title: Heteroaggregation of graphene oxide with minerals in aqueous phase.
abstract: Upon release into waters, sediments, and soils, graphene oxide (GO) may interact with fine mineral particles. We investigated the heteroaggregation of GO with different minerals, including montmorillonite, kaolinite, and goethite, in aqueous phase. GO significantly enhanced the dispersion of positively charged goethite (>50%) via heteroaggregation, while there was no interaction between GO and negatively charged montmorillonite or kaolinite. Electrostatic attraction was the dominant force in the GO-goethite heteroaggregation (pH 4.0-8.5), and the dissolved Fe ions (<0.16 mg/L) from goethite were unable to destabilize GO suspension. The GO-goethite heteroaggregation was further quantitatively investigated through GO adsorption study. All adsorption isotherms of GO at different solution pH (4.0 and 6.5) followed the Linear model. The apparent intercept (1.0-6.9 mg/g) was observed for all the adsorption isotherms, indicating that this fraction of adsorbed GO was difficult to desorb from goethite (defined here as irreversible adsorption) under the tested conditions. Desorption hysteresis was observed, which could be explained by the formation of multilayered GO-goethite complex with high configurational stability. These findings are useful for understanding the interaction of GO with mineral surfaces, and potential fate and toxicity of GO under natural conditions in aquatic environments, as well as in soils and sediments.
authors.affiliation: College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Marine Environment and Ecology, and Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China , Qingdao 266100, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.forename: Feifei
authors.initials: F
authors.lastname: Liu
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Xuesong
authors.initials: X
authors.lastname: Cao
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry; D007616:Kaolin / Q000737:chemistry; D008903:Minerals / Q000737:chemistry; D012987:Soil; D013535:Suspensions; D014867:Water
chemical_list: D058085:Iron Compounds; D008903:Minerals; D012987:Soil; D013535:Suspensions; D014867:Water; D001546:Bentonite; C094886:goethite; D007616:Kaolin; D006108:Graphite