Preparation of graphene oxide/chitosan composite beads and its adsorption performance for nibium
GONG Yu1,KONG Ya-fei1,2,MA Zhen-zhen1WANG Jian-fang1,TANG Zhi-yong1,QIU Hai-ou*1
1.Faculty of Materials Science and Chemistry,China University of Geosciences Wuhan,Wuhan 430074,China; 2.114 Geological Brigade of Buraeu of Geology and Mineral Exploration and Development Guizhou Province,Zunyi 563000,China
Abstract：Graphene oxide (GO) was synthesized with improved Hummers method. Glutaraldehyde cross-linked chitosan (GCCS) and graphene oxide/chitosan composite beads (GOCS) with three different mass fraction of GO (2%, 5% and 10%) were prepared by chitosan (CS) and GO, and characterized. The adsorption property of niobic oxalic acid complex onto GOCS was studied. The results showed that the adsorption of Nb onto GOCS was optimum at 5% GO and pH 3 in 1 mmol/L H2C2O4 solution. The adsorption isotherm obeyed the Langmuir isotherm model, implying that the adsorption was monolayer adsorption, and the maximum adsorption capacity was estimated to be 38.46 mg/g. The adsorption kinetics of Nb onto GOCS followed a pseudo-second-oder kinetic model. Thermodynamic experiments showed that the adsorption of Nb onto GOCS was spontaneous and exothermic. The desorption rate was 84.9% using 5 mL of 1 mol/L HNO3. The adsorption rate and desorption rate were not significantly decreased after three cycles of adsorption-desorption, implying that the reproductively was good.
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