The mobility of uranium (U) in various disposal environments of a deep geological repository is controlled by various geochemical conditions and parameters. In particular, oxidation state of uranium is considered as a major factor to control the mobility of uranium in most of geological environments. In this study, therefore, we investigated the geochemical behaviors of uranium in grounwater samples from natural analogue study sites located in the Ogcheon Metamorphic Belt (OMB). Groundwater samples were taken using a packer system from Boeun Hoenam-myun site and Geumsan Suyoung-ri site where several boreholes were dilled with various depths. The geochemical properties and parameters such as temperature, pH, Eh, EC, and DO were directly measured in the site using an in-line measurement method. The concentrations of major cations and anions in the groundwater samples were measured by using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometry) and IC (Ion Chromatography), respectively. The concentrations of trace elements including U and Th were measured by using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) The concentrations of U in the groundwater samples are very low for the Hoenammyun site (0.03~0.69 ppb) and Suyoung-ro site (0.39~1.74 ppb) even though the two sites are uranium deposits and redox conditions are weakly oxidizing. The speciation, saturation index (SI), pH-Eh (Poubaix) diagram were calculated using the Geochemist’s Workbench (GWB 9.0) program and the recent OECD/NEA thermochemical database for U. Calculation results for U speciation in the groundwater samples show that major dissolved uranium species in the groundwater samples are mainly as calcium uranyl carbonate complexes such as Ca2UO2(CO3)3(aq) and CaUO2(CO3)3 2- for almost all groundwater samples. The calculated results for SI and Poubaix diagram also show that the dominant uranium solid phase is a uranyl silicate mineral, uranophane (Ca(H2O)(UVIO2)2 (SiO2)2(OH)6), not uraninite (UIVO2). Since the determination of Eh values for natural groundwater samples is very difficult and uncertain work, we analyzed and discussed the effect of Eh on the geochemical behaviors of U in the groundwater. However, these calculation results are not consistent with the observation for U minerals in rock samples using electron microscopic techniques. Thus, we need further studies to explain the discrepancy between calculation and observation results.

This study aimed to provide better understanding of the bedrock aquifer bacterial communities and their functions in deep geological repository (DGR) environment. Two study sites of uranium deposits in the Ogcheon Metamorphic Belt were selected: Boeun and Guemsan. From two study sites, six groundwater samples were obtained with different boreholes and depths: OB1 (Boeun, 25 m), OB3 (Boeun, 80 m), GS1 (Guemsan, 25 m), GS2 (Guemsan, 85-90 m), GS3-I (Guemsan, 32- 38 m), GS3-II (Guemsan, 70-74 m). The physicochemical properties of groundwater were analyzed by multi-parameter sensors, ion chromatography (IC), and inductively coupled plasma optical emission spectroscopy (ICP-OES). Illumina Miseq sequencing was performed to investigate bacterial community in six groundwater samples. In addition, the number of sulfate-reducing bacteria (SRB) was quantified by a quantitative PCR (qPCR). Bacterial community composition varied in response to boreholes and depths. A total of 14 different phyla and 36 classes were detected from six groundwater samples. Overall, Proteobacteria, Actinomycetota, and Bacteroidota were dominant in the phylum level. SRB and iron-reducing bacteria (IRB) were detected in all groundwater samples even though organic carbon sources were not abundant (0.7-3.3 mg-total organic carbon/L). This result shows a potential to immobilize uranium in DGR environment. In particular, SRB, Desulfosporosinus fructosivorans and Humidesulfovibrio mexicanus were mainly detected in GS1 and GS2 groundwater samples, which attributed to higher dissimilatory sulfite reductase functional gene copy number in GS1 and GS2 groundwater samples. Statistical analysis was performed to understand the correlation between environmental factors and core bacterial species. Dissolved oxygen (DO), Fe, and Mn concentrations were positively correlated with Curvibacter fontanus while Undibacterium rivi had a negative correlation with pH. These results indicate that bacterial community could be changed in response to environmental variation. Further study with a greater number of samples is necessary to obtain statistically reliable and meaningful results for a safe DGR system.

Raman characteristics of various minerals constituting natural rocks collected from uranium deposits in Okcheon metamorphic zone in Korea are presented. Micro-Raman spectra were measured using a confocal Raman microscope (Renishaw in Via Basis). The focal length of the spectrometer was 250 mm, and a 1800 lines/mm grating was installed. The outlet of the spectrometer was equipped with a CCD (1,024256 pixel) operating at -70°C. Three objective lenses were installed, and each magnification was 10, 50, and 100 times. The diameter of the laser beam passing through the objective lens and incident on the sample surface was approximately 2 m. The laser beam power at 532 nm was 1.6 mW on the sample surface. Raman signal scattered backward from the sample surface was transmitted to the spectrometer through the same objective lens. To accurately determine the Raman peak position of the sample, a Raman peak at 520.5 cm-1 measured on a silicon wafer was used as a reference position. Since quartz, calcite, and muscovite minerals are widely distributed throughout the rock, it is easy to observe with an optical microscope, so there is no difficulty in measuring the Raman spectrum. However, it is difficult to identify the uraninite scattered in micrometer sizes only with a Raman microscope. In this case, the location of uraninite was first confirmed using SEM-EDS, and then the sample was transferred to the Raman microscope to measure the Raman spectrum. In particular, a qualitative analysis of the oxidation and lattice conditions of natural uraninite was attempted by comparing the Raman properties of a micrometer-sized natural uraninite and a laboratory-synthesized UO2 pellet. Significantly different T2g/2LO Raman intensity ratio was observed in the two samples, which indicates that there are defects in the lattice structure of natural uraninite. In addition, no uranyl mineral phases were observed due to the deterioration of natural uraninite. This result suggests that the uranium deposit is maintained in a reduced state. Rutile is also scattered in micrometer-sizes, similar to uraninite. The Raman spectrum of rutile is similar in shape to that of uraninite, making them confused. The Raman spectral differences between these two minerals were compared in detail.

The bioreduction process from soluble U(VI) to insoluble U(IV) has been extensively studied in the field of radionuclides migration. Since acetic acid (AcOH) is widely used as an electron donor for bioreduction of U(VI), it is necessary to understand the effect of U(VI)-AcOH complexes that exist in different species depending on pH on this process. Changes in samples before and after bioreduction can be compared using time-resolved laser luminescence spectroscopy (TRLLS), which measures the characteristic luminescence spectra of different U(VI) species. Although luminescence properties of U(VI)-AcOH species were reported, experiments were conducted under conditions below pH 4.5. In this study, spectrophotometry and TRLLS for U(VI)-AcOH species (10−100 μM U(VI) and 20 mM AcOH) were performed in pH ranges extending to neutral and alkaline pH regions similar to groundwater conditions as well as acidic pH region. Two different complexes (UO2(AcO)+, UO2(AcO)2 with U(VI) and acetate ratios of 1:1, 1:2) were observed in the acidic pH region. The 1:1 complex, which appears as the pH increases, has no luminescence properties, but its presence can be confirmed because it serves to reduce the luminescence intensity of UO2 2+. In contrast, the 1:2 complex exhibits distinct luminescence properties that distinguish it from UO2 2+. The 1:3 complex (UO2(AcO)3 -) expected to appear with increasing pH was not observed. Two different complexes ((UO2)3(OH)5 +, (UO2)3(OH)7 - with U(VI) and OH ratios of 3:5, 3:7) were observed as the major species in the neutral pH region, but their luminescence lifetimes are remarkably short compared those in the absence of AcOH. Solid U(VI) particles were observed in the alkaline pH region, and they also had completely different luminescence properties from the aforementioned U(VI)-AcOH and U(VI)-hydrolysis species. Based on these results, the effect of pH in the presence of AcOH on the bioreduction process from U(VI) to U(IV) will be discussed.

Bacterial metabolisms influence the behavior of uranium (U) in deep geological repository (DGR) system because bacteria are ubiquitous in the natural environment. Nevertheless, most studies for the U(VI) bioreduction have focused on a few model bacterium, such as Shewanella putrefaciens, Desulfovibrio desulfuricans, and Geobacter sulfurreducens. In this study, the potential of aqueous U(VI) ((U(VI)aq) reduction by indigenous bacteria was examined under anaerobic conditions with addition of 20 mM sodium acetate for 24 weeks. Three different indigenous bacterial communities obtained from granitic groundwater at depths of 44–60 m (S1), 92–116 m (S2), and 234–244 m (S3) were applied for U(VI)aq reduction experiments. The S2 groundwater contained the highest U concentration of 885.4 μg/L among three groundwater samples, where U mainly existed in the form of Ca2UO2(CO3)3(aq). The S2 groundwater amended 20 mM of sodium acetate was used for the U(VI)aq bioreduction experiment. Variations in the U(VI)aq concentration and redox potential were monitored for 24 weeks to compare U(VI)aq removal efficiency in response to indigenous bacteria. The U(VI)aq removal efficiencies varied among three indigenous bacteria: 57.8% (S3), 43.1% (S2), and 37.7% (S1). The presence of the thermodynamically stable uranyl carbonate complex resulted in the incomplete U(VI)aq removal. Significant shifts in indigenous bacterial communities were observed through highthroughput 16S rRNA gene sequencing analysis. Two SRB species, Thermodesulfovibrio yellowstonii and Desulfatirhabdium butyrativorans, were dominant in the S3 sample after the anaerobic reaction, which enhanced the bioreduction of U(VI)aq. The precipitates produced by bacterial activity were determined to be U(IV)-silicate nanoparticles by a transmission electron microscope (TEM)-energy dispersive spectroscope (EDS) analysis. These results demonstrated that considerable U immobilization is possible by stimulating the activity of indigenous bacteria in the DGR environment.

The mobility of uranium (U) in the environment of a deep geological repository is controlled by various geochemical conditions and parameters. In particular, oxidation state of uranium is considered as a major factor to control the mobility of uranium in most of geological environments. In this study, therefore, we investigated the mobility of uranium in a deep geological repository by a natural analogue approach using a uranium deposit in the Ogcheon Metamorphic Belt (OMB). Uranium contents of rock samples from the study site ranged from 1.3 to 71 ppm (average 17.4 ppm). Uranium minerals found in the study site were mostly uraninite (UIVO2+x) and uranothorite ((UIV, Th)SiO4). The concentrations of U in the groundwater samples were very low (0.025~0.690 ppb) even though redox conditions are weakly oxidizing. Calculation results for U speciation in groundwater samples showed that major dissolved uranium species in the groundwater samples are mainly as calcium uranyl (UO2 2+) carbonate complexes such as Ca2UO2(CO3)3(aq) and CaUO2(CO3)3 2-. However, the activity ratios between 234U and 238U (AR(234U/238U)) showed U behavior in reducing conditions although the groundwater conditions were not reducing conditions and major dissolved U species were U(VI) species. Results from electron microscopic analyses for rock samples showed that major uranium minerals were U(IV) minerals such as uraninite and uranothorite. We could not identify other uranyl minerals and altered minerals from uraninite. This means that the geochemical condition of the study site has been maintained a reducing condition although the groundwater condition was a weakly oxidizing condition. Thus, the dissolution of uranium is strongly limited by the low solubility of uraninite. It is not obvious how the reducing condition of the study site has been maintained. Reducing agents such as pyrite, organic materials, and reducing bacteria might contribute to maintaining the reducing condition although further studies will be necessary. Results from this study imply that uranium mobility will be greatly limited by low dissolution of uraninite into groundwater if the reducing condition is well reserved. This limited mobility of uranium will be also contributed by low possibility of uraninite alteration into uranyl minerals which have a higher solubility than uraninite.

Several countries have been operating radioactive waste disposal (RWD) programs to construct their own repositories and have used natural analogues (NA) studies directly or indirectly to ensure the reliability of the long-term safety of deep geological disposal (DGD) systems. A DGD system in Korea has been under development, and for this purpose a generic NA study is necessary. The Korea Atomic Energy Research Institute has just launched the first national NA R&D program in Korea to identify the role of NA studies and to support the safety case in the RWD program. In this article, we review some cases of NA studies carried out in advanced countries considering crystalline rocks as candidate host rocks for high-level radioactive waste disposal. We examine the differences among these case studies and their roles in reflecting each country’s disposal repository design. The legal basis and roadmap for NA studies in each country are also described. However because the results of this analysis depend upon different environmental conditions, they can be only used as important data for establishing various research strategies to strengthen the NA study environment for domestic disposal system research in Korea.

In south Korea, most of uranium deposits are distributed in the Ogcheon belt, which is one of two late Precambrian to Paleozoic fold belts (the Imjingang and Ogcheon belts). A study site of the Ogcheon metamorphic belt (OMB) in Hoenam-myun, Boeun-gun was selected for the natural analogue study by preliminary site investigation for several candidate study sites. Three boreholes were drilled in the site and some rock cores and groundwater samples were taken from the boreholes. Various analytical studies for the samples are now being performed. Thus, in this study, various basic characteristics of the study site such as occurrence, geological, mineralogical, and chemical properties were investigated for a future study. Base rocks containing uranium in the OMB are usually black slate and coaly slate. Coaly slate usually shows a higher content of uranium and larger grain size of uranium than black slate. Uranium minerals found in the OMB are uraninite, uranothorite, brannerite, ekanite, coffinite, francevillite, uranophane, autunite, and torbernite depending on the base rock types. Uranothorite is abundant in black slate whereas uraninite is mostly abundant in coaly slate. Chemical compositions of the solid and groundwater samples from the study site were also analyzed by using ICP-MS/OES (Inductively Coupled Plasma Mass Spectrometry) and XRF (X-ray Fluorescence). This will contribute to determine uranium minerals in the solid samples and uranium speciation in the groundwater. The results of this study will contribute to performing future natural analogue studies in domestic uranium deposits and provide basic information and knowledge for understanding long-term geochemical behaviors of radionuclides in a high-level radioactive repository.

Spent nuclear fuel (SNF) is the main source of high-level radioactive wastes (HLWs), which contains approximately 96% of uranium (U). For the safe disposal of the HLWs, the SNF is packed in canisters of cast iron and copper, and then is emplaced within 500 m of host rock surrounded by compacted bentonite clay buffer for at least 100,000 years. However, in case of the failure of the multi-barrier disposal system, U might be migrated through the rock fractures and groundwater, eventually, it could reach to the biosphere. Since the dissolved U interacts with indigenous bacteria under natural and engineered environments over the long storage periods of geologic disposal, it is important to understand the characteristics of U-microbe interactions under the geochemical conditions. In particular, a few of bacteria, i.e., sulfate-reducing bacteria (SRB), are able to reduce soluble U(VI) into insoluble U(IV) under anaerobic conditions by using their metabolisms, resulting in the immobilization of U. In this study, the aqueous U(VI) removal performance and change in bacterial community in response to the indigenous bacteria were investigated to understand the interactions of U-microbe under anaerobic conditions. Three different indigenous bacteria obtained from different depths of granitic groundwater (S1: 44–60 m, S2: 92–116 m, and S3: 234–244 m) were used for the reduction of U(VI)aq. After the anaerobic reaction of 24 weeks, the changes in bacterial community structure in response to the seeding indigenous bacteria were observed by high-throughput 16S rDNA gene sequencing analysis. The highest uranium removal efficiency of 57.8% was obtained in S3 sample, and followed by S2 (43.1%) and S1 (37.7%). Interestingly, SRB capable of reducing U(VI) greatly increased from 4.8% to 44.1% in S3 sample. Among the SRB identified, Thermodesulfovibrio yellowstonii played a key role on the removal of U(VI)aq. Transmission electron microscopy (TEM) analysis showed that the dspacing of precipitates observed in this study was identical with that of uraninite (UO2). This study presents the potential of U(VI)aq removal by indigenous bacteria under deep geological environment.

Time-resolved laser fluorescence spectroscopy (TRLFS) and excitation-emission matrix (EEM) spectroscopy were used to study the interaction of U(VI) and natural organic matters (NOMs) in groundwater. Various types of groundwaters (DB-1, DB-3 from KURT site and OB-1, OB-3 from a U deposit in Ogcheon metamorphic belt) were used as samples. Pulsed Nd-YAG laser at 266 nm (Continuum Minilite) was used as the light source of TRLFS. The laser pulse energy of 1.0 mJ was fixed for all measurements. The luminescence spectrum was recorded using a gated intensified chargecoupled device (Andor, DH-720/18U03 iStar 720D) attached to the spectrograph (Andor, SR-303i). EEM spectra were measured using a spectrofluorometer (Horiba Scientific, Aqualog) equipped with a 150 W ozone-free xenon arc lamp. Excitation spectra were recorded by scanning the excitation wavelength from 200 to 500 nm. Emission spectra were measured using a CCD in the wavelength range of 242–823 nm. In the case of the recently collected DB-1 samples, it was observed that the U and NOM quantities decreased compared to the samples collected before 2016. For some DB-1 samples, the amount of dissolved organic carbon indicating the presence of NOM was significantly reduced, and changes consistent with this phenomenon were observed in the EEM spectrum. The time-resolved luminescence characteristics (peak wavelengths and lifetime) of U(VI) in the DB-1 samples agree well with those of Ca2UO2(CO3)3(aq). This U(VI) species remains stable, even in samples taken five years ago. The estimated amounts of U and NOM from the spectroscopic data of DB-3, OB-1, and OB-3 samples are relatively low compared to DB-1 samples. When a known amount of U(VI) was mixed in each groundwater, the time-resolved luminescence spectrum exhibited a characteristic spectral shape different from the expected luminescence intensity. This phenomenon is presumed to be due to the interaction between U(VI) and NOM in groundwater. The results of this study suggest that the chemical speciation of NOM as well as U(VI) is required to understand U behavior in groundwater.

Several previous simulation studies using various geochemical models have been carried out in several major analogue sites. The cases are beneficial when these studies provided the possibility of testing the geochemical models to be used to describe the migration of radionuclides in a future radioactive waste repository system. It was possible to interpret the complex transport behaviour of radionuclides such as uranium and thorium in an environment. We organize major natural analogue study sites from the previous literatures that provided information on the general geochemistry of the sites, in terms of groundwater composition and mineralogy. Also, we calculated aqueous speciation and the solid phases most likely to control their solubilities. The results obtained from the previous studies and this study vary depending on the tools used and on the conceptual models followed. Also, the results differed from the actual measured concentrations of trace metals or radionuclide analogues. The results obtained from these tests identify the main mathematical limitations of available geochemical models. However, the modelling results using a geochemical code with the thermodynamic database simulated well the observed behaviour of radionuclides, especially to identify the dominant processes controlling actinide mobilization and fixation. It was a useful outcome in terms of building confidence on the current geochemical tools to predict the concentrations of radionuclide analogues once the major geochemical characteristics were known. This study allows improving specific aspects of geochemical modelling using major natural analogue sites.

Deep geological repository (DGR) has been considered as a globally accepted strategy to dispose high-level radioactive wastes. During long storage periods of 100,000 years, uranium (U) could be migrated through fractures in deep granite aquifers and interact with indigenous bacteria under anaerobic condition. Anaerobic bacteria can reduce U(VI) and further precipitate in the form of U(IV)-oxide minerals by transferring electrons through c-type cytochrome. In this point of view, a comprehensive understanding of uranium-microorganisms interaction is necessary to guarantee the safety of high-level radioactive waste disposal. Although diverse bacterial communities are present in DGR environment, a number of studies have been focused on some model bacteria, such as Desulfovibrio, Geobacter, and Shewanella spp.. In this study, indigenous bacterial community in deep granitic groundwater at 234–244 m was inoculated to sterile uranium-contaminated granitic groundwater amended with 20 mM of sodium acetate, and then incubated under anaerobic condition for 12 weeks. Bio-reduction of U(VI) to U(IV) by indigenous bacteria in uranium-contaminated groundwater was investigated during whole operation period. Initial U(VI) concentration of 885.4 μg·L−1 gradually decreased to 586.1 μg·L−1, resulting in approximately 33.8% of aqueous U(VI) removal efficiency. Oxidation-reduction potential (ORP) value was gradually decreased from 175.4 mV to –243.0 mV after the incubation of 12 weeks. The decrease in ORP value was attributed to the presence of aerobic bacteria and facultative anaerobic bacteria in indigenous bacterial community. The shift in bacterial community structure was observed by 16S rRNA gene high-throughput sequencing analysis. Proteobacteria (55.6%), Firmicutes (24.1%), Actinobacteria (5.5%), and Bacteroidetes (5.4%) were dominant in initial indigenous bacterial community, while Proteobacteria (94.8%) was found to be the only abundant phylum after the reaction. In addition, great increase in the relative abundance of sulfate-reducing bacteria (SRB) was observed: the relative abundance of SRB increased from 11.4% to 44.3% after the reaction. This result indicates that the SRB played a key role in the removal of aqueous U(VI). This finding shows the potential of aqueous U(VI) removal by indigenous bacteria in DGR environment.

Uranium isotopes (238U, 235U, and 234U) found in natural environments and their activity ratios (235U/238U and 234U/238U) have been used as an important tool in investigating various geological processes, especially in natural analogue studies. Occurrence and fractionation of uranium isotopes in nature between 238U, 235U, and 234U were investigated. Various measurement methods have been used for the determination of isotopic ratios and geochronology. Thus, we reviewed and summarized the measurement methods such as alpha spectrometry, gamma spectrometry, thermal ionization mass spectrometry (TIMS), secondary ion mass spectrometry (SIMS) with sensitive high resolution ion microprobe (SHRIMP), and multiple-collector inductively coupled plasma mass spectrometry (MCICPMS). Research status of natural analogue studies carried out using uranium isotopes and their isotopic ratios were also reviewed and summarized in terms of long-term behaviors of radionuclides in various foreign uranium deposits as analogues of high-level radioactive waste repositories. Research results for mineralogical, geochemical, and biogeochemical behaviors of uranium in various natural analogue sites were collected and analyzed to investigate the migration and retardation processes of uranium through geological media. These long-term behaviors of uranium and uranium isotopes include dissolution/precipitation of uranium minerals, interactions of uranium with various fracture minerals including sorption and incorporation, redox reactions by minerals and microbes, and hydrological groundwater flow thorough rock fracture systems including identification of flow paths and groundwater circulation. The results of this study will contribute to performing future natural analogue studies in domestic uranium deposits and provide basic information and knowledge for understanding long-term geochemical and geochronological behaviors of radionuclides in a high-level radioactive repository.

Background: Early rehabilitation after partial meniscectomy is important to recover the balance of the vastus medialis oblique and vastus lateralis and prevent pathological problems in the lower extremities and the whole body. Objective: To compare muscle activations for patients after partial meniscectomy. Design: Dual-group Pretest-Posttest Design from the Quasi-Experimental Research. Methods: Twenty participants after partial meniscectomy were recruited and were randomly divided into a Q-setting sensorimotor training group (QSMTG) and Q-setting exercise group (QSEG). Muscle activity of the vastus medialis oblique and vastus lateralis was measured before and after intervention. Results: In the two groups, the vastus medialis oblique and vastus lateralis activations increased significantly (P<.05). The Q-setting sensorimotor training group showed more increases than the Q-setting exercise group, and there were significant differences between the groups (P<.05). The activation ratio of the vastus medialis oblique and vastus lateralis had increasingly significant differences in the Q-setting sensorimotor training group (P<.05), and there were no significant differences between the groups (P>.05). Conclusion: Q-setting exercise with sensorimotor training was a useful method that improved the balance of vastus medialis oblique (VMO) and vastus lateralis (VL) activity after meniscectomy.

Background: Flexible flat foot is that the medial longitudinal arch collapses in weight bearing and returns normal arch when weight is removed and the weight bearing shifts toward medial part of the foot, which can cause pathological problems in the alignment of the lower extremities and the entire body. Objective: To compare the foot pressure for adults with flexible flat foot. Design: Quasi-Experimental Study Methods: 24 participants with flexible flat foot were recruited and were randomly divided into Visual feedback Short Foot Exercise (VSFE) group and Short Foot Exercise (SFE) group. To compare changes of foot pressure about pre and post intervention, the contact pressure measurement was conducted. Results: In the VSFE, significant differences were observed for the foot pressure of the 1st toe, 1st, 3rd and 4-5th metatarsal, midfoot, medial and lateral heel (p<.05). The foot pressure of the 3rd and 4-5th metatarsal, midfoot showed significant differences in the SFE (p<.05). The contact pressure of the 1st toe, 3rd metatarsal showed significant differences between the groups. Conclusions: Visual feedback short foot exercise can be useful for moving the pressure from medial to lateral part, and can prevent possible pathological problems.

The ultimate goal of seawater reverse osmosis brine management is to achieve minimal liquid discharge while recovering valuable resources. The suitability of an integrated system of membrane distillation (MD) with sorption for the recovery of rubidium (Rb⁺) and simultaneous SWRO brine volume reduction has been evaluated for the first time. Polymer encapsulated potassium copper hexacyanoferrate (KCuFC(PAN)) sorbent exhibited a good selectivity for Rb⁺ sorption. The integrated MD-KCuFC (PAN) system with periodic membrane cleaning, enabled 65% water recovery. A stable MD permeate flux was achieved with good quality permeate. KCuFC (PAN) showed a high regeneration and reuse capacity. Ammonium chloride air stripping followed by resorcinol formaldehyde resin filtration enabled to recover Rb⁺ from the desorbed solution.