The adsorption of CO₂ and CO₂/CH₄ mixtures on kaolinite was calculated by grand canonical Monte Carlo (GCMC) simulations with different temperatures (283.15, 293.15, and 313.15 K) up to 40 MPa. The simulation results show that the adsorption amount of CO₂ followed the Langmuir model and decreased with an increasing temperature. The excess adsorption of CO₂ increased with an increasing pressure until the pressure reached 3 MPa and then decreased at different temperatures. The $S_{C{O}_2/C{H}_4}$ decreased logarithmically with increasing pressure, and the $S_{C{O}_2/C{H}_4}$ was lower with a higher temperature at the same pressure. The interaction energy between CO₂ and kaolinite was much higher than that between CH₄ and kaolinite at the same pressure. The interaction energy between the adsorbent and adsorbate was dominant, and that between CO₂ and CO₂ and between CH₄ and CH₄ accounted for less than 20% of the total interaction energy. The isothermal adsorption heat of CO₂ was higher than that of CH₄, indicating that the affinity of kaolinite to CO₂ was higher than that of CH₄. The strong adsorption sites of carbon dioxide on kaolinite were hydrogen, oxygen, and silicon atoms, respectively. CO₂ was not only physically adsorbed on kaolinite, but also exhibited chemical adsorption. In gas-bearing reservoirs, a CO₂ injection to displace CH₄ and enhance CO₂ sequestration and enhanced gas recovery (CS-EGR) should be implemented at a low temperature.

Whey protein isolate (WPI) fibrils were prepared using an acid hydrolysis induction process. Carbon nanotubes (CNTs) and carbon nano-onions (CNOs) were made via the catalytic chemical vapor deposition (CVD) of methane. WPI fibril–CNTs and WPI fibril–CNOs were prepared via hydrothermal synthesis at 80 °C. The composites were characterized by SEM, TEM, FTIR, XRD, Raman, and TG analyses. The interplay between WPI fibrils and CNTs and CNOs were studied. The WPI fibrils with CNTs and CNOs formed uniform gels and films. CNTs and CNOs were highly dispersed in the gels. Hydrogels of WPI fibrils with CNTs (or CNOs) could be new materials with applications in medicine or other fields. The CNTs and CNOs shortened the WPI fibrils, which might have important research value for curing fibrosis diseases such as Parkinson’s and Alzheimer’s diseases. The FTIR revealed that CNTs and CNOs both had interactions with WPI fibrils. The XRD analysis suggested that most of the CNTs were wrapped in WPI fibrils, while CNOs were partially wrapped. This helped to increase the biocompatibility and reduce the cytotoxicity of CNTs and CNOs. HR-TEM and Raman spectroscopy studies showed that the graphitization level of CNTs was higher than for CNOs. After hybridization with WPI fibrils, more defects were created in CNTs, but some original defects were dismissed in CNOs. The TG results indicated that a new phase of WPI fibril–CNTs or CNOs was formed.