Adsorption mechanisms of chromate and phosphate on hydrotalcite: A combination of macroscopic and spectroscopic studies

Liang Ching Hsu, Yu Min Tzou, Po Neng Chiang, Wei Min Fu, Ming Kuang Wang, Heng Yi Teah, Yu Ting Liu

研究成果: Article

抄録

Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO4) and phosphate (PO4) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO4 and PO4 on HT were 0.16 and 0.23 mmol g−1. Regarding adsorption kinetics, CrO4 and PO4 adsorption on HT could be well described by the second order model, and the rate coefficient of CrO4 and PO4 on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO4 and PO4 were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO4 and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO4 adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO4. This study determined the adsorption behaviors of CrO4 and PO4 on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.

元の言語English
ページ(範囲)180-187
ページ数8
ジャーナルEnvironmental Pollution
247
DOI
出版物ステータスPublished - 2019 4 1

Fingerprint

hydrotalcite
Chromates
Adsorption
Phosphates
Complexation
Adsorbents
Kinetics
Anions
Negative ions
X ray absorption fine structure spectroscopy

Keywords

    ASJC Scopus subject areas

    • Toxicology
    • Pollution
    • Health, Toxicology and Mutagenesis

    これを引用

    Adsorption mechanisms of chromate and phosphate on hydrotalcite : A combination of macroscopic and spectroscopic studies. / Hsu, Liang Ching; Tzou, Yu Min; Chiang, Po Neng; Fu, Wei Min; Wang, Ming Kuang; Teah, Heng Yi; Liu, Yu Ting.

    :: Environmental Pollution, 巻 247, 01.04.2019, p. 180-187.

    研究成果: Article

    Hsu, Liang Ching ; Tzou, Yu Min ; Chiang, Po Neng ; Fu, Wei Min ; Wang, Ming Kuang ; Teah, Heng Yi ; Liu, Yu Ting. / Adsorption mechanisms of chromate and phosphate on hydrotalcite : A combination of macroscopic and spectroscopic studies. :: Environmental Pollution. 2019 ; 巻 247. pp. 180-187.
    @article{6c02f75e134b4ce3846189344cac4bbb,
    title = "Adsorption mechanisms of chromate and phosphate on hydrotalcite: A combination of macroscopic and spectroscopic studies",
    abstract = "Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO4) and phosphate (PO4) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO4 and PO4 on HT were 0.16 and 0.23 mmol g−1. Regarding adsorption kinetics, CrO4 and PO4 adsorption on HT could be well described by the second order model, and the rate coefficient of CrO4 and PO4 on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO4 and PO4 were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO4 and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO4 adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO4. This study determined the adsorption behaviors of CrO4 and PO4 on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.",
    keywords = "Adsorption, Chromate, Hydrotalcite, Phosphate, XAFS",
    author = "Hsu, {Liang Ching} and Tzou, {Yu Min} and Chiang, {Po Neng} and Fu, {Wei Min} and Wang, {Ming Kuang} and Teah, {Heng Yi} and Liu, {Yu Ting}",
    year = "2019",
    month = "4",
    day = "1",
    doi = "10.1016/j.envpol.2019.01.012",
    language = "English",
    volume = "247",
    pages = "180--187",
    journal = "Environmental Pollution",
    issn = "0269-7491",
    publisher = "Elsevier Limited",

    }

    TY - JOUR

    T1 - Adsorption mechanisms of chromate and phosphate on hydrotalcite

    T2 - A combination of macroscopic and spectroscopic studies

    AU - Hsu, Liang Ching

    AU - Tzou, Yu Min

    AU - Chiang, Po Neng

    AU - Fu, Wei Min

    AU - Wang, Ming Kuang

    AU - Teah, Heng Yi

    AU - Liu, Yu Ting

    PY - 2019/4/1

    Y1 - 2019/4/1

    N2 - Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO4) and phosphate (PO4) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO4 and PO4 on HT were 0.16 and 0.23 mmol g−1. Regarding adsorption kinetics, CrO4 and PO4 adsorption on HT could be well described by the second order model, and the rate coefficient of CrO4 and PO4 on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO4 and PO4 were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO4 and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO4 adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO4. This study determined the adsorption behaviors of CrO4 and PO4 on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.

    AB - Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO4) and phosphate (PO4) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO4 and PO4 on HT were 0.16 and 0.23 mmol g−1. Regarding adsorption kinetics, CrO4 and PO4 adsorption on HT could be well described by the second order model, and the rate coefficient of CrO4 and PO4 on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO4 and PO4 were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO4 and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO4 adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO4. This study determined the adsorption behaviors of CrO4 and PO4 on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.

    KW - Adsorption

    KW - Chromate

    KW - Hydrotalcite

    KW - Phosphate

    KW - XAFS

    UR - http://www.scopus.com/inward/record.url?scp=85060958096&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=85060958096&partnerID=8YFLogxK

    U2 - 10.1016/j.envpol.2019.01.012

    DO - 10.1016/j.envpol.2019.01.012

    M3 - Article

    VL - 247

    SP - 180

    EP - 187

    JO - Environmental Pollution

    JF - Environmental Pollution

    SN - 0269-7491

    ER -