TY - JOUR
T1 - Fate of adsorbed Pb(II) on graphene oxide under variable redox potential controlled by electrochemical method
AU - Zhang, Jianfeng
AU - Li, Yao
AU - Xie, Xiaodan
AU - Zhu, Weihuang
AU - Meng, Xiaoguang
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/4/5
Y1 - 2019/4/5
N2 - Lead removal using graphene oxide (GO) and GO based adsorbents has attracted increasing attention worldwide, whereas the potential release of previously adsorbed Pb(II) from GO surfaces induced by exposure to variable redox conditions is presently underappreciated. The current study revealed that reduction of GO to r-GO (the reduced form) was coupled with a decrease of oxygen-containing groups (OCGs) under reductive potential, and the maximum adsorption capacity of GO for Pb(II) decreased from 931.66 to 714.78 mg g−1 after electrochemical reduction. The release of adsorbed Pb(II) from GO-Pb(II) increased gradually when the potential dropped from 0 to −600 mV. The content of released Pb(II) decreased when the potential reached −700 mV because of the reduction of Pb(II) to insoluble Pb(0). Cyclic voltammetry (CV) analysis demonstrated that there are three reductive potentials, e.g. −760, −400, and −120 mV, related to the reduction of OCGs. X-ray photoelectron spectroscopy indicated that the reducing sequence of three OCGs, namely C–O, C[dbnd]O and O–C[dbnd]O groups, depended on the applied potential. This application of an electrochemical method to investigate adsorbed Pb(II) from spent GO absorbent provides valuable information about heavy metal transportation in environments containing GO under varying redox conditions.
AB - Lead removal using graphene oxide (GO) and GO based adsorbents has attracted increasing attention worldwide, whereas the potential release of previously adsorbed Pb(II) from GO surfaces induced by exposure to variable redox conditions is presently underappreciated. The current study revealed that reduction of GO to r-GO (the reduced form) was coupled with a decrease of oxygen-containing groups (OCGs) under reductive potential, and the maximum adsorption capacity of GO for Pb(II) decreased from 931.66 to 714.78 mg g−1 after electrochemical reduction. The release of adsorbed Pb(II) from GO-Pb(II) increased gradually when the potential dropped from 0 to −600 mV. The content of released Pb(II) decreased when the potential reached −700 mV because of the reduction of Pb(II) to insoluble Pb(0). Cyclic voltammetry (CV) analysis demonstrated that there are three reductive potentials, e.g. −760, −400, and −120 mV, related to the reduction of OCGs. X-ray photoelectron spectroscopy indicated that the reducing sequence of three OCGs, namely C–O, C[dbnd]O and O–C[dbnd]O groups, depended on the applied potential. This application of an electrochemical method to investigate adsorbed Pb(II) from spent GO absorbent provides valuable information about heavy metal transportation in environments containing GO under varying redox conditions.
KW - Adsorption/desorption
KW - Electrochemically reduced graphene oxide
KW - Graphene oxide
KW - Pb(II)
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U2 - 10.1016/j.jhazmat.2018.12.073
DO - 10.1016/j.jhazmat.2018.12.073
M3 - Article
C2 - 30594715
AN - SCOPUS:85059062864
SN - 0304-3894
VL - 367
SP - 152
EP - 159
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -