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Mixed‐Mode Remediation of Cadmium and Arsenate Ions Using Graphene‐Based Materials
Author(s) -
Lath Supriya,
Navarro Divina,
Tran Diana,
Kumar Anu,
Losic Dusan,
McLaughlin Michael J.
Publication year - 2018
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201800073
Subject(s) - sorption , arsenate , adsorption , graphene , arsenic , chemistry , cadmium , oxide , environmental remediation , contamination , inorganic chemistry , chemical engineering , environmental chemistry , organic chemistry , ecology , engineering , biology
Cadmium (Cd) and arsenate (As) are notorious environmental contaminants, and co‐contamination usually requires opposing treatment strategies due to their differing physico‐chemical properties. Developing adsorbents that can bind both contrasting contaminants simultaneously is desirable. Two prepared graphene materials, graphene oxide (GO) and iron‐oxide‐modified reduced‐GO (FeG), are evaluated for Cd‐ and As‐sorption, and performance is compared to a mixed‐mode commercial adsorbent. Negatively charged GO shows affinity toward cationic Cd, and positively charged FeG shows affinity toward anionic As. Sorption is pH dependent: Increase in pH‐promotes Cd‐sorption and retards As‐sorption. GO displays excellent Cd‐sorption even in acidic conditions. The maximum amounts adsorbed by GO and FeG are 782 μmol Cd g −1 and 408 μmol As g −1 , respectively. Competition by calcium strongly suppresses Cd‐sorption, whereas competition by phosphate does not hinder As‐sorption. A mixture of GO and FeG demonstrates successful simultaneous sorption of Cd and As from co‐contaminated solutions, including a natural water sample, displaying greater sorption than the commercial adsorbent. Data highlight the potential application of graphene materials in effective mixed‐mode remediation of multiple contaminants (cations and anions).