Nickel Impregnation Research Articles

Preparation of carbon molecular sieves and its impregnation with Co and Ni for CO2/N2 separation

The carbon molecular sieves (CMSs) prepared by carbonaceous materials as precursors are effective in CO2/N2 separation. However, selectivity of these materials is too low, since hydrocarbon cracking for developing the desired microporosity in carbonaceous materials has not been done effectively. Hence, in this study, cobalt and nickel impregnation on the precursor was conducted to introduce catalysts for hydrocarbon cracking. Cobalt and nickel impregnation, carbonization under N2 atmosphere, and chemical vapor deposition (CVD) by benzene were conducted on the extruded mixtures of activated carbon and coal tar pitch under different conditions to prepare CMSs. The best CMS prepared by carbon deposition on the cobalt-impregnated samples exhibited CO2 adsorption capacity of 54.79 mg/g and uptake ratio of 28.9 at 0 °C and 1 bar. In terms of CO2 adsorption capacity and uptake ratio, CMSs prepared by carbon deposition on non-impregnated and cobalt-impregnated samples presented the best results, respectively. As benzene concentration and CVD time increased, equilibrium adsorption capacity of CO2 decreased, and uptake ratio increased. Cobalt was found to be the best catalyst for benzene cracking in the CVD process.

Hydrotalcite Catalyst for Hydrocracking Calophyllum inophyllum Oil to Biofuel: A Comparative Study with and without Nickel Impregnation

This research aims to study the effect of nickel impregnation into hydrotalcite catalyst that use to convert Calophyllum inophyllum oil into biofuel through hydrocracking process. Hydrocracking process was carried out under mild condition (350 °C and 20 bar) for two hours in a slurry batch reactor. The adding nickel affected the reaction conversion, yield, and selectivity of gasoil. The process of oxygen removal from the compounds in the oil was characterized by Fourier Transform Infrared Spectroscopy (FTIR), and the compositions of the products were determined by Gas Chromatography-Mass Spectrometry (GC-MS). The results of the study successfully proved that nickel impregnated into hydrotalcite catalyst increased the conversion, yield, and selectivity of gasoil up to 98.57 %, 54.15 %, and 81.31 %, respectively.

Effect of Pt doping on activity and stability of Ni/MgAl2O4 catalyst for steam reforming of methane at ambient and high pressure condition

Effect of addition of Pt noble metal to Ni/MgAl2O4 catalyst for steam reforming of methane was studied at atmospheric pressure and at high pressure (10 bar). Pt loading of the catalyst was varied from 0.01 wt.% to 1.0 wt.%. Catalyst characterization studies showed that the degree of reduction of the catalyst increased from 44.9% for Ni/MgAl2O4 to 67.7% for the catalyst doped with 1.0 wt.% Pt, which was attributed to H2 spill over effect. With increasing Pt loading, the metal dispersion passed through a maxima and the highest dispersion of active metals was obtained with a Pt doping of 0.1 wt.%. Increase in Pt concentration had no effect on the concentration of NiAl2O4 that had already formed during calcination at 850 °C after nickel impregnation. Addition of Pt significantly increased the catalytic activity of Ni/MgAl2O4 for the steam reforming of methane at both reactor pressures. Comparison of Pt doped Ni/MgAl2O4 with Pt/MgAl2O4 showed that only lower loading of Pt produced a synergetic effect. The highest catalytic activity was obtained with 0.1 wt.% Pt doped Ni/MgAl2O4. Above this Pt loading the catalytic activity decreased. The highest activity of 0.1 wt.% Pt doped catalyst was credited to an increase in active metal dispersion, while the decrease in catalytic activity on further addition of Pt was attributed to agglomeration of active metals. High pressures decreased the conversion and stability of each Pt doped catalyst. However, at the same operating conditions there was a marginal increase in the catalyst stability due to Pt doping and the decline in catalyst activity with run time was lowest for 0.1 wt.% Pt doped Ni/MgAl2O4 catalyst.

Effect of Nickel Impregnation on Wood Gasification Mechanism

To study its catalytic effect, nickel were inserted intentionally by impregnation into the biomass. In this context, the influence of the Ni amount in the solution during wood impregnation has been analyzed in terms not only of catalytic activity and samples compositions but also on the wood structure. Willow was impregnated with different concentrations of nickel nitrate solutions and then characterized with thermogravimetric and elementary analyses. Using thermodynamic calculation, the speciation of Ni and the pH variation in the impregnation solution was predicted. It was found that the stable aqueous form of Ni were Ni2+ and NiNO3 +. It was also found that wood impregnation in high-concentrated solutions (more than 0.5 wt%), modified the wood structure and complicated the understanding of its behavior during thermal treatment. The amount of Ni which shows a maximum efficiency during char gasification is 1.6 wt% in the wood sample. This amount corresponds to a sample prepared with a 0.5 wt% of Ni in the impregnation solution. However, to keep the wood structure during the impregnation step, it is recommended to impregnate the wood with lower amount of Ni, around 0.1 wt%. During gasification tests, Ni has shown a catalytic performance between 450 and 600 °C where the rate of char gasification was increasing. This result was confirmed with an increase in the syngas production. The presence of nickel has also generated a decrease in the char gasification temperature by 100 °C.

Influence of Nickel Impregnation on Behavior and Kinetic Characteristics of Oak Pyrolysis

Influence of Nickel Impregnation on Behavior and Kinetic Characteristics of Oak Pyrolysis

Enhancing adsorption of nitrate using metal impregnated alumina

The adsorption capacity and selectivity are vital for designing economically feasible treatment system for drinking water. This work is aimed at enhancing the selectivity of nitrate adsorption through metal impregnation. Impregnation of Mg, Fe, Co, Ni, Zn and Cu on alumina was investigated. Nickel impregnation was found to be the best, with an increase in 13 times the nitrate adsorption capacity compared to unmodified alumina. The optimal pH for nitrate adsorption using nickel-modified alumina was in a wide range from 3 to 7. The nitrate adsorption capacity was not influenced by the presence of fluorides and phosphates, whereas carbonates and sulphates were found to decrease the adsorption capacity by 50%. The adsorbents were also tested on drinking water samples from Madhya Pradesh, India. The nitrate adsorption capacity of nickel-impregnated alumina was still 10 times higher compared to the bare adsorbent.

Supported NiW catalysts with tunable size and morphology of active phases for highly selective hydrodesulfurization of fluid catalytic cracking naphtha

This article reports a novel method for preparing supported NiW hydrodesulfurization (HDS) catalysts with tunable size and morphology of active phases to achieve highly selective HDS performance in hydro-upgrading fluid catalytic cracking (FCC) naphtha. The proposed approach features the combined use of W-based hybrid nanocrystals (HNCs) as the W precursor and the promoting effect optimization of Ni promoter. The W-based HNCs synthesized under mild hydrothermal conditions are monodispersed particles with an average size of ca. 2nm and show a core–shell structure with W6O192− as the inorganic core and short-chain quaternary ammonium cations as the organic shell. The use of W-based HNCs facilitates the formation of highly dispersed W species and WS2 active phases with enhanced stacking, thus yielding a larger number of accessible Ni–W–S edge sites upon nickel impregnation. Moreover, we found that the advantageous W dispersion in the HNC-derived monometallic catalyst precursor allows further modification of the size and morphology of the active phase via the optimized incorporation of Ni promoter, leading to the formation of Ni–W–S edge sites with a lower percentage of brim sites and thereby resulting in considerably higher selective HDS performance for FCC naphtha than its counterpart prepared by the conventional impregnation method. The proposed approach makes it easy to tune the size and morphology of WS2 nanoparticles, shedding light on the rational design of supported WS2 catalysts for FCC naphtha selective HDS.

Combined steam and CO2 reforming of CH4 using coke oven gas on nickel-based catalyst: Effects of organic acids to nickel dispersion and activity

Combined steam and carbon dioxide reforming with CH4 (CSCR) has been investigated using Ni/Al2O3 catalysts, where γ-Al2O3 support was previously modified with four different organic acids before nickel impregnation, to verify the effects of different nickel distributions induced from the modified acid sites to the catalytic activity. The CSCR reactions were performed at T=750°C, P=1.0MPa, space velocity of 36,000L(total mixed gas)/(kgcat·h), and CH4/CO2/CO/H2/H2O molar ratio=1/0.38/0.29/2.09/1.2, which is the typical compositions of the coke oven gas in steel industry. The Ni/Al2O3 prepared by formic acid for the pretreatment of γ-Al2O3 showed a higher catalytic activity due to the maintenance of smaller nickel particles even after a high temperature CSCR reaction. The types of organic acids significantly changed the surface properties of γ-Al2O3 by varying the isoelectric points, which are strongly depending on pKa values of organic acids, and it concomitantly alters the dispersion of nickel precursor with the different deposition depths in γ-Al2O3 pores by largely changing the particle size distribution and the metal-support interaction. The surface-enriched nickel containing Ni/Al2O3 pretreated with oxalic acid was also applied to derive the kinetic parameters using Langmuir–Hinshelwood–Hougen–Watson (LHHW) mechanism by showing an activation energy of ∼240kJ/mol for the CSCR reaction.

Liquid and Gaseous Fuel from Waste Plastics by Sequential Pyrolysis and Catalytic Reforming Processes over Indonesian Natural Zeolite Catalysts

In this study, the performance of several differently treated natural zeolites in a sequential pyrolysis and catalytic reforming of plastic materials i.e. polypropylene (PP) and polystyrene (PS) were investigated. The experiments were carried out on two stage reactor using semi-batch system. The samples were degraded at 500°C in the pyrolysis reactor and then reformed at 450°C in the catalytic reformer. The results show that the mordenite-type natural zeolites could be used as efficient catalysts for the conversion of PP and PS into liquid and gaseous fuel. The treatment of natural zeolites in HCl solution showed an increase of the surface area and the Si/Al ratio while nickel impregnation increased the activity of catalyst. As a result, liquid product was reduced while gaseous product was increased. For PP, the fraction of gasoline (C 5 -C 12 ) increased in the presence of catalysts. Natural zeolite catalysts could also be used to decrease the heavy oil fraction (>C 20 ). The gaseous products were found that propene was dominated in all conditions. For PS, propane and propene were the main components of gases in the presence of nickel impregnated natural zeolite catalyst. Propene was dominated in pyrolysis over natural zeolite catalyst. The high quality of gaseous product can be used as a fuel either for driving gas engines or for dual-fuel diesel engine.

Electrolytic Nickel Impregnation of Porous Anodic Aluminum Oxide Films Using AC Voltage as Solar Selective Absorber

Anodized aluminum oxide films on aluminum substrates 1050 (99.5% Al) was impregnated with nickel by electrodeposition technique. In these paper, we report the synthesis of Ni using the galvanostat mode, and also some experimental modification in the frequency and voltage values, in order to optimize the amount content of Ni on aluminum substrate The data values of the total reflectance were analyzed in the visible solar spectrum and near infrared as a function of voltage, frequency and time of the impregnation process. Several experiments were performed in order to correlate these parameters with the nickel content in the bottom of the pores of the film and its reflectance properties. By morphological analysis found that samples with average nickel content of 10% of the total pore volume not exhibit good properties of a selective absorber, however the samples containing 60% of the total pore volume, present in the reflectance spectrum visible solar 5% and 90% in the infrared solar spectrum so it can be considered a good selective absorber films makes these coatings are prospects for implementation in solar collectors.

Electrodeposited nickel composite coating containing in-situ nickel impregnated alumina particles

In this paper, preparation of nickel composite coating containing in-situ impregnated alumina particles is reported for the first time. Nickel impregnation in alumina particles was realized during electrodeposition through the pores present in the alumina particles that acted as conduits. The impregnation of Ni was confirmed by scanning electron microscopy and electron probe microanalysis. This study suggests that the use of porous particles may be a preferred route to improve the adhesion of particles and microhardness in electrodeposited metal matrix composites.

Growth of Carbon Nanomaterials on Granular Activated Carbon

Since the discovery of carbon nanotubes (CNT) and subsequent Carbon Nanomaterials (CNMs), there has been an ever increased academic and industrial interest on there various fields of application due to their exceptional mechanical and electrical properties. In this work, granular activated carbon (GAC) made from palm Kernel shell (PKS) of mesh size 8x12 was impregnated with nickel as substrate catalyst for the growth of Carbon Nanomaterials (CNMs) in a chemical decomposition (CVD) reactor. Various percentages by weight of the nickel (1%, 3%, 5% and 7%) were impregnated on the GAC surface for CNM growth. The CNM growth took place at a fixed reaction temperature and gas flow rates for both the hydrogen gas and carbon source. Characterization of the novel composite material was carried out by using SEM, FESEM and TEM. The results show that growth was successful as at 1% nickel impregnation, while a denser network distribution and rougher surface of CNM was observed at 7% nickel. The growth of CNMs on a larger substrate GAC should make handling of the CNMs easier and it is expected to also open new doors of application in water treatment and oil refining.

Effect of preparation variables on the activity of Ni-W/Al2O3 hydrotreating catalysts

Studies have been carried out on the influence of preparation parameters on the activity of nickel-tungsten (Ni-W) catalysts, used to promote the hydrotreatment of model compounds representative of nitrogen, sulphur, oxygen and aromatic containing compounds which typically occur in coal derived liquids. The preparation variables considered for optimisation were the pH of the impregnating solution, the impregnation order, the starting Ni salts, the Ni/Ni + W ratio, the drying conditions and the calcination temperature. It was found that changes in pH, within the range where binding of the starting ions to alumina takes place, is not a significant variable influencing the activity. The use of nickel nitrate as a precursor yields better catalysts. If W is impregnated first it is redistributed during subsequent nickel impregnation, and better catalysts are obtained when Ni is impregnated first. The optimum Ni/Ni + W ratio is between 0.3 and 0.4, based on the total active metals present on the catalyst. The hydrodesulphurisation hydrodeoxygenation and hydrogenation activities decrease with increase in the drying temperature; the reverse is true for hydrodenitrogenation. An optimum activity is obtained when drying at 100°C in a closed oven. The optimum calcination temperature was found to be 500°C.

Adsorption Parameters and Surface Species in the Nickel—Molybdenum Alumina System

Isotherms corresponding to the adsorption of ammonium heptamolybdate solutions on nickel–alumina supports have been studied. Such isotherms exhibit two distinct adsorption regions, with both the support and the adsorbed species contributing to their formation. Two types of site are available for adsorption on the support and, depending on the molybdenum concentration present in solution, either monomeric (at low concentrations) or polymeric molybdenum species (at high concentrations) are formed and adsorbed. Monomer adsorption occurs at low concentrations, whereas polyanion adsorption predominates at high concentrations; the latter is reflected in an abrupt increase in molybdenum concentration adsorbed on the support. The adsorption isotherms measured at 20°C and 50°C, and TPR and XPS studies indicate that the samples prepared at 50°C contain a lower quantity of octahedral molybdenum, although dispersion of the molybdenum on the surface is higher. In addition, a direct relationship exists between the dispersion of the active component and the hydrodesulphurization activity of the sample. The presence of nickel on the support does not affect the total number of sites occupied by molybdenum. However, when the nickel content on the solid is increased, the molybdenum species occupy a higher proportion of octahedral sites. XPS studies have shown that samples with a higher nickel content possess a better dispersion of molybdenum species and exhibit a higher intrinsic activity. Enhanced molybdenum dispersion and thiophene conversion was associated with samples in which molybdenum adsorption occurred before nickel impregnation. For all the series studies, the maximum value in the intrinsic acitivity occurred at the same value of the Ni/Mo atomic ratio. This provides convincing evidence that the precursor ratio is important in this catalyst system.

Caikng Property of Coal Treated with Liquid Ammonia

As a part of the investigation of the nickel-catalyzed gasification of coal which was pretreated with liquid ammonia, the caking properties of the treated coals were studied. The crucible swelling number was determined, and also the caking behavior of coal in a fluidized bed was observed with the naked eye. The ammonia treatment together with nickel impregnation makes the caking property decrease. Some coal lost its caking property upon ammonia treatment and exposure to air. The coals with the crucible swelling number less than 1 can be handled in a fluidized bed. Slow heating rates made it possible to handle coals with higher caking tendency. The crucible swelling number was f ound to be a good indication to judge the possibility of fluidizability of coal, whether it was an original one or a treated one.

ChemInform Abstract: INFRARED STUDY OF HYDROXYL GROUPS ON NICKEL OXIDE AND SILICA‐SUPPORTED NICKEL CATALYSTS

AbstractDie thermische Zersetzung von Ni(OH)2 sowie die Zersetzung und Reduktion von Ni‐Trägerkatalysatoren auf S102 wurden IR‐spektroskopisch untersucht.

Infrared study of hydroxyl groups on nickel oxide and silica‐supported nickel catalysts

AbstractThe decomposition of nickel hydroxide and the decomposition and reduction of some silica supported catalysts have been studied by means of IR spectroscopy.In the spectrum of decomposed nickel hydroxide two bands remain at 3676 and 3575 cm−1 which may be assigned to the existence of free and disturbed hydroxyl groups on the nickel oxide surface. The presence of these groups only partially explains the previously published water retention after decomposition. The band at 3676 cm−1 also remains in the spectrum of a silica‐supported nickel impregnation catalyst after heat treatment and disappears readily after reduction with hydrogen. IR absorption bands at other positions in other types of supported nickel catalysts possibly originate from the formation of nickel hydrosilicates.The decomposition of nickel hydroxide was also studied by means of thermogravimetry and it was found that the rate of decomposition at 225°C could be described by a first order law, provided that the degree of conversion was defined as being one at the apparent decomposition stage of about 80%.

Use of chemical nickel impregnation in turbine construction for pearlitic steel parts

Use of chemical nickel impregnation in turbine construction for pearlitic steel parts