A binary solvent synthetic strategy is proposed for the construction of C 2 -symmetric molecule-based hydrogen-bonded organic frameworks (HOFs) with permanent ultra-micropores and surface polarization derived from tunable coplanar open oxygen atoms. The activated HOFs BTBA-1 a and PTBA-1 a show highly selective separation of CO 2 /N 2 with a record high ideal adsorbed solution theory (IAST) selectivity > 2000 under ambient temperature and pressure.Carbon dioxide (CO 2 ) sequestration from gaseous mixtures with minimal energy costs is of significance for global fuel gases utilization and greenhouse gas emission reduction. Developing advanced adsorption techniques with high capacity and high selectivity of CO 2 provides an energysaving way in this regard. [1] However, critical challenges still lie in the controllable architecture of adaptable adsorbents with tailor-made pore channels, and the task-specific engineering of the local surface chemistry. Specifically, to achieve selective CO 2 capture and separation, ultra-micropores matching the kinetic diameter of CO 2 need to be created in the frameworks of the adsorbents, which enable exclusion of the larger-sized gas molecules according to the size-sieving effect. [2] Meanwhile, polar functionalities or charge-dense sites should be introduced within the pore channels. [3] This allows to differentiate CO 2 from mixture gas molecules with similar kinetic diameters, such as N 2 , CH 4 , and O 2 , based on the difference in their polarizability. [4] Furthermore, reversible adsorption, as well as regeneration of porous materials, is also challenging for current industrial technologies.Hydrogen-bonded organic frameworks (HOFs) are emerging as a new category of porous crystalline materials constructed by reversible hydrogen bonds of rigid building blocks. [5] Because of the metal-free nature, ease of solutionprocessing, and facile regeneration, HOFs possess substantial potential for applications in gas storage and separation, catalysis, molecular recognition, [6] etc. In the past few years, [
Nanoparticles with different color were covalently-bonded onto cotton fabrics, which provides a promising clean coloration method resulting lower COD, TSS, chroma and hazardous ions concentration in the wastewater than the limits of the standards.
Ion-containing polymers
are of great importance for its unique structure and properties. An
ion-containing polyamide 6 (PA6) was prepared by grafting an ionic
liquid, 1-vinyl-3-butyl imidazole chloride [VBIM][Cl], onto the main
chain of PA6 using radiation-induced grafting. The grafted ions on
the PA6 main chain significantly influenced the structure and properties
of the PA6 matrix. The ions form nanoscale aggregations without inducing
further microphase separation. Acting as a physical “cross-linking
point,” each aggregation enhanced inter/intrachain interactions,
which increased the viscosity, storage modulus, and relaxation time
and reduced the ability of PA6 to crystallize. However, the bulky
cations of the grafted ionic liquid can also be seen as “spacers,”
which enlarge the distance among chains and reduce the strength of
the hydrogen bonds inherently existing in the PA6 matrix. The “cross-linking
points” and “spacers” of ions as well as the
hydrogen bonds of PA6 take effect collectively in the system. Moreover,
the ion-containing PA6 retains good melt processability compared with
PA6, despite increased viscosity, and can be easily melt-spun into
fibers. Fibers prepared from ion-containing PA6 showed improved mechanical
properties and antistatic performance and exhibited the expected antibacterial
properties, especially with regard to Escherichia coli. Inspiringly, covalently bonding ions to the PA6 main chain offers
a new strategy for fabricating functional fibers with permanent antistatic
and antibacterial properties.
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