Optimal strategy for carbon capture and storage infrastructure: A review

To effectively reduce CO₂, CO₂ mitigation technologies should be employed tactically. This paper focuses on carbon capture and storage (CCS) as the most promising CO₂ reduction technology and investigates how to establish CCS strategy suitably. We confirm a major part of the optimal strategy for CCS infrastructure planning through a literature review according to mathematical optimization criteria associated with facility location models. In particular, the feasibility of large scale CCS infrastructure is evaluated through economic, environmental, and technical assessment. The current state-of-the-art optimization techniques for CCS infrastructure planning are also addressed while taking numerous factors into account. Finally, a list of issues for future research is highlighted.     

Preparation of spherical macroporous silica in an aerosol phase

Macroporous silica (MS) and macro/mesoporous silica (MMS) were prepared by spray drying a polystyrene (PS) latex sol containing a silica source, followed by calcination. As a silica source, 3-aminopropyl triethoxysilane (APS) was used for MS while either silica sol (SS) or tetraethoxyothosilicate using P123 templating (P123-TEOS) was used for MMS. Spray drying and calcination could also take place in a once-through aerosol reactor. The transformation of the silicon alkoxides to silica and decomposition of PS occurred at similar temperatures. Therefore, for APS-originated MS, the metal additives such as silver and nickel were required to accelerate the former. In addition, the nickel was well dispersed in the silica matrix during calcination even at 800 °C, in turn to thermally stabilize the porous structures. The wall-preforming additives were unnecessary for PS/SS and PS/P123-TEOS, since the SS drying and P123 templating, respectively, took place at lower temperature than PS decomposition. The porosities of all the porous silica prepared ranged from 0.54 to 0.57, which were close to the volume fraction of PS in the PS-alkoxides mixture solidified right after spray drying.     

Strontium(II) ion uptake on poly(N‐vinyl imidazole)‐based hydrogels

In this article, we report on the extraction of Sr(II) ions from aqueous solution with a series of poly(N‐vinyl imidazole)‐based hydrogels. The hydrogels were synthesized by the crosslinking of N‐vinyl imidazole with four different crosslinkers with γ rays as initiators. The well‐characterized hydrogels were used as Sr(II) sorbents. Sr(II) uptake was determined with a colorimetric method with Rose Bengal anionic dye. Scanning electron microscopy–energy‐dispersive spectroscopy analysis of the Sr(II)‐loaded polymers was recorded to ascertain the uptake of Sr(II) ions. The experimental adsorption values were analyzed with the Freundlich and Temkin equations, and the kinetics of adsorption were investigated with a pseudo‐second‐order sorption kinetic model. The results show that the equilibrium data fit well in the Freundlich isotherm and followed a pseudo‐second‐order kinetic model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

LiNi<Subscript>0.4</Subscript>Co<Subscript>0.3</Subscript>Mn<Subscript>0.3</Subscript>O<Subscript>2</Subscript> thin film electrode by aerosol deposition

LiNi_0.4Co_0.3Mn_0.3O₂ thin film electrodes are fabricated from LiNi_0.4Co_0.3Mn_0.3O₂ raw powder at room temperature without pretreatments using aerosol deposition that is much faster and easier than conventional methods such as vaporization, pulsed laser deposition, and sputtering. The LiNi_0.4Co_0.3Mn_0.3O₂ thin film is composed of fine grains maintaining the crystal structure of the LiNi_0.4Co_0.3Mn_0.3O₂ raw powder. In the cyclic voltammogram, the LiNi_0.4Co_0.3Mn_0.3O₂ thin film electrode shows a 3.9-V anodic peak and a 3.6-V cathodic peak. The initial discharge capacity is 44.6 μAh/cm², and reversible behavior is observed in charge-discharge profiles. Based on the results, the aerosol deposition method is believed to be a potential candidate for the fabrication of thin film electrodes.     

Structural and optical properties of ZnS thin films deposited by RF magnetron sputtering

Zinc sulfide [ZnS] thin films were deposited on glass substrates using radio frequency magnetron sputtering. The substrate temperature was varied in the range of 100°C to 400°C. The structural and optical properties of ZnS thin films were characterized with X-ray diffraction [XRD], field emission scanning electron microscopy [FESEM], energy dispersive analysis of X-rays and UV-visible transmission spectra. The XRD analyses indicate that ZnS films have zinc blende structures with (111) preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM data also reveal that the films have nano-size grains with a grain size of approximately 69 nm. The films grown at 350°C exhibit a relatively high transmittance of 80% in the visible region, with an energy band gap of 3.79 eV. These results show that ZnS films are suitable for use as the buffer layer of the Cu(In, Ga)Se₂ solar cells.     

Halogen plasma erosion resistance of rare earth oxide films deposited on plasma sprayed alumina coating by aerosol deposition

Dense yttria, erbia and dysprosia films with thicknesses of 44.8 ± 1.7, 51.6 ± 0.9 and 36.8 ± 3.1 μm, respectively, were deposited on plasma sprayed alumina coating by aerosol deposition (AD). The rare earth oxide films remarkably enhanced the erosion resistance of the plasma sprayed alumina coating upon exposure to the halogen gas plasma. The enhanced plasma erosion resistances were related to their low surface porosity as well as the low vapor pressures of the rare earth fluorides and chlorides compared with those of corresponding aluminum halogenides. Electrical breakdown voltages of the samples with yttria, erbia and dysprosia films on the plasma sprayed alumina coating were 5.5, 6.2 and 5.3 kV, respectively, at room temperature and 4.0, 4.2 and 3.9 kV, respectively, at 573 K. The breakdown voltages at RT and 573 K were more than double that of the plasma sprayed alumina coating without the AD films.     

Microstructural evolution of YSZ electrolyte aerosol-deposited on porous NiO-YSZ

Dense, crack-free, ～7.5 μm thick, 8 mol% yttria stabilized zirconia (YSZ) film was aerosol deposited on porous NiO-YSZ anode substrates at room temperature without additional high-temperature sintering. The films’ microstructures and gas permeability were observed after annealing at various temperatures. The dense, gas-tight film that was observed up to 1000 °C became porous at higher temperatures probably due to structural instability related to oxygen non-stoichiometry. A cell using such film as electrolyte showed an open cell voltage of 1.10 V and a maximum power density of 0.51 W/cm² at 750 °C.     

Molecular brushes with extreme grafted side chain densities

A series of densely grafted poly(n-butyl acrylate) (PBA) molecular brushes with four different grafting densities were synthesized by the “grafting-from” approach using atom transfer radical polymerization (ATRP). A novel monomer, isopropylidene-2,2-Bis(methoxy)propionic hydroxyethylmethacrylate (IMPHMA), was synthesized and copolymerized with methyl methacrylate (MMA) under different monomer feed ratios to yield a series of linear poly(methyl methacrylate-stat-IMAPA), [PMMA-s-(PIMPHMA)]. The resulting copolymers were deprotected and transformed to macroinitiators, [PMMA-s-(PHEMA-IMPHMA-Br)]. n-Butyl acrylate (BA) was grafted from these macroinitiators to yield a series of molecular brushes, [PMMA-s-{(PIMPHMA)-g-PBA}], with various side chain lengths. Molecular brushes were characterized by gel permeation chromatography (GPC) and ¹H NMR. PBA side chains were cleaved by acid hydrolysis, and the resulting linear PBA polymers were characterized by GPC to study initiation efficiency during the synthesis of molecular brushes. The initiation efficiency increased with polymerization time and decreased with macroinitiators that had more initiation sites. Atomic force microscopy (AFM) measurements demonstrated the characteristic molecular structure by resolving individual brush molecules.     

Effect of grain size on the mechanical properties and crack formation of HPFRCC containing deformed steel fibers

This research investigated the influence of sand grain size on the behavior of high-performance fiber-reinforced cementitious composites (HPFRCC). Four types of sand with different grain sizes were investigated using the same matrix composition containing 2.0% hooked and twisted fibers by volume. The compressive strength was significantly greater for the finer sand grains, despite little difference in the packing density. The better compressive strength was mainly due to the denser calcium silicate hydrate (CSH) resulting from an intensive pozzolanic reaction with the finer silica sand, rather than to an improvement in packing density. The interfacial bond strength of those fibers was notably improved, having favorable effects on the mechanical properties and multiple crack formation of HPFRCCs. Although both fibers showed superior properties in mortars with a finer sand grain, twisted fiber produced more sensitive behavior according to the sand grain size.     

An efficient microwave-assisted Suzuki reaction using Pd/MCM-41 and Pd/SBA-15 as catalysts in solvent-free condition

Palladium catalysts, Pd/MCM-41 and Pd/SBA-15 were prepared by impregnation of an aqueous solution of [Pd(NH₃)₄]Cl₂ on MCM-41 and SBA-15. Palladium contents of Pd/MCM-41 and Pd/SBA-15 are 8.4% and 8.7%, respectively. It has been shown that these catalysts are very suitable to microwave-assisted Suzuki reactions under solvent-free condition. It is also found that the base additives for this reaction are K₂CO₃, Cs₂CO₃ or CsF. Thus, phenylboronic acid and phenyl iodide with Pd/MCM-41 produce biphenyl by microwave irradiation for 10 min in 97.4% yield. Phenyl bromide, instead of phenyl iodide, also proceeds the reaction with phenylboronic acid using Pd/MCM-41 or Pd/SBA-15 yielding biphenyl by microwave irradiation for 10 min in excellent yield. Whereas the reaction of phenyl chloride with phenylboronic acid gives poor yield in same condition. Various aryl iodides and aryl bromides are tested. In this paper our recent results of microwave-assisted Suzuki reaction using Pd/MCM-41 and Pd/SBA-15 under solvent-free condition are described.