Papers by Keyword: Synthesis

Abstract: Sodium borohydride (NaBH₄) has several advantages as a hydrogen storage material compared to other hydrogen storage materials, such as metal hydrides, porous carbon, or other complex compounds. These advantages include a high storage capacity, the ability to release hydrogen under mild conditions, good chemical and thermal stability, and being non-toxic and environmentally friendly. These advantages make NaBH₄ the leading choice for hydrogen storage. In some of our previous investigations, we have studied the electrochemical release of hydrogen from NaBH₄, resulting in the formation of NaBO₂. The next problem is how to recover NaBO₂ to convert it back into NaBH₄. The method developed in this study is an electrochemical method with advantages in process control and scalability. This paper aims to convert NaBO₂ back into NaBH₄ electrochemically. The electrosynthesis of NaBH₄ from NaBO₂ was carried out in a two-chamber electrochemical cell separated by a bipolar membrane. The power supply controlled the current. The current used varied from 0.5 to 2 A. The concentration of NaBH₄ formed was analyzed using the iodate titration method. The formation of NaBH₄ occurs in the cathode chamber. The concentration of NaBH₄ increases with increasing electrolysis time. In general, the reaction rate of NaBH₄ formation increases at a current of 2 A. Meanwhile, the reaction rate of NaBH₄ formation at currents of 0.5 A and 1 A is almost the same. The greater the current used, the faster the NaBO₂ reduction process in the cathode chamber. The integral analysis method calculates the reaction order by integrating the reaction rate equation. The reaction orders tested are zero order, 1^st order, and 2^nd order. The best curve-matching results are shown in the second-order reaction rate equation. At a current of 2 A, the comparison curve between the data and the equation still indicates a relatively low fit. However, the second-order reaction rate equation gives the best results. The reaction rate constant is between 0.0406 and 0.0472 L mol^-1s^-1.

Abstract: The research consists of incorporating CTAB into the layers of the the bentonite structure, integrating acid-treated bentonite with cetyltrimethylammonium bromide (CTAB), and obtaining an organic material adsorbent. The physical and chemical properties of the sample modifications are identified by employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric/thermal analysis (TGA/DTA). The bentonite used in this study was recovered from the Trebia deposit, located on the north-western flank of the Tidiennit massif in the Nador region (northeast Morocco). The composite developed in the present study is a practical adsorbent for the treatment of industrial wastewater. CTAB was successfully inserted into acid-activated bentonite, demonstrating intercalation processes through X-ray diffraction, FTIR, SEM, and TGA/DTA. The modified Bentonite structure showed increased interlayer space due to the introduction of molecules or ions. The TGA/DTA graphs confirmed the hydrophobic alteration of Bentonite, with reduced clay dehydration and a surfactant decomposing on the surface and interlayer spaces. Morphologically, CTAB formed large particles and cavities.

Abstract: This study investigates the in-situ synthesis of cordierite–mullite ceramic using stevensite-rich-Ghassoul (39.6 wt.%), Bio-kaolin (24.7 wt.%), and andalusite (35.7 wt.%) as starting materials. Uni-axially pressed mixtures at 96 MPa were subjected to sintering at 1250, 1300, 1350, and 1380°C to determine the optimal temperature for cordierite–mullite composite. The phase evolution, microstructure, porosity, and thermal expansion of samples sintered 1250 to 1380° C for 2 h were investigated. The behavior and mechanical properties were evaluated using 3-point bending and indirect tensile tests. Results revealed the crystallization of cordierite and mullitization of andalusite at temperatures of 1190°C and 1300°C, respectively. Cordierite and andalusite were the predominant phases observed at 1250°C, with a gradual mullitization of andalusite as the temperature increased up to 1380°C. Rietveld quantitative phase analysis results indicate that, at a sintering temperature of 1380°C, cordierite and mullite constitute 57.4 wt% and 31.4 wt%, respectively. The sample sintered at 1380°C exhibited the optimal performance with the following properties: maximum bending and indirect tensile strengths of 31.9 ± 1.1 MPa and 26.6 ± 2.8 MPa, respectively, a flexural modulus of 34.9±2.5 GPa, a coefficient of thermal expansion of 3.6±0.4x10-6 𝐂𝐂−𝟏𝟏 and an open porosity.

Abstract: Nanoclays in 2D layered silicate materials are versatile and dynamic materials with tremendous potential for advanced functional applications. Small particle size, large surface area, and high porosity are the prominent factors that support the use of nanoclays in many different industrial applications. Apart from these well-known features, with their development capabilities such as mechanical strength, thermal and dimension stability, and permeability, nowadays, nanoclays are the most desired material especially in the production of composite materials and products due to their performance-enhancing effects. This paper provides an overview of the latest applications and improvements of polymer/nanoclay composites. Structures, chemical compositions, surface modification methods before use, synthesis techniques of nanoclay composites, and their usage for innovative applications in various fields regarding the latest developments are briefly summarized.

Abstract: Currently, great attention is paid to the creation of polymer composites using functional fillers and polymer matrices of various types, including thermoplastic and thermosetting types. These fillers also make it possible to increase the protective properties of the polymer against electromagnetic radiation by several orders of magnitude. The aim of the study is to study of the process of synthesis of functional fillers for polymer composites for protection against electromagnetic radiation. As a result of the studies conducted, the process of synthesizing functional fillers for polymer composites for electromagnetic radiation protection has been comprehensively examined. It has been shown that the recrystallization of titanium oxide from solution-melts of KCl-NaCl and KCl-NaCl-∑TiClₙ is possible under a flow of inert gas in the presence of a reducing agent, resulting in thread-like crystals of fibrous form. In the process, thread-like rutile crystals with cross-sectional dimensions of 3–30 μm and lengths of 10³–10⁴ microm were obtained. It has also been established that blowing KCl-NaCl-TiCl₄ without TiO₂ with inert gas in the absence of a reducing agent results in the crystallization of metallic titanium in the form of hollow microspheres. The obtained functional fillers have great potential in the development of polymer composite materials for electromagnetic radiation protection, providing a high combination of strength and spectral characteristics.

Abstract: This study relates to the development of geopolymer concrete (GPC) and empirical models which can be used to predict strength and durability under different curing temperatures. The binders and alkaline activators used for the GPC production were characterized to determine their physical and chemical properties. The partial and pure geopolymer concrete samples were produced. The partial replacement of Geopolymer concrete (GPC) samples was done with cement at varying percentages of 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5 and 20% to determine the optimum cement stabilization. Fourier transform infrared spectroscopy (FTIR) results show key absorbance level at the zone between 950.1 and 3250.12 cm⁻¹. It means that enhancement of the laboratory-produced (bespoke) superplasticizer enhanced the performance of GPC by reducing the viscosity and enriching the flow behaviour of the concrete. The optimal geopolymer product showed substantial strength and durability enhancements at 70°C followed by declining values at temperatures above 70°C, indicating material deterioration. A positive correlation between hot-state temperature, strength and durability properties was also established. Furthermore, scrutiny of the model shows that overall dataset points for training and test sets are clustered close to the diagonal line, signifying that the model provides precise estimation of the strength and durability features. .

Abstract: This work, report a simple synthesis of carbon quantum dots (CQDs) derived from Simmondsia chinensis (Jojoba) seed meal. Simmondsia chinensis seed meal was used because it has rich phytochemical contents. The structural, morphological, functional group and optical properties of the obtained CQDs were studied using X-ray diffraction spectroscopy (XRD), Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Zeta potential, UV-vis and spectrophotometer, respectively. The TEM shows that the obtained CQDs have an average size of 8.48 nm. The photoluminescence spectroscopy revealed that the synthesized CQDs can emit tunable bluish photoluminescence with maximum emission intensity was observed at 400 nm under 340 nm excitation wavelength.

Abstract: Copper sulphide (Cu₂S) is an indirect gap p-type semiconductor belonging to I-VI group. The wet chemical route was used to synthesize manganese (Mn) doped copper sulphide nanoparticles with a decrease in particle size by increasing the concentration of manganese element. These nanoparticles were analyzed by using the various characterization techniques like ultraviolet-visible (UV) absorption spectroscopy, photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The dip coating method was used to prepare Mn doped Cu₂S thin films on fluorine doped tin oxide (FTO) glass slides with varying the dip time. These thin films were heat treated in air atmosphere at 420°C for 20 minutes and investigated by using the various analysis techniques like scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive analysis by X-rays (EDAX) and mapping. The detailed explanation of obtained experimental results is discussed in this paper.

Abstract: The research is intended to synthesize copper(II) with Phenobarbital (PB) complex in 1 : 4 mole ratio. The sole reflux method is designated to synthesize reactant within methanol solvent. Cu(II) complex is characterized using Atomic Absorption Spectrophotometry (AAS), UV-Vis Spectrophotometer, Fourier-transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Conductivity meter, and Magnetic Susceptibility Balance (MSB). The Cu(II)-PB complex signified 1 absorption peak at 517.5 nm with 2Eg → 2T₂g transition. Complex is then composed by 6 electron donors of Cu ion-bound ligand, forming the octahedral geometry. Complex possesses the molecule formula of [Cu(PB)₃]Cl₂, this signifies only the PB that bound to Cu(II) ion as ligand through Oxygen and Nitrogen atom donors. There is no evidence of H₂O molecules coordinated as ligand. Complex is electrolyte along with Cl^- as counter ion that neutralized the complex charge. Complex is also being paramagnetic with the value of μeff of 1.74 BM.

Abstract: Pelletising, i.e. transformation of fine dusty materials into lump materials (pellets, briquettes, pellets), is an important technical task solved in many sectors of the national economy - ferrous and non-ferrous metallurgy, chemical industry and in a number of other industries. The process of pelletising ores and ore concentrates is of the greatest importance for the production of iron and steel, i.e. for ferrous metallurgy. The most common method of pelletising is pelletising - granulation of iron ore concentrates in special granulation plants, usually with the use of binders. As a result of pelletising, so-called pellets are produced, which are subjected to hardening firing (roasting pellets) or achieve the required level of properties without high-temperature treatment (non-roasting pellets) through the use of special binders. The current trend is the transition from firing methods of pellet hardening to non-firing (low-temperature) methods.