Vahit Atakan

Quantification of Hydroxyl Content in Ceramic Oxides: A Prompt γ Activation Analysis Study of BaTiO3

Thermogravimetric analysis (TGA) and Fourier transform-infrared spectroscopy (FT-IR) techniques for water content determination were compared with a neutron characterization technique, prompt gamma activation analysis (PGAA). Residual H content in the samples, heat treated at various temperatures, was measured with PGAA and compared with the results obtained from TGA. Two major difficulties in TGA were overlapping of mass loss regimes due to removal of different species and residual water that could not be removed, even though the samples were heated above 900 degrees C. After 3 h of heat treatment at 900 degrees C, 0.007% mass fraction H remained in the sample. FT-IR spectra confirmed the presence of H semiquantitatively. It is concluded that residual H remains even after high-temperature treatments.

A Novel Strategy for Carbon Capture and Sequestration by rHLPD Processing

Monoethanolamine (MEA) scrubbing is an energy intensive process for Carbon Capture and Sequestration (CCS) due to the regeneration of amine in stripping towers at high temperature (100-120 oC) and the subsequent pressurization of CO2 for geologic sequestration. In this paper, we introduce a novel method, reactive hydrothermal liquid phase densification (rHLPD), which is able to solidify (densify) monolithic materials without using high temperature kilns. Then we integrate MEA-based CCS processing and mineral carbonation by using rHLPD technology. This integration is designated as rHLPD-Carbon Sequestration (rHLPD-CS) process. Our results show that the CO2 captured in the MEA-CO2 solution was sequestered by the mineral (wollastonite CaSiO3) carbonation at a low operating temperature (60 oC) and simultaneously monolithic materials with a compressive strength of ~121 MPa were formed. This suggests that the use of rHLPD-CS technology eliminates the energy consumed for CO2-MEA stripping and CO2 compression and also sequesters CO2 to form value-added products, which have a potential to be utilized as construction and infrastructure materials. In contrast to the high energy requirements and excessive greenhouse gas emissions from conventional Portland cement manufacturing, our calculations show that the integration of rHLPD and CS technologies provides a low energy alternative to production of traditional cementitious binding materials.

Engineered solution synthesis of rare-earth nanomaterials and their optical properties

This paper will summarize our work on rare-earth nanomaterials for infrared photonic applications. Our research focuses the use of solvothermal methods to prepare these materials in particulate and molecular form with controlled physical and chemical characteristics. Thermochemical computations are used to facilitate direct crystallization of the desired material from the solvothermal medium. The impact of the chemical and physical characteristics of nanopowder and molecular characteristics on optical properties will be discussed in reference to conventional glasses and single crystals.