Influence of Current Velocity on Uranium Adsorption from Seawater Using an Amidoxime-Based Polymer Fiber Adsorbent

Ladshaw, Austin; Kuo, Lih; Strivens, Jonathan E.; Wood, Jordana R.; Schlafer, Nicholas J.; Yiacoumi, Sotira; Tsouris, Costas; Gill, Gary A.

doi:10.1021/acs.iecr.6b04539

Cited by 31 publications

(43 citation statements)

References 21 publications

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“…For the velocities between 0.48 cm/s and 5.52 cm/s, the results indicate there is a strong, positive relationship between linear velocity and mass transfer, as expected. The highest linear velocity of 8.24 cm/s deviates downward from the trend, suggesting the mass-transfer coefficient is reaching a plateau where it will no longer increase with increasing linear velocity (Ladshaw et al, 2017).…”

Section: Influence Of Current Velocitymentioning

confidence: 90%

“…46 2-11 Relationship between the optimal values of the mass-transfer coefficient, K, and the linear velocities in the flume experiments. Adapted from Ladshaw et al (2017 . .…”

Section: List Of Figuresmentioning

confidence: 99%

“…Specifically, Ladshaw et al (2017) subjected the AF1 adsorbent to linear velocities ranging from 0.48-8.24 cm/s in a recirculating flume configuration to determine the affect the linear velocity had on the adsorbent's uptake of uranium.…”

Section: Influence Of Current Velocitymentioning

confidence: 99%

“…To describe adequately the experimental data, an adsorption model was developed by Ladshaw et al (2017) that accounted for the reaction and mass-transfer kinetics. In particular, the concentration of uranium in the adsorption domain as a function of the adsorption reaction and mass transfer from bulk solution was taken to be…”

Section: Influence Of Current Velocitymentioning

confidence: 99%

“…In particular, the flume experiments showed extreme differences in adsorption capacity as a function of linear velocity, as seen in figure 2-10. This suggests that the external mass-transfer resistance had not been successfully removed (Ladshaw et al, 2017).…”

Section: Influence Of Current Velocitymentioning

confidence: 99%

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Extraction of uranium from seawater : design and testing of a symbiotic system

Haji¹

2017

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Seawater is estimated to contain 4.5 billion tonnes of uranium, approximately 1000 times that available in conventional terrestrial resources. Finding a sustainable way to harvest uranium from seawater will provide a source of nuclear fuel for generations to come, while also giving all countries with ocean access a stable supply. This will also eliminate the need to store spent fuel for potential future reprocessing, thereby addressing nuclear proliferation issues as well. While extraction of uranium from seawater has been researched for decades, no economical, robust, ocean-deployable method of uranium collection has been presented to date. This thesis presents a symbiotic approach to ocean harvesting of uranium where a common structure supports a wind turbine and a device to harvest uranium from seawater. The Symbiotic Machine for Ocean uRanium Extraction (SMORE) created and tested decouples the function of absorbing uranium from the function of deploying the absorbent which enables a more efficient absorbent to be developed by chemists.The initial SMORE concept involves an adsorbent device that is cycled through the seawater beneath the turbine and through an elution plant located on a platform above the sea surface. This design allows for more frequent harvesting, reduced downtime, and a reduction in the recovery costs of the adsorbent. Specifically, the design decouples the mechanical and chemical requirements of the device through a hard, permeable outer shell containing uranium adsorbing fibers. This system is designed to be used with the 5-MW NREL OC3-Hywind floating spar wind turbine.To optimize the decoupling of the chemical and mechanical requirements using the shell enclosures for the uranium adsorbing fibers, an initial design analysis of the enclosures is presented. Moreover, a flume experiment using filtered, temperaturecontrolled seawater was developed to determine the effect that the shells have on the uptake of the uranium by the fibers they enclose. For this experiment, the AI8 amidoxime-based adsorbent fiber developed by Oak Ridge National Laboratory was used, which is a hollow-gear-shaped, high surface area polyethylene fiber prepared by radiation-induced graft polymerization of the amidoxime ligand and a vinylphosphonic acid comonomer.The results of the flume experiment were then used to inform the design and fabrication of two 1/10th physical scale SMORE prototypes for ocean testing. The 3 AI8 adsorbent fibers were tested in two shell designs on both a stationary and a moving system during a nine-week ocean trial, with the latter allowing the effect of additional water flow on the adsorbents uranium uptake to be investigated. A novel method using the measurement of radium extracted onto MnO 2 impregnated acrylic fibers to quantify the volume of water passing through the shells of the two systems was utilized.The effect of a full-scale uranium harvesting system on the hydrodynamics of an offshore wind turbine were then investigated using a 1/150th Froude scale wave tank test. These ...

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Section: Influence Of Current Velocitymentioning

confidence: 90%

“…46 2-11 Relationship between the optimal values of the mass-transfer coefficient, K, and the linear velocities in the flume experiments. Adapted from Ladshaw et al (2017 . .…”

Section: List Of Figuresmentioning

confidence: 99%

Section: Influence Of Current Velocitymentioning

confidence: 99%

Section: Influence Of Current Velocitymentioning

confidence: 99%

Section: Influence Of Current Velocitymentioning

confidence: 99%

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Extraction of uranium from seawater : design and testing of a symbiotic system

Haji¹

2017

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Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime‐Based Adsorbents in Natural Seawater

et al. 2018

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Recent advances in the development of amidoxime‐based adsorbents have made it highly promising for seawater uranium extraction. However, there is a great need to understand the influence of temperature on the uranium sequestration performance of the adsorbents in natural seawater. Here the apparent enthalpy and entropy of the sorption of uranium (VI) and vanadium (V) with amidoxime‐based adsorbents were determined in natural seawater tests at 8, 20, and 31 °C that cover a broad range of ambient seawater temperature. The sorption of U was highly endothermic, producing apparent enthalpies of 57 ± 6.0 and 59 ± 11 kJ mol−1 and apparent entropies of 314 ± 21 and 320 ± 36 J K−1 mol−1, respectively, for two adsorbent formulations. In contrast, the sorption of V showed a much smaller temperature sensitivity, producing apparent enthalpies of 6.1 ± 5.9 and −11 ± 5.7 kJ mol−1 and apparent entropies of 164 ± 20 and 103 ± 19 J K−1 mol−1, respectively. This new thermodynamic information suggests that amidoxime‐based adsorbents will deliver significantly increased U adsorption capacities and improved selectivity in warmer waters. A separate field study of seawater uranium adsorption conducted in a warm seawater site (Miami, FL, USA) confirm the observed strong temperature effect on seawater uranium mining. This strong temperature dependence demonstrates that the warmer the seawater where the amidoxime‐based adsorbents are deployed the greater the yield for seawater uranium extraction.

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