Sorption of polar organic solvents and water by graphite oxide: Thermodynamic approach

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• 作者：Mikhail V. Korobov^a ; ^{mkorobov49@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Aleksandr V. Talyzin^b ; Anastasiya T. Rebrikova^a ; Elizaveta A. Shilayeva^a ; Natalya V. Avramenko^a ; Alexander N. Gagarin^a ; Nikolay B. Ferapontov^a
• 刊名：Carbon
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：102
• 期：Complete
• 页码：297-303
• 全文大小：512 K

文摘

Sorption of polar organic solvents CH₃OH, C₄H₈O (THF), CH₃CN, C₃H₇NO (DMF), C₂H₆OS (DMSO), C₅H₉NO (NMP) and water was quantitatively evaluated for Hummers (H-GO) and Brodie (B-GO) graphite oxides at T = 298K and at melting temperature (Tm) of the solvents. H-GO showed stronger sorption compared to B-GO for all studied solvents and the increase of sorption upon lowering temperature was observed for both H-GO and B-GO. Thermodynamic equations allowed to explain earlier reported “maximums” of swelling/sorption in the binary systems H-GO – solvent at Tm. The specific relation between the values of enthalpies of sorption and melting leads to the change of sign in enthalpies of sorption at Tm and causes maximal swelling/sorption. The same thermodynamic explanation was given for the “maximum” on the swelling vs. pressure dependence in B-GO and H-GO – H₂O systems earlier reported at pressure of phase transition “liquid water-ice VI”. Notably higher sorption of H₂O was observed for H-GO compared to H-GO membrane (H-GOm) at high relative humidity (RH), RH > 0.75. Experimental sorption isotherm of H-GOm was used to simulate permeation rates of water through H-GOm and to estimate effective diffusion coefficient of water through the membrane.