This review focuses on state-of-the-art solutions and strategies for MOF/polymer interface issues in mixed matrix membranes.

To improve the stability and recyclability of enzymes immobilized on metal-organic frameworks (MOFs), graphene oxide (GO) with surface oxygen-rich functional groups was selected to form ZIF-8/GO nanocomposites with the zeolitic imidazolate framework (ZIF-8) for cytochrome c (Cyt c) immobilization. It was found that the functional groups on the GO surface were involved in the growth of ZIF-8 without affecting the crystal structure but their particle size was reduced to about 200 nm. The storage stability and resistance to organic solvents of Cyt c were obviously improved after the immobilization on the ZIF-8/GO nanocomposite. On one hand, compared with Cyt c@ZIF-8 and Cyt c@GO with 30 and 60% protein leakage, Cyt c@ZIF-8/GO displayed little protein leakage after 60 h of storage. On the other hand, Cyt c@ZIF-8/GO retained a residual activity of approximately 100% after being stored in ethanol and acetone for 2 h, whereas the free enzyme, Cyt c@ZIF-8, and Cyt c@GO retained only about 10, 50, and 40%, respectively. In addition, the Cyt c@ZIF-8/GO nanocomposites can be utilized up to four cycles with virtually no loss of activity and may be further applied on HO biosensing systems. The synergistic effect between MOFs and GO in ZIF-8/GO nanocomposites provides infinite possibilities as immobilized enzyme carriers.

We measured the rheological properties of mesophase pitch + coal mixtures at temperatures up to 873 K and used quench tests during carbonization to observe the effects of coal particles on foaming and pore development in activated carbon discs (ACD). We observed that high ratios of coal to pitch increased the mixture's viscosity in a low pressure foaming process, which restricted growth of large bubbles during foaming and produced stronger carbon foams. The highest strength ACD, with compressive strength of 56±3 MPa, was obtained using a pitch to coal mass ratio of 1:2 (bulk density = 0.91 g•cm N2. These adsorption results suggest the activated carbon discs have potential as structured adsorbents for gas separation or storage applications.

The electrical properties and electromagnetic shielding effectiveness (EM SE) of nanocomposites consisting of heat‐treated carbon nanofibers (Pyrograf® III PR‐19, CNF) in a linear low density polyethylene (LLDPE) matrix were assessed. Heat treatment (HT) of carbon nanofibers at 2500°C significantly improved their graphitic crystallinity and intrinsic transport properties, thereby increasing the EM SE of the nanocomposites. Nanocomposites containing 11 vol% (20 wt%) PR‐19 HT displayed a DC electrical conductivity of about 1.0 ± 0.1 × 101 S/m (n = 4), about 10 orders of magnitude better than that of as‐received PR‐19 CNF nanocomposites. Over a frequency range of 30 MHz to 1.5 GHz, nanocomposites (2.5 mm thick) containing PR‐19 HT displayed EM SE average values of about 14 ± 2 dB (n = 4). Absorption was determined to be the main EM SE mechanism for the heat‐treated CNF nanocomposites. The nanocomposites possessed a modulus of 632 ± 36 MPa (n = 6) (nominally twice that of pure LLDPE) and a strain‐to‐failure of 180 ± 98% (n = 6), indicating that a significant ductility is retained in the nanocomposites. Such nanocomposites display potential as absorptive electromagnetic interference shielding materials for thin films and micromolding. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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We used carbon nanotubes (CNTs) as modifying particles and potassium hydroxide as a porogen to prepare mesoporous pitch-derived activated carbon discs (ACD) with high surface areas. The parameters investigated in this study included the concentration of CNTs (1%, 2%, 3.5% and 5%), the dispersion of the CNTs in the pitch using a 750 W sonic probe, the oxidation of the CNTs with H2O2, and the aspect ratio of the CNTs. The highest surface area ACD was obtained with 2 % oxidized CNTs dispersed in the pitch with the ultrasonic probe (ACD-2%-SO, SBET = 2089 m 2 •g-1). The ACDs prepared with the sonic probe and with 2 %wt or more of raw and oxidized CNTs exhibited larger mesopore volumes than those ACDs prepared with 1 % CNTs. A series of quench tests performed during the foaming process by withdrawal of the carbon from the tube furnace at 673 K, 773 K and 873 K revealed that mesopores in ACD develop at temperatures ranging from 773 K to 873 K, whereas micropores formed between 873 K and 1073 K. The adsorption capacities of N2 and CO2 on ACD-2%-SO were measured with a gravimetric apparatus at 298 K and 303 K at pressures up to 4000 kPa. The uptake of CO2 on ACD-2%-SO at a temperature of 298 K was 3.33 mol/kg at 100 kPa and 11.51 mol/kg at 3496 kPa.

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, Surfaceetched halloysite nanotubes in mixed matrix membranes for efficient gas separation, Separation and Purification Technology (2016), doi: http://dx.doi.org/10.1016/j.seppur. 2016.09.015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractPossessing the advantages of both polymeric membranes and the specific inorganic nanoparticles or nanotubes, mixed matrix membranes (MMMs) have captured the imagination of researchers for a possible technological breakthrough for efficient gas separation. However, it is still very challenging to achieve defect-free interface between fillers and polymer matrix. In this study, the naturally abundant and low cost halloysite nanotubes (HNTs) were applied as fillers for MMMs synthesis. To improve the filler dispersion and filler-matrix interface affinity, the raw HNTs were modified by either alkali etching or (3-Aminopropyl) triethoxysilane grafting. After surface etching, the defect holes were formed on the surfaces of etched-HNTs, resulting in the rougher HNT walls and significant increment of surface area and CO 2 adsorption capacity.