Yichao Lin

Polyethyleneimine Incorporated Metal-Organic Frameworks Adsorbent for Highly Selective CO2 Capture

A series of polyethyleneimine (PEI) incorporated MIL-101 adsorbents with different PEI loadings were reported for the first time in the present work. Although the surface area and pore volume of MIL-101 decreased significantly after loading PEI, all the resulting composites exhibited dramatically enhanced CO2 adsorption capacity at low pressures. At 100 wt% PEI loading, the CO2 adsorption capacity at 0.15 bar reached a very competitive value of 4.2 mmol g−1 at 25°C, and 3.4 mmol g−1 at 50°C. More importantly, the resulting adsorbents displayed rapid adsorption kinetics and ultrahigh selectivity for CO2 over N2 in the designed flue gas with 0.15 bar CO2 and 0.75 bar N2. The CO2 over N2 selectivity was up to 770 at 25°C, and 1200 at 50°C. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO2 capture.

Direct synthesis of amine-functionalized MIL-101(Cr) nanoparticles and application for CO2 capture

A pure amine-functionalized MIL-101(Cr) has been synthesized for the first time by a simple method. The as-prepared nanoparticles are around 50 nm. In addition, the resulting amine-functionalized MIL-101(Cr) displayed excellent CO2 adsorption capacity, up to 15 mmol g−1 at 16 °C.

Remarkable CO2/CH4 selectivity and CO2 adsorption capacity exhibited by polyamine-decorated metal–organic framework adsorbents

Solid porous dual amine-decorated metal-organic framework (MOF) adsorbents with tunable porosity have been prepared. The adsorbents exhibit remarkable CO2/CH4 selectivity and CO2 adsorption capacity at low pressures.

Enhanced selective CO2 adsorption on polyamine/MIL-101(Cr) composites

The global climate change induced by greenhouse gases has stimulated active research for developing efficient strategies to mitigate CO2 emission. In the present study, we prepared a series of polyamine/metal–organic framework (MOF) composites as highly selective CO2 adsorbents from a CO2/N2 mixture, which is relevant to CO2 capture in flue gas. We show that loading polyethyleneimine (PEI) into MIL-101(Cr) frameworks can significantly enhance the selective CO2 adsorption capacity at low pressure and ambient temperature. Further, the comparative study reveals that both the particle size of the MOF and the molecular-weight of PEI play an important role in the CO2 capture ability. Regarding the particle size, smaller MIL-101(Cr) particles can facilitate the loading of PEI into the inner pores and result in lower surface area/pore volume. Thus, the resulting PEI/MIL-101(Cr) composites possess lower CO2 adsorption capacity, but are compensated by higher selectivity of CO2 over N2. On the other hand, lower molecular-weight linear PEI could readily diffuse into the inner pores and effectively block the N2 adsorption. As a result, the as-prepared A-PEI-300 sample in this work exhibits an excellent CO2 uptake of 3.6 mmol g−1 and ultrahigh CO2/N2 selectivity at 0.15 bar and 25 °C. In contrast, the higher molecular-weight branched PEI is advantageous at elevated temperature, since the composites can retain high CO2 adsorption capacity owing to the large amount of primary amine groups. Overall, polyamine/MOF composites are shown to be good candidate adsorbents for CO2 capture from flue gas. To achieve the optimal CO2 capture ability, comprehensive optimization of the polyamine and MOF structures should be performed.

Amine-functionalized metal–organic frameworks: structure, synthesis and applications

We present a review on some recent studies on the syntheses, structures and properties of amine-functionalized metal–organic frameworks (MOFs), and highlight the benefits of amino functionality towards potential applications. Owing to the strong interaction between CO2 and basic amino functionalities, amine-functionalized MOFs have attracted much attention mainly for CO2 capture. Besides the most widely used in situ synthesis method, post-modification and physical impregnation methods are developed to prepare amine-functionalized MOFs with extremely high CO2 sorption capacity at low pressures. On the basis of the similar mechanism, amine-functionalized MOF-based membranes, including pure amine-functionalized MOF membranes and mixed matrix membranes, exhibit excellent CO2/H2, CO2/CH4 and CO2/N2 separation performance. Furthermore, amine-functionalized MOFs also demonstrate potential applications in catalysis.

Flammability properties and electromagnetic interference shielding of PVC/graphene composites containing Fe3O4 nanoparticles

The effects of combined graphene/Fe3O4 nanoparticles on the flame retardancy and smoke suppression of PVC were studied. The dispersion state of graphene in the PVC matrix was improved with the help of Fe3O4 nanoparticles. As a result, the peak values of heat release rate and smoke production rate measured by cone calorimetry were obviously decreased in the PVC/graphene/Fe3O4 composites. According to the results from TGA tests and structural characterization of residual char, the improved flame retardancy was partially attributed to the formation of a network-like structure due to the good dispersion state of graphene in the PVC matrix, and partially to the carbonization of degradation products of PVC catalyzed by Fe3O4 nanoparticles. In addition, ternary PVC composites showed higher mechanical properties than pure PVC. More importantly, the resulting material possessed both electrical and magnetic properties. As a result, the ternary composites showed favorable electromagnetic shielding efficiency in the X-band frequency region (8–12 GHz), due to the formation of conducting interconnected graphene-based networks in the insulating PVC matrix and the magnetic properties.

A hollow ceramic fiber supported ZIF-8 membrane with enhanced gas separation performance prepared by hot dip-coating seeding

A hollow ceramic fiber supported ZIF-8 membrane has been prepared by a hot dip-coating seeding method followed by secondary growth. The obtained membrane exhibits excellent H2 permselectivity.

A NbO type microporous metal–organic framework constructed from a naphthalene derived ligand for CH4 and C2H2 storage at room temperature

A novel NbO type microporous metal–organic framework [Cu2(C26H12O8)(H2O)2]·(DMF)2·(MeCN)3·(H2O)4, (ZJU-7, ZJU = Zhejiang University; H4L = 5,5′-(naphthalene-1,4-diyl)diisophthalic acid; DMF = N,N-dimethylformamide; MeCN = acetonitrile) has been synthesized and structurally characterized. With open metal sites, suitable pore spaces and moderately high permanent porosity, the activated ZJU-7a exhibits moderately high CH4 storage of 160 cm3(STP) per cm3 at 35 bar and 298 K. Meanwhile, ZJU-7a also displays moderate C2H2 gravimetric storage of 180 cm3 g−1 at 1 atm and 298 K.

Facile synthesis of Fe-MOF/RGO and its application as a high performance anode in lithium-ion batteries

The use of metal organic frameworks (MOFs) as new promising electrode materials in lithium-ion batteries (LIBs) has attracted significant attention. However, the low electrical conductivity of MOFs has resulted in the poor cycle performance of LIBs. Here, we report a facile synthesis route of Fe-MOF/reduced graphene oxide (RGO) composites using a solvothermal method. When used as anode materials for LIBs, the synthesized Fe-MOF/RGO (5%) composite shows superior Li storage with a reversible capacity of 1010.3 mA h g−1 after 200 cycles and an excellent rate performance. The improved electrochemical performance may be attributed to the synergistic effect of MOFs with high theoretical capacities and RGO with high electrical conductivity.

Effect of polystyrene long branch chains on melt behavior and foaming performance of poly(vinyl chloride)/graphene nanocomposites

Several poly(vinyl chloride)-g-polystyrene graft copolymers (PVC-g-PS) with well defined molecular structures were synthesized via atom transfer radical polymerization (ATRP) from the structural defects of PVC. The effects of PS branch chains on the shear and extensional rheology as well as foaming properties were investigated. Compared to linear PVC, the introduction of PS branches results in increased complex viscosity, an elevated value of storage modulus at low shear frequencies, more pronounced shear-thinning behavior, more significant upshifted deviation from linear behaviour and a strain hardening phenomenon. Under the same foaming conditions, most of the resulting PVC-g-PS foams exhibit a closed cell structure, increased cell density and uniform cell size distribution while the linear PVC foam has serious cell coalescence. Moreover, graphene nanosheets could be well dispersed in the PVC-g-PS matrix due to the π–π stacking with PS relative to the PVC without PS branch chains. As expected, both the nucleation effect and increased melt viscosity from well-dispersed graphene sheets significantly improve the foaming behavior of PVC-g-PS/graphene nanocomposites, in comparison with the poor foamability of PVC/graphene composites due to the non-uniform dispersion of graphene.