The aim and originality of our current study are to use the original biomass (activated carbon) obtained by functionalizing waste banana peels (commonly found in Turkey) with acid in NaBH4 methanolysis and to examine its contribution to the hydrogen generation rate (HGR). Our study consisted of three stages. In the first stage, the optimum conditions were determined by examining the catalyst under parameters such as different acid types, different carbonization temperatures, and different carbonization times. Thus, based on the maximum HGR value, the optimum conditions were determined as H3PO4, 600 °C, and 40 min. In the second step, the effects of parameters such as acid concentration, NaBH4 concentration, catalyst amount, and temperature on HGR were investigated. As a result of methanolysis experiments (condition: catalyst amount: 100 mg, acid amount: 30%, NaBH4 concentration: 2.5%, temperature: 30 °C, carbonization temperature: 400 °C, and carbonization time: 40 min.), the maximum HGR value, the reaction completion time and activation energy were found as 65,625 mLmin− 1gcat−1, 0.233 min, and 4.56 kJ/mol, respectively. It was observed that the obtained activation energy was lower than that of some catalysts available in the literature. In addition, the structural and morphological examination of the banana peel (catalyst) with high HGR and low activation energy revealed that the acid functionalization process was successfully carried out.

The biocarbon (SKPH) was obtained from Sargassum spp., and it was evaluated electrochemically as support for the CO2 reduction. The biocarbon was synthesized and activated with KOH, obtaining a high surface area (1600 m2 g− 1) due to the activation process. Graphitic carbon formation after pyrolysis was confirmed by Raman spectroscopy. The XRD results show that SKPH has an amorphous structure with peaks corresponding to typical amorphous carbonaceous materials. FTIR was used to determine the chemical structure of SKPH. The bands at 3426, 2981, 2851, and 1604 cm− 1 correspond to O–H, C-H, and C-O stretching vibrations, respectively. Then, it compares SKPH films with different carbon films using two electrolytic systems with and without charge transfer. The SKPH film showed a capacitive behavior in the KOH, H2SO4, and, KCl systems; in the acid medium, the presence of a redox couple associated with carbon functional groups was shown. Likewise, in the [Fe(CN)6]−3 and Cu(II) systems, the charge transfer process coupled with a capacitive behavior was described, and this effect is more noticeable in the [Fe(CN)6]−3 system. Electrodeposition of copper on SKPH film showed two stages Cu(NH 3)2+ 4 /Cu(NH 3)+ 2 and Cu(NH 3)+ 2 ∕Cu in ammonia media. Hydrogen formation and the activity of CO2 are observed on SKPH film and are favored by the carbon’s surface chemistry. Cu/SKPH electrocatalyst has a catalytic effect on electrochemical reduction of CO2 and inhibition of hydrogen formation. This study showed that the SKPH film electrode responds as a capacitive material that can be used as an electrode for energy storage or as metal support.

Enhancing the capacitive deionization performance requires the inner structure expansion of porous activated carbon to facilitate the charge storage and electrolyte penetration. This work aimed to modify the porosity of coconut-shell activated carbon (AC) through CO2 activation at high temperature. The electrochemical performance of CO2- activated AC electrodes was evaluated by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy, which exhibited that AC-800 had the superior performance with the highest capacitance of 112 F/g at the rate of 0.1 A/g and could operate for up to 4000 cycles. Furthermore, in the capacitive deionization, AC-800 showed salt removal of 9.15 mg/g with a high absorption rate of 2.8 mg/g min and Ni(II) removal of 5.32 mg/g with a rate close to 1 mg/g.min. The results promote the potential application of CO2- activated AC for desalination as well as Ni-removal through capacitance deionization (CDI) technology.

Laminaria japonica is a type of brown algae widely consumed in Asian countries and contains many essential nutrients and exhibits anti-obesity, antioxidant, and anti-inflammatory effects. In this study, the antioxidant and immunomodulatory effects of a Laminaria japonica water extract (LJE) were investigated using an in vitro model. Mean total polyphenol content of LJE was 2.16±0.11 μg GAE/mg, and LJE dose-dependently inhibited ABTS radical activity but did not scavenge DPPH radicals. In addition, LJE enhanced nitric oxide (NO) production and upregulated the mRNA expressions of proinflammatory cytokines (i.e., tumor necrosis factor-α and interleukin-6) in RAW 264.7 cells. On the other hand, LJE inhibited NO production and downregulated proinflammatory cytokine mRNA levels in endotoxin-stimulated RAW 264.7 cells. Thus, our data show that LJE has moderate antioxidant activity and biphasic immunomodulatory effects on RAW 264.7 cells. In summary, the study indicates that LJE has potential therapeutic use as a novel biphasic immuno-modulator.

Kale (Brassica oleracea var. acephala) is one of the most frequently consumed leafy vegetables globally, as it contains numerous nutrients; essential amino acids, phenolics, vitamins, and minerals, and is particularly rich in glucosinolates. However, the differences in the biosynthesis of glucosinolates and related gene expression among kale cultivars has been poorly reported. In this study, we investigated glucosinolates profile and content in three different kale cultivars, including green (‘Man-Choo’ and ‘Mat-Jjang’) and red kale (‘Red-Curled’) cultivars grown in a vertical farm, using transcriptomic and metabolomic analyses. The growth and development of the green kale cultivars were higher than those of the red kale cultivar at 6 weeks after cultivation. High-performance liquid chromatography (HPLC) analysis revealed five glucosinolates in the ‘Man-Choo’ cultivar, and four glucosinolates in the ‘Mat-Jjang’ and ‘Red-Curled’ cultivars. Glucobrassicin was the most predominant glucosinolate followed by gluconastrutiin in all the cultivars. In contrast, other glucosinolates were highly dependent to the genotypes. The highest total glucosinolates was found in the ‘Red-Curled’ cultivar, which followed by ‘Man-Choo’ and ‘Mat-Jjang’. Based on transcriptome analysis, eight genes were involved in glucosinolate biosynthesis. The overall results suggest that the glucosinolate content and accumulation patterns differ according to the kale cultivar and differential expression of glucosinolate biosynthetic genes.

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016–2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 μas < θE < 26 μas, which is consistent with the gap in Einstein timescales near tE ∼ 0.5 days found by Mr´oz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of freefloating planet candidates (FFPs) dNFFP/d logM = (0.4 ± 0.2) (M/38 M⊕)−p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index γ = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of ‘Oumuamua-like objects. In particular, if we assume that ‘Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System’s endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

Concrete is used as the main engineering barrier in low and intermediate level radioactive waste disposal facilities. As the time passed, the radionuclides stored in repository may contact with groundwater and leak into the ecosystem through the rock media. In this process, the radionuclides can react with calcite via sorption or coprecipitation, because calcite is the major mineral of concrete. Under the various background conditions in repository, frequent dissolution-precipitation reactions can happen. Dissolution of Sr-coprecipitated calcite may be different from that of SrCO3(s) which can mislead the safety performance of radioactive Sr and the estimate of Sr mobility based on the solubility of SrCO3(s). Strontium is not only one of the fission products but also emits beta rays with a long half-life almost 29 years. The strontium may be released or retarded by the dissolution-precipitation reactions in repository. In this study, the dissolution of Sr-coprecipitated with respect to calcite was tested in various environment conditions. The Sr-coprecipitated calcite, (Sr,Ca)CO3(s) was synthesized by coprecipitation method in alkaline condition. The 250 mL of 0.1 M of CaCl2 solution was mixed with 250 mL of 1.14 mM SrCl2·6H2O solution. Then, independently prepared 500 mL of 0.1 M Na2CO3 solution was mixed with the mixed solution of CaCl2 and SrCl2. The precipitates could be made and they were aged for 3 days at room temperature. Then, the supernatant was separated by the centrifugation and the solid at the bottom was dried in an oven at temperature 80°C. After that, the Srcoprecipitated calcite powder was washed using the DI water several times and dried again before use. Characterization of solid powder was conducted by XRD and SEM, and the ICP-MS and ICP-AES were used to analyze the concentrations of Ca and Sr. The batch dissolution experiment was conducted with a solid-to-solution ratio of 10 g/L groundwater in polyethylene tubes. The oxidative groundwater was synthesized by simulating the chemical composition of KAERI Underground Research Tunnel (KURT) DB-3 groundwater. Different temperatures and pHs were prepared and tested for the release of Sr and Ca from the coprecipitated (Sr,Ca)CO3(s) to compare the results with the release of Sr and Ca from SrCO3(s) and CaCO3(s), respectively. Such as, these results will be used to provide better understanding of Sr release and mobility in various repository environments.

Polycarboxylic ether-based high-range water reducer (PCE) has been proposed to use due to the operational advantages of reduced water content and increased fluidity of cementitious mixtures. But the concern about using PCE can increase the mobility of radionuclides as well. Nuclear Decommissioning Authority (NDA) showed that the PCE formulations increased radionuclide solubility in free solution. Solubility of U(VI), 239Pu, 241Am with the cementitious materials tested with 3:1 pulverized fuel Ash/Ordinary Portland Cement (PFA:OPC) and 9:1 Ground Granulated Blast Furnace Slag/OPC (GGBS:OPC) with PCE that increased at least one and, in some cases, more than three orders of magnitude (between 10-9 and 10-4 mol dm-3) for these radionuclides in the cement-equilibrated solution. It is possible that the relatively low molecular weight substances present in the PCE cement mixture increase the solubility of radionuclides. In addition, the organic substances that are easily miscible with water can contribute to increase the solubility. In this study, several radionuclides (Nb, Ni, Pd, Zr, and Sn) that may be present in intermediate and low-level waste (LIW) repositories were selected based on the half-life and the estimated dose accordingly, and the solubility tests were conducted with and without PCE in solution. To simulate the field condition of the underground repository, synthetic groundwater was prepared based on the recipe by the KAERI Underground Research Tunnel (KURT) DB-3 GW and used as a solvent. The solubility limiting solid phase (SLSP) of each radionuclide was determined using Geochemist’s WorkBench (GWB) model. The selected solid phases are Ni(OH)2, ZrSiO4, Nb2O5, Pd(metal), and SnO2, respectively, and the solubility experiments were conducted with 1.0wt% of PCE per total weight and 0.5 g / 250 ml of selected radionuclide’s SLSP for 90 days at room temperature (25°C). Compared with and without PCE presence in solution, the selected radionuclides also showed an increased solubility with the presence of water reducing agent like PCE. This results can be used to correctly estimate the mobility of target radionuclides with the presence of PCE in repository environments.

Radioactive nickel (Ni59 and Ni63) is a major radionuclide that needs to be determined for quantifying the total radioactivity in radioactive waste disposal repository. Also, radioactive waste containing organic wastes, such as cotton and tissue can be decomposed to produce the Isosaccharinic acid (ISA) in a disposal facility. The presence of ISA in the disposal facility could increase the mobility of radionuclides. Therefore, it is necessary to confirm the mobility of Ni with the presence of ISA in the repository. This study investigated the effect of ISA on the sorption and the solubility of Ni in synthesized groundwater. The sorption test was conducted in different time intervals with Ni and ISA. Nickel nitrate hexahydrate and Ca(ISA)2 were used after purchase. Granite was used as the solid medium to simulate the major rock type of the repository. Ni and ISA solution with the medium were mixed using a platform shaker for 6 days. After 6 days, the solid parts were separated by centrifugation and additional syringe filters, and the supernatant was analyzed for Ni and ISA concentration using ICP-MS and IC, respectively. The solubility experiments were conducted at different temperatures (20, 40, and 80°C). Nickel hydroxide was used as the solubility limiting solid phase. To balance the ionic strength and confirm the effect of ISA on Ni solubility, 0.01 M of CaCl2 solution was prepared in a sample without ISA, and 0.01 M of Ca(ISA)2 solution was prepared in a sample with ISA. In solubility tests, the solution was also analyzed by ICP-MS and IC for Ni and ISA, respectively. The concentration of Ni was found to increase with ISA compared to Ni concentration without ISA. The concentration of ISA was not changed during the solubility test periods. For solubility tests, the concentration of Ni also increased according to the increase in temperature. The solid phase was characterized by XRD, FT-IR, and SEM-EDS. Based on the results of this study, the presence and effect of ISA on radioactive Ni mobility should be carefully investigated to secure the long-term safety assessment for the low and intermediate-level waste repository.

In the present work, a three-phase AC arc plasma torch system is proposed to separate inorganic radioactive materials from the organic liquid waste. For this purpose, first, assuming the resistance of arc plasma ranges between 0.1 and 0.2 ohm, we designed a three-phase AC arc plasma power supply with the power level of 20 kW. Then, a three phase arc plasma torch consisting of three carbon rods with the diameter of 20 mm was designed and mounted on a cylindrical combustion chamber with the inner diameter of 150 mm. Detail design and basic performance of the plasma system were presented and discussed for application to the treatment of radioactive slurry wastes.

In this work, we report the basic performance of a 100 kW class mobile plasma melting system consisting of two 24-ft commercial containers, each in charge of the plasma utilities and melting process. In this system, a 100 kW class transferred type plasma torch has been installed together with a crucible having an inner volume of 2,884 cm3. Filling the inner volume of the crucible with the simulated metal waste, such as bolts and nuts, melting tests have been carried out for 5 min by varying plasma input power from 50 kW to 100 kW. By measuring the volume of metal waste before and after melting test, then, the volume reduction rates were estimated and discussed.