Studies On The Ion Transfer Reactions At The Liquid/Liquid Interface Supported By MCM-41 Organic/Inorganic Hybrid Mesoporous Silica Membrane

Hybrid mesoporous silica membranes (HMSMs) are a kind of novel membrane materials with a unique structure of pores-in-pores. Due to their different structures and properties from those conventional mesoporous silica membranes, HMSMs have presented widely potential applications in adsorption, separation, and catalysis and attracted great attention during the past decade. Liquid/liquid (L/L) interface (or oil/water interface) electrochemistry is an important branch of electrochemistry and electroanalytical chemistry. It is to study the transfer process of charge, including electron and ion, at the L/L interface (movable and soft interface) and to reveal its rules by means of various electrochemical techniques and methods. Untill now, the miniaturization of L/L interface has become a trend in its development process, because such a miniaturized L/L interface can reduce its ohmic drop and charging current. Meanwhile, L/L interface electrochemistry has attracted much attention owing to its close correlation with the studies on extraction, chemical sensing mechanism, drug release, and mimicking biomembrane etc.Based on the previous research in our group, MCM-41 HMSMs was synthesized in this work using PET as the hard template and anionic surfactant CTAB as the soft template. At the same time, HMSMs with or without CTAB were used to support the L/L interface in order to investigate the effect of surfactants on ion transfer (IT) reactions at the L/L interface. The main results are as follows:CV responses for ITs at such meso-W/DCE interface arrays are closely related to CTAB. On the one hand, the HMSM-supported W/DCE interface with symmetric linear diffusion field can be formed inside the silica-CTAB nanochannels of HMSM due to their relatively hydrophobic inner environment caused by CTAB, which results in symmetrically peak-shaped CV curves. On the other hand, CTAB can dramatically enhance the transfer peak current responses of some anions and even lower their Gibbs transfer energies from W to DCE due to an anion-exchange process between anions and the bromide of CTAB associated with partial ion-dehydration. All above results demonstrate that HMSM-supported W/DCE interface is expected to provide a new strategy to study anion transfer processes and improve the electroanalytical performance for anion detection at the L/L interface, as well as offer new insight into the transport processes of hydrated anions across biomembrane in bioscience.