Structural inversion refers to the reverse reactivation of extensional faults that influence basin shortening accommodated by contractional faults or folds. On the Korean peninsula, Miocene inversion structures have been found, but the Cretaceous rocks on Geoje Island may have undergone inversion as early as the Upper Cretaceous. To evaluate the structural inversion on Geoje Island, located on the eastern side of South Korea, and to determine the effects of preexisting weakness zones, field-based geometric and kinematic analyses of faults were performed. The lithology of Geoje Island is dominated by hornfelsified shale, siltstone, and sandstone in the Upper-Cretaceous Seongpori formation. NE and NW-oblique normal faults, conjugate strike-slip (NW-sinistral transpressional and E-W-dextral transtensional) faults, and NE-dextral transpressional faults are the most prominent structural features in Geoje Island. Structural inversion on Geoje Island was evidenced by the sinistral and dextral transpressional reactivation of the NW and NE-trending oblique normal faults respectively, under WNW-ESE/NW-SE compression, which was the orientation of the compressive stress during the Late Cretaceous to Early Cenozoic.

Biomass-derived porous carbon is an excellent scientific and technologically interesting material for supercapacitor applications. In this study, we developed biomass-derived nitrogen-doped porous carbon nanosheets (BDPCNS) from cedar cone biomass using a simple KOH activation and pyrolysis method. The BDPCNS was effectively modified at different temperatures of 600 °C, 700 °C, and 800 ℃ under similar conditions. The as-prepared BDPCNS-700 electrode exhibited a high BET surface area of 2883 m2 g− 1 and a total pore volume of 1.26 cm3 g− 1. Additionally, BDPCNS-700 had the highest electrical conductivity (11.03 cm− 1) and highest N-doped content among the different electrode materials. The BDPCNS-700 electrode attained a specific capacitance of 290 F g− 1 at a current density of 1 A g− 1 in a 3 M KOH electrolyte and an excellent longterm electrochemical cycling stability of 93.4% over 1000 cycles. Moreover, the BDPCNS-700 electrode had an excellent energy density (40.27 Wh kg− 1) vs power density (208.19 W kg− 1). These findings indicate that BDPCNS with large surface areas are promising electrode materials for supercapacitors and energy storage systems.

In this study, UiO-66-NH2 was synthesized and incorporated with graphene aerosol (UiO-66-NH2/GA) and ethylenediamine functionalized graphene oxide (UiO-66-NH2/GO-NH2). These composites were characterized using infrared spectroscopy, powder X-ray diffraction, ultraviolet–visible light spectroscopy, scanning electron microscope, and energy-dispersive X-ray spectroscopy. UiO-66-NH2/GO-NH2 exhibited 93% adsorption of quinoline in 5 h, UiO-66-NH2 and UiO-66-NH2/GA presented 80.4% and 86.5%, respectively. The high adsorption observed on UiO-66-NH2/GO-NH2 was attributed to the unique electronic properties, and hydrogen bonding between the nitrogen atom of quinoline and NH2- phenyl fragment of UiO-66-NH2, and N–H of ethylenediamine. GO also offered combined strong π–π interactions on its surface, and the oxygen coverage (~ 50%) on GO within the structure is responsible for the formation of strong hydrogen bonds with quinoline. Theoretical calculation suggested that UiO-66-NH2/GO-NH2 presented a more favourable adsorption energy (− 18.584 kcal/ mol) compared to UiO-66-NH2 (− 16.549 kcal/mol) and UiO-66-NH2/GA (− 13.991 kcal/mol). These results indicate that nanocomposites have a potential application in quinoline capture technologies in the process of adsorptive denitrogenation.

By polymerizing acrylonitrile in the presence of ammonium persulfate as an initiator and Pterocladia capillacea-activated carbon (P-AC) as a filler, a composite material polyacrylonitrile/Pterocladia capillacea-activated carbon (PAN/P- AC) was developed. By reacting hydroxylamine with the composite's nitrile groups, the prepared composite was functionalized by amidoximation. FTIR spectrometry, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller (BET) analysis were all applied to thoroughly characterize the fabricated adsorbent. For the treatment of Cr(VI) ions from synthetic solutions, the adsorption properties of amidoximated polyacrylonitrile/Pterocladia capillacea-activated carbon (PAO/P-AC) were investigated. The pH effect, uptake kinetics, adsorption isotherms, and thermodynamics studies were used to characterize adsorption properties. As a kinetic model analysis, the data confirmed that the pseudo-second-order rate equation matched well the adsorption process. With coefficients of determination (R2) of 0.9998, the Tempkin isotherm model had the lowest error, suggesting that it is the best fitted model to describe this adsorption mechanism. Thermodynamic parameters demonstrated that Cr(VI) adsorption was endothermic.

Sugarcane bagasse has been used as a substrate for the development of microporous nano-activated carbons for the treatment and elimination of dissolved materials from aquatic environment. The activated carbon was produced using chemical activation in one-step method with zinc chloride ( ZnCl2) as the activating agent at a carbonization temperatures range from 500 to 900 °C. The effects of temperature and time of carbonization on the activated carbon product properties were thoroughly studied. The activated carbons that resulted were characterized using the N2 adsorption/desorption isotherms, Brunauer–Emmett–Teller method (BET), pore property analysis, micropore (MP) surface area, t-plot surface area, TGA, FTIR, SEM, TEM, and EDX analyses. The prepared activated carbon’s point of zero charge, Boehm titration process, iodine removal percentage, and methylene blue number were also investigated. The prepared activated carbon’s maximum surface area was achieved using a 2/1 impregnation ratio (dried sugarcane bagasse/ZnCl2) at 600 °C temperature of carbonization and 60 min residence time. 1402.2 m2/ g, 0.6214 and 1.41 cm3/ g, respectively, were the largest surface area, total pore volume, and micropore volume. As the activation temperature increased, the total pore volume increased and the BET study measured a pore diameter of 0.7 nm and a mean pore diameter of 1.77 nm.

This work reports utilization of apple leaves as a source of activated carbon. Activated carbon from apple leaves is prepared by two different methods, thermal activation where AC1 is obtained and chemical activation using H3PO4 and ZnCl2 where AC2 and AC3 are obtained, respectively. XRD analysis revealed that all types of prepared ACs have a semi-crystalline nature with a mean crystallite size of 13, 21.02, and 39.47 nm for AC1, AC2, and AC3, respectively. To identify the most suitable desorption temperature, the exothermic behavior was discovered for the three types of ACs by DSC. The exothermic onset temperatures are 340 °C, 200 °C, 400 °C, or AC1, AC2, and AC3, respectively. The point of zero charge for the three types of ACs is 8.6, 7.3, and 2.5 for AC1, AC2, and AC3, respectively. The BET surface area analysis data demonstrated that mesoporous structure was developed in AC1 and AC2, while a microporous structure was developed in AC3. Quantum chemical calculations for ACs is carried out using Density Functional Theory (DFT). Application of the prepared ACs in adsorption of basic dye C.I. base blue 47 is studied. The maximum removal efficiency was 65.1%, 96% and 99% for AC1, AC2, and AC3, respectively under the influence of different operating aspects. Adsorption data are modeled by Langmuir, Freundlich, and Temkin isotherms. The data revealed that adsorption of basic dye C.I. base blue 47 on AC1 follows Langmuir isotherm and adsorption on AC2 and AC3 follows Freundlich isotherm.

This work reveals a modified method for the preparation of activated carbon (P-ACA) using low-cost materials (mix natural asphalt: polypropylene waste). The P-ACA was prepared at 600 °C by assisting KOH and HF. The morphological variations and chemical species of the P-ACA were characterized using SEM–EDX and FTIR. The active surface area, density and ash content of the P-ACA were also investigated. Adsorption properties of P-ACA were used for the thermodynamic and kinetic study of 4-((2-hydroxy naphthalenyl) diazenyl) antipyrine (HNDA), which was prepared as a novel azo dye in this work. The optimal conditions (initial concentration, adsorbent dose, contact time and temperature) of the adsorption process were determined. Adsorption isotherms (Freundlich and Langmuir) were applied to the experimental data. These isothermal constants were used to describe the nature of the adsorption system, and the type of interaction between the dye and the P-ACA surface. The results have indicated that the mixture (Natural asphalt-polypropylene waste) is efficient for the synthesis of P-ACA. The synthesized P-ACA demonstrates the presence of pores on the surface with various diameter ranges (from 1.4 to 4.5 μm). Furthermore, P-ACA exhibits an active surface area of 1230 m2 g−1, and shows a high adsorption capacity for HNDA.

Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.

Even in an era where 8-meter class telescopes are common, small telescopes are considered very valuable research facilities since they are available for rapid follow-up or long term monitoring observations. To maximize the usefulness of small telescopes in Korea, we established the SomangNet, a network of 0.4{1.0 m class optical telescopes operated by Korean institutions, in 2020. Here, we give an overview of the project, describing the current participating telescopes, its scientic scope and operation mode, and the prospects for future activities. SomangNet currently includes 10 telescopes that are located in Australia, USA, and Chile as well as in Korea. The operation of many of these telescopes currently relies on operators, and we plan to upgrade them for remote or robotic operation. The latest SomangNet science projects include monitoring and follow-up observational studies of galaxies, supernovae, active galactic nuclei, symbiotic stars, solar system objects, neutrino/gravitational-wave sources, and exoplanets.