Size and composition analyses of colloids in deep granitic groundwater using microfiltration/ultrafiltration while maintaining in situ hydrochemical conditions

Aosai, Daisuke; Yamamoto, Yuhei; Mizuno, Takashi; Ishigami, Toru; Matsuyama, Hideto

doi:10.1016/j.colsurfa.2014.08.007

Cited by 11 publications

(4 citation statements)

References 39 publications

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“…The latter corresponds to about 140 nm, if the range of the size calibration is extrapolated. Aosai et al 34 investigated the size distribution of rare earth elements (REEs) in granitic groundwater samples collected from a different borehole at the same depth in the Mizunami URL as that of the present study, using an in situ micro/ultraltration device and scanning electron microscopy energy dispersive Xray spectroscopy (SEM-EDX). They found that more than 50% of REEs were associated with colloids with size ranges of 10 kDa to 0.2 mm and 0.2-0.45 mm, consisting of Fe, Al, Mg, and Si.…”

Section: Fl-fff Size Distribution and Composition Of Colloids In The ...mentioning

confidence: 95%

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Saito

Hamamoto

Mizuno

et al. 2015

J. Anal. At. Spectrom.

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Section: Fl-fff Size Distribution and Composition Of Colloids In The ...mentioning

confidence: 95%

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Saito

Hamamoto

Mizuno

et al. 2015

J. Anal. At. Spectrom.

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“…Colloids, such as particles and macromolecules ranging from 1 to 1000 nm in size, are widespread in various natural water sources [1]. Groundwater contains inorganic colloids, such as fragments of rock and clay minerals from dissolution and precipitation of the rock, and organic colloids such as humic substances [2][3][4][5]. Additionally, it has been clearly shown that the migration velocity of radionuclides can either increase or decrease in the presence of colloids [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Concentration and characterization of organic colloids in deep granitic groundwater using nanofiltration membranes for evaluating radionuclide transport

Aosai

Saeki

Iwatsuki

et al. 2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Understanding the properties of organic colloids is important for geological disposal of high-level radioactive waste in terms of radionuclide transport. To analyze organic colloids in deep groundwater, concentration techniques using adsorption resins and reverse osmosis (RO) membranes have been widely applied, because their concentrations in deep groundwater are very low and detection of the organic colloids in raw groundwater is difficult. However, these techniques have respective disadvantages such as chemical disturbance and membrane fouling caused by cations. To overcome their disadvantages, we propose a new concentration method using nanofiltration (NF) membranes to concentrate organic colloids rapidly without chemical disturbance and to selectively remove monovalent and divalent ions, which may cause inorganic and/or organic fouling. Concentration performance of the NF and RO membranes for aqueous solutions for humic acids was evaluated using a laboratory-scale membrane test unit. The time course of permeate flux and concentration of humic acids were measured. These membranes were applied to the concentration of actual groundwater obtained at a depth of 300 m at the Mizunami Underground Research Laboratory in Japan. The permeate flux and concentration of major ions and organic colloids were measured. The organic colloids concentrated by the NF membrane were successfully analyzed using pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS) owing to their high concentrations and low concentrations of salts.The NF membrane was useful for the concentration of organic colloids and rare earth elements (REEs) in deep groundwater, and the findings of the organic colloid structures revealed by Py-GC/MS provided valuable information for evaluating the effect of organic colloids on radionuclide transport.

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“…Groundwater generally contains inorganic colloids such as fragments of granites and clay minerals resulting from dissolution and precipitation of host rock [31]. Inorganic colloids would also cause membrane fouling during the condensation process, although the membrane fouling with inorganic colloids was not observed in this study.…”

Section: Condensation Of Organic Colloids In Groundwatermentioning

confidence: 66%

Efficient condensation of organic colloids in deep groundwater using surface-modified nanofiltration membranes under optimized hydrodynamic conditions

Aosai

Saeki

Iwatsuki

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The transport of radionuclides by organic colloids in deep groundwater is one of the important issues for the geological disposal of high-level radioactive waste. Because of their low concentration, it is difficult to directly analyze organic colloids in deep groundwater. Hence, it is useful to utilize porous membranes for the condensation which can increase the concentration of organic colloids in groundwater physically without alteration of their properties, although some part of the components is lost by membrane fouling. In this study, hydrodynamic conditions were optimized, and surfaces of nanofiltration (NF) membranes were modified using a cationic phosphorylcholine polymer, poly(2-methacryloyloxyethyl phosphorylcholine-co-2-aminoethyl methacrylate) (p(MPC-co-AEMA)), for preventing membrane fouling and improving condensation efficiency. Aqueous solutions of humic acid or bovine serum albumin (BSA) were used as models of organic colloids, and they were condensed using a laboratory-scale cross-flow filtration apparatus equipped with a commercial sulfonated polyethersulfone NF membrane. The effects of hydrodynamic conditions, such as the applied transmembrane pressure (TMP) and stirring rate, and membrane surface modification on condensation efficiency were evaluated. A low TMP and high stirring rate effectively improved the recovery yield of humic acids and BSA. The membrane surface coated with p(MPC-co-AEMA) was significantly effective for preventing the decline in permeate flux, caused by fouling with BSA. Deep groundwater, obtained from a depth of 300 m at the Mizunami Underground Research Laboratory in Japan, was condensed. The recovery yield of the organic colloids in the deep groundwater condensation test at 5-fold condensation was improved from 62% to 92% by the optimized hydrodynamic conditions and membrane surface modification for prevention of membrane fouling. The composition of organic colloids in the condensates was analyzed using pyrolysis gas chromatography coupled with mass 3 spectrometry.

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Size and composition analyses of colloids in deep granitic groundwater using microfiltration/ultrafiltration while maintaining in situ hydrochemical conditions

Cited by 11 publications

References 39 publications

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Concentration and characterization of organic colloids in deep granitic groundwater using nanofiltration membranes for evaluating radionuclide transport

Efficient condensation of organic colloids in deep groundwater using surface-modified nanofiltration membranes under optimized hydrodynamic conditions

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