Enhancing Uranium Uptake by Amidoxime Adsorbent in Seawater: An Investigation for Optimum Alkaline Conditioning Parameters

被引：62

作者：

Das, S. ^{[1
]}

Tsouris, C. ^{[1
]}

Zhang, C. ^{[1
]}

Kim, J. ^{[1
]}

Brown, S. ^{[2
]}

Oyola, Y. ^{[1
]}

Janke, C. J. ^{[1
]}

Mayes, R. T. ^{[1
]}

Kuo, L. -J. ^{[3
]}

Wood, J. R. ^{[3
]}

Gill, G. A. ^{[3
]}

Dai, S. ^{[1
,2
]}

机构：

[1] Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA

[2] Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA

[3] Pacific NW Natl Lab, Marine Sci Lab, Sequim, WA 98382 USA

来源：

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH | 2016年 / 55卷 / 15期

关键词：

CHELATING FUNCTIONAL-GROUP; POLYMERIC ADSORBENT; FIBER ADSORBENTS; RECOVERY; ADSORPTION; STABILITY; BEHAVIOR; RESINS;

D O I：

10.1021/acs.iecr.5b02735

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 degrees C). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentration of similar to 7-8 ppm and pH 8. Fourier transform infrared spectroscopy and solid-state NMR analyses indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 degrees C resulted in an increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. Scanning electron microscopy showed that long conditioning times may also lead to adsorbent degradation.

引用

页码：4294 / 4302

页数：9

共 23 条

[1] DEVELOPMENT OF SORBERS FOR THE RECOVERY OF URANIUM FROM SEAWATER .2. THE ACCUMULATION OF URANIUM FROM SEAWATER BY RESINS CONTAINING AMIDOXIME AND IMIDOXIME FUNCTIONAL-GROUPS [J].