Papers by Keyword: Impregnation

Abstract: Regeneration of industrial catalysts is a better way of increasing the catalytic activity of a catalyst. These catalysts are used in the production of sulfuric acid, in the conversion of sulfur dioxide to sulfur trioxide. They lose their efficiency and activity over time, so it is preferable to regenerate the catalyst instead of discarding it as waste, using a thermal regeneration method followed by chemical treatment by impregnation with different percentages of V₂O₅, 10%, 20% and 30%. They are then examined using techniques known as XRD and FTIR. The IR spectrum shows that the catalyst doped with 30% V₂O₅ has the same bands as the fresh catalyst. Finally, the catalytic test carried out by iodometric assay shows that the catalyst regenerated with 20% V₂O₅ has a conversion rate of 63%, identical to that of fresh catalyst.

Abstract: The development of controlled release fertilizer (CRF) was motivated by the necessity to mitigate the loss of nutrients resulting from expeditious release rates in fertilizers, which can lead to significant nutrient loss, including 40-70% N, 80- 90% P, and 50-70% K. To address this issue, the transformation of tobacco stem biomass into biochar as CRF signifies a significant advancement in the effective management of sustainable crop remnants. Nevertheless, given the comparatively limited nutrient content in biochar, its impregnation with nutrient solution is imperative. The objective of this study is to ascertain the optimal operating conditions to produce tobacco stem-based biochar (TSB) from temperature and pyrolysis holding time. Additionally, the study seeks to determine the most effective operating conditions for TSB impregnation, considering parameters such as nutrient solution concentration and stirring speed, to produce TSB impregnated (TSBI). The materials resulting from this process will undergo analysis to determine their proximate, bulk density, porosity, pH value, and NPK nutrient content. The results demonstrated that TSB-3, produced at 600°C for 1 hour, exhibited the highest fixed carbon content of 73.09%, accompanied by a porosity of 77.47% and a pH value of 9.51. Furthermore, the findings demonstrated that TSBI-6, when utilized in conjunction with a 15% nutrient solution concentration and a speed of 300 rpm, led to a 23.91% (31.78%) increase in N nutrition, a 73.18% (7.83%) increase in P nutrition, and a 87.88% (14.85%) increase in K nutrition. Consequently, TSBI emerges as a promising constituent component of CRF, demonstrating potential for widespread application in sustainable agriculture due to its capacity to enhance nutrient utilization efficiency.

Abstract: A modified natural zeolite will be used as a catalyst in the isomerization process of glucose to fructose. It is modified by inserting Fe into its pores with the impregnation method so that the active site of the catalyst is formed as part of the isomerization process. This study aimed to make a catalyst from Fe-impregnated natural zeolite and determine its catalytic performance under various pH, temperature, and isomerization time conditions. The zeolite was activated using 6M H₂SO₄ and 0.5M KMnO₄. The zeolite impregnation process was carried out using 1% (%w/v) FeCl₃.6H₂O solution with a ratio of (1:8) and continued with calcination at 500°C for 4 hours. The Fe-zeolite catalyst was characterized to determine the degree of crystallinity and crystal form, functional groups of its constituent compounds, and surface area. The isomerization process was carried out as a substrate of 10% glucose solution and 1 g of Fe-zeolite catalyst at various temperatures of 40, 50, and 60°C; pH 5, 7, and 9; a sampling time of every 15 minutes for 1 hour. The best fructose yield from the isomerization process was at a reaction temperature of 60°C, pH 5, and 45 min with a yield of 0.837%. It concluded that the Fe-Zeolite catalyst did not give a significant effect on the glucose isomerization process. It is expected that other researchers conduct similar research with different types of metal impregnated to give better results on the glucose isomerization process.

Abstract: The original Java bentonite has been improved by a new method of multi-step impregnation using over-concentrated ammonium under nature temperature. The achieved materials were characterized using SEM-EDX, XRD, FTIR, and BET analysis and then applied in cationic dye adsorption. The specific case in peak XRD analysis of ammonium impregnation was detected at 18°, and the spectra at 532.3 and 470.6 cm^-1 of the FTIR analysis were detected as the ammonium vibration and oscillation bending. Surface structure analysis from SEM-EDX showed the smooth and expanded material achieved, supported by surface area analysis of BET, which described the increase of surface area materials from 61.791, 73.089, and 178.710 m²/g for the bent, bent-Na, and bent-NH, respectively. The highest adsorption capacity on bentonite impregnated by ammonium was achieved at 526.316 mg/g and 128.205 mg/g for rhodamine B and malachite green, respectively. The adsorption mechanism was feasible in endothermic and fitted to pseudo-second-order and Langmuir isotherm adsorption model. The new method of ammonium impregnation on bentonite successfully improved the adsorption ability.

Abstract: Natural montmorillonite (MMT) was facilely impregnated with a mixed solution of protonated chitosan (CS) and KNO₃, which was then subsequently impregnated with sodium tripolyphosphate (TPP) to ionically crosslink with chitosan, resulting in the MMT/xCS-20KNO3-TPP nanocomposites. The initial content of chitosan to MMT was varied from 2.5, 5 and 10 wt%, and while the TPP:chitosan weight ratio was kept at 1:5. The K⁺ and NO₃^- ions interacted ionically and were entrapped in the MMT basal spacing and the free volume of TPP crosslinked chitosan of the MMT/xCS-20KNO3-TPP nanocomposites. These nanocomposites were able to successfully prolong the K⁺ and NO₃^- releases, in which the cumulative released values (%R) ranging from 21 – 26 % for K⁺ and 0.37 – 0.65 % for NO₃^-. The presence of protonated amine in the chitosan played the dominant effect on the release profile of NO₃^- ion more than that of the K⁺ ion. The higher the chitosan content employed in the impregnation method, the more crosslinked chitosan structure in the MMT/xCS-20KNO3-TPP nanocomposites, resulting in decreased K⁺ and NO₃^- releases at each pre-determined soaking duration. The MMT/xCS-20KNO3-TPP nanocomposites have been considered as a promising choice for environmentally friendly fertilizers.

Abstract: The addition of zinc oxide (ZnO) as impregnation for activated carbon (AC) with the hydrothermal method has been performed in this research. Vetiver distillation waste has been used as a precursor for activated carbon synthesized with pyrolisis methods. Carbon is activated by a chemical process using KOH. Enhancement of amorph structure and function group by addition of zinc oxide has been characterized by Raman Spectroscopy, Fourier Transform Infra-Red (FT-IR), and X-Ray Diffraction (XRD). Furthermore, cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) has been done to show the electrochemical properties enhancement of the ZnO/AC compared to pristine AC. At the current density of 1 A/g, the specific capacitance of VRW-ACM has a value of 277 F/g. After the impregnation process, the specific capacitance of VRW-ACM-ZnO has been improved by 44.4% compared to VRW-ACM. The result showed that the activated carbon-based vetiver root waste impregnated with ZnO has the potential to be applied as supercapacitors electrodes.

Abstract: Silica nanocapsules (SiNC) utilization as adsorbent in pollution control have gained much attraction as SiNC are highly porous, have high surface area, excellent thermal and mechanical stability and a tuneable physicochemical property. In this study, microemulsion technique was used to synthesized SiNC. Effect of stirring rate as well as the effect of different method of amine functionalization i.e. grafting, wet impregnation, co-condensation, on the physicochemical properties of SiNC were studied. The stirring rate have significant effect on the physical properties of the SiNC. As the stirring speed increased from 200 rpm to 600 rpm, the particle diameter and the surface area decreases, 695 to 600 nm and 773 to 654 m²/g, respectively. The SEM and TEM analysis shows higher stirring rate produced surface with extensive damage while lower stirring rate produced a smoother surface. Different functionalization method affected the amount of amine groups incorporated into the SiNC. The FTIR spectra shows that the impregnation method incorporates higher amount of amine as indicated by the higher peak transmissions in the region 3450 – 3250 cm^-1. However, amine functionalization of SiNC resulted in decrease of surface area as surface pore of the SiNC were occupied by the amine moieties’ molecules. The optimum condition for synthesizing amine functionalized SiNC were determined to be at stirring rate of 450 rpm through wet impregnation method as the SiNC produced were of spherical shape with smooth surface, and a relatively high surface area of 695 m2/g and pore diameter of 601 nm. These physicochemical characteristics shows the synthesized amine functionalized SiNC have promising qualities for application as adsorbents.

Abstract: It is of great interest to be able to remove residues of impregnating material from the resulting article in order to reduce the cost of manufacturing such parts. To this end, a thermodynamic calculation allows you to obtain the necessary conditions for obtaining high-quality products.

Abstract: The paper presents the results of studies of the profile of the impregnated diamond surface depending on the grain size and initial roughness of the matrix. The experiments were carried out by impregnating powders of different grit size into a matrix made of low-carbon low-alloy steel with HB180 hardness using a ball indenter. The roughness parameters were measured using a contact profilometer. The height and step parameters of roughness and the curve of the profile bearing length were evaluated. In studying the effect of grain size on the surface profile, it was found that the optimal grain size should be 0.5...0.8 of the initial surface mean spacing profile irregularities. The shape of the Abbott-Firestone curve in this case corresponds to a flat profile. Experiments carried out with varying the initial roughness of the samples confirmed the dependence of the optimum grain size on the mean spacing of the profile irregularities. The developed research procedure can be used to design technological processes of hardening parts, tools and accessories by diamond impregnation.

Abstract: The paper considers approaches that can lead to the growth of micro-and nanocrystals on the surface of coatings formed on valve metals by plasma electrolytic oxidation (PEO). Among these approaches, there are the use of electrolytes-suspensions, the addition of organic compounds to the electrolytes, the thermal annealing of ‘PEO layer/metal’ composites, including impregnated ones.