The Pacific Northwest National Laboratory (PNNL) has been conducting marine testing of uranium adsorbent materials for the Fuel Resources Program, Department of Energy, Office of Nuclear Energy (DOE-NE) beginning in FY 2012. The marine testing program is being conducted at PNNL's Marine Sciences Laboratory (MSL), located at Sequim Bay, along the coast of Washington. One of the main efforts of the marine testing program is the determination of adsorption capacity and adsorption kinetics for uranium and selected other elements (e.g. vanadium, iron, copper, nickel, and zinc) for adsorbent materials provided primarily by Oak Ridge National Laboratory (ORNL), but also includes other Fuel Resources Program participants. This report summarizes the major marine testing results that have been obtained to date using time series sampling for 42 to 56 days using either flow-through column or recirculating flume exposures. The major results are highlighted in this report and the full data sets are appended as a series of Excel spreadsheet files. Over the four year period (2012-2016) that marine testing of amidoxime-based polymeric adsorbents was conducted at PNNL's Marine Science Laboratory, there has been a steady progression of improvement in the 56-day adsorbent capacity from 3.30 g U/kg adsorbent for the ORNL 38H adsorbent to the current best performing adsorbent prepared by a collaboration between the University of Tennessee and ORNL to produce the adsorbent SB12-8, which has an adsorption capacity of 6.56 g U/kg adsorbent. This nearly doubling of the adsorption capacity in four years is a significant advancement in amidoxime-based adsorbent technology and a significant achievement for the Uranium from Seawater program. The achievements are evident when compared to the several decades of work conducted by the Japanese scientists beginning in the 1980's (Kim et al., 2013). The best adsorbent capacity reported by the Japanese scientists was 3.2 g U/kg adsorbent for a 180 day deployment at temperatures between 15 and 25 °C (Kim et al., 2013) The majority of the capacities the Japanese scientists reported were less than 2 g U/kg adsorbent (Kim et al., 2013). Repeated time series measurements of a common formulation of amidoxime-based adsorbent, the ORNL AF series, by both flow-through column (3.91 ± 0.11 g U/kg adsorbent). and recirculating flume exposures (4.03 ± 0.12 g U/kg adsorbent) produced 56-day adsorption capacities that agreed extremely well. This excellent agreement generates confidence that the testing procedures are accurate and reliable and moreover, that the technology to produce the adsorbents is highly reliable and reproducible, lending additional confidence of the robustness and homogeneity of the production technology.
Lithium is a critical industrial material and an indispensable component in manufacturing Li batteries. However, Li resources are limited and geographically uneven in the Earth’s crust, and its mining is not sustainable due to the low efficiency and complicated separation and refining processes. Here, we report a one-step technology to electrochemically extract Li from low-concentration solutions (brines, seawater, or used Li-ion batteries) into a form to directly produce commercial battery materials, eliminating the costly Li separation/purification steps. By using this approach, Li was selectively extracted and converted into battery cathodes (e.g., spinel LiMn2O4 and layered LiNi x Mn y Co z O2) through heat treatment. Techno-economic analysis indicates that the prepared cathode materials have economic superiorities over even commercial cathodes. With the importance of Li-ion batteries to the overall decarbonization strategy, the demonstration of a one-step Li extraction to a ready-to-use material could expand the access to Li resources at a lower cost by eliminating processing steps.
Marine testing at Broad Key Island (BKI), FL was conducted to validate adsorption capacity and adsorption kinetics results obtained for several formulations of the ORNL amidoxime-based polymeric adsorbents in Sequim Bay, WA in another location with different oceanographic and water quality conditions (e.g. temperature, dissolved organic carbon, salinity and trace element content). Broad Key is a small island off the southeast coast of Florida at the southern end of Biscayne Bay, approximately 30 miles south of Miami. The Rosensteil School of Marine and Atmospheric Sciences (RSMAS) of the University of Miami operates a research station on the island. Flow-through column and recirculating flume experiments were conducted at BKI using ambient filtered seawater and identical exposure systems as were used at the Pacific Northwest National Laboratory's (PNNL) Marine Sciences laboratory (MSL). Testing was conducted in two periods in FY 2015 and FY 2016 with five different amidoxime-based adsorbent materials, four produced by ORNL (AF1, AI8, AF8, and AF1-DMSO) and one by LCW technologies (LCW-10). All exposures were conducted at ambient seawater temperatures, with moderate temperature control on the ambient seawater to mitigate large daily swings in the seawater temperature. The ORNL adsorbents AF1, AI8 and AF1-AO-DMSO all had fairly similar adsorption capacities (6.0 to 6.6 g U/ kg adsorbent) after 56 days of exposure at ambient temperature (26 to 31 °C) and salinity (35.7 to 37.4), but the AF8 adsorbent was considerably lower at 4.4 g U/kg adsorbent. All the adsorbents tested at BKI had higher capacities than was observed at PNNL, with the higher temperatures likely a major factor contributing to this difference. In general, the elemental distribution (expressed as a relative percentage) on all the adsorbents agreed well, including good agreement with the elemental distribution pattern for AF1 adsorbent exposed at PNNL. The most notable exception to a uniform elemental distributional pattern across the various adsorbents occurs with vanadium. The relative mass
This study analyzes how solution pH and ionic strength influence the sorption of polycyclic aromatic hydrocarbons (PAHs) onto humic acids (HA) coated aluminum oxide. A series of batch experiments were performed to obtain the apparent sorption coefficient (K p ) for systems with different humic acid concentrations, pH values, ionic strengths, and K ow values of the sorbate. According to those results, the value of K p increases as the ionic strength or hydrophobicity of the PAHs increases, or as the pH value decreases. In addition, the fluorescence quenching method was used to measure the HA-PAHs binding constant K dom , allowing the estimation of K p by an overall mechanistic sorption model (OMS model). In most cases, 515 516 LEE, HUANG, AND KUO these two approaches display the same trends and have similar results, thereby confirming the feasibility of applying this model to the aqueous chemistry of the third-phase effect and analyzing the environmental system.
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