title: Facile and highly efficient removal of trace Gd(III) by adsorption of colloidal graphene oxide suspensions sealed in dialysis bag.
abstract: A facile, highly efficient and second-pollution-free strategy to remove trace Gd(III) from aqueous solutions by adsorption of colloidal graphene oxide (GO) suspensions in dialysis bag has been developed. The effects of pH, ionic strength and temperature on Gd(III) adsorption, and the pH-dependent desorption were investigated. The maximum adsorption capacity of Gd(III)on GO at pH=5.9±0.1 and T=303K was 286.86mgg(-1), higher than any other currently reported. The Gd(III)-saturated GO suspension could resume colloidal state in 0.1M HNO3 with desorption rate of 85.00% in the fifth adsorption-desorption cycle. Gd(III) adsorption rate on GO was dependent more on pH and ionic strength than on temperature. The abundant oxygen-containing functional groups such as carboxyl and hydroxyl played a vital role on adsorption. The thermodynamics and kinetics investigations revealed that the adsorption of Gd(III) on GO was an endothermic, spontaneous and monolayer absorption process, which well fitted the pseudo-second-order model. GO could be a promising adsorbent applied in the enrichment and removal of lanthanides from aqueous solutions. More significantly, the combination of colloidal GO suspension with dialysis membrane facilely solves the re-pollution of the treated solutions due to the great difficulties in separation and recovery of GO.
authors.affiliation: School of Materials Science & Engineering, Nanchang University, Nanchang 330031, PR China; Research Center of Rare Earths & Micro/Nano Functional Materials, Nanchang University, Nanchang 330031, PR China. Electronic address: dragon0791@sohu.com.
authors.forename: Weifan
authors.initials: W
authors.lastname: Chen
authors.affiliation: School of Materials Science & Engineering, Nanchang University, Nanchang 330031, PR China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Materials Science & Engineering, Nanchang University, Nanchang 330031, PR China.
authors.forename: Mingpeng
authors.initials: M
authors.lastname: Zhuo
authors.affiliation: School of Materials Science & Engineering, Nanchang University, Nanchang 330031, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Materials Science & Engineering, Nanchang University, Nanchang 330031, PR China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Research Center of Rare Earths & Micro/Nano Functional Materials, Nanchang University, Nanchang 330031, PR China.
authors.forename: Yongxiu
authors.initials: Y
authors.lastname: Li
mesh_terms: D000327:Adsorption; D003102:Colloids / Q000737:chemistry*; D003956:Dialysis; D005682:Gadolinium / Q000302:isolation & purification*; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D049329:Nanostructures; D013535:Suspensions; D013696:Temperature; D013816:Thermodynamics
chemical_list: D003102:Colloids; D013535:Suspensions; D006108:Graphite; D005682:Gadolinium
keywords: Colloidal suspension; Dialysis bag; Gd(III) removal; Graphene oxide; Second-pollution