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Title: Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions

Abstract

The objective of this project was to move the testing of uranium adsorbents from the laboratory to the field. We were successfully able to test fibers in both a flume and ocean environment under varying conditions to quantify the adsorptive properties and uranium uptake of adsorbents under coastal ocean conditions. Through this testing we have identified numerous challenges to be overcome prior to large-scale deployment of these fibers This project began in Phase I with laboratory experiments examining the effects of flow rates and water filtration on the absorption of uranium to fibers in flowthrough columns. In this experiment we found that fibers adsorb most efficiently at a flow rate of 250 ml/min, on a per liter basis. However faster flow rates increase exposure volume and allowed for slightly greater total U absorption. Therefore a balance between current speeds that are too fast and potentially break down fibers and those that are slower will be important to consider, alongside bio-fouling and exposure time, when deciding which current regimes are best to place fibers in the ocean. Phase II examined biofouling, comparing exposure of fibers in filtered flume water to that in a coastal ocean environment. Results from the dock andmore » flume parallel experiment indicate a strong effect of biofouling on the capacity of the adsorbent fibers to adsorb uranium towards the very end of the experiment. Dock and flume samples showed comparable adsorption rates with the flume maximum achieved at day 49 with an adsorbance of 3.4 g U/kg-ads while the dock maximum was reached at day 42 with an adsorbance of 2.7 g U/kg-ads. Biofouling mitigation techniques were also examined. A comparison of 5 m and 12 m samples showed less growth at 12 meters where there is less light as well as less growth on the copper cages, which are toxic to many marine organisms. Overall despite biofouling, particles and other elements present, the fibers adsorbed uranium up to 2.7 g U/kg-ads in our open water dock experiments. This is lower than the maximum achieved in the flume of 3.4 g U/kg-ads and much lower than rates observed with synthetic seawater in laboratory experiments. Phase III involved two parts: working at Woods Hole Oceanographic Institution (WHOI) we examined the feasibility of reusing fibers after ocean deployment. Fiber reuse is an important consideration for operational costs associated with deployment. At present our data implies that reuse after open ocean exposure may not be significantly more effective than a single long deployment of fibers. The second part of Phase III involved collaboration with A. Slocum and M. Haji at MIT to examine the effects of various enclosures for fibers. This also involved testing a rotating system, designed to be deployed as part of an offshore wind turbine.« less

Authors:
 [1];  [1]
  1. Woods Hole Oceanographic Inst., Woods Hole, MA (United States)
Publication Date:
Research Org.:
Woods Hole Oceanographic Institution, Woods Hole, MA (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1463250
Report Number(s):
13-4905
13-4905
DOE Contract Number:  
NE0000713
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; SEAWATER; BIOLOGICAL FOULING; MATERIALS RECOVERY; URANIUM

Citation Formats

Buesseler, Ken, and Drysdale, Jessica. Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions. United States: N. p., 2018. Web. doi:10.2172/1463250.
Buesseler, Ken, & Drysdale, Jessica. Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions. United States. doi:10.2172/1463250.
Buesseler, Ken, and Drysdale, Jessica. Thu . "Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions". United States. doi:10.2172/1463250. https://www.osti.gov/servlets/purl/1463250.
@article{osti_1463250,
title = {Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions},
author = {Buesseler, Ken and Drysdale, Jessica},
abstractNote = {The objective of this project was to move the testing of uranium adsorbents from the laboratory to the field. We were successfully able to test fibers in both a flume and ocean environment under varying conditions to quantify the adsorptive properties and uranium uptake of adsorbents under coastal ocean conditions. Through this testing we have identified numerous challenges to be overcome prior to large-scale deployment of these fibers This project began in Phase I with laboratory experiments examining the effects of flow rates and water filtration on the absorption of uranium to fibers in flowthrough columns. In this experiment we found that fibers adsorb most efficiently at a flow rate of 250 ml/min, on a per liter basis. However faster flow rates increase exposure volume and allowed for slightly greater total U absorption. Therefore a balance between current speeds that are too fast and potentially break down fibers and those that are slower will be important to consider, alongside bio-fouling and exposure time, when deciding which current regimes are best to place fibers in the ocean. Phase II examined biofouling, comparing exposure of fibers in filtered flume water to that in a coastal ocean environment. Results from the dock and flume parallel experiment indicate a strong effect of biofouling on the capacity of the adsorbent fibers to adsorb uranium towards the very end of the experiment. Dock and flume samples showed comparable adsorption rates with the flume maximum achieved at day 49 with an adsorbance of 3.4 g U/kg-ads while the dock maximum was reached at day 42 with an adsorbance of 2.7 g U/kg-ads. Biofouling mitigation techniques were also examined. A comparison of 5 m and 12 m samples showed less growth at 12 meters where there is less light as well as less growth on the copper cages, which are toxic to many marine organisms. Overall despite biofouling, particles and other elements present, the fibers adsorbed uranium up to 2.7 g U/kg-ads in our open water dock experiments. This is lower than the maximum achieved in the flume of 3.4 g U/kg-ads and much lower than rates observed with synthetic seawater in laboratory experiments. Phase III involved two parts: working at Woods Hole Oceanographic Institution (WHOI) we examined the feasibility of reusing fibers after ocean deployment. Fiber reuse is an important consideration for operational costs associated with deployment. At present our data implies that reuse after open ocean exposure may not be significantly more effective than a single long deployment of fibers. The second part of Phase III involved collaboration with A. Slocum and M. Haji at MIT to examine the effects of various enclosures for fibers. This also involved testing a rotating system, designed to be deployed as part of an offshore wind turbine.},
doi = {10.2172/1463250},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {8}
}