Discovery of a hyperalkaline liquid condensed phase: significance toward applications in carbon dioxide sequestration.

Bicarbonate ion-containing solutions such as seawater, natural brines, bovine serum and other mineralizing fluids have been found to contain hyperalkaline droplets of a separate, liquid condensed phase (LCP), that have higher concentrations of bicarbonate ion (HCO ) relative to the bulk solution in which they reside. The existence and unique composition of the LCP droplets have been characterized by nanoparticle tracking analysis, nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, dissolved inorganic carbon analysis and refractive index measurements. Carbon dioxide can be brought into solution through an aqueous reaction to form LCP droplets that can then be separated by established industrial membrane processes as a means of concentrating HCO .

Three-Dimensional Printable Sodium Carbonate Composite Sorbents for Efficient Biogas Upgrading.

We have developed a new class of sodium carbonate/silicone composite sorbents that selectively capture carbon dioxide (CO) and can purify biogas to natural gas pipeline-quality biomethane. These nontoxic composites can be three-dimensionally printed or extruded at low costs, can have high specific CO sorption rates (in excess of 5 μmol s g bar) and high selectivity due to their chemical mechanism, and can be regenerated with low-energy air stripping. Therefore, these composite sorbents combine the high selectivity of liquid sorbents with the high specific sorption rates and low regeneration energies found in many solid sorbents.

Evaluating the Performance of Micro-Encapsulated CO Sorbents during CO Absorption and Regeneration Cycling.

We encapsulated six solvents with novel physical and chemical properties for CO sorption within gas-permeable polymer shells, creating Micro-Encapsulated CO Sorbents (MECS), to improve the CO absorption kinetics and handling of the solvents for postcombustion CO capture from flue gas. The solvents were sodium carbonate (NaCO) solution, uncatalyzed and with two different promoters, two ionic liquid (IL) solvents, and one CO-binding organic liquid (COBOL). We subjected each of the six MECS to multiple CO absorption and regeneration cycles and measured the working CO absorption capacity as a function of time to identify promising candidate MECS for large-scale carbon capture.

Encapsulated liquid sorbents for carbon dioxide capture.

Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas.

Direct electrolytic dissolution of silicate minerals for air CO2 mitigation and carbon-negative H2 production.

We experimentally demonstrate the direct coupling of silicate mineral dissolution with saline water electrolysis and H2 production to effect significant air CO2 absorption, chemical conversion, and storage in solution. In particular, we observed as much as a 10(5)-fold increase in OH(-) concentration (pH increase of up to 5.3 units) relative to experimental controls following the electrolysis of 0.

Review of methane mitigation technologies with application to rapid release of methane from the Arctic.

Methane is the most important greenhouse gas after carbon dioxide, with particular influence on near-term climate change. It poses increasing risk in the future from both direct anthropogenic sources and potential rapid release from the Arctic. A range of mitigation (emissions control) technologies have been developed for anthropogenic sources that can be developed for further application, including to Arctic sources.

Pore conductivity control at the hundred-nanometer scale: an experimental and theoretical study.

We report on the observation of an unexpected mechanism that controls conductivity at the 100-nm scale on track-etched polycarbonate membranes. Transport measurements of positively charged methyl viologen performed by absorption spectroscopy under various pH conditions demonstrate that for 100-nm-diameter pores at pH 2 conductivity is blocked, while at pH 5 the ions move through the membrane according to diffusion laws. An oppositely charged molecular ion, naphthalene disulfonate, in the same membrane, shows the opposite trend: diffusion of the negative ion at pH 2 and very low conductivity at pH 5.

The influence of ionic strength on the interaction of viruses with charged surfaces under environmental conditions.

The influence of ionic strength on the electrostatic interaction of viruses with environmentally relevant surfaces was determined for three viruses, MS2, Q beta, and Norwalk. The virus is modeled as a particle comprised of ionizable amino acid residues in a shell surrounding a spherical RNA core of negative charge, these charges being compensated for by a Coulomb screening due to intercalated ions. A second model of the virus involving surface charges only is included for comparison.

Dielectrophoretic forces on the nanoscale.

We have developed a method of calculation of the dielectrophoretic force on a nanoparticle in a fluid environment where variations in the electric field and electric field gradients are on the same nanoscale as the particle. The Boundary Element Dielectrophoretic Force (BEDF) method involves constructing a solvent-accessible or molecular surface surrounding the particle, calculating the normal component of the electric field at the surface boundary elements, and then solving a system of linear equations for the induced surface polarization charge on each element. Different surface elements of the molecule may experience quite different polarizing electric fields, unlike the situation in the point dipole approximation.

Electrostatic potentials and fields in the vicinity of engineered nanostructures.

We have developed a method for calculating the electrostatic potentials and fields in the vicinity of geometrically complex engineered nanostructures composed of varying materials in electrolytes of arbitrary pH and ionic strength. The method involves direct summation of charged Debye-Hückel spheres composing the nanostructural surfaces and, by including charge redistribution on the surface of conducting materials held at constant potential, is applicable to mixed boundary conditions. The method is validated by comparison to analytical solutions for an infinite plane (Gouy-Chapman), an infinite cylinder (Bessel functions), and an infinite plane which contains a hole and which is held at constant potential.

Investigation of pyrochlore-based U-bearing ceramic nuclear waste: uranium leaching test and TEM observation.

A durable titanate ceramic waste form (Synroc) with pyrochlore (Ca(U,Pu)Ti2O7) and zirconolite (CaZrTi2O7) as major crystalline phases has been considered to be a candidate for immobilizing various high-level wastes containing fissile elements (239Pu and 235U). Transmission electron microscopy study of a sintered ceramic with stoichiometry of Ca(U(0.5)Ce(0.

Determination of H2O and CO2 concentrations in fluid inclusions in minerals using laser decrepitation and capacitance manometer analysis.

Water and carbon dioxide concentrations within individual and selected groups of fluid inclusions in quartz were analyzed by using laser decrepitation and quantitative capacitance manometer determination. The useful limit of detection (calculated as ten times the typical background level) is about 5 x 10(-10) mol of H2O and 5 x 10(-11) mol of CO2; this H2O content translates into an aqueous fluid inclusion approximately 25 micrometers in diameter. CO2/H2O determinations for 38 samples (100 separate measurements) have a range of H2O amounts of 5.