Distribution coefficient prediction using multimodal machine learning based on soil adsorption factors, XRF, and XRD spectrum data.

The distribution coefficient (K) plays a crucial role in predicting the migration behavior of radionuclides in the soil environment. However, K depends on the complexities of geological and environmental factors, and existing models often do not reflect the unique soil properties. We propose a multimodal technique to predict K values for radionuclide adsorption in soils surrounding nuclear facilities in Republic of Korea.

A comparative study on the Cs adsorption/desorption and structural changes in different clay minerals.

We investigated the structural changes in clay minerals after Cs adsorption and understood their low desorption efficiency using an ion-exchanger. We focused on the role of interlayers in Cs adsorption and desorption in 2:1 clay minerals, namely illite, hydrobiotite, and montmorillonite, using batch experiments and XRD and EXAFS analyses. The adsorption characteristics of the clay minerals were analyzed using cation exchange capacity (CEC), maximum adsorption isotherms (Q), and radiocesium interception potential (RIP) experiments.

Magnetic hierarchical titanium ferrocyanide for the highly efficient and selective removal of radioactive cesium from water.

Selective adsorption is the most suitable technique for eliminating trace amounts of Cs from various volumes of Cs-contaminated water, including seawater. Although various metal ferrocyanide (MFC)-functionalized magnetic adsorbents have been developed for the selective removal of Cs and magnetic recovery of adsorbents, their adsorption capacity for Cs remains low. Here, magnetic hierarchical titanium ferrocyanide (mh-TiFC) was synthesized for the first time for enhanced Cs adsorption.

Enhanced removal of cesium from hydrobiotite using polyacrylonitrile (PAN)-based nickel ferrocyanide beads.

The desorption of cesium (Cs) from contaminated clay minerals remains challenging because of the restricted efficiency of the removal process. Therefore, in the present study, a bead-type adsorbent was added during the conventional acid washing process to improve the removal of Cs from a clay mineral. As the Cs adsorbent, polyacrylonitrile-based nickel potassium hexacyanoferrate (NiFC-PAN) was used to selectively adsorb Cs in a strongly acidic solution containing competing ions.

Post-substitution of magnesium at Ca of nano-hydroxyapatite surface for highly efficient and selective removal of radioactive Sr from groundwater.

We have modified the ion-exchange affinity of nano-Hydroxyapatite (Ca(PO)OH, HAP) surface for the rapid and selective adsorption of Sr from groundwater. The modification was achieved by the post-substitution of cations (Na, Mg, Cu, Ba, Fe, and Al) for parent Ca within surface structure of HAP. The diffraction patterns of modified HAP showed a slight shift of the (002) peak between 25° and 27° 2θ depending the ionic radius of the substituted cation.

Characteristic and remediation of radioactive soil in nuclear facility sites: a critical review.

A huge amount of radioactive soil has been generated through decommissioning of nuclear facilities around the world. This review focuses on the difficulties and complexities associated with the remediation of radioactive soils at the site level; therefore, laboratory studies were excluded from this review. The problems faced while remediating radioactive soils using techniques based on strategies such as dry separation, soil washing, flotation separation, thermal desorption, electrokinetic remediation, and phytoremediation are discussed, along with appropriate examples.

Cesium Removal from Nonexpandable Illite Clay by Chloride Salt Treatment.

Extracting cesium (Cs) from nonexpandable illite clay is important in the remediation of radioactive Cs-contaminated soil. In this study, we investigated a chloride salt treatment technique for the removal of Cs from illite. Cs-loaded illite samples with initial Cs concentrations of 2430 and 690 ppm were treated using a NaCl-MgCl-CaCl ternary salt system at 400-850 °C under ambient pressure to suppress Cs loss by vaporization.

Sorption behavior of cesium on silt and clay soil fractions.

The effect of clay mineral composition on Cs adsorption behavior of silt and clay fractions (SC-fractions) of soil was investigated. Surface soil samples were collected within 2 km of Kori and Wolsong nuclear power plants in South Korea, and SC-fractions (<20 μm) were separated. The physicochemical properties of SC-fractions and types of clay minerals contained in the SC-fractions were analyzed.

Cs desorption behavior during hydrothermal treatment of illite with oxalic acid.

The desorption of radioactive cesium (Cs) in soil is influenced by the clay mineral type, adsorption site, and concentration of Cs. In this study, experiments to detect desorption of non-radioactive and radioactive Cs from illite using oxalic acid were performed for 2 days at 70 °C in hydrothermal conditions. The results showed that the Cs removal efficiency by oxalic acid and inorganic acid treatment was similar at high concentration (22.

Application of polyethylenimine-coated magnetic nanocomposites for the selective separation of Cs-enriched clay particles from radioactive soil.

The separation of Cs-enriched fine particles is a highly effective way to reduce the volume and radioactivity of contaminated soil. This work demonstrated the application of polyethylenimine (PEI)-coated FeO nanocomposites and a mesh filter for the selective separation of clay particles from Cs-contaminated soil. The PEI coating on the FeO nanoparticles enhanced the binding force between the magnetic nanoparticles and clay minerals electrostatic attraction; thus, approximately 100% of the clay particles were magnetically separated from solution by FeO-PEI nanocomposites at a low dose (0.

Enhanced removal of cesium by potassium-starved microalga, Desmodesmus armatus SCK, under photoheterotrophic condition with magnetic separation.

This study investigated the feasibility of using photoheterotrophic microalga, Desmodesmus armatus SCK, for removal of cesium (Cs) followed by recovery process using magnetic nanoparticles. The comparison of three microalgae results indicated that D. armatus SCK removed the most Cs at both 25 °C and 10 °C.

Selective separation of Cs-contaminated clay from soil using polyethylenimine-coated magnetic nanoparticles.

We evaluated the feasibility of using magnetic nanoparticles (MNPs) coated with polyethylenimine (PEI), a cationic polymer, to remediate radioactive contaminated soil by separating Cs-contaminated clay from the soil. The influences of the solution pH, PEI-to-MNPs mass ratio, and the PEI-MNPs dose on the magnetic separation performance were systematically examined. The highest SE% of illite from solution through electrostatic attraction was approximately 100% at a mass ratio of 0.

Desorption of cesium from hydrobiotite by hydrogen peroxide with divalent cations.

In this study, hydrogen peroxide (HO) was used to enhance the cation-exchange treatment for Cs desorption from clay minerals. Among various investigated clay minerals, hydrobiotite (HBT), which has interstratified layers of vermiculite and biotite, exhibited the highest Cs sorption capacity and the most favorable HO activation because of its high Fe content. In X-ray diffraction analysis, HBT treated with HO and 0.

Removal of radioactive cesium from an aqueous solution via bioaccumulation by microalgae and magnetic separation.

We evaluated the potential sequestration of cesium (Cs) by microalgae under heterotrophic growth conditions in an attempt to ultimately develop a system for treatment of radioactive wastewater. Thus, we examined the effects of initial Cs concentration (100-500 μM), pH (5-9), K and Na concentrations (0-20 mg/L), and different organic carbon sources (acetate, glycerol, glucose) on Cs removal. Our initial comparison of nine microalgae indicated that Desmodesmus armatus SCK had removed the most Cs under various environmental conditions.

Co-production of biodiesel and alginate from Laminaria japonica.

A process to produce both biodiesel and alginate in an integrated manner from a brown seaweed, Laminaria japonica, was established. Mannitol, a major carbon constituent in L. japonica, served to produce neutral lipids via the heterotrophic cultivation of an oleaginous yeast, Cryptococcus sp.

Development of practical decontamination process for the removal of uranium from gravel.

In this study, a practical decontamination process was developed to remove uranium from gravel using a soil washing method. The effects of critical parameters including particle size, HSO concentration, temperature, and reaction time on uranium removal were evaluated. The optimal condition for two-stage washing of gravel was found to be particle size of 1-2 mm, 1.

Hydrodynamic cavitation as a novel pretreatment approach for bioethanol production from reed.

In this study, hydrodynamic cavitation (HC) was employed as a physical means to improve alkaline pretreatment of reed. The HC-assisted alkaline pretreatment was undertaken to evaluate the influence of NaOH concentration (1-5%), solid-to-liquid ratio (5-15%), and reaction time (20-60 min) on glucose yield. The optimal condition was found to be 3.

Enhancement of volatile fatty acids production from rice straw via anaerobic digestion with chemical pretreatment.

Rice straw is one of the most abundant renewable biomass sources and was selected as the feedstock for the production of volatile fatty acids (VFAs) from which microbial biodiesel can be produced. Two kinds of chemical pretreatments involving nitric acid and sodium hydroxide were investigated at 150 °C with 20 min of reaction time. The nitric acid pretreatment generated the most hemicellulose hydrolyzate, while significant reduction of the lignin occurred with sodium hydroxide pretreatment.

Effects of ammonium carbonate pretreatment on the enzymatic digestibility and structural features of rice straw.

Rice straw was pretreated with ammonium carbonate ((NH₄)₂CO₃), a major intermediate of ammonia-based carbon capture process, and evaluated for the effects of critical pretreatment parameters including (NH₄)₂CO₃ concentration (5-25%), temperature (60-90°C), and reaction time (4-24 h) on enzymatic digestibility. Pretreatment of rice straw at 80°C for 12 h using 20% (NH₄)₂CO₃ and 1:10 solid to liquid ratio resulted in enzymatic digestibility of 72.2%, which was higher than that pretreated with the same moles of aqueous ammonia.

Enhanced glucose yield and structural characterization of corn stover by sodium carbonate pretreatment.

Na2CO3 was employed as an efficient yet cheap alkaline catalyst for the pretreatment of corn stover. To systematically obtain an optimal condition, the effects of critical pretreatment parameters including Na2CO3 concentration (2-6%), temperature (120-160 °C), and reaction time (10-30 min) on glucose yield were evaluated in lab-scale using response surface methodology. The best conditions were found to be Na2CO3 of 4.

Effect of nitric acid on pretreatment and fermentation for enhancing ethanol production of rice straw.

In this study, nitric acid (HNO₃) was evaluated as an acid catalyst for rice straw pretreatment, and, after neutralization, as a sole nitrogen source for subsequent fermentation. Response surface methodology was used to obtain optimal pretreatment condition with respect to HNO₃ concentration (0.2-1.

Adsorption of methylene blue dye from aqueous solution by sugar extracted spent rice biomass.

This study was aimed at using sugar extracted spent rice biomass (SRB) as a potential adsorbent to remove methylene blue (MB) dye from aqueous solution. The SRB was used without any modification. A three factor full factorial experimental design (2(3)) was employed to investigate the effect of factors (adsorbent dose, dye concentration, temperature) and their interaction on the adsorption capacity and color removal.

Generation of electricity from FeCl3 pretreatment of rice straw using a fuel cell system.

This study explored a new approach to the pretreatment of lignocellulosic biomass using FeCl3 combined with a fuel cell system to generate electricity. After pretreatment, ferric iron (Fe(3+)), a strong catalyst in the hydrolysis of carbohydrate, was found to be reduced to ferrous iron (Fe(2+)) by means of the oxidation of xylose and lignin. Ferrous iron, as a fuel, was employed to the anode part of a fuel cell, generating power of 1110 mW/m(2).

Development of a hybrid microbial fuel cell (MFC) and fuel cell (FC) system for improved cathodic efficiency and sustainability: the M2FC reactor.

In an effort to improve the efficiency and sustainability of microbial fuel cell (MFC) technology, a novel MFC reactor, the M2FC, was constructed by combining a ferric-based MFC with a ferrous-based fuel cell (FC). In this M2FC reactor, ferric ion, the catholyte in the MFC component, is regenerated by the FC system with the generation of additional electricity. When the MFC component was operated separately, the electricity generation was maintained for only 98 h due to the depletion of ferric ion in the catholyte.