title: Ambivalent Effect of Thermal Reduction in Mass Rejection through Graphene Oxide Membrane.
abstract: We report ambivalent rejection behavior of a graphene oxide membrane (GOM) having a reduced interlayer spacing. Ultrathin GOMs having a thickness of 50 nm were fabricated using a vacuum filtration method followed by subjecting the samples to thermal reduction at 162 °C. The interlayer spacing of GOMs was reduced by 1 Å on thermal reduction as compared with that of the natural GOMs. The rejection rate with dye molecules was tested using dyes having three different types of charges in a dead-end filtration instrument. Rejection rate of the reduced GOM with the dyes having an opposite charge was improved up to 99.7%, indicating the dominant effect of the physical sieving diameter. In contrast, in the case of ion permeation of natural GOM, a higher rejection rate for several metal ions was observed as compared with that of GOMs having 1 Å smaller interlayer spacing, indicating the dominant effect of surface charges on the GOM samples.
authors: School of Mechanical Engineering, Korea University , Seoul, Republic of Korea.
authors: Jin-Hyeok
authors: JH
authors: Jang
authors: School of Mechanical Engineering, Korea University , Seoul, Republic of Korea.
authors: Ju Yeon
authors: JY
authors: Woo
authors: Composite Laboratory, Agency for Defense Development , Daejeon, Republic of Korea.
authors: Jaeyeol
authors: J
authors: Lee
authors: School of Mechanical Engineering, Korea University , Seoul, Republic of Korea.
authors: Chang-Soo
authors: CS
authors: Han
mesh_terms: D005374:Filtration; D006108:Graphite; D007477:Ions; D010087:Oxides
chemical_list: D007477:Ions; D010087:Oxides; D006108:Graphite