Effect Of Potassium Addition Research Articles

The Effect of Potassium on TiO2 Supported Bimetallic Cobalt–Iron Catalysts

The effect of potassium addition on Fischer–Tropsch catalysts containing 10 wt% cobalt and 2 wt% iron supported on pure TiO2 was studied using a continuous flow reactor at atmospheric pressure, a syngas feed with H2/CO = 1.7 and GHSVsyngas = 1944 mLsyngas gcat−1 h−1. The FTS reaction was performed in a range of temperature 275–350 °C. Differences in textural, structural, chemical and redox properties of the materials were evaluated by N2 adsorption/desorption isotherms, XRD, XPS, and TPR. As compared to the catalyst without potassium, forming large quantity of methane at each of the three temperatures, the potassium promoted catalysts formed less methane and consistent amount of alcohols. Moreover, the potassium containing samples produced more of the heavier hydrocarbons and more CO2 at the higher temperature as compared to the potassium free sample. According to the structural-activity relationship potassium acted as both, structural and electronic modifier.

The Effect of Potassium Addition on Oil Palm (Elaeis guineensis Jacq.) Roots Anatomic Properties under Drought Stress

The availability of water is one of the main limiting factors for oil palm growth and production. Potassium (K) is an essential nutrient for plants because of its role in controlling metabolic and physiological activities. This study aimed to examine the effect of different K fertilizer doses on root anatomic properties under drought stress. The experiment was arranged in factorial Randomized Complete Block Design (RCBD) with two factors. The first factor was drought stress, consisting of three levels of fractions of transpirable soil water (FTSW) (FTSW 1 (control: field capacity); FTSW 0.35 (moderate drought); FTSW 0.15 (severe drought)) and the second factor was K dose (sourced from KCl), consisting of five levels (K0: 0%; K1: 50%; K2: 100%; K3: 150%; K4: 200%). The results showed that there was an interaction between the addition of K doses and the tolerance level of oil palm plants to drought stress. The addition of 100% K gave higher results in the parameters of xylem diameter, phloem diameter and cortex cell width compared to the plants without K. The results disclosed that 200% K application on moderate drought stress and severe drought stress in oil palm seedlings could widen xylem diameter, phloem diameters, strengthen cell such as epidermal cells, cortex cells, thickness of endodermic cells, thickness of sclerenchyma cells and increase hardness of cell compared to field capacity. As for the parameters of thick endodermic cells, stele diameter and sclerenchyma diameter, an addition of 50% K could give higher results.

Effect of potassium addition and several levels of nitrogen on growth and yield of two cultivars of wheat under sprinkler irrigation system

For the purpose of evaluating the effect of adding the potassium and several levels of nitrogen in the growth and yield two cultivars of wheat under sprinkler irrigation system. Afield experiment was carried out during the 2016-2017 season in Ain Tamur in Karbala City. The study contained two factors. The first factor was two cultivars of wheat Adnan 99 and G5 while the second factor was addition of chemical fertilizers T1 addition of 200 kg h-1 of urea without adding potassium, T2 addition of 260 kg h-1 of urea without adding potassium, T3 addition of 400 kg h-1of urea without adding Potassium, T4 addition of 200 kg h-1 of urea and 50 kgh-1of potassium sulphate, T5 addition of 260 kg h-1of urea and 50 kgh-1 of Potassium Sulphate, T6 addition of 400 kgh-1of urea and 50 kgh-1 of potassium. The Randomized Complete Block Design (RCBD) was used with two factors and five replicates. The results showed the exceeding of Adnan 99 cultivar by giving the highest rates of spike length 7.34 cm, grains number in the spike 32.30 grain spike-1, weight of 1000 grains 35.16 gm, grains yield 2.58 ton h-1 harvest index 34.9%; and the exceeding of G5 in the plant height 60.88 cm, spikes number 283.6 spike m-2, and biological yield 7.71 ton h-1. In addition, the results showed the exceeding of T6 treatment by giving the highest rates of plant height 67. 29 cm, spikes number 320.5 spike m-1, spike length 8.77 cm, weight of 1000 grain 37.75 gm grains yield 3.57 ton h-1, biological yield 10.00 ton h-1 , and harvest index 36.3%.The results also showed a significant interaction between Chemical fertilization and cultivars in the most studied characters. It can be concluded from this study that the addition of potassium and nitrogen has anobvious effect in increasing grain yield.

Effect of potassium addition on bimetallic PtSn/θ-Al2O3 catalyst for dehydrogenation of propane to propylene

PtSn/θ-Al2O3 catalysts with different amounts of K (0.14, 0.22, 0.49, 0.72, and 0.96 wt%) are prepared to investigate the K effects on the PtSn catalyst in propane dehydrogenation (PDH). KPtSn catalyst with 0.xx wt% K, 0.5 wt% Pt and 0.75 wt% Sn is designated as xx-KPtSn. PDH was performed at 873 K and a gas hourly space velocity (GHSV) of 53,000 mL/gcat h. The temperature-programmed desorption (NH3-TPD), temperature-programmed reduction (TPR) and CO chemisorption of the KPtSn catalysts with K added revealed the potassium addition blocked the acid sites, promoted the reduction of Sn oxide and decreased the Pt dispersion. The formations of cracking products and higher hydrocarbons on acid sites were suppressed by the K effect of blocking the acid sites. In contrast, K addition at more than 0.72 wt% rather increased cracking products and the amount of coke, resulting in the severe deactivation of catalysts. The high cracking products on the KPtSn catalysts with the high amount of K should not be related to the acid sites, because the acid sites were monotonously decreased with an increase in the amount of K. Instead, the potassium affected the characteristics of PtSn. The interaction between Pt and Sn could be weakened by enriching the reduced Sn, because the K component promoted the reduction of Sn oxide in the TPR experiments. Therefore, the 14-KPtSn catalyst with the low amount of K exhibits the highest stability and selectivity among the prepared KPtSn catalysts due to the compromise of the advantageous (blocking the acid sites) and bad (weakening the interaction between Pt and Sn) effects of the K addition in PDH.

Effect of potassium addition on a long term performance of Co–ZnO–Al2O3 catalysts in the low-temperature steam reforming of ethanol: Co-precipitation vs citrate method of catalysts synthesis

The promotion effect of potassium on Co–ZnO–Al2O3 catalysts in the steam reforming of ethanol has been studied with samples prepared by co-precipitation and citrate methods. Experimental results of catalytic activity, selectivity and coke deposition phenomena are reported. Potassium addition (1 and 2wt.%) had a significant influence on catalytic efficiency at various ethanol+water vapours streams (H2O:EtOH=21:1, 15:1, 12:1 molar ratios). It acts as a promoter improving catalyst stability, activity as well as marginalizing coke deposition on the catalyst surface. Catalysts prepared by the co-precipitation method, with smaller cobalt active phase crystallites and with potassium deposited on the catalyst surface are more stable in the steam reforming of ethanol than those with large crystallites prepared by citrate method, into which potassium was introduced together with all others components. The efficiency of the potassium promotion is higher when it is deposited on the catalyst surface with smaller cobalt active phase crystallites. The water excess equivalent to the H2O:EtOH molar ratio higher than 15:1 has been necessary for the stable SRE. Even potassium-promoted K–Co–ZnO–Al2O3 catalyst needs the ethanol–water feed with a large excess of water.

Effect of potassium addition on bimetallic PtSn supported θ-Al2O3 catalyst for n-butane dehydrogenation to olefins

PtSn/θ–Al2O3 catalysts with different amount of potassium (0.4, 0.7, 0.95, 1.2 and 1.45wt.%) were prepared by an impregnation method, and their catalytic activity in n-butane dehydrogenation was investigated at 823K, an atmospheric pressure and a GHSV of 18,000mL(gcath)−1. The compositions listed in order of n-C4= yields at 823K were as follows: K0.95(PtSn)1.5>(PtSn)1.5>K0.4(PtSn)1.5>K0.7(PtSn)1.5>K1.2(PtSn)1.5>K1.45(PtSn)1.5>K0.9(Pt)1.5. The K0.9(Pt)1.5 and K0.95(Sn)1.5 catalyst severely deactivated in n-butane dehydrogenation. The (PtSn)1.5 (without K) catalyst showed the highest n-butane conversion, while K0.95(PtSn)1.5 did the highest n-C4= yield. The small amount of potassium on bimetallic PtSn/θ-Al2O3 catalyst improved n-C4= selectivity, but slightly decreased n-butane conversion, resulting in the increase of n-C4= yield. The effect of potassium was caused by blocking the acid sites of Pt catalyst. The TPR and HAADF STEM-EDS study suggested the reduction procedure of the Pt, Sn and K species. However, the higher loaded potassium (1.2 and 1.45wt.%) doped (PtSn)1.5 catalysts were rather highly deactivated because the sizes of Pt particles were increased by weakening the interaction between Pt and Sn. The n-C4= selectivity of the (PtSn)1.5 catalyst increased with respect to the reaction, while that of the potassium doped catalysts maintained the high n-C4= selectivity from the beginning of the reaction. Also, different alkali metals (Ca, Na and Li) were tested for the comparison with K. The potassium doped catalyst showed the highest n-C4= yield among the other alkali metals for n-butane dehydrogenation.

Catalytic activity of Cu-containing oxide systems with K2CO3 additives in the oxidation of diesel soot by oxygen

It is shown by XRD that mixed oxide phases Cu0.92Co2.08O4 and Cu4MgO5 are formed along with the oxides CuO, Co3O4, MgO, and CaO under certain conditions. The positive catalytic effect of individual oxides (CuO and Co3O4) and mixed oxide systems (CuO-Cu0.92Co2.08O4, CuO-CaO, and Cu-MgO-Cu4MgO5) on the oxidation of diesel soot at 280–580°C is established, and a series of catalytic activities CuO-Cu0.92Co2.08O4 > CuO-MgO-Cu4MgO5 > CuO-CaO = CuO > Co3O4 is revealed. Using TEM, the surface micromorphology of crystallites that form oxide systems is characterized. It is found that a catalytic system’s activity increases as the size and surface smoothness of crystallites diminishes. According to data from X-ray photoelectron spectroscopy, a considerable increase in the concentration of O2 in soot with CuO and Co3O4 additives after its oxidation by oxygen is observed without changing the oxidation state of Cu and Co oxidation. The promoting effect of potassium additives in the form of K2CO3 on the investigated catalytic systems during soot oxidation is revealed.

The effects of potassium addition on the rate of quartz dissolution in the CMAS and CAS systems

Quartz dissolution in melts in the KCAS and KCMAS systems results in the formation of a silica- and potassium-enriched boundary layer next to the dissolving crystals. The presence of potassium in CAS melts has no discernible effect on dissolution rate compared with that in K-free melts with otherwise similar composition despite a small decrease in the diffusivity of silica in the potassium-bearing melts. The decrease in silica diffusivity is offset by an increase in the solubility of silica in the K-bearing melts. Addition of potassium to CMAS melts results in a large decrease in the dissolution rate of quartz. Even though the solubility of silica is enhanced, the addition of potassium leads to large changes in the structure of the melt in the boundary layer (as measured by NBO/T), which results in a large decrease in the diffusivity of silica and thus slower dissolution. There is significant diffusive coupling of Al2O3, CaO and MgO during dissolution, which leads to local uphill diffusion of these components. K2O is decoupled from the other components, as shown by its much thicker diffusion zone. Potassium moves through the boundary layer as a result of two homogeneous reactions: uphill diffusion in which potassium diffuses into the silica-enriched melt adjacent to the dissolving quartz crystal and downhill diffusion in the region furthest from the crystal–melt interface where SiO2 and K2O diffuse away from the interface together.

The effect of potassium addition on plasma parameters in argon dc plasma arc

The effect of potassium addition on the radial distribution of temperature and electron number density in a U-shaped direct current (dc) argon plasma operating at different arc currents has been studied by optical emission spectroscopic techniques and the power interruption method. Spatially resolved electron number densities (ne) have been determined from measured radial profiles of Balmer-Hβ spectral line. The obtained electron number densities have been used for thermodynamic temperature (TLTE) evaluation with the assumption that the arc plasma is in a state of local thermodynamic equilibrium. The excitation temperatures (Texc) have been determined from the absolute integral emissivity of the argon line at 430.01 nm. For heavy particle temperature (Th) evaluations we have used a power interruption method. The obtained results have shown that an addition of KCl decreases both electron number density and temperature of the arc column. The magnitude of such an influence on plasma parameters increases with an increase in the KCl concentration and decreases with an increase in the arc current.

Effect of potassium addition on the product selectivity of Ru:Mn/alumina supported catalyst system for Fischer–Tropsch reaction

The catalytic behavior of a series of Ru/Al 2 O 3 catalysts promoted with various levels of Mn and K prepared by co-impregnation method were investigated in the CO hydrogenation reaction. Catalytic studies showed that the addition of Mn enhances the production of Fischer–Tropsch products and K promotion in particular enhances the production of unsaturated hydrocarbons while inhibiting the methanation reaction. The influence of K and Mn on the Fischer–Tropsch product selectivity in CO hydrogenation studies is discussed in terms of ensemble and electronic effect; and the production of new surface site Ru:Mn:K in accordance with our characterization results.

Effect of Potassium Addition on Coprecipitated Iron Catalysts for Fischer-Tropsch Synthesis Using Bio-oil-syngas

The effects of potassium addition and the potassium content on the activity and selectivity of coprecipitated iron catalyst for Fischer-Tropsch synthesis (FTS) were studied in a fixed bed reactor at 1.5 MPa, 300C, and contact time (W/F) of 12.5 gcath/mol using the model bio-oil-syngas of H2/CO/CO2/N2 (62/8/25/5, vol%). It was found that potassium addition increases the catalyst activity for FTS and the reverse water gas shift reaction. Moreover, potassium increases the average molecular weight (chain length) of the hydrocarbon products. With the increase of potassium content, it was found that CH4 selectivity decreases and the selectivity of liquid phase products (C5+) increases. The characteristics of FTS catalysts with different potassium content were also investigated by various characterization measurements including X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller surface area. Based on experimental results, 100Fe/6Cu/16Al/6K (weight ratio) was selected as the optimal catalyst for FTS from bio-oil-syngas. The results indicate that the 100Fe/6Cu/16Al/6K catalyst is one of the most promising candidates to directly synthesize liquid bio-fuel using bio-oil-syngas.

The effect of potassium addition on the state of the components in the oxide precursor of the (Ni)(Mo)/γ-Al 2O 3 water-gas shift catalysts: FT-IR, diffuse reflectance and Raman spectroscopic studies

One-component samples containing K, Ni, and various concentrations of Mo were prepared by incipient wetness impregnation technique. Bi- and tri- component samples have been prepared from the calcined one- and bi-component samples following the same procedure. The samples were characterized by SSA, FT-IR, DRS and Raman measurements. The decrease of the ratio Ni 2+(Td)/Ni 2+(Oh) with the increase of Mo loading and the re-dispersion of Mo phase after the Ni addition on the one-component Mo containing samples proved the occurrence of interactions between these components in the bi-component NiMo-containing samples. Most probably Ni–Mo–O surface species with different number of Mo-oxo and Ni-oxo entities are formed, depending on the Ni/Mo atomic ratio. It may be accepted, that the Ni 2+ ions are partially localized into the molybdate layer without forming well-defined phases. Two kinds of K + ions have been determined in the corresponding samples, interacting (“ bounded” K + ions) and not interacting (“ free” K + ions) with the rest of the supported phases. The potassium deposition increased the dispersion of Mo phase and influenced the coordination state of the Mo 6+ and Ni 2+ ions in the bi-component KMo-, KNi-containing samples and the tri-component KNiMo-containing samples. It provoked partial transformation of the polymeric Mo 6+(Oh) species into monomeric Mo 6+(Td) ones and Ni 2+(Td) species predomination over Ni 2+(Oh) ones. Most probably, new complex K–Ni–Mo–O species were formed on the support surface in the case of the tri-component samples.

Effect of potassium addition on YBa2Cu3Ox superconductors

Long period post-annealing in the oxygen atmosphere is necessary for YBa2Cu3Ox (Y123) bulk superconductors to impart superconductivity. We have investigated whether Y123 shows good superconductivity without oxygen annealing by potassium addition. If K+ ion substitutes on Ba2+ site since the size of K+ ion is close to that of Ba2+ ion, we can expect hole doping effect without additional oxygen annealing. We confirmed that the sample without potassium addition exhibited no superconductivity, while the sample with potassium addition had the onset Tc of above 90K. This implies that the potassium addition certainly promotes the superconductivity of Y123.

Scientific Basis for the Use of Hypotonic Solutions with Ultrasonic Liposuction

A number of plastic surgeons have advocated using hypotonic solution in ultrasound lipoplasty, theorizing that induced adipocyte swelling increases membrane susceptibility to ultrasonic disruption. Additionally, it has been theorized that potassium increases membrane permeability. This study aimed to determine the effect of solution osmolality on adipocyte diameter, the time course of hypotonic solution action, and the effect of potassium addition on adipocyte diameter. Base solutions with three different osmolalities were prepared: normal saline (NS) (154 mOsm/l), 1/2NS (77 mOsm/l), and 1/4NS (38.5 mOsm/l). Each solution was modified to contain 0, 5, and 10 mEq/l of potassium and adjusted to starting osmolality. Adipocytes of six patients were suspended in the nine solutions, and diameters were determined at 0, 15, 30, and 45 min. Diameters were measured using imaging software (Kodak ID 3.6). At time 0, the average adipocyte diameter was 79 +/- 8 microm, and no difference was seen in any of the solutions. Cells in the NS group showed no significant increase in diameter over 45 min. The 1/2NS group achieved an 8% +/- 1.9% increase in diameter at 45 min (p < 0.05). The 1/4NS group showed an increase by 14% +/- 2.4% (p < 0.01) at 15 min, and 15% +/- 2.3% (p < 0.01) at 45 min. Potassium had no independent effect on cell diameter. Hypotonic solution can significantly increase human adipocyte diameter. The findings showed that 1/2NS had a significant effect within 15 min. Tumescent solutions with an osmolality of 1/4NS may be useful in facilitating ultrasonic lipoplasty.

Influence of Educt Preparation on Gasification of Corn Silage in Supercritical Water

Supercritical water gasification of corn silage was investigated in a continuous down-flow reactor. The influence of potassium addition, particle diameter, maize sort, and dry matter content on the gasification efficiency and gas composition was discussed. The effect of potassium addition on the gasification of corn starch was compared with the effect of potassium addition in case of corn silage. Four different crushing units were used. The results obtained using each unit were discussed. Three corn silage with different maturity grades and two corn silage with different growing conditions were investigated. The dry organic matter was varied from 2.5 to 20 wt %. The gasification efficiency and gas composition depends on the biomass concentration. Plugging was observed at higher concentrations. Increase of the pressure inhibited and reduced plugging levels. The residence time was varied for a kinetic study. The gasification efficiency can be modeled with zero-order kinetics, but it is influenced by the concentration.

Effect of potassium addition on the properties of a TiO 2-modified Pd catalyst for the selective hydrogenation of acetylene

The effect of potassium (K) addition on the performance of a TiO 2-modified Pd catalyst in the hydrogenation of acetylene was investigated. When K was added to Pd-Ti/SiO 2, the resulting catalyst showed an improved selectivity for ethylene production over a wide range of conversions, when the catalyst was reduced at 300 °C. This is in contrast to the case of K-free Pd-Ti/SiO 2, which showed an improved selectivity only when the catalyst was reduced at high temperatures, e.g. 500 °C. Analyses of the catalyst surface using infrared, X-ray photoelectron spectroscopy and CO chemisorption indicate that the K-containing Pd surface is modified with the Ti species after the catalyst is reduced at relatively low temperatures. The origin of the facilitated modification is the formation of potassium titanates, which have a lower melting point than that of TiO 2 and therefore migrate onto the Pd surface after the catalyst is reduced at lower temperatures compared to the case of TiO 2.

Effects of potassium addition on the acidity and reducibility of chromia/alumina dehydrogenation catalysts

Dehydrogenation catalysts based on chromia supported on γ-alumina, containing about 6 wt.% of chromium and increasing amounts of potassium (up to 1.8 wt.%), were prepared and characterised by means of several techniques, such as N 2 adsorption at 77 K, X-ray powder diffraction (XRPD), UV-Vis diffuse reflectance spectroscopy (DRS), electron paramagnetic resonance (EPR), temperature programmed reduction (TPR), microcalorimetry and chemical analyses. The catalytic behaviour of the samples was investigated in the propane dehydrogenation reaction at 813 K and the effect of potassium loading was examined. The addition of increasing amounts of the alkali metal, as expected, determined a general decrease in the surface acidity. The sites strength distribution was greatly influenced, due to the fact that, at loadings above 0.5 wt.%, potassium preferentially caused the disappearance of weak and medium acid sites. EPR showed a decrease of Cr III species (especially α-Cr 2O 3) on potassium increasing. TPR profiles of the K-containing samples showed the presence of two reduction peaks, ascribable to two different kinds of Cr VI surface species with a different reduction behaviour. All catalysts showed a maximum of activity as a function of time-on-stream, due to reduction of Cr VI to Cr III species in the first reaction period, and then a decrease, due to deactivation by coking. Propene selectivity was high in all cases and was positively affected by the presence of potassium in concentrations up to 1 wt.%.

Catalytic performance of K-promoted Rh/USY catalysts in preferential oxidation of CO in rich hydrogen

K-promoted Rh/USY (molar ratio: K/Rh=3) catalyst was found to exhibit high performance in preferential oxidation of CO in rich hydrogen. Such high performance was maintained in the presence of steam and CO 2. The CO oxidation activity of the K-Rh/USY catalyst was independent of the partial pressure of H 2, while the activity of the unpromoted Rh/USY catalyst was decreased significantly in hydrogen-rich stream. The effect of potassium addition on the catalyst structure was investigated and is discussed in terms of the differences in the catalytic performance.

Selective oxidation of hydrogen sulfide over potassium promoted vanadium oxide on a alumina catalysts

The effect of potassium addition to alumina supported vanadium catalysts on the catalytic activity for the selective oxidation of H2S is investigated. XRD, XPS and XANES have been used to characterize a series of K-V/Al2O3catalysts. The enhanced sulphur yield has been correlated with the crystallinity of vanadium.

The Effect of Potassium Addition on the Surface Chemical Structure and Activity of Supported Iron

The surface activity of a Fe–K/ZrO2sample prepared from iron citrate and potassium carbonate has been investigated by the FTIR spectroscopy of adsorbed CO and NO and compared with the behavior of a Fe/ZrO2sample. The addition of potassium produces a strong decrease of the BET area and of the amounts of the adsorbed molecules. At the same time the spectrum of the sample reduced with H2at 573–773 K shows, under anhydrous conditions, the presence of small patches of reduced Fe0, not easily formed on Fe/ZrO2under the same thermal and reducing conditions. The formation of new phases containing iron and potassium in close combination, such as mixed iron–potassium oxalates and potassium ferrites that fully cover the zirconia surface, was inferred from FTIR data. CO adsorption favors the partial surface reduction of these phases producing small Fe-carbonyl clusters in tight contact with potassium and Fe,K-carboxylate surface species. The adsorption of NO, producing nitrosyl species on the reduced iron particles and nitrite groups on the potassium phase is in good agreement with the results of adsorbed CO. These results are confirmed by quantitative determinations of adsorbed gases and by TPR experiments.