Intercalation redox materials have shown great promise for efficient water desalination due to available faradaic gallery sites.Symmetric capacitive deionization(CDI)cells previously demonstrated using MXenes were oft...Intercalation redox materials have shown great promise for efficient water desalination due to available faradaic gallery sites.Symmetric capacitive deionization(CDI)cells previously demonstrated using MXenes were often limited in their salt adsorption capacity(SAC)and voltage window of operation.In this study,current collector-and binder-free Ti3C2Tx MXene electrode architectures are designed with porous carbon as the positive electrode to demonstrate hybrid CDI(HCDI)operation.Furthermore,MXene current collectors are fabricated by employing a scalable doctor blade coating technique and subsequently spray coating a layer of a small flake MXene dispersion.Hydrophilic redox-active galleries of MXenes are capable of intercalating a variety of aqueous cations including Na+,K+,and Mg2+ions,showing volumetric capacitances up to 250 F cm-3.As a result,a salt removal capacity of 39 mg g-1 with decent cycling stability is achieved.This study opens new avenues for developing freestanding,binder-and additivefree MXene electrodes for HCDI applications.展开更多
Enhanced oil recovery(EOR)operations increasingly depend on emulsion-based formulations that exhibit long-term stability under reservoir conditions while minimizing surfactant dosage.In this context,hybrid systems com...Enhanced oil recovery(EOR)operations increasingly depend on emulsion-based formulations that exhibit long-term stability under reservoir conditions while minimizing surfactant dosage.In this context,hybrid systems combining nanoparticles and surfactants offer a promising route to achieving both interfacial stability and formulation efficiency.Among potential nanoparticle candidates,Ti_(3)C_(2)T_(x)MXene exhibits high surface area and interfacial activity.However,its application in diesel-in-water Pickering emulsions under EOR-relevant conditions has not been explored.Challenges such as high hydrophilicity and strong electrostatic repulsion have limited the use of unmodified MXene as a standalone stabilizer in colloidal systems.To address this limitation,diesel-in-water Pickering emulsions were formulated using DL-Ti_(3)C_(2)T_(x)MXene combined with Tween 40(0.5 wt%)and antifoam(0.15 wt%),aiming to investigate their synergistic stabilization behavior across MXene concentrations ranging from 0.1 to 1.5 wt%.The MXene-only system exhibited complete and immediate phase separation,whereas the hybrid emulsions demonstrated markedly enhanced stability,with no phase separation observed at 0.1 and 0.5 wt%after 24 h.A concentration-dependent trend was evident.At lower MXene contents,interfacial adsorption improved,and droplet sizes remained small and uniform.At higher concentrations(≥1.0 wt%),aggregation increased,and demulsification became more pronounced.Interfacial tension decreased steadily with increasing MXene content,reaching 0.86 mN/m at1.5 wt%,while zeta potential remained strongly negative(-47.7 mV at 0.5 wt%),indicating sufficient electrostatic repulsion.Rheological analysis revealed a transition to shear-thinning behavior at higher MXene contents,confirming the formation of internal network structures.Compared to other reported systems based on silica(SiO2),zinc oxide(ZnO),or functionalized MXenes,the MXene-Tween 40formulation achieved superior short-and long-term emulsion stability without requiring surface modification or external stimuli.To the best of our knowledge,this is the first study to report the successful stabilization of diesel-in-water Pickering emulsions using unmodified Ti_(3)C_(2)T_(x)MXene.These findings highlight the synergistic interaction between MXene and Tween 40 and present a robust,surfactant-lean formulation suitable for oilfield applications.展开更多
基金financial support from Qatar National Research Fund(a member of Qatar Foundation)through the NPRP Grant#9-254-2-120Support from the National Science Foundation(CMMI-1635233)
文摘Intercalation redox materials have shown great promise for efficient water desalination due to available faradaic gallery sites.Symmetric capacitive deionization(CDI)cells previously demonstrated using MXenes were often limited in their salt adsorption capacity(SAC)and voltage window of operation.In this study,current collector-and binder-free Ti3C2Tx MXene electrode architectures are designed with porous carbon as the positive electrode to demonstrate hybrid CDI(HCDI)operation.Furthermore,MXene current collectors are fabricated by employing a scalable doctor blade coating technique and subsequently spray coating a layer of a small flake MXene dispersion.Hydrophilic redox-active galleries of MXenes are capable of intercalating a variety of aqueous cations including Na+,K+,and Mg2+ions,showing volumetric capacitances up to 250 F cm-3.As a result,a salt removal capacity of 39 mg g-1 with decent cycling stability is achieved.This study opens new avenues for developing freestanding,binder-and additivefree MXene electrodes for HCDI applications.
基金support of the Qatar National Research Fund(QNRF),grant reference number GSRA9-L-2-0511-22005。
文摘Enhanced oil recovery(EOR)operations increasingly depend on emulsion-based formulations that exhibit long-term stability under reservoir conditions while minimizing surfactant dosage.In this context,hybrid systems combining nanoparticles and surfactants offer a promising route to achieving both interfacial stability and formulation efficiency.Among potential nanoparticle candidates,Ti_(3)C_(2)T_(x)MXene exhibits high surface area and interfacial activity.However,its application in diesel-in-water Pickering emulsions under EOR-relevant conditions has not been explored.Challenges such as high hydrophilicity and strong electrostatic repulsion have limited the use of unmodified MXene as a standalone stabilizer in colloidal systems.To address this limitation,diesel-in-water Pickering emulsions were formulated using DL-Ti_(3)C_(2)T_(x)MXene combined with Tween 40(0.5 wt%)and antifoam(0.15 wt%),aiming to investigate their synergistic stabilization behavior across MXene concentrations ranging from 0.1 to 1.5 wt%.The MXene-only system exhibited complete and immediate phase separation,whereas the hybrid emulsions demonstrated markedly enhanced stability,with no phase separation observed at 0.1 and 0.5 wt%after 24 h.A concentration-dependent trend was evident.At lower MXene contents,interfacial adsorption improved,and droplet sizes remained small and uniform.At higher concentrations(≥1.0 wt%),aggregation increased,and demulsification became more pronounced.Interfacial tension decreased steadily with increasing MXene content,reaching 0.86 mN/m at1.5 wt%,while zeta potential remained strongly negative(-47.7 mV at 0.5 wt%),indicating sufficient electrostatic repulsion.Rheological analysis revealed a transition to shear-thinning behavior at higher MXene contents,confirming the formation of internal network structures.Compared to other reported systems based on silica(SiO2),zinc oxide(ZnO),or functionalized MXenes,the MXene-Tween 40formulation achieved superior short-and long-term emulsion stability without requiring surface modification or external stimuli.To the best of our knowledge,this is the first study to report the successful stabilization of diesel-in-water Pickering emulsions using unmodified Ti_(3)C_(2)T_(x)MXene.These findings highlight the synergistic interaction between MXene and Tween 40 and present a robust,surfactant-lean formulation suitable for oilfield applications.
