained when using Ca(OH) 2 .
KW - Ca(OH)
KW - Fe–Al layered double hydroxide
KW - Mg–Al layered double hydroxide
KW - arsenic removal
KW - sludge
KW - water treatment
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U2 - 10.1080/02757540.2018.1534964
DO - 10.1080/02757540.2018.1534964
M3 - Article
AN - SCOPUS:85058231732
VL - 35
SP - 128
EP - 142
JO - Chemistry and Ecology
JF - Chemistry and Ecology
SN - 0275-7540
IS - 2
ER -