Application of the cross-flow ultrafiltration technique to the study of colloidal uranium, thorium, radium isotopes and organic carbon in seawater

Chen Min; Guo Laodong; Huang Yipu; Gao Zhongyong; Cai Yihua; Cai Minggang

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Article Navigation > Haiyang Xuebao > 2000 > 22(5): 51-59

Chen Min, Guo Laodong, Huang Yipu, Gao Zhongyong, Cai Yihua, Cai Minggang. Application of the cross-flow ultrafiltration technique to the study of colloidal uranium, thorium, radium isotopes and organic carbon in seawater[J]. Haiyang Xuebao, 2000, 22(5): 51-59.

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Application of the cross-flow ultrafiltration technique to the study of colloidal uranium, thorium, radium isotopes and organic carbon in seawater

1.
Department of Oceanography, Xiamen University, Xiamen 361005
2.
Department of Oceanography, Texas A & M University, 5007 Avenue U, Galveston, TX 77551, USA

Received Date: 1999-05-10
Rev Recd Date: 2000-03-24

Abstract

Abstract

A ctnss-flow ultrafiltration system,including a prefilter (0.22 μm),a Masterflex pump and a polysulfone hollow fiber 10 KDa ultrafiltration membrane (Amicon H10P10-20),is evaluated for its feasibility in sampling colloidal uranium,thorium,radium isotopes and organic carbon (0C) in seawater.The retention characteristics and sorptive potential of the 10 KDa ultrafilter are examined through laboratory experiments using a 40 KDa fluoresceintagged dextran and standard ²³⁴Th as tracers.The mass balance of ²³⁴U,²³⁸U,²³⁴Th,²²⁴Ra,²²⁶Ra and OC during ultrafiltration is also evaluated.The results show that the 10 KDa ultrafiltration membrane can indeed tetain the 40 KDa dextran with a retention coficient of 0.85.However,sorptive loss of the 40 KDa dextran to the system is 18%.Mass balance of uranium,thorium,radium isotopes and OC are excellent,with recoveries ranging from 95% to 98%,indicating that losses or contamination problems during ultrafiltration are minimal.The concentration of ²³⁴Th in the permeate,when plotted as a function of concentration factor,is found to fit an ultrafiltration permeation model.Percentage of colloids in the dissolved phase decreases as follows:thorium isotopes,organic carbon,radium isotopes about equaling uranium isotopes,which is consistent with their geochemical properties,i.e.,thorium is a particle-reactive nuclide while uranium and radium are more soluble in seawater.
- Cross-flow ultrafiltration,
- marine colloids,
- thorium isotopes,
- urariium isotopes,
- radium isotopes

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References(19)

References

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