Surfactant Assisted Synthesis of Homogeneous Calcium Based CO₂ Sorbent at Room Temperature
Pages 175-185
Chee Yew Henry Foo, Abdul Rahman Mohamed, Keat Teong Lee and Dahlan Irvan

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.03.6

Published: 18 September 2014

Abstract: Calcium oxide (CaO) sorbents have been recently used for removal of CO₂ gases in fossil fuel-fired power plant. However, there are some limitations of CaO in CO₂ capturing such as rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation. Therefore, this paper has demonstrated a novel synthesis method to produce CaO at room temperature to avoid abovementioned drawbacks. In addition, introduction of ionic surfactant of sodium dodecyl sulfate to the CaO formation solution has shown a positive result of formation of homogeneous spherical particle with a mean Z-average diameter of 345.2 nm and polydispersion index (PDI) of 0.335 by dynamical light scattering measurement. Subjected to a high calcination temperature of 1200^oC, developed CaO is able to maintain a CO₂ uptake capacity of 0.1025 g_CO2/g_sorbent under 30 minutes of carbonation time. Despite its lower CO₂ uptake capacity compared to maximum theoretical limit of 0.78 g_CO2/gsorbent, CaO particles is able to withstand a high calcination temperature of 1200^oC and reported a particle size distribution ranged from 0.4 - 1.2µm after calcination which is just slightly larger than fresh developed CaO. Given that such small narrow distributed size of CaO, developed CaO at room temperature is good for packed-bed reactor in calcium looping processes and more studies are required to find a suitable support for fluidized bed reactor type. This successful synthesis story of CaO particle at room temperature has unraveled the possibility to develop nanosized CaO at room temperature in order to achieve high CO₂ uptake capacity while enjoying its superior thermal stability over multiple carbonation/calcination cycles. .

Solubilization of Hydroxypropyl-β-Cyclodextrin on Cholesterol in Aqueous Solution
Pages 48-52
Changjun Zou, Lu Zhou, Yali Wang and Lu Li

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.02.1

Published: 30 May 2014

Abstract: Hydroxypropyl-β-Cyclodextrin (HP-β-CD), prepared via reaction of β-Cyclodextrin (β-CD) and propylene oxide (PO), is utilized to research solubilization of HP-β-CD on cholesterol in aqueous solution. HP-β-CD is characterized by Fourier Transform Infrared Spectrometry (FT-IR), and concentrations of cholesterol solution are measured by ultraviolet and visible (UV VIS) spectrophotometer. The research on optimal synthesis conditions of HP-β-CD indicates that sodium hydroxide amounts have the most effect on yields of product. The maximum solubilization multiples of HP-β-CD reaches 15, below which molecular rate of HP-β-CD and cholesterol in inclusion complex is 1:1.

Thermally Stable Multilamellar Structure of DNA/Cationic Lipid Complex in the Bulk State
Pages 53-57
Ching-Mao Wu and Szu-Yin Lin

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.02.2

Published: 30 May 2014

Abstract: The effect of temperature on the two types of multilamellar structures, L_I and L_II, formed by the complexes of DNA with a cationic lipid, cholesteryl 3β-N-(dimethylamionethyl) carbamate (DC-Chol), in the bulk state has been investigated by small angle X-ray scattering (SAXS). L_I phase composing of A-DNA intercalated between the lipid bilayers with tilted tails was formed at lower lipid-to-base pair molar ratio (x < 2), while L_II phase consisting of B-DNA bound to untilted lipid was formed at x > 2. In addition to the differences in lipid packing state and DNA conformation, these two lamellar phases also displayed different thermal stability. L_I phase was highly thermally stable as its interlamellar distance remained essentially unperturbed even after the denaturation of A-DNA in the complex at elevated temperature. By contrast, the interlamellar distance of L_II phase decreased with increasing temperature due to the release of bound water and B-DNA denaturation.

Refractive Properties of Binary Mixtures Formed by an Isomer of Chlorobutane and Butyl Ethyl Ether
Pages 58-64
Diego F. Montaño, Héctor Artigas, M. Carmen López and Carlos Lafuente

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.02.3

Published: 30 May 2014

Abstract: Refractive indices of the binary mixtures containing an isomer of chlorobutane (1-chlorobutane, 2-chlorobutane, 2-methyl-1-chloropropane, or 2-methyl-2-chloropropane) and butyl ethyl ether have been measured at seven temperatures from T = 283.15 to 313.15 K From these data refractive index deviations were calculated and correlated with a Redlich-Kister polynomial expansion. The refractive index deviations were found positive. Finally, from these refractive indices both densities and surface tensions of the studied systems were predicted and compared with previously reported values.

Preferential Solvation of Acetaminophen in Propylene Glycol + Water Co-Solvent Mixtures
Pages 65-73
María Ángeles Peña, Daniel Ricardo Delgado and Fleming Martínez

DOI: http://dx.doi.org/10.6000/1929-5030.2014.03.02.4

Published: 30 May 2014

Abstract: The preferential solvation parameters defined as the differences between the local mole fraction of solvents around analgesic drug acetaminophen and those for the bulk co-solvent composition in propylene glycol + water mixtures were derived from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals (IKBI) and the quasi-lattice-quasi-chemical (QLQC) methods. It is found that acetaminophen is sensitive to solvation effects, so according to IKBI method the preferential solvation parameter δx_PG,A, is negative in water-rich mixtures but positive in medium compositions and in co-solvent-rich mixtures. It is conjecturable that in water-rich mixtures the hydrophobic hydration around the aromatic ring and methyl group present in the drug plays a relevant role in the solvation. The bigger drug solvation by co-solvent in mixtures of similar solvent proportions and in propylene glycol-rich mixtures could be due mainly to polarity effects. Otherwise, according to QLQC method, this drug is preferentially solvated by the co-solvent in all the mixtures.