On the gas storage properties of 3D porous carbons derived from hyper-crosslinked polymers

The preparation of porous carbons by post-synthesis treatment of hypercrosslinked polymers is described, with a careful physico-chemical characterization, to obtain new materials for gas storage and separation. Different procedures, based on chemical and thermal activations, are considered; they include thermal treatment at 380 degrees C, and chemical activation with KOH followed by thermal treatment at 750 or 800 degrees C; the resulting materials are carefully characterized in their structural and textural properties. The thermal treatment at temperature below decomposition (380 degrees C) maintains the polymer structure, removing the side-products of the polymerization entrapped in the pores and improving the textural properties. On the other hand, the carbonization leads to a different material, enhancing both surface area and total pore volumethe textural properties of the final porous carbons are affected by the activation procedure and by the starting polymer. Different chemical activation methods and temperatures lead to different carbons with BET surface area ranging between 2318 and 2975 m(2)/g and pore volume up to 1.30 cc/g. The wise choice of the carbonization treatment allows the final textural properties to be finely tuned by increasing either the narrow pore fraction or the micro- and mesoporous volume. High pressure gas adsorption measurements of methane, hydrogen, and carbon dioxide of the most promising material are investigated, and the storage capacity for methane is measured and discussed

Functionalization of 3D Polylactic Acid Sponge Using Atmospheric Pressure Cold Plasma

The deposition of organic functionalities on biomaterials to immobilize biomolecules is a research area of great interest in the medical field. The surface functionalization of a 3D porous scaffolds of PDLLA with carboxyl (-COOH) and amino (-NH2) groups by cold plasma treatment at atmospheric pressure is described in this paper. Two methods of continuous and pulsed plasma deposition were compared to assess the degree of functionalization of the internal porous 3D scaffold. In particular, the pulsed plasma treatment was found to functionalize uniformly not only the sample surface but also inside the open cavities thanks to its permeability and diffusion in the porous 3D scaffold. The species developed in the plasma were studied by optical emission spectroscopy (OES) technique, while the functionalization of the sponges was evaluated by the Diffuse Reflectance Fourier-Transform Infrared Spectroscopy (DR-FTIR) technique using also the adsorption of ammonia (NH3) and deuterated water (D2O) probe molecules. The functional groups were deposited only on the front of the sponge, then the structural characterization of both front and back of the sponge has demonstrated the uniform functionalization of the entire scaffold

A method of preparing a microporous carbon and the microporous carbon thereby obtained

A process is described for the preparation of a microporous carbon from a hyper-cross- linked polymer of formula (II), in which A is selected from a C atom, a Si atom, a Ge atom, a Sn atom, an adamantane group, an ethane group and an ethene group, in which each of B, C, D and E are ring structures selected from radicals of the compounds benzene, naphthalene, anthracene, phenanthrene, pyrene, optionally having one or more substituents selected from nitro, amine, hydroxyl, sulfonyl, halogen, phenyl, alkyl, haloalkyl, hydroxyalkyl, aminoalkyl, aryl, alkenyl and alkynyl groups, and in which n is an integer between 200 and 6000

Theoretical prediction of high pressure methane adsorption in porous aromatic frameworks (PAFs)

The adsorption isotherms of methane in four micro- and mesoporous materials, based on the diamond structure with (poly)phenyl chains inserted in all the C-C bonds, have been simulated with Grand Canonical Monte Carlo technique. The pressure range was extended above 250 bar and the isotherms were computed at 298, 313, and 353 K, to explore the potentiality of these materials for automotive applications, increasing the capacity of high-pressure tanks or storing a comparable amount of gas at much lower pressure. The force field employed in the simulations was optimized to fit the correct behavior of the free gas in all the pressure range and to reproduce the methane-phenyl interactions computed at high quantum mechanical level (post Hartree-Fock). All the examined materials showed a high affinity for methane, ensuring a larger storage of gas than simple compression in all the conditions: two samples exceeded the target proposed by U.S. Department of Energy for methane storage in low-pressure fuel tanks (180 cm(3) (STP)/cm(3) at 35 bar and room temperature)

A gas-adsorbing porous organic polymer and method of preparing thereof

The invention relates to a gas-adsorbing porous organic polymer of the general formula (II), characterized in that it comprises ultramicropores having pore size lower than 7 Angstrom (A). The invention also relates to the method of preparing the gas-adsorbing porous organic polymer of formula (II) and the use of said polymer in a method of storing a gas preferably selected from the group consisting of hydrogen, methane and carbon dioxide

Understanding methane adsorption in porous aromatic frameworks: An FTIR, Raman, and theoretical combined study

We present a vibrational study of PAF-302, belonging to the class of porous aromatic frameworks (PAFs), recently synthesized and applied in several applications involving gas adsorption. The precursor, tetrakis(4-bromophenyl) methane (TBPM), and the polymer were studied with FTIR and Raman spectroscopies to investigate the structure of PAF-302, whereas the system after methane adsorption was studied by FTIR, also varying the CH4 loading, to get some hints on the strength of the interactions with adsorbed methane. Theoretical calculations of the harmonic frequencies of TBPM, methane, and methane/aromatic model systems were performed at high theory level (MP2 with extended basis set) to support the assignment of vibrational bands and to estimate the interactions causing the observed frequency shifts upon methane adsorption. The analysis shows that the polymerization process is essentially complete and that the adsorbed CH4 molecules interact with two phenyl rings, though stronger interactions can be envisaged. The computed interaction energies are compatible with the isosteric heats of adsorption previously measured for methane in PAF-302. A Grand Canonical Monte Carlo (GCMC) approach was used to simulate CH4 adsorption isotherms at different temperatures (87-115 K) and in the 0-0.020 bar pressure range, thus allowing us to estimate the loading of methane in the FTIR adsorption study. \ua9 2014 American Chemical Society

CO2 capture and reduction to liquid fuels in a novel electrochemical setup by using metal-doped conjugated microporous polymers

An electrochemical device for the reduction of CO2 back to liquid fuels is here presented. The key of this novel electrocatalytic approach is the design and development of the gas diffusion membrane (GDM), which is obtained by assembling (i) a proton selective membrane (Nafion), (ii) a nanocomposite electrocatalyst based on metal-doped conjugated microporous polymer (CMP) and (iii) a C-based support working as the gas diffusion layer. CMP is a very attractive material able to adsorb CO2 selectively with respect to other gases (such as H2, O2, N2, etc.), also in mild conditions (r.t. and atmospheric pressure). Particularly, tetrakis-phenylethene conjugated microporous polymer (TPE-CMP) was synthesized through Yamamoto homo-coupling reaction. TPE-CMP was modified by depositing noble (Pt) and non-noble (Fe) metal nanoparticles to create the active catalytic sites for the process of CO2 reduction directly on the polymer surface where CO2 is adsorbed. The metal-doped TPE-CMP electrocatalysts were fully characterized by infrared spectroscopy (IR), thermo-gravimetric analysis (TGA) and transmission electron microscopy (TEM). Then, the as-assembled GDM was tested in our homemade semi-continuous three-electrode electrochemical cell working in gas phase at 60 \ub0C, coupled with a cold trap for the accumulation of the liquid products. Results showed the better performances of the metal-doped TPE-CMP in terms of total productivity (C1\u2013C8 oxygenates) with respect to other kinds of materials that do not show high CO2 adsorption capacity

An electrochemical reactor for the CO2 reduction in gas phase by using conductive polymer based electrocatalysts

We discussed here on a novel approach to reduce CO2 back to liquid fuels by using an electrochemical device working in gas phase. Operating under solvent-less conditions is very attractive and has many advantages with respect to a slurry reactor working in liquid phase: easier recovery of the products, no problems of CO2 solubility, different reaction mechanism favouring C-C bond formation and producing longer chains of products. The materials used as electrocatalysts consist of conjugated microporous polymers (TPE-CMP) doped with Pt nanoparticles (acting as active phase) and mixed with carbon nanotubes (CNT) to guarantee a high electronic conductivity. The presence of the polymer may strongly enhance CO2 absorption due to its pore structure which is completely \u3c0-conjugated. The electrocatalytic composite materials were fully characterized and tested in the electrocatatalytic process of CO2 conversion in gas phase. The catalytic experiments were performed by using a homemade electrochemical cell with three-electrode configuration. The two compartments are separated by a membrane electrode assembly (MEA) consisting of a proton conductive membrane in contact with a gas diffusion layer. The active composite material was located between these two layers. Results showed good performances in terms of liquid product formation (methanol, ethanol, acetone, isopropanol, etc.) due to the high local concentration of CO2 on the polymer surface where the active metal nanoparticles are deposited. The results are very promising and open new possibilities in the electrocatalytic conversion of CO2 to liquid fuels by exploiting solar energy and closing the CO2 cycle of its production/consumptio

Musculoskeletal Disorders in Patients with Diabetes Mellitus: A Cross-Sectional Study

Introduction. A variety of musculoskeletal disorders (MS) have been associated with diabetes mellitus (DM). This study aimed at assessing the prevalence and associated factors of MS disorders in Moroccan diabetic patients. Methods. A cross-sectional study enrolled consecutive patients with DM. We recorded demographic features of patients and characteristics of DM. MS disorders and vascular complications were assessed by clinical examinations and investigations. Associated factors of MS disorders were assessed by univariate and multivariate analyses. Result. 376 subjects were included; 84.6% had type 2 DM. The participants’ median age was 54 years [45–62]; 41% had one or more vascular complications. 34.4% had one or more MS disorders. Osteoarthritis was present in 19.4% of patients. Hand disorders were seen in 14.4%. Shoulder capsulitis was present in 12.5%. Long duration of diabetes and dyslipidemia were associated with increased prevalence of hand abnormalities (P=0.017; P=0.019, respectively). Age and dyslipidemia were associated with shoulder capsulitis (P=0.019; P=0.047, respectively). Female gender, overweight, and nephropathy were associated with increased odds of osteoarthritis (P=0.009, P=0.004, and P=0.032, respectively). Conclusion. MS disorders are frequent in this population and associated with various factors. HbA1c level does not appear to be associated with development of MS disorders