Calcium Nitrate Solution Research Articles

Corrosion behavior of low carbon steel in technological aqueous calcium nitrate solutions

Corrosion behavior of low carbon steel in technological aqueous calcium nitrate solutions

Improvised Media for In Vitro Pollen Germination of some Species of Apocynaceae

Pollen germination forms one of the most important stage post pollination prior to fertilization. This is essential for proper seed setting and seed development. In vitro pollen germination test is the most reliable way of assessing the pollen viability. In the present study pollen grains of seven genera under Apocynaceae family namely, Allamanda, Alstonia, Catharanthus, Nerium, Plumeria, Thevetia and Tabernaemontana were tested in some basic cultural media, such as Brewbaker’s media, 6% Glucose solution, 4% Calcium Nitrate solution and 3% Boron solution. Alstonia pollen grains exhibited highest percentage of germination rate in all the cultural media. Glucose and Brewbaker’s media is found to be highly suitable for efficient pollen germination in all the genera. Boron solution is effective for germination of pollen grains of tree species. In vitro pollen germination can be easily carried out in laboratories. These results can be utilised in plant breeding programmes to improve cultivar and varieties. DOI: http://dx.doi.org/10.3126/ije.v3i3.11074 International Journal of Environment Vol.3(3) 2014: 146-153

Electrostatic charge interaction: a case study on tapered PMMA fiber for calcium nitrate detection

Purpose – This paper aims to propose and demonstrate a simple fiber optic sensor using a tapered plastic multimode fiber as a probe for measurement of calcium nitrate concentrations in de-ionized water. Design/methodology/approach – The working mechanism is based on the observed increment in the transmission of the sensor that is immersed in calcium nitrate solution of higher concentration. The tapering of the plastic fiber is carried out by etching method using acetone, sand paper and de-ionized water. Findings – Tapered fiber with diameter 0.45 mm gives the highest sensitivity of 0.028 mV/% due to better interaction between the evanescent field and the calcium nitrate solution with a good slope linearity of more than 98 per cent for a 1.07 per cent limit of detection in a straight probe arrangement. The use of calcium and nitrate ions within the sensing medium demonstrates the strong dependency of the sensor output trend on the electrolytic nature of the chemical solutions. Originality/value – Demonstration of tapered plastic multimode fiber sensor probe for measurement electrolytic chemical solutions.

Composto orgânico com altos teores de níquel e sua biodisponibilidade no sistema solo planta

A utilização de biossólidos industriais na agricultura pode proporcionar aumento de níquel no solo, porém sua biodisponibilidade é influenciada por diversos fatores e, muitas vezes, resíduos com elevados teores de níquel não estão associados à sua alta absorção pela planta. O objetivo foi avaliar a solubilidade do níquel no solo, sua biodisponibilidade e acumulação em plantas. O experimento foi conduzido em vasos em delineamento inteiramente casualizado com seis doses de níquel: 0, 9, 18, 36, 72 e 144 mg de níquel kg-1 de solo, via fonte orgânica (biossólido compostado) e mineral (cloreto de níquel) com 4 repetições. Utilizou-se um Cambissolo Háplico como substrato e o morangueiro como planta indicadora. Avaliaram-se os teores no solo pelos extratores: ácido nítrico + clorídrico concentrado (3:1), nitrato de cálcio a 0,5 mol L-1, ácido nítrico a 1,0 mol L-1 e o pirofosfato de sódio a 0,1 mol L-1 além, ainda, dos teores de níquel na raiz, coroa, parte aérea e fruto. As maiores e menores extrações de níquel no solo foram observadas pela aplicação da fonte orgânica e extração com o ácido nítrico e clorídrico concentrado e pelo nitrato de cálcio, respectivamente. Ambas as fontes aumentaram os teores de níquel nos tecidos avaliados, com menores aumentos para fonte orgânica. Os maiores teores foram observados em raiz e os menores em coroa.

Improvement of the hydroxyapatite mechanical properties by direct microwave sintering in single mode cavity

The main purpose of this study consists in investigating the direct microwave sintering of hydroxyapatite (HA) in a single mode cavity. Firstly, stoichiometric HA powders were synthesized by a coprecipitation method from diammonium phosphate and calcium nitrate solutions and shaped by slip-casting. Then, using the one-step microwave process, dense pellets with fine microstructures were successfully obtained in short sintering timespan. A parametric study permitted to determine the influence of powder grain size, sintering temperature and dwell time on the sintered samples microstructures. The Young's modulus (E) and hardness (H) were measured by nanoindentation and the values discussed according to the microstructure. Finally, the resulting mechanical properties determined on the microwave sintered samples (E = 148.5 GPa, H = 9.6 GPa, σcompression = 531.3 MPa and KIC = 1.12 MPa m1/2) are significantly higher than those usually reported in the literature, whatever the sintering process, and could allow the use of HA for structural applications.

Nanosilica supported CaO: A regenerable and mechanically hard CO2 sorbent at Ca-looping conditions

This work presents a CO2 sorbent that may be synthesized from low-cost and widely available materials following a simple method basically consisting of impregnation of a nanostructured silica support with a saturated solution of calcium nitrate. In a first impregnation stage, the use of a stoichiometric CaO/SiO2 ratio serves to produce a calcium silicate matrix after calcination. This calcium silicate matrix acts as a thermally stable and mechanically hard support for CaO deposited on it by further impregnation. The CaO-impregnated sorbent exhibits a stable CaO conversion at Ca-looping conditions whose value depends on the CaO wt% deposited on the calcium silicate matrix, which can be increased by successive reimpregnations. A 10wt% CaO impregnated sorbent reaches a stable conversion above 0.6 whereas the stable conversion of a 30wt% CaO impregnated sorbent is around 0.3, which is much larger than the residual conversion of CaO derived from natural limestone (between 0.07 and 0.08). Moreover, particle size distribution measurements of samples predispersed in a liquid and subjected to high energy ultrasonic waves indicate that the CaO-impregnated sorbent has a relatively high mechanical strength as compared to limestone derived CaO.

Morphological Changes and Function of Calcium Oxalate Crystals in Eddo Roots in Hydroponic Solution Containing Calcium at Various Concentrations

Morphological changes and function of calcium oxalate crystals in eddo roots in hydroponic solution containing calcium at various concentrations were investigated. Bundles of needle-shaped crystals in crystal idioblasts were tubularly arranged in the peripheral part of cortex in the apical zone of primary roots. Under scanning electron microscopy and optical microscopy, crystals in the idioblasts of roots cultured in 1 mM calcium nitrate solution were larger than those in 0 mM calcium solution but smaller than those in the solutions containing either 15 mM calcium nitrate or 15 mM calcium chloride. The number and area of crystal bundles in the sections of the apical zone in 1 mM calcium nitrate solution were significantly larger than those in 0 mM calcium solution and smaller than those in the solutions containing 15 mM calcium. The calcium mapping image obtained by energy dispersive X-ray spectrometry showed that the amount of calcium in crystal idioblasts was increased with increasing calcium concentration in the solutions. However, the weight percentage of calcium per cortex parenchyma cell in root apical zone did not vary significantly with the concentration of calcium in the solutions. In the root zone apart from the root apex having no crystals, the weight percentage of calcium per cortex parenchyma cell in the solutions containing 15 mM calcium was significantly higher than that in either 0 mM calcium or 1 mM calcium nitrate solution. These results suggested that the crystals in the tubular arrangement participated in the regulation of calcium levels in the apical zone of primary roots.

Modification of One-Dimensional TiO2Nanotubes with CaO Dopants for High CO2Adsorption

One-dimensional calcium oxide (CaO-) based titanium dioxide (TiO2) nanotubes were successfully synthesized through a rapid electrochemical anodization and chemical wet impregnation techniques. In this study, calcium nitrate solution was used as a calcium source precursor. The reaction time and concentration of calcium source on the formation of CaO-TiO2nanotubes were investigated using field emission microscopy, energy dispersion X-ray spectroscopy, and X-ray diffraction. The adsorption capacity of CO2was determined by thermal gravimetric analyzer. A maximum of 4.45 mmol/g was achieved from the CaO-TiO2nanotubes (6.64 at% of Ca). The finding was attributed to the higher active surface area for CaO to adsorb more CO2gas and then formed CaCO3compound during cyclic carbonation-calcination reaction.

Influence of various sources of nitrogen on the growth of Scots pine seedlings and the IAA content in needles

One year old pine seedlings transferred from the nursery and potted in a greenhouse were watered with nitrogen solutions of different form and concentration (urea 0.36 mM and 0.90 mM, ammonium tartrate 0.36 mM and 1.79 mM, calcium nitrate 0.36 mM, 1.79 mM and 3.58 mM). After 10 months the growth and IAA content in needles were compared. Nitrogen fertilization affected shoot growth considerably, but its effects on root growth were less pronounced. The highest shoot weight was obtained after application of ammonium tartrate in 1.79 mM concentration. The lowest concentration of urea (0.36 mM) caused the same effect, as did the most concentrated calcium nitrate solution (3.58 mM). Auxine content increased in the needles after nitrogen fertilization as compared with control. The highest accumulation of IAA was found in seedlings treated with low concentrations of urea.

Investigation of Bio-Mimetic Synthesis SH/KGM/HAP Scaffold

Sodium hyaluronate / konjac glucomannan (SH/KGM) porous scaffolds were prepared via blending sodium hyaluronate and konjac glucomannan. The ammonia was used as cross-linker in blending process. The SH/KGM scaffolds were soaked into calcium nitrate solution and then followed by immersing into simulated body fluid to get SH/KGM/HAP porous scaffolds. X-ray diffraction and fourier transform infrared spectroscopy (FTIR) were used to characterize the crystallization and chemical structure of SH/KGM and SH/KGM/HAP scaffold materials. The scanning electron microscope (SEM) was used to analysis the morphology of SH/KGM/HAP scaffold and BMSCs on surface of the scaffold. The results show that hydroxyl-apatite produced on the surface of the SH/KGM, which appears as spherical particles in the SH/KGM/HAP scaffold surface, and the SH/KGM/HAP porous scaffold possesses good biocompatibility with cell.

Processing and properties of biphasic calcium phosphates bioceramics obtained by pressureless sintering and hot isostatic pressing

Abstract Calcium phosphate powders were obtained from coprecipitation method using diammonium phosphate and calcium nitrate solutions. The adjustment of experimental parameters and Ca/P initial ratio allowed synthesizing stoichiometric HA and β-TCP powders and four biphasic calcium phosphates (BCP) with compositions equal to 20/80, 40/60, 60/40, 80/20, of HA and TCP respective in mass. Two sintering techniques, pressureless sintering and hot isostatic pressing (HIP) were performed to compare the sinterability of the stoichiometric and biphasic compounds. By pressureless sintering, densities higher than 98% were obtained. Results illustrate the negative impact of hydroxyapatite on the densification of BCP but its benefit effect on grain growth inhibition. After HIP treatment, transparent ceramics were obtained. The mechanical behavior of these fully densified compounds was examined in order to determine the role of the chemical composition on mechanical properties.

Processing and properties of calcium phosphates bioceramics by hot isostatic pressing

Stoichiometric β-tricalcium phosphate (β-TCP), hydroxyapatite (HA) and biphasic calcium phosphate (TCP/HA 60/40 %wt, BCP40) powders were synthesized by chemical precipitation of aqueous solutions of diammonium phosphate and calcium nitrate. After a calcination treatment and a milling step, powders were shaped by slip-casting. The sintering temperature effect on the density and the average grain size was investigated. By natural sintering, densities between 98 and 99.8% were obtained. Hot Isostatic Pressing (HIP) treatment was carried out after a pre-sintering of these materials. Transparent or translucent samples were obtained, indicating a relative density very close to the theoretical value (>99.9%). Mechanical properties (three-point bending strength, fracture toughness, Young's modulus and Vickers hardness) were measured on hipped materials with similar grain size (∼0.7μm).

The accumulation of nitrogen, phosphorus and potassium in cut chrysanthemum (Dendranthema grandiflorum) cv. Jospithoven

The objective of this study was to evaluate the accumulation of NPK in cut chrysanthemum, cv. Jospithoven, at different phenologic phases, in the summer. The experiment was carried out in greenhouse environment, in Goias State, Brazil. The population density was 80 seedlings m-2. The experimental design was completely randomized, with plots split in time, and four replications. The plant portion factor (stem, leaf, inflorescence and whole plant) was applied to plots, and the development phases (45, 60, 75, 90, 105, and 120 days) applied to sub-plots. The plant nutrition was 133 g m-2 of thermophosphate Yoorin and 150 g m-2 of fertilizer formula 5-25-15, which was added to the circulating nutritive solution of calcium nitrate (20 g m-2), during all the evaluated period, alternated with potassium sulfate (30 g m-2) and potassium nitrate (30 g m-2), each fifteen days. It was concluded that NPK demand by chrysanthemum var. Jospithoven, during the growing cycle, ranges according to the plant age and the organ studied, having been more accentuatedin the leaves and 105 days after sowing.

Extraction Studies of Phosphoric Acid Tributyl Ester from Nitric Acid Solutions Using Dodecane in the Presence of Inextractable Metal Nitrates

Sodium nitrate and calcium nitrate are not extracted by phosphoric acid tributyl ester (TBP) in the plutonium uranium extraction (PUREX) process. The effect of these inextractable metal nitrates on the solubility and distribution data of TBP has been studied. The solubility of TBP in water in the presence of different concentrations of sodium nitrate is determined, and salting coefficient of TBP is calculated. It has been observed that the solubility of TBP in nitric acid decreases in the presence of both inextractable nitrates, that is, sodium nitrate and calcium nitrate. The effect of inextractable metal nitrates on the equilibrium data for the TBP–dodecane–nitric acid system has been studied. The distribution coefficient value of TBP is greater in the presence of sodium nitrate solutions as compared with calcium nitrate solutions due to more salting out of TBP. Because sodium nitrate is a better salting agent than calcium nitrate, the variation in the concentration of nitric acid at equilibrium was more in sodium nitrate solutions in comparison with that in calcium nitrate solutions. The data obtained will be useful in separating dissolved TBP from acidic waste for safe disposal of nuclear waste.

Novel Preparation and Characterization of Calcium-Strontium Hydroxyapatite

Calcium-strontium hydroxyapatite [Ca5-xSrx(PO4)3OH, Ca-SrHA] were prepared by a novel coprecipitation process. The homogeneous aqueous solution of calcium nitrate, strontium nitrate and phosphoric acid was used as starting material, and ammonia was used as precipitator. A series of Ca-SrHA samples had been synthesized by adding ammonia into the precursor solution to pH10 and following aging at 60°C for 18h. The samples were characterized by X-ray diffraction, Fourier transformed infrared spectroscopy and scanning electron microscopy. The results show that so-prepared samples present essential characteristics of Ca-SrHA. All samples have a short rod-like morphology. The cell parameters of Ca5-xSrx(PO4)3OH are linear to the value of x, and the infrared absorption bands of PO43- groups shift to lower wave numbers with the increase of x.

Novel low temperature processing techniques for apatite ceramics and chitosan polymer composite bulk materials and its mechanical properties

A co-precipitation method was used for processing chitosan (CHI)/calcium hydrogen phosphate dehydrate (DCPD) hybrid material. CHI solution was mixed into 1.0-M calcium nitrate solution. CHI/DCPD hybrid material was prepared by the above explained addition of CHI and Ca ion source to 1.0-M diammonium hydrogen phosphate solution. It was observed by transmission electron microscopy that CHI and DCPD were mixed within submicron meter scale. CHI/HA bulk materials derived from the CHI/DCPD hybrid materials were obtained by using a hydrothermal hot-pressing (HHP) method. A pressure of 40MPa was initially applied to the sample. An HHP autoclave was heated up to 150°C for 2h. Modified 3-point bending tests were conducted to obtain an easy estimate of the fracture toughness for the CHI/HA bulk materials made with the HHP method. The critical stress intensity factor Kc of the fabricated CHI/HA bulk materials was enhanced from 0.30 to 0.40MPam1/2 by the hybridization of CHI into DCPD.

Processing and properties of transparent hydroxyapatite and β tricalcium phosphate obtained by HIP process

Stoichiometric β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) powders were synthesized by chemical precipitation of aqueous solutions of diammonium phosphate and calcium nitrate. After a calcination treatment and a milling step, the powders were shaped by slip casting. The sintering temperature effect on the relative density and the average grain size was investigated. By natural sintering at 1200 and 1120°C, densities of 98% and 99% were obtained for HA and TCP, respectively. After determination of minimum temperatures to obtain only closed porosity and a pre-sintering at these temperatures, hot isostatic pressing (HIP) treatment was carried out. Transparent or translucent samples were obtained, indicating a relative density very close to the theoretical value (>99.9%). Mechanical properties (three-point bending strength, fracture toughness, Young's modulus and Vickers hardness) were measured on both materials with similar grain size (∼ 1μm). Bending strengths of 181 and 105MPa were measured for TCP and HA, respectively.

Preparation and properties of TiCxN1 − x coatings containing calcium on titanium surface by plasma electrolytic carbonitriding

The TiCxN1−x coatings containing calcium (Ca–TiCxN1−x) were prepared on the surface of titanium through plasma electrolytic carbonitriding (PEC/N) technique in a certain concentration of electrolyte solution of triethanolamine, urea and calcium nitrate. The effects of parameters, such as discharge time, on the Ca–TiCxN1−x coatings were investigated, and the phase composition, morphologies, surface chemical components, anticorrosion and hardness were also examined, respectively. The results show that the plasma discharge time significantly affects the microstructure and composition of the coatings. In addition, introduction of the Ca–TiCxN1−x coatings into the Ti surface can clearly improve the wear resistance and anticorrosion. Moreover, MTT assay demonstrates that the Ca–TiCxN1−x coatings can improve the cell viability, showing excellent cytocompatibility.

Biodiesel production from waste cooking palm oil using calcium oxide supported on activated carbon as catalyst in a fixed bed reactor

A reactor has been developed to produce high quality fatty acid methyl esters (FAME) from waste cooking palm oil (WCO). Continuous transesterification of free fatty acids (FFA) from acidified oil with methanol was carried out using a calcium oxide supported on activated carbon (CaO/AC) as a heterogeneous solid-base catalyst. CaO/AC was prepared according to the conventional incipient-wetness impregnation of aqueous solutions of calcium nitrate (Ca(NO3)2·4H2O) precursors on an activated carbon support from palm shell in a fixed bed reactor with an external diameter of 60 mm and a height of 345 mm. Methanol/oil molar ratio, feed flow rate, catalyst bed height and reaction temperature were evaluated to obtain optimum reaction conditions. The results showed that the FFA conversion increased with increases in alcohol/oil molar ratio, catalyst bed height and temperature, whereas decreased with flow rate and initial water content in feedstock increase. The yield of FAME achieved 94% at the reaction temperature 60 °C, methanol/oil molar ratio of 25: 1 and residence time of 8 h. The physical and chemical properties of the produced methyl ester were determined and compared with the standard specifications. The characteristics of the product under the optimum condition were within the ASTM standard. High quality waste cooking palm oil methyl ester was produced by combination of heterogeneous alkali transesterification and separation processes in a fixed bed reactor. In sum, activated carbon shows potential for transesterification of FFA.

Purification of potassium nitrate solutions by coprecipitation of impurities on hydrated aluminum oxide

Coprecipitation of 3d-element impurities from solutions of calcium nitrate with hydrated aluminum oxide (collector) was studied using radioactive tracers. The structure of the collector was studied by 1H NMR and IR spectroscopy.