1M NaOH Research Articles

Synthesizing Interpenetrated Triazine-based Covalent Organic Frameworks from CO2.

Crystalline triazine-based covalent organic frameworks (COFs) are aromatic nitrogen-rich porous materials. COFs typically show high thermal/chemical stability, and are promising for energy applications, but often require harsh synthesis conditions and suffer from low crystallinity. In this work, we propose an environmentally friendly route for the synthesis of crystalline COFs from CO2 molecules as a precursor. The mass ratio of CO2 conversion into COFs formula unit reaches 46.3 %. The synthesis consists of two steps; preparation of 1,4-piperazinedicarboxaldehyde from CO2 and piperazine, and condensation of the dicarboxaldehyde and melamine to construct the framework. The CO2 -derived COF has a 3-fold interpenetrated structure of 2D layers determined by powder X-ray diffraction, high-resolution transmission electron microscopy, and select-area electron diffraction. The structure shows a high Brunauer-Emmett-Teller surface area of 945 m2 g-1 and high stability against strong acid (6 M HCl), base (6 M NaOH), and boiling water over 24 hours. Post-modification of the framework with oxone has been demonstrated to modulate hydrophilicity, and it exhibits proton conductivity of 2.5×10-2 S cm-1 at 85 °C, 95 % of relative humidity.

Facile synthesis of novel magnesium oxide nanoparticles for pesticide sorption from water.

The quantum of pesticides in surface as well as drinking water has become a serious health hazard. In this experiment, magnesium oxide nanoparticles (MgO NPs) were synthesized using leaves of purple-colored rice variety (Crossa) and utilized for simultaneous removal of three pesticides, namely, thiamethoxam, chlorpyriphos, and fenpropathrin from water. The biogenic MgO NPs were characterized using SEM-EDX, FTIR, XRD, DLS, etc. The optimum synthesis parameters (1M NaOH, 80°C, and 2h) resulted in maximum yield of MgO NPs (87.7mg), minimum hydrodynamic diameter (35.12nm), poly dispersity index (0.14) and mean zeta potential (-11mV). Sorption data of the three pesticides fitted well with non-linear Langmuir and Freundlich isotherm models and non-linear pseudo-second-order kinetic model. The maximum adsorption capacity of MgO NPs for the three pesticides was 87.66µg/mg, as obtained from the Langmuir isotherm model. Under optimum conditions (initial concentration, 40mg/L; dose, 30mg/30mL; and pH, 9), 60.13, 80.53, and 92.49% removal of thiamethoxam, chlorpyriphos, and fenpropathrin was achieved with a 100% desirability, respectively. Thus, the biogenic MgO NPs could be an efficient adsorbent of pesticides and could be recommended for pesticide decontamination in water treatment plants and domestic water purifier systems.

EFFECT OF BORAX ON SETTING TIME OF GEOPOLYMER CONCRETE BASED ON FLY ASH TYPE C

Geopolymer concrete is a new type of concrete that does not use cement as a binder at all. In addition to replacing cement, the use of fly ash in concrete can reduce coal emissions from many coal-fired power plants. However, geopolymer concrete has drawbacks, one of which is that it has a setting time that tends to be too fast. Therefore, this study aims to determine the effect of adding borax on the hardening time and compressive strength of geopolymer concrete. With the addition of 1%, 3%, 5%, and 10% borax. The ratio of activator Na2SiO3 and NaOH is used 2.5:1 with a molarity of 10M NaOH. Variations in the addition of borax during mixing include 1%, 3%, 5% and 10% by weight of fly ash. The test results showed that the higher the borax content added, the longer the setting time. The longest final setting time was achieved in geopolymer concrete with the addition of 10% borax for 480 minutes.

Efficient Decoupled Alkaline Water Electrolysis Using a Low-Cost Sodium Manganate Solid Redox Mediator

As an ideal energy carrier with clean, high efficiency and high energy density (142.351 kJ g-1), hydrogen is the most promising alternative to fossil fuels when it comes to decarbonizing the planet and energy supply. Today, however, the vast majority of hydrogen production occurs through fossil-fuel intensive processes which release vast amounts of CO₂ defeating the promise of decarbonizing the world. Among other hydrogen production processes, hydrogen production by electrolysis of water has broad application prospects as an alternative approach, and is very attractive for green energy development due to its advantages of cleanliness, environmental protection and zero emission.(1) Alkaline water electrolysis has dominated the current electrochemical hydrogen production industry for the past few decades, but issues such as gas product mixing and the use of renewable energy sources (e.g., solar, wind) remain inherent challenges.(2) To this end, in this paper, low-cost Na0.44MnO2 was chosen as a solid redox mediator to decouple the evolution of H2 and O2 in alkaline conditions, which can produce high-purity gas products directly in membrane-less electrolytic cells without gas purification. As an intermediate carrier for charge storage, the decoupling efficiency can reach 97% at a constant current of 2 mA/1.5 cm2. In addition, we performed the evolutionary reactions of hydrogen and oxygen separately under intermittent renewable energy conditions to achieve direct conversion of solar to hydrogen energy, which greatly enhances the flexibility of hydrogen production and further confirms the potential practical application of Na0.44MnO2. Figure 1. (a) CV curve of the Na0.44MnO2 electrode, and LSV curves of the Pt electrode for the HER and the RuO2/IrO2 electrode for the OER at a scan rate of 1 mV s-1 in 1M NaOH. (b) The charging/discharging curves of the Na0.44MnO2 electrode at different current densities. (c) Decoupled water electrolysis with Na0.44MnO2 electrode. (d) The stability performance of the separate H2/O2 generation at a current of 5 mA with a step time of 400 s. (e) Hydrogen purity test. Reference M. G. Schultz, T. Diehl, G. P. Brasseur and W. Zittel, science, 302, 624 (2003).M. Carmo, D. L. Fritz, J. Mergel and D. Stolten, International journal of hydrogen energy, 38, 4901 (2013).

Pressure-Electrochemistry as a Pathway to Novel Metal Hydrides

We have developed a pressure-electrochemical cell apparatus to electrochemically insert hydrogen into metals at applied pressures of 1GPa. The coupling of pressure and potential (P^2) was motivated by our recent density functional theory calculations that predicted the stability of novel metal hydride phases when both pressure and potential are applied [1]. In this work, we adapted a traditional piston-cylinder pressure apparatus into a pressure-electrochemical cell by replacing the inert pressure transmitting medium with a proton-conducting liquid electrolyte (1M NaOH + polyvinyl alcohol) such that it not only provides hydrostatic pressure but also reduces into hydrogen, which is then absorbed into the metal cathode. The pressure being applied by the electrolyte was verified by measuring an increase in the electrical resistance of manganin alloy with pressure. We then electrochemically hydrogenated yttrium foil under varying pressures ranging from 0.25 to 1GPa, measuring the extent of hydrogenation post-mortem using x-ray diffraction. We find that the application of pressure suppresses hydrogen evolution, improving the current efficiency of hydrogenation of Y into YH3 from 45% at 0.25GPa to 75% at 1GPa. The development of the pressure-electrochemical apparatus unlocks a new pathway in potentially synthesizing novel metal hydrides.[1] P.-W. Guan, R. J. Hemley, V. Viswanathan, Proceedings of the National Academy of Sciences. 118, e2110470118 (2021).

Synergistic Effect of SBA-15 Templated Mesoporous NiFe2O4 and Mxene Nanocomposite for Alkaline Hydrogen Evolution Reaction

Hydrogen production via electrocatalytic water splitting has been considered as the most promising way to provide clean fuel for sustainable energy generation. Nevertheless, one of the challenges for such technology is the development of cheap and abundant electrocatalytic materials that can efficiently facilitate hydrogen evolution reaction (HER). Therefore, this study is aimed to investigate the synergistic effect between mesoporous NiFe2O4 (m-NiFe2O4) with high surface area of 102.4 m2/g and MXene. Here, the mesoporosity feature of NiFe2O4 was made via nanocasting method where SBA-15 was used as hard template. Meanwhile, MXene was fabricated using etching and exfoliation method. Based on the result, it was found that the integration of the two material was able to significantly improve the performance of both pristine m-NiFe2O4 and Mxene in facilitating HER in alkaline condition at 1M NaOH. This is proven by the comparative values of both onset and overpotential of the as-prepared electrocatalysts.

Exploration of aqueous electrolyte on the interconnected petal-like structure of Co-MOFs for high-performance paper-soaked supercapacitors

The electrolyte is a crucial component in supercapacitors (SCs), along with the electrode material, which can affect the electrochemical parameters, such as specific capacitances (Cs), energy density (ED), cyclic stability, and potential window. Therefore, the present work explores the effect of different electrolytes on the performance of Co-MOFs/FSS electrodes for SCs. The Co-MOFs/FSS electrode was synthesized on a flexible stainless-steel (FSS) substrate using the reaction-diffusion framework method, and its structural, morphological, and compositional characteristics were analyzed. The SCs performance of Co-MOF/FSS was examined across multiple electrolytes (1M KOH, 1M LiOH, and 1M NaOH). The SCs performance of Co-MOFs/FSS increased in the following sequence: 1M LiOH > 1M NaOH > 1M KOH. Furthermore, the dependence of concentration variation of LiOH electrolyte on Co-MOFs/FSS for SCs was studied. In 2M LiOH electrolyte, the Co-MOFs/FSS demonstrated a maximum Cs of 650 F g− 1 and specific capacity (Csp) of 262 C g− 1 at 5 mV s− 1. Furthermore, it exhibited a favourable retention rate of 71 % over 5000 GCD cycles at 10 mA cm−2. It also possessed higher ED and Power Density (PD) of 14.10 Wh kg−1 and 666 W kg−1 at 1 mA cm−2 respectively. Further, a flexible symmetric paper-soaked Co-MOFs/FSS//Co-MOFs/FSS device was fabricated, and its electrochemical performance was assessed. The fabricated device exhibited a higher Cs of 122 F g− 1 and Csp of 171 C g− 1 at 10 mV s− 1. Additionally, it showed good retentivity of 46 % after the 3000th cycle at 15 mA; and exhibited higher ED of 6.78 Wh kg−1 and PD of 1500 W kg−1 at 6 mA. This study highlights the importance of selecting the appropriate electrolyte for enhancing the electrochemical performance of Co-MOFs/FSS electrode material.

Synergism of andisol soil and foundry sand mixture as adsorbent of nickel (II) metal ion

A mixture of andisol soil and foundry sand as Ni2+ ion adsorbent was studied in this research. Andisol soil and foundry sand were activated using 3M NaOH. The characterizations of adsorbents were carried out by Fourier Transform Infrared Analyzer (FTIR), Scanning Electron Microscopy-mapping Energy Dispersive X-Ray (SEM-EDX), and Surface Area Analyzer (SAA). The mixture was made by mixing andisol soil and foundry sand with various compositions of 100:0, 75:25, 50:50, 25:75, and 0:100 (wt%). The adsorption of Ni2+ metal ion performed on pH solution of 3-7 and contact time of 10-110 minutes with the batch system. Based on the research, the optimum conditions for the adsorption of Ni metal in the adsorbent mixture of andisol soil and foundry sand were 75:25 (wt%) at pH 6 and contact time of 95 minutes with an adsorption capacity of 0.3967 mg/g and adsorption percentage 72.59%. Adsorption kinetics tend to follow pseudo-second-order. The type of adsorption isotherm is more dominant following the Langmuir isotherm. Nickel metal adsorption capacity in electroplating waste is 0.2777 mg/g.

Green Zeolite Synthesis Assisted with Plants Extract

The study explores the hydrothermal synthesis of zeolite using kaolin clay from Perak in the presence of two different reduction mediums, namely turmeric extract and ginger extract, and a 2M NaOH solution, measuring their efficiency and potential for green synthesis. Before the zeolite synthesis and transformation, the kaolin clay was heated at a temperature of 650 oC for 4 hours in the furnace to produce the metakaolin phase. The synthesized zeolite involves the reaction of NaOH with potential reduction plant extracts to assist the transformation of zeolite. The characterization of the synthesized particles after being ground into a fine powder and subsequently undergoing testing and characterization via X-ray diffraction (XRD) revealed the existence of zeolite phases in both plants with slightly different zeolite compositions. Synthesis mixtures with turmeric plants show better composition of the zeolite phase as compared to ginger mixtures. Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDX) also revealed that the synthesized product using turmeric plant extract was able to produce zeolite LTA with a good grade. The current experimental work shows the possibility of obtaining a well crystalline zeolite from Malaysian kaolin, assisted with plant extract reduction medium.

Pemanfaatan Limbah Sabut dan Tempurung Kelapa Sawit sebagai Silica Gel

The increase in the area of oil palm in Indonesia also causes an increase in the amount of palm oil waste. Waste in the form of coir and palm shells is thrown away. While the content of silica (SiO2) in both materials is feasible to be utilized. Silica gel is a form of utilization of oil palm coir and shells. The results of X-Ray Fluorescence (XRF) analysis showed that the silica (SiO2) content in palm coir ash was 27.5%, while 36.10% was in palm shell ash. Silica gel is an adsorbent produced by the sol-gel method, namely the formation of a gel derived from precursor compounds. The precursor compound in the formation of silica gel is sodium silicate solution (Na2SiO3) which is produced from the extraction process of coir ash and palm shells using sodium hydroxide (NaOH) solvent. The concentration of NaOH used varied, namely 1, 3, 5, 7, and 9 M. The aging times used for the formation of silica gel also varied, namely 4, 8, 12, 16, and 20 hours. Dry silica gel with the highest quantity of 5.4115 grams was obtained by adding NaOH with a concentration of 9 M and a aging time of 20 hours. While the silica gel which has the most suitable water content and Fourier Transform Infra Red (FTIR) graphic pattern with Kiesel Gel 60 G is silica gel resulting from the addition of 3M NaOH with a aging time of 8 hours. However, the results of the Structural Equation Modeling (SEM) analysis of silica gel showed results that were not in accordance with silica gel in general.

Studies on Water–Aluminum Scrap Reaction Kinetics in Two Steps and the Efficiency of Green Hydrogen Production

This work aims to explain aluminum hydrolysis reaction kinetics based on a properly chosen theoretical model with machined aluminum waste chips as well as alkali solutions up to 1M as a promoter and to estimate the overall reaction profit. The purpose of this work is to assess the optimal alkali concentration in the production of small- and medium-scale green hydrogen. To obtain results with better accuracy, we worked with flat Al waste chips, because a flat surface is preferable to maximally increase the time for the created hydrogen bubbles to reach the critical gas pressure. Describing the reaction kinetics, a flat shape allows for the use of a planar one-dimensional shrinking core model instead of a much more complicated polydisperse spheric shrinking core model. We analyzed the surface chemical reaction and mass transfer rate steps to obtain the first-order rate constant for the surface reaction and the diffusion coefficient of the aqueous reactant in the byproduct layer, respectively. We noted that measurements of the diffusion coefficient in the byproduct layer performed and discussed in this paper are rare to find in publications at alkali concentrations below 1M. With our reactor, we achieved a H2 yield of 1145 mL per 1 g of Al with 1M NaOH, which is 92% of the theoretical maximum. In the estimation of profit, the authors’ novelty is in paying great attention to the loss in alkali and finding a crucial dependence on its price. Nevertheless, in terms of consumed and originated materials for sale, the conversion of aluminum waste material into green hydrogen with properly chosen reaction parameters has positive profit even when consuming an alkali of a chemical grade.

Analysis of Hydrogen Gas Production Results in Water Electrolysis Process on Genset Characteristics

Hydrogen gas is a type of alternative fuel for transportation that can serve a number of other potential needs. Water electrolysis is one way to get hydrogen gas. This study aims to determine the results of water electrolysis with three catalysts and mixed metal electrodes which are then applied to generator motor engines. The research method used was an experimental method with variations in electrolysis using KOH and NaOH base catalysts, H2SO4 acid catalysts, and stainless steel 316 electrodes. The best results for H2 gas production in this study were obtained with a 2M H2SO4 catalyst with a gas yield of 244.9mL H2 gas, while The lowest yield in this study was the 1M concentration of 1M NaOH catalyst of 12.5mL. The best results for H2 gas production were varied with pertalite fuel and then tested with a generator engine. Testing the generator motor engine is measured arm length and mass with a machine dynamometer. After testing, the data is obtained which is then analyzed to obtain the value of torque (Nm) and electric motor power (kW), and driving motor power (HP). The maximum energy produced pertalite + H2 gas has increased by 2.27kW on the electric motor and power of 4.13HP on the driving motor, while for pertalite fuel alone the power generated is 1.44kW on the electric motor and power of 2.62HP on the driving motor.[1] S. A. Grigoriev, V. N. Fateev, D. G. Bessarabov, and P. Millet, “Current status, research trends, and challenges in water electrolysis science and technology,” Int. J. Hydrogen Energy, vol. 45, no. 49, pp. 26036–26058, 2020, doi: 10.1016/j.ijhydene.2020.03.109.[2] Y. Song, X. Zhang, K. Xie, G. Wang, and X. Bao, “High-Temperature CO2 Electrolysis in Solid Oxide Electrolysis Cells: Developments, Challenges, and Prospects,” Adv. Mater., vol. 31, no. 50, pp. 1–18, 2019, doi: 10.1002/adma.201902033.[3] A. Nechache and S. Hody, “Alternative and innovative solid oxide electrolysis cell materials: A short review,” Renew. Sustain. Energy Rev., vol. 149, 2021, doi: 10.1016/j.rser.2021.111322.[4] O. Schmidt, A. Gambhir, I. Staffell, A. Hawkes, J. Nelson, and S. Few, “Future cost and performance of water electrolysis: An expert elicitation study,” Int. J. Hydrogen Energy, vol. 42, no. 52, pp. 30470–30492, 2017, doi: 10.1016/j.ijhydene.2017.10.045.[5] S. Wang, A. Lu, and C. J. Zhong, “Hydrogen production from water electrolysis: role of catalysts,” Nano Converg., vol. 8, no. 1, 2021, doi: 10.1186/s40580-021-00254-x.[6] N. A. Burton, R. V. Padilla, A. Rose, and H. Habibullah, “Increasing the efficiency of hydrogen production from solar powered water electrolysis,” Renew. Sustain. Energy Rev., vol. 135, no. July 2020, p. 110255, 2021, doi: 10.1016/j.rser.2020.110255.[7] J. Brauns and T. Turek, “Alkaline water electrolysis powered by renewable energy: A review,” Processes, vol. 8, no. 2, 2020, doi: 10.3390/pr8020248.[8] S. Anwar, F. Khan, Y. Zhang, and A. Djire, “Recent development in electrocatalysts for hydrogen production through water electrolysis,” Int. J. Hydrogen Energy, vol. 46, no. 63, pp. 32284–32317, 2021, doi: 10.1016/j.ijhydene.2021.06.191.[9] W. Tong et al., “Electrolysis of low-grade and saline surface water,” Nat. Energy, vol. 5, no. 5, pp. 367–377, 2020, doi: 10.1038/s41560-020-0550-8.[10] T. Nguyen, Z. Abdin, T. Holm, and W. Mérida, “Grid-connected hydrogen production via large-scale water electrolysis,” Energy Convers. Manag., vol. 200, no. September, p. 112108, 2019, doi: 10.1016/j.enconman.2019.112108.[11] A. Buttler and H. Spliethoff, “Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas and power-to-liquids: A review,” Renew. Sustain. Energy Rev., vol. 82, no. February, pp. 2440–2454, 2018, doi: 10.1016/j.rser.2017.09.003.[12] I. V. Pushkareva, A. S. Pushkarev, S. A. Grigoriev, P. Modisha, and D. G. Bessarabov, “Comparative study of anion exchange membranes for low-cost water electrolysis,” Int. J. Hydrogen Energy, vol. 45, no. 49, pp. 26070–26079, 2020, doi: 10.1016/j.ijhydene.2019.11.011.[13] L. Peng and Z. Wei, “Catalyst Engineering for Electrochemical Energy Conversion from Water to Water: Water Electrolysis and the Hydrogen Fuel Cell,” Engineering, vol. 6, no. 6, pp. 653–679, 2020, doi: 10.1016/j.eng.2019.07.028.[14] S. Klemenz, A. Stegmüller, S. Yoon, C. Felser, H. Tüysüz, and A. Weidenkaff, “Holistic View on Materials Development: Water Electrolysis as a Case Study,” Angew. Chemie - Int. Ed., vol. 60, no. 37, pp. 20094–20100, 2021, doi: 10.1002/anie.202105324.[15] H. K. Ju, S. Badwal, and S. Giddey, “A comprehensive review of carbon and hydrocarbon assisted water electrolysis for hydrogen production,” Appl. Energy, vol. 231, no. May, pp. 502–533, 2018, doi: 10.1016/j.apenergy.2018.09.125.[16] F. ezzahra Chakik, M. Kaddami, and M. Mikou, “Effect of operating parameters on hydrogen production by electrolysis of water,” Int. J. Hydrogen Energy, vol. 42, no. 40, pp. 25550–25557, 2017, doi: 10.1016/j.ijhydene.2017.07.015.[17] F. Gutiérrez-Martín, L. Amodio, and M. Pagano, “Hydrogen production by water electrolysis and off-grid solar PV,” Int. J. Hydrogen Energy, vol. 46, no. 57, pp. 29038–29048, 2021, doi: 10.1016/j.ijhydene.2020.09.098.

Nanosilica Extraction from Grumusol Soil

Grumusol soil is a type of soil that contains significant amounts of silica. Silica content in grumusol soil can reach up to 90%. The aim of this research was to determine the characteristics of silica nanostructures in Grumusol soil. The stages of the research were carried out including the preparation of raw materials, silica extraction, and XRD analysis. The raw material preparation stage is carried out by cleaning the grumusol soil from dirt. The second stage was carried out by synthesizing silica with the base extraction method and followed by acid deposition. The final stage is X-Ray Diffracion (XRD) analysis. The results of the research that has been carried out is the FWHM value of 0.0900 (<0.1) which indicates that the crystals produced have very good crystals with a very regular structure. The crystal size which includes nanosilica is 39.5076-48.6633 nm for 3M NaOH with 1 and 3 hours extraction time and 5M NaOH with 1 hour extraction time

InSitu Integrated Fabrication for Multi-Interface Stabilized and Highly Durable Polyaniline@Graphene Oxide/Polyether Ether Ketone Special Separation Membranes.

Special separation membranes are widely employed for separation and purification purposes under challenging operating conditions due to their low energy consumption, excellent solvent, and corrosion resistance. However, the development of membranes is limited by corrosion-resistant polymer substrates and precise interfacial separation layers. Herein, polyaniline (PANI) is employed to achieve insitu anchoring of multiple interfaces, resulting in the fabrication of polyaniline@graphene oxide/polyether ether ketone (PANI@GO/PEEK) membranes. Insitu growth of PANI achieves the adequate bonding of the PEEK substrate and GO separation interface, which solves the problem of solution processing of PEEK and the instability of GO layers. By bottom-up confined polymerization of aniline, it could control the pore size of the separation layer, correct defects, and anchor among polymer, nano-separation layer, and nano-sheet. The mechanism of membrane construction within the confined domain and micro-nano structure modulation is further explored. The membranes demonstrate exceptional stability realizing over 90% rejection in 2m HCl, NaOH, and high temperatures. Additionally, -membranes exhibit remarkable durability after 240 days immersion and 100h long-term operation, which display themethanol flux of 50.2 L m-2 h-1 and 92% rejection of AF (585g mol-1 ). This method substantially contributes to special separation membranes by offering a novel strategy.

Preliminary Study of Cesium Immobilization in a Geopolymer Matrix

Geopolymers are modern synthetic materials that have many beneficial characteristics, e.g. excellent mechanical properties, fire- and heat-resistance, minimal shrinkage and can be molded into shape. Given their aforementioned characteristics, geopolymers could be applicable as conditioning materials, e.g. to handle hazardous waste and radioactive materials. However, their long-term applicability needs to be investigated.The aim of this study is to investigate the mobility of Cs-137 radionuclides in embedding materials. Different geopolymeric matrices - namely kaolinite, bentonite, zeolites and red mud - were tested. The leach test was performed according to the ASTM C1308-08(2017) standard and the activity concentration of Cs-137 isotopes was measured by gamma spectrometry using a high-purity germanium (HPGe) semiconductor detector. According to our preliminary results, the matrices that resulted in the most significant immobilization effect were those in which bentonite, cement, fly ash and 8M NaOH were used, releasing approximately 10% of the cesium.

Direct Synthesis of Mn3[Fe(CN)6]2·nH2O Nanosheets as Novel 2D Analog of Prussian Blue and Material for High-Performance Metal-Ion Batteries.

Rechargeable metal-ion batteries (RMIBs) are prospective highly effective and low-cost devices for energy storage. Prussian blue analogues (PBAs) have become a subject of significant interest for commercial applications owing to their exceptional specific capacity and broad operational potential window as cathode materials for rechargeable metal-ion batteries. However, the limiting factors for its widespread use are its poor electrical conductivity and stability. The present study describes the direct and simple synthesis of 2D nanosheets of MnFCN (Mn3[Fe(CN)6]2·nH2O) on nickel foam (NF) via a successive ionic layer deposition (SILD) method, which provided more ion diffusion and electrochemical conductivity. MnFCN/NF exhibited exceptional cathode performance for RMIBs, delivering a high specific capacity of 1032 F/g at 1 A/g in an aqueous 1M NaOH electrolyte. Additionally, the specific capacitance reached the remarkable levels of 327.5 F/g at 1 A/g and 230 F/g at 0.1 A/g in 1M Na2SO4 and 1M ZnSO4 aqueous solutions, respectively.

Preparation of Eco-Friendly Chelating Resins and Their Applications for Water Treatment.

In the present study, two chelating resins were prepared and used for simultaneous adsorption of toxic metal ions, i.e., Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Pb2+ (MX+). In the first step, chelating resins were prepared starting with styrene-divinylbenzene resin, a strong basic anion exchanger Amberlite IRA 402(Cl-) with two chelating agents, i.e., tartrazine (TAR) and amido black 10B (AB 10B). Key parameters such as contact time, pH, initial concentration, and stability were evaluated for the obtained chelating resins (IRA 402/TAR and IRA 402/AB 10B). The obtained chelating resins show excellent stability in 2M HCl, 2M NaOH, and also in ethanol (EtOH) medium. The stability of the chelating resins decreased when the combined mixture (2M HCl:EtOH = 2:1) was added. The above-mentioned aspect was more evident for IRA 402/TAR compared to IRA 402/AB 10B. Taking into account the higher stability of the IRA 402/TAR and IRA 402/AB 10B resins, in a second step, adsorption studies were carried out on complex acid effluents polluted with MX+. The adsorption of MX+ from an acidic aqueous medium on the chelating resins was evaluated using the ICP-MS method. The following affinity series under competitive analysis for IRA 402/TAR was obtained: Fe3+(44 µg/g) > Ni2+(39.8 µg/g) > Cd2+(34 µg/g) > Cr3+(33.2 µg/g) > Pb2+(32.7 µg/g) > Cu2+ (32.5 µg/g) > Mn2+(31 µg/g) > Co2+(29 µg/g) > Zn2+ (27.5 µg/g). While for IRA 402/AB 10B, the following behavior was observed: Fe3+(58 µg/g) > Ni2+(43.5 µg/g) > Cd2+(43 µg/g) > Cu2+(38 µg/g) > Cr3+(35 µg/g) > Pb2+(34.5 µg/g) > Co2+(32.8 µg/g) > Mn2+(33 µg/g) > Zn2+(32 µg/g), consistent with the decreasing affinity of MX+ for chelate resin. The chelating resins were characterized using TG, FTIR, and SEM analysis. The obtained results showed that the chelating resins prepared have promising potential for wastewater treatment in the context of the circular economy approach.

Effet of hematite (Fe2O3) from natural iron ore as a catalyst in MgH2 as hydrogen storage materials

The main obstacle that hinders the application of fuel cell fuels for vehicles today is the hydrogen storage tube. Therefore, this paper will report the results of a study on MgH2-based hydrogen storage materials with Fe2O3 catalyst inserted (5 wt%, 10 wt%, 15wt%) and prepared by mechanical alloying technique for 10 hours. Fe2O3 samples were obtained from the Lhoong Setia Mining site in Jantang Village, Lhoong, Aceh Besar. The initial sample separation process was carried out manually using a bar magnet. Furthermore, hematite extraction was carried out with the addition of 1M HCL and NaOH each. Then the milling process of MgH2-Fe2O3 samples was carried out using a planetary ball mill. The results of the X-ray diffraction test showed that the MgH2 phase was the most dominant/mainstream phase. Thermal testing with DSC showed that the H2 desorption process experienced a decrease in temperature from 194.56 °C with a milling time variation of 7 hours.

Mechanical Strength and Microstructure of GGBS-SCBA based Geopolymer Concrete

This paper deals with the attempt to develop and study the performance of ground granulated blast furnace slag (GGBS) and sugarcane bagasse ash (SCBA) based sustainable geopolymer concrete. NaOH (8M, 10M, and 12M) and Na2SiO3 were used as alkaline activators with a ratio of 2.5. SCBA mainly acted as amorphous silica and has been utilized as a substitute material for GGBS. The effect of SCBA contents (0%, 5%, 10%, 15% & 20% by the mass of binder) in terms of fresh, hardened, microstructural, and correlation properties of geopolymer concrete developed have been evaluated. Different tests such as the slump cone test, compression test, split tensile test, flexure test, and ultrasonic pulse velocity test were conducted. Scanning electron microscopy, Energy dispersive analysis, and X-ray diffraction analysis were investigated for understanding the microstructural properties. The research findings have shown that with an increase in molarity from 8M to 12M there is an increase in the strength properties of geopolymer concrete. The results in this current study show that 28 days compressive strength was found to increase by 4–15% when the NaOH molarity was increased from 8M to 10M and 8–21% when the NaOH molarity was increased from 8M to 12M. The geopolymer concrete developed with 20% SCBA and 80% GGBS with 8M NaOH solution and SS/SH ratio of 2.5 can be used for a target strength of 30–35 MPa. Scanning electron microscope images show a packed and dense matrix, which clearly outlines the reason behind the attainment of higher strength in higher molarity of GGBS-SCBA based geopolymer concrete samples and the presence of CASH gel confirmed this in the geopolymer matrix. Furthermore, there is a strong correlation between the experimental findings and the model equations proposed. These presented models will be useful in improving the strength of geopolymer concrete incorporating agricultural and industrial wastes.

Fabricated of the SCC Reference Specimen for Increasing of In-Service Inspection Accuracy in Nuclear Power Plant

To achieve the safety assurance of the nuclear power plants, in-service inspection have were enforced periodic for nondestructive test in weldment. Among them, the ultrasonic evaluation is widely used for the measurement of the defects. Generally, non-destructive inspectors have calibrated a UT machine using the reference specimen in the artificial cracks such as EDM, mechanical notch. As the reflected ultrasonic signal of real crack was detected amplitude value 50% lower than artificial cracks. Therefore, domestic ultrasonic inspectors have a little experience in measuring actual cracks generated in the nuclear power plant field, such as SCC(Stress corrosion cracks, below SCC) and thermal fatigue cracking. Accordingly, in order to improve the inspection accuracy of non-destructive inspectors during operation inspection of nuclear power plant structures, it is necessary to have a lot of experience in inspecting actual cracks.In this study, non-penetration SCC for using in educational specimen of the NDT inspector were fabricated by using the simulated nuclear environment system in base metal of STS 304 pipe. The size of the used pipe were 8 inch(80 sch., thickness 12.7mm). The end of the pipe was used a flange to simulating a fixed environment of the nuclear power plant structure. To accelerate the fabrication of SCC, a corrosive environment was composed by used a blending corrosion solution of the NaOH 1M and Na2S9-H2O 0.1M inside the pipe. The potential of hydrogen of the caustic solution was 14. The fabricated SCC was confirmed for crack size and shape by used UT and RT.