John P. Baltrus

CO2 capture by amine-enriched fly ash carbon sorbents

The capture of CO2 from gas streams has been achieved by the utilization of amine-enriched fly ash carbon sorbent system. The initial fly ash carbon sorbents were generated by the chemical treatment of carbon-enriched fly ash concentrates with a 3-chloropropylamine-hydrochloride (CPAHCL) solution at 25 ◦ C. It was determined that these amine-enriched fly ash carbon sorbents performed at a 9% CO2 capture capacity based on commercially available sorbents. The chemical sorption performance of these amine-enriched fly ash carbon sorbents will be described within this paper.

Performance of immobilized tertiary amine solid sorbents for the capture of carbon dioxide

The capture of carbon dioxide (CO2) from a simulated flue gas stream was achieved by utilizing immobilized tertiary amine solid sorbents. The tertiary amine immobilized in these solid substrates was 1, 8 Diazabicyclo-[5.4.0]-undec-7-ene (DBU) and it has the stoichiometric capability of capturing carbon dioxide at a 1:1 R-NH2:CO2 molar ratio. This is a unique feature compared to other primary and secondary amines which capture CO2 at a 2:1 molar ratio, thus making the immobilized DBU solid sorbents competitive with existing commercially available sorbents and liquid amine-based capture systems. The immobilized DBU solid sorbents prepared in this study exhibit acceptable CO2 capture capacities of 3.0 mol CO2/kg sorbent at 298 K; however, at the critical operational temperature of 338 K, the capacity was reduced to 2.3 mol/kg sorbent. The DBU sorbents did exhibit acceptable stability over the adsorption/desorption temperature range of 298–360 K based on XPS and TGA analyses.

Size-dependent photocatalytic reduction of CO2 with PbS quantum dot sensitized TiO2 heterostructured photocatalysts

The photocatalytic reduction of CO2 to value-added chemicals, such as CH4, is a promising carbon management approach which can generate revenue from chemical sales to offset the cost of implementing CO2 capture technologies. To make photocatalytic conversion approaches efficient, economically practical, and industrially scalable, catalysts capable of utilizing visible and near infrared (IR) photons need to be developed. Here we investigate the sensitization of TiO2 catalysts using PbS quantum dots (QDs) which lead to the size dependent photocatalytic reduction of CO2 at frequencies ranging from the violet to the orange-red edge of the electromagnetic spectrum (λ ∼ 420 to 610 nm). Under broad band illumination (UV- NIR), the PbS QDs enhance CO2 photoreduction rates with TiO2 by a factor of ∼5 in comparison to unsensitized photocatalysts. X-ray photoelectron spectroscopy (XPS) is used to investigate the deactivation mechanism of the QD sensitizers after prolonged photoexcitation. The synthesis, characterization, and catalytic testing of these PbS sensitized TiO2 heterostructures will aid the development of more robust, visible light active photocatalysts for carbon management applications.

Copolymer-templated nitrogen-enriched porous nanocarbons for CO2 capture

Nitrogen-enriched porous carbon materials made via the carbonization of polyacrylonitrile containing block copolymer act as efficient and highly selective CO(2) sorbents. Nitrogen content and surface area, which are both influenced by pyrolysis temperature and atmosphere, are crucial for CO(2) adsorption performance.

In-situ and ex-situ characterization of TiO2 and Au nanoparticle incorporated TiO2 thin films for optical gas sensing at extreme temperatures

Sensor technologies that can operate under extreme conditions including high temperatures, high pressures, highly reducing and oxidizing environments, and corrosive gases are needed for process monitoring and control in advanced fossil energy applications. Sensor technologies based on optical waveguide-based techniques are highly attractive for passive, embedded, and remote sensing. A critical enabling technology for optical waveguide sensors is the development of advanced optical thin film coatings which have a desired set of optical properties that change in a rapid, selective, and sensitive manner to a particular quantity of interest. TiO2 and Au nanoparticle incorporated TiO2 nanocomposite thin films were prepared through sol-gel deposition techniques and their respective optical responses to a 4% H2/N2 mixture were investigated in the visible / near-IR range of 400–1000 nm. A tendency for Au nanoparticles to occupy special sites on the TiO2 microstructure, such as grain boundaries, twin boundaries, a...

Surface Plasmon Resonance Label-free Monitoring of Antibody Antigen Interactions in Real Time*

Detection of biologically active compounds is one of the most important topics in molecular biology and biochemistry. One of the most promising detection methods is based on the application of surface plasmon resonance for label‐free detection of biologically active compounds. This method allows one to monitor binding events in real time without labeling. The system can therefore be used to determine both affinity and rate constants for interactions between various types of molecules. Here, we describe the application of a surface plasmon resonance biosensor for label‐free investigation of the interaction between an immobilized antigen bovine serum albumin (BSA) and antibody rabbit anti‐cow albumin IgG1 (anti‐BSA). The formation of a self‐assembled monolayer (SAM) over a gold surface is introduced into this laboratory training protocol as an effective immobilization method, which is very promising in biosensing systems based on detection of affinity interactions. In the next step, covalent attachment via artificially formed amide bonds is applied for the immobilization of proteins on the formed SAM surface. These experiments provide suitable experience for postgraduate students to help them understand immobilization of biologically active materials via SAMs, fundamentals of surface plasmon resonance biosensor applications, and determination of non‐covalent biomolecular interactions. The experiment is designed for master and/or Ph.D. students. In some particular cases, this protocol might be adoptable for bachelor students that already have completed an extended biochemistry program that included a background in immunology.

Measurement of adsorption of air-entraining admixture on fly ash in concrete and cement

Abstract A method using UV–Vis spectrophotometry for measuring the adsorption of air-entraining admixture (AEA) on the components of cements was optimized. The method was then used to measure the adsorption of AEA on a series of Class F fly ash samples with carbon concentrations of up to 14.6%. Class F fly ash carbons were found to have a very low capacity for AEA compared to Portland cement. The adsorption capacities of the fly ashes were compared to their carbon concentrations and foam index values. A lack of correlation between adsorption capacity and foam index was primarily due to differences in equilibration times used for the two measurements. Ultimately the Foam Index Test was found to be unsatisfactory for measuring the adsorption of AEA by fly ash carbon. The UV–Vis method is not necessarily a better choice for measuring AEA adsorption by carbon because soluble Ca 2+ and Mg 2+ ions from the fly ash were found to interfere with the UV–Vis method due to the formation of precipitates.

Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

Capture of carbon dioxide by solid amine sorbents

The reaction of tetraethylorthrosilcate (TEOS) with y-aminopropyltriethoxysilane (APTS) has produced stable solid amine sorbents for the capture of carbon dioxide. The resulting amine-enriched silicon sorbent (SBA-15) has been proven to be competitive with existing environmental CO2 controlled life sorbents based on the immobilised amine technology. XPS analysis has indicated that the amine groups (N1s Peak) were incorporated onto the surfaces of this amine-based sorbent in the range of 7%. The performance of the SBA-15 was comparable to the commercially available immobilised amine sorbent (IAS).

Surface characterization of Pd/Al2O3 sorbents for mercury capture from fuel gas

The surface composition of a series of Pd/alumina sorbents has been characterized to better understand the factors influencing their ability to adsorb mercury from fuel gas. Both a temperature effect and a dispersion effect were found. Maximum adsorption of Hg occurred at the lowest temperature tested, 2048C, and decreased with increasing temperatures. Maximum adsorption of Hg on a per-atom basis of Pd is observed at low loadings of Pd (58.5% Pd) due to better dispersion of Pd at those loadings; a change in its partitioning occurs at higher loadings. The presence of H2S in the fuel gas acts to promote the adsorption of Hg through its association with Hg in the Pd lattice.