Search

The objective of this study is to fabricate porosity-controlled polyethylene terephthalate porous materials using a CO2-assisted polymer compression (CAPC) method. In a previous study, the CAPC method was used to fabricate porous polymer materials by compressing fabric sheets in the presence of CO2. However, the controllability of the porosity was not clear in the previous study. In this study, it is shown that the porosity of porous polymer materials could be easily controlled by adjusting the operating conditions of the CAPC method, using polyethylene terephthalate (PET) nonwoven fabric sheets. Using mercury porosimetry, a decrease in the porosity induced by compression accompanied by a decrease in the pore size is demonstrated. Scanning electron micrographs strongly indicate the plasticization of PET fibers by CO2.

Biomass conversion to carbonaceous materials and their use in various applications, such as capacitors, catalyst supports, and adsorbents, have attracted considerable attention from the viewpoint of green chemistry. In this regard, chicken egg white is one of the most important biomass, which can act as an in situ nitrogen doping source. In this paper, nitrogen-rich porous carbon material was synthesized from egg white biomass via pyrolysis at 600 °C under nitrogen atmosphere, followed by chemical activation with KOH at 500 °C. The results showed that the as-synthesized porous carbon material has a high content of nitrogen and high surface area, on which nitrogen can tune the surface hydrophobicity–hydrophilicity through interaction with water molecules. Then, the copper nanoparticles were immobilized on the surface of nitrogen-rich activated carbon by a chemical reduction method. Nanocatalyst structure was characterized by elemental analysis, TEM, AFM, Raman, FT-IR, porosimetry and atomic adsorption techniques. Finally, catalytic activity was evaluated for the one-pot synthesis of triazole in aqueous medium. The nanocatalyst offers some advantages such as excellent activity, low loading of catalyst, good yields of products and short reaction times.

Porous ceramics have several industrial applications; however, most of them are prepared using toxic chemicals and submicron size ceramic particles. Here, an environmentally friendly gel casting method is employed by dispersing magnesium aluminate (MgAl2O4) nanoparticles in egg albumin-based aqueous solution in the presence of sucrose, to develop porous ceramic structures. The sintered ceramic foams are found to be cellular in nature and porous, as confirmed by scanning electron microscopy and mercury porosimetry studies, respectively. MgAl2O4 nanoparticle loading plays a significant role in controlling microstructural properties i.e. cell size, pore size distribution, the amount of porosity, and pore morphology in the final sintered bodies. The rheological measurements are carried out to understand the morphological changes in the sintered body. The obtained porous MgAl2O4 foam with an interconnected cellular structure could find potential applications as an adsorptive material, catalyst support or in humidity sensors. In the present study, the as-prepared ceramic body with multimodal porosity is found to be an efficient separator for Congo red removal from contaminated water.

This work describes the synthesis and characterization of pure ZnO and Ni-doped ZnO materials using agarose gel as a template for H2S desulfurization. H2S gas is not only harmful to the environment, but also corrosive to metals and poisonous to fuel reformer and fuel cell catalysts. Removal of H2S is an important step in fuel processing technology. This synthetic approach resulted in highly porous network ZnO based sorbent materials. The phase structure and morphology of these two materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area measurements, and mercury porosimetry. The H2S desulfurization performance of the as-synthesized ZnO and Ni-doped ZnO materials versus commercial ZnO was studied in a simulated fuel processing operation at 400 °C with an initial H2S concentration of 400 ppmv. It is shown that the sulfur adsorption capacity is greatly affected by the size and morphology of the particles. Desulfurization analysis revealed that commercial ZnO exhibits a low saturation capacity of 245 mg S per g while as-synthesized ZnO has a capacity of 457 mg S per g. Notably, when ZnO was doped with 4 wt% Ni, the sorbent capacity increased still further to 730 mg S per g.

Made available in DSpace on 2018-12-11T17:28:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Hierarchical porous γ-Al2O3 samples were prepared by a soft template method based on the integration of sol-gel transition with spinodal phase separation, using aluminum isopropoxide combined with low molecular weight poly(ethylene oxide) (PEO, Mw = 4 × 103 g mol-1) as phase separation inducer. The boehmite structure formed from the hydrolysis and condensation of aluminum isopropoxide was investigated by means of FTIR and time-resolved SAXS analyses. The boehmite layers acted as the primary building blocks of the gel phase networks. The growth of the gel network reduced the compatibility with PEO, inducing spinodal phase separation between the gel-rich and solvent-rich phases. The results of the TG and FTIR analyses indicated that the PEO was preferentially dissolved in the solvent-rich phase. Mercury porosimetry, N2 physisorption, and SEM measurements revealed that the porous γ-Al2O3 possessed an interconnected macro-mesoporous hierarchical structure. Appropriate selection of the starting composition enabled control of the average pore sizes and the volume fractions of the macro- and mesopore families present in the γ-Al2O3 ceramics. The high Al2O3 surface area (675 m2 g-1) obtained in this work could be explained by the high mesopore volume (3.3 cm3 g-1) and the fine structure of the ceramic skeleton. Instituto de Química UNESP Univ Estadual Paulista, Rua Professor Francisco Degni, 55 Synchrotron SOLEIL l'Orme des Merisiers, BP48, Saint Aubin Instituto de Química UNESP Univ Estadual Paulista, Rua Professor Francisco Degni, 55

Polysulfone (PSF)/fluorinated ethylene propylene (FEP) mixed matrix membranes (MMMs) with super hydrophobic surface were successfully fabricated via non-solvent induced phase separation (NIPS) method. The effects of FEP content on the morphology, roughness, wettability, pore size, and mechanical property of PSF/FEP MMMs were characterized by scanning electron microscope, confocal microscopy, contact angle goniometer, mercury porosimetry, and tensile testing instrument, respectively. When the FEP content was 9 wt%, the average roughness of M-4 reached 0.712 μm. Meanwhile, the water contact angle (CA) and the water sliding angle (SA) was 153.3° and 6.1°, respectively. M-4 showed super hydrophobicity with a micro- and nanoscale structure surface. Then, M-4 was used for separating of water-in-oil emulsion, showing high separation efficiency for water-in-kerosene and water-in-diesel emulsions of 99.79% and 99.47%, respectively. The flux and separation efficiency changed slightly after 10 cycles. Therefore, this study indicated that the obtained PSF/FEP MMM with super hydrophobic surface could be used for efficient water-in-oil emulsion separation.

Organic aerogels are a class of material most suited for their transformation into electrically conducting porous carbon networks. Typically, polymeric aerogels are prepared via base- or acid-catalyzed polymerization of organic monomers. In this work, we report the first synthesis of graphene oxide (GO) induced gelation of poly(urethane–amide) networks which upon pyrolysis yield monolithic N-doped amorphous carbon/reduced GO (rGO) aerogels. Here GO plays a significant multifunctional role of (i) inducing the gelation of poly(urethane–amide) networks; and (ii) tailoring the physical properties of N-doped amorphous carbon–rGO aerogels. The resulting aerogels were characterized by X-ray diffraction (XRD), N2 sorption porosimetry, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Fourier-transform Raman spectroscopy (FT-Raman), field emission scanning electron microscopy (FE-SEM), and high resolution transmission electron microscopy (HR-TEM) which support the formation of a highly porous carbon/rGO network. Importantly, the obtained N-doped amorphous carbon/rGO aerogels (0.76 wt% of GO) are electrically conducting with a pore volume, pore diameter and surface area of 0.39 cm3 g−1 (69% mesopores), 36 nm and 260 m2 g−1 respectively. The significantly enhanced specific capacitance is derived from the tailored 3-D mesoporous structure of the N-doped amorphous carbon/rGO aerogels which consist of large pore volumes and a predominant number of accessible mesopores allowing a low resistance path for inward and outward diffusion of electrolyte ions and endowing a high charge storage capability resulting in a superior specific capacitance of 260 F g−1. The nanoporous networks in the as-prepared N-doped amorphous carbon/rGO serve as channels for quick ionic and electronic conduction. In addition to the enhanced physical properties achieved by addition of a minimal amount of GO, the increased specific capacitance can also be credited to the effective N-doping in ACGA-2 resulting in alteration of the electronic structure of rGO with an increase in charge carrier density, and modification of interfacial and quantum capacitance.

Carbon nanotubes (CNTs) are one of the most promising candidates as adsorbents in many fields due to their unique structural characteristics. In this paper, hierarchical porous CNTs/carbon (CNTs/C) composite spheres were prepared and their strength and adsorption of vitamin B12 (VB12) were investigated. The initial porous CNT spheres were fabricated by freeze casting followed by freeze drying. Afterwards, the primary porous CNT spheres were further reinforced and tailored by chemical vapor infiltration (CVI) and steam activation. Consequently, the composite CNTs/C spheres with hierarchical porous structure and high strength were successfully fabricated. SEM and polarized light microscopy observations showed that, in addition to macro-sized radial through-pores in the spheres, many micro-sized pores were distributed uniformly in the wall of the radial tunnel-like through-pores. Mercury porosimetry and BET tests indicated that the width of the radial lamellar channels was about 5–15 μm, and the average diameter of the mesopores was about 3.8 nm. Adsorption of VB12 for these hierarchical porous CNTs/C spheres could reach 51.48 mg g−1, which is about 3.7 and 3.4 times those of traditional activated carbon beads and macroporous resin beads, respectively.

This article deals with the importance of potato starch in two different applications, as a pore former and also as a binder in microporous/mesoporous ceramic adsorbents for the removal of toxic metal pollutants in water. These porous ceramic adsorbents have unique and high adsorption and ion exchange properties in addition to an intricate structure, and were obtained by mixing 50% potassium polytitanates (PPTs) and 50% potato starch (PS). Cylindrical pieces were obtained through a typical extrusion process. Additionally, a heat treatment in different stages was applied to these cylinders and later they were crushed to 2–5 mm size. The physicochemical behavior of the adsorbents was assessed before and after the sintering process using different techniques: thermal analysis, chemical analysis, optical microscopy, SEM, TEM, XRD, BET, mercury porosimetry, determination of mechanical properties and physicochemical methods. Amounts of PS of 5–50 weight percent were applied with PPT in order to produce adsorbents with a properly configured structure. The mechanical properties and results of adsorption tests showed that the adsorbents removed cations of lead and nickel from the solution excellently. PPTs have technological and academic importance attributed to the fact that they have not yet been studied in linked form. It is possible to reduce diseases in people across the five continents by treatment of polluted water using these materials, and they also provide an opportunity for usage of potato waste.

A nanocomposite of polyaniline formed within ionic liquid derived ordered mesoporous carbon (PANi@IOMC) was prepared by polymerization of aniline in the presence of IOMC for electrochemical capacitors. The morphology and structure of the nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and porosimetry. To fabricate the supercapacitor electrode, an appropriate mixture of the PANi@IOMC nanocomposite and activated carbon was sonicated in acetone, and then the resulting dispersion was coated on the carbon fiber paper using a spray-coating technique. Because of the relatively high surface area of the nanocomposite for faradaic redox reactions, a maximum specific capacitance of 542 F g−1 in addition to 85% specific capacitance retention after 1000 successive charge–discharge cycles were obtained. The excellent electrochemical performance of the nanocomposite compared to the pure PANi or IOMC, was attributed to the covalent bonding between PANi and the carbon structure in the presence of N-phenyl-p-phenylenediamine (NPP) as an initiator for linking the polymer chains to the surface. The results of the present work highlight the efficiency of the interfacial chemistry of NPP in generating the nanocomposite with enhanced conductivity and high surface area.

Nano Ag/ZnO is successfully synthesized by a new simple and low cost method employing Zn(NO3)2·6H2O, AgNO3, and urea. X-ray diffraction (XRD), transmission electron microscopy (TEM), adsorption/desorption porosimetry (BET) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the catalyst. The amount of Ag loading on ZnO (9.276 × 10−5, 7.391 × 10−5, 3.632 × 10−5, and 3.286 × 10−5 mol%) was determined by induced coupled plasma (ICP). The resulting ZnO-supported Ag nanoparticles efficiently catalyzed the oxidation reactions of alkyl-substituted benzenes with hydrogen peroxide (H2O2) as a cheap and environmentally friendly oxidant under solvent-free conditions. This catalytic reaction gave good to excellent yield of products by using mild reaction conditions and no additives were employed during the reaction.

Philippine lignite with high inherent moisture and oxygen was upgraded by improving the slurryability through microwave irradiation. The physicochemical properties of the upgraded lignite were characterized through Fourier transform infrared spectroscopy, N2 adsorption porosimetry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The solid concentration of coal water slurry (CWS) that was prepared using the upgraded lignite increased from 51% to 53.4%, and the apparent CWS viscosity decreased from 862 mPa s to 687 mPa s at a shear rate of 100 s−1. These results can be attributed to several reasons. (1) The inherent moisture and hydrophilicity of the upgraded lignite was reduced after microwave irradiation. (2) Hydroxyl and carboxyl, which had the strongest hydrophilicity among the oxygen functional groups, decreased, whereas the carbonyl and ether, which only slightly affected the hydrophilicity, increased. (3) The specific surface area of the upgraded lignite initially decreased because of particle expansion, which was then augmented with increasing microwave time. (4) The aluminosilicate crystalline phase was generated through the mineral interactions in the upgraded lignite, and the soluble alkali ions, such as Ca2+, Mg2+, and Na+, increased on the particle surfaces. It is promising to continuously upgrade Philippine lignite in a tunnel-type microwave irradiation system to improve its slurribility for industrial-scale application.

Mesoporous silica thin films were patterned at the sub-micron scale utilizing the ion hammering effect in order to combine the advantages of mesoporous character and surface morphology, while preserving the interconnected pore system or creating laterally separated porous volumes surrounded by nonpermeable compact zones. Porous silica coatings were prepared by a sol–gel method with an ordered and disordered pore system using micellar templates. A hexagonally ordered Langmuir–Blodgett type monolayer of silica spheres was applied as a mask against Xe+ ion irradiation. The ion energy was chosen according to Monte-Carlo simulations to achieve structures with high lateral contrast between irradiated and unirradiated, i.e., masked areas. The disordered pore system proved to be more resistant against ion bombardment. Although the created surface morphologies were similar, the main character of the pore system could be tailored to be interconnected or separated by controlling the ion fluence. Confocal fluorescence images and ellipsometric porosimetry measurements confirmed that the contribution of transition zone between the intact masked and damaged regions to the porosity is negligible. Furthermore, the majority of the porous volume can be preserved as an interconnected pore system by the application of low ion fluence. By increasing the fluence value, however, separated porous volumes can be created at the expense of the total pore volume.

Micellar-enhanced ultrafiltration (MEUF) is a promising technology to remove organic contaminants from wastewater. A laboratory experiment was carried out to study the performance of four Gemini surfactant systems (CG12, CG16, CG12 + Brij35, CG16 + Brij35) for treating synthetic wastewater. The results show that CG16–Brij35 possesses the lowest flux behavior and the best rejection efficiencies toward phenol and surfactants. Pore blocking models are utilized to estimate membrane fouling of surfactant systems. For CG12 and CG12 + Brij35 systems, internal pore blocking, intermediate pore blocking and cake formation models occur simultaneously. Internal pore blocking and cake formation are the main fouling mechanisms of CG16 micelles. With respect to CG16–Brij35, cake layer is the main type of fouling mechanism. The increased pore blocking degree follows the order of CG12 < CG16 < CG12 + Brij35 < CG16 + Brij35. Furthermore, SEM, ATR-FTIR and a mercury porosimeter are used to analyze membrane surface morphology, membrane material characteristics and membrane fouling layer, as well as examine and verify fouling mechanisms. Due to high flux behavior, excellent phenol rejection and low membrane fouling, CG12 is a more desirable selection. Studies output helps to understand the fouling mechanism of MEUF in the presence of Gemini surfactants, and gave valuable evidence to optimize operation strategies.

In the present work, we demonstrate a facile and cost-effective strategy for synthesizing hierarchical flower-like super-structures consisting of porous NiCo2O4 nanosheets. The morphologies and surface areas of NiCo2O4 samples can be tailored by changing the reaction time. The synthesized NiCo2O4 samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and by using an accelerated surface area and porosimetry analyzer (ASAP 2020M). The NiCo2O4 samples exhibit high activity and superior cycling stabilities in ORR. In addition, the magnetic properties of NiCo2O4 samples are also studied in detail.

Electron-beam-induced grafting of hydrophilic polymers was applied to modify PVDF membranes for biomedical applications. Grafting was performed by immersing the membrane in an aqueous solution of different hydrophilic polymers followed by electron-beam irradiation. The two polymer types are able to cross-link by recombination of adjacent radicals formed via the irradiation. Although the untreated membrane was already quite hydrophilic, the modification resulted in even lower water contact angles at the membrane surface indicating improved water wettability. The presence of different functional groups originating from the hydrophilic polymers was detected on the membrane surface by electrokinetic measurements. SEM investigations as well as porosimetry experiments showed that the grafted hydrophilic polymer layer is very thin; therefore, the membrane pore structure is not negatively affected. Soxhlet extraction revealed the stability of the modification for selected polymers: surface contact angles were comparable after extraction, and total organic carbon investigation of the extraction water revealed no significant loss of organic material. Investigated mechanical properties confirmed an increased stability due to cross-linking of the polymers. Undesired hemolysis was not detected with hemocompatibility tests, and coagulation was decreased with selected hydrophilic polymers. Because of the absence of any toxic material during surface modification and the high stability of the product, this method is believed to be suitable for the modification of membranes for medical applications, e.g. for improving the hemo- or biocompatibility.

Single-crystalline bismuth titanates (Bi12TiO20) with the cubic phase and various morphologies (flower-, belt-, tetrahedral-like) were controllably fabricated by using a mild template-free hydrothermal process. The samples were fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM, nitrogen porosimetry measurement, UV-vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The influence of the solvent and the concentration of NO3− in the reaction system on the crystallinity and morphology of the Bi12TiO20 samples was investigated in detail. Bi12TiO20 crystals were used as the sunlight-driven photocatalysts to degrade aqueous dye methyl orange (MO) and p-nitrophenol (PNP), and the influence of Bi12TiO20 morphology on the photocatalytic activity was discussed. Finally, the recyclability of Bi12TiO20 was evaluated through three consecutive runs.

The controlled pyrolysis of mesoporous polysaccharide-derived materials, from starch and alginic acid, formed carbonaceous materials (Starbons®) and were demonstrated as efficient materials for the removal of dyes from wastewater. The resulting materials were characterised by solid-state NMR, N2 adsorption porosimetry, FT-IR, scanning electron microscopy (SEM) and tunnelling electron microscopy (TEM). The material’s efficiency for dye adsorption was tested using methylene blue (MB) and acid blue 92 (AB) dyes. Adsorption data indicated that the mesoporosity of the material had a far greater influence on the adsorption capacity and speed of adsorption, than high surface area alone. Mesoporous Starbon® (A300) was evaluated against commercially available activated carbon (Norit) and demonstrated a superior adsorption capacity of MB; 186 mg g−1vs. 42 mg g−1. The kinetic activity of Starbon® was also determined with A800 showing the fastest rate of adsorption compared to S800 and Norit, suggesting that it is a more suitable material for water purification.

Mesoporous silica films with vertically aligned hexagonal pores have been produced via the electrochemically assisted surfactant assembly (EASA) method using cetyltrimethylammonium bromide (CTAB) surfactant. Mesoporous silica powder has also been synthesised using the same surfactant. The pore walls of the silica powder and films have been grafted with organosilane reagents. The size of the pore, degree of grafting and effect on the properties of the pore have been investigated using porosimetry, contact angle, NMR and CHN analysis. The degree of grafting was found to be dependent upon the size of the grafting agent, with the smallest steric bulk grafting most effectively. It was found that the grafting of the pores with Me3SiCl greatly increased the hydrophobicity of the pore and reduced water penetration. Grafting with larger groups caused the film surface to be hydrophobic but had little effect on the penetration of water into the pores.