Sodium Carbonate Solution Research Articles

Adsorption kinetics and equilibrium performance of Di-n-butyl phosphate on XAD-4 and XAD-7 from alkaline medium

ABSTRACT The present study investigates the feasibility of adsorption method for the removal of Di-n-butyl phosphate from sodium carbonate solution on adsorbents such as XAD-4 and XAD-7. The fundamental aspects of equilibrium and kinetics of adsorption have been studied. The experimental equilibrium data were fitted well with Sips isotherm, and maximum solid uptake capacity for monolayer coverage (qm) was found to be 0.363 × 10−3 mol/g and 0.385 × 10−3 mol/g for XAD-4 and XAD-7, respectively. The adsorption kinetics was well described by the pseudo-first-order model, and estimated first-order rate constant values were found to be 0.041 min−1 for XAD-4 and 0.027 min−1 for XAD-7. The transport mechanism of solute from the bulk solution to adsorbent was described in detail with suitable mathematical model, and experimental kinetic data were superimposed on numerically solved concentration profiles to calculate external mass transfer coefficient (kf) and effective diffusivity (De). The values of kf and De were estimated as 4.632 × 10−7 m/s and 8.849 × 10−13 m2/s, respectively, for XAD-4, whereas for XAD-7, the values were found to be 2.132 × 10−6 m/s and 1.389 × 10−12 m2/s. XAD-7 is found to have slightly better adsorption capacity and transport characteristics than XAD-4.

Emergence of Power-Law Particle Size Distribution in Microfluidic Calcium Carbonate Precipitation: An Extended Yule Process with a Ripening Effect.

Precipitation of calcium carbonate in bulk solutions is well known to result in a bell-shaped or bimodal particle size distribution. However, it is unclear how the distribution behaves if precipitation occurs in a small, confined volume. In this Letter, we conduct microfluidic experiments where sodium carbonate and calcium chloride solutions are continuously injected into a microchannel to precipitate calcium carbonate particles. Results show that, regardless of the variations in reagent concentrations, mixing schemes, flow rates, and precipitation time, sizes of precipitated particles in the channel are power law distributed, with an exponent of 1.4. The data are described by an extended Yule process with the introduction of a ripening term. Since the Yule process is a general mechanism for power law generation, the extended Yule process proposed here provides a general model for systems where growth and ripening simultaneously present.

An inorganic hydrophobic layer connected by rivets endows the bamboo with high fire retardant, mechanical, and mold-proof properties

This study investigated the mineralization process of calcium carbonate on bamboo surfaces using aqueous solutions of calcium propionate and sodium carbonate as precursors. The mineralization process was carried out once, three times, and five times, and its effects on fire-retardant, mechanical, and mold-proof properties were examined. Scanning electron microscopy revealed that calcium carbonate bonded with bamboo cells through a rivet structure, resulting in a pronounced roughness of the mineralized layer. Mineralized bamboo exhibited improved fire-retardant properties, with decreases of the maximum heat release rate and total heat release rate by 20–32 % and 8–13 %, respectively. Additionally, mineralized bamboo displayed enhanced mechanical properties, increase of modulus of elasticity (MOE) and modulus of rupture (MOR) by 1–3 % and 3–10 %, respectively. After five cycles of deposition, the initial contact angle of the mineralized bamboo became 159°, and the infestation value of Aspergillus niger mold was almost zero, indicating satisfactory hydrophobicity and mold-proof properties. Mineralization of bamboo surfaces with calcium carbonate substantially improved the properties of bamboo and extended its application in various fields.

Study on phase transformation and reaction behavior of alumina extraction process by calcification of aluminum dross

The aluminum dross generated during the aluminum alloy processing and regeneration process contains a large amount of harmful highly reactive aluminum nitride and salts, which can cause environmental pollution. A novel method for preparing calcium aluminate by dry calcification of aluminum dross is proposed in this paper to extract valuable aluminum resources while achieving efficient detoxification. Detection methods such as XRD, XRF, and standard dissolution procedures have been applied to characterize the phase transition and reaction behavior of the aluminum extraction process. The results indicate that calcium additives can react with aluminum components in aluminum dross to generate 12CaO·7Al2O3 (C12A7), which is soluble in sodium carbonate solution, thereby separating it from other impurities. Under the optimal roasting conditions, the leaching rate of alumina is 87.89%, and the removal rate of nitrogen, chlorine, and soluble fluorine elements exceeds 99%.Excessive sodium carbonate is required to ensure that the hydrolysis product of C12A7 is calcium carbonate, avoiding the formation of hydrated calcium aluminate precipitates. The optimal leaching conditions are sodium carbonate concentration of 80 g L−1, caustic soda concentration of 5 g L−1, liquid-solid ratio of 8 mL g−1, and leaching time of 30 min. The leaching reaction of calcium aluminate conforms to the unreacted core model controlled by internal diffusion, and the apparent activation energy of the reaction is 18.05 kJ mol−1.

Properties of cell wall polysaccharides of raw nectarine fruits after treatment under conditions that modulate gastric digestion

The results of the study of the physicochemical properties of the high-molecular-weight soluble and insoluble components of nectarine cell walls obtained by fruit treatment under conditions that modulate of gastric digestion are presented. Homogenized nectarine fruits were sequentially treated by natural saliva and simulated gastric fluid (SGF) at pH 1.8 and 3.0. The isolated polysaccharides were compared with polysaccharides obtained by sequential extraction of nectarine fruit with cold, hot, and acidified water, solutions of ammonium oxalate and sodium carbonate. As a result, high-molecular-weight water-soluble pectic polysaccharides, weakly bound in the cell wall, were dissolved in the simulated gastric fluid, regardless of pH. Homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) were identified in all pectins. It was shown that their quantity and ability to form highly viscous solutions determine high values of the rheological characteristics of the nectarine mixture formed under simulated gastric conditions. The modifications occurring with the insoluble components under the influence of acidity of SGF were importance. They determined difference in the physicochemical properties of both the insoluble fibres and the nectarine mixtures.

To the question of application of new physical and chemical geotechnologies in the development of uranium ore deposits

Background. Underground uranium leaching is a promising geotechnological process due to its potential to provide for a radical increase in the technical and economic efficiency, as well as environmental safety, of uranium deposit development. In this article, we discuss the main results in this direction obtained by specialists of the Russian State University for Geological Prospecting.Aim. To study the processes of uranium leaching by activated solutions, which undergo electrophotochemical treatment prior to contacting with the ore.Materials and methods. Activation preparation of leaching solutions enables the synthesis of active hydrated forms of oxygen and hydrogen with collectivized protons and hydroxyl ions clustered by water molecules. Following the stage of pre-oxidation with an active carbonate solution, a model downhole leaching with chloride-hypochlorite, soda, and sulfuric acid solutions was carried out. Testing percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits by activated solutions was conducted at laboratory installations designed by the the Russian State University for Geological Prospecting jointly with the Institute of Mining of Far-East Branch of the Russian Academy of Sciences and Zabaikalsky State University. As a result, the potential of a significant increase in uranium extraction was noted.Results. When leaching with sodium carbonate and ammonium carbonate solutions, the uranium extraction from ore samples from the Sugraly deposit comprised 52% and 59%, respectively. At the same time, the use of an activated solution of sodium percarbonate, which combines the functions of an oxidizing agent and a complexing agent, resulted in an 87–88% uranium extraction into productive solutions during 21 days without preliminary pre-oxidation.Conclusion. The results obtained confirm the prospects of using mine (block) and downhole uranium leaching with activated solutions.

UV-Spectrophotometric Determination of the Active Pharmaceutical Ingredients Meloxicam and Nimesulide in Cleaning Validation Samples with Sodium Carbonate

The spectrophotometric methods of determination of the active pharmaceutical ingredients meloxicam and nimesulide were reviewed and a simple UV-spectrophotometric method for the determination of these active pharmaceutical ingredients in industrial equipment cleaning validation samples was proposed. The methods were based on extraction of the residual quantities of meloxicam and nimesulide from the manufacturing equipment surface by the concentrated sodium carbonate solution and the subsequent UV-spectrophotometric determination of the basic forms of the drugs at the wavelength of 362 nm for meloxicam and at 397 nm for nimesulide. The calibration graphs were linear in the range from 5 to 25 mg/L of both nimesulide and meloxicam, the molar attenuation coefficients were 6100 m2/mol for nimesulide and 9100 m2/mol for meloxicam, the limit of detection was 0.8 mg/L for nimesulide and 1.9 mg/L for meloxicam and the limit of quantification was 2.5 mg/L for nimesulide and 5.8 mg/L for meloxicam. The methods were selective with respect to the common excipients, showed a good accuracy (the relative uncertainty did not exceed 7%) and precision (the relative standard deviation did not exceed 4%), did not require lengthy sample preparation or sophisticated laboratory equipment and were suitable for the routine analysis of cleaning validation samples.

Получение концентрата иттрия из коллективного концентрата редкоземельных элементов в карбонатных средах

The paper presents the results of a study of the extraction of rare earth elements of their collective carbonate concentrate in aqueous solutions of sodium carbonate under various conditions. The possibility of selective extraction of yttrium and heavy group lanthanides with the production of 70% rough yttrium concentrate is shown.

Recovery of Aconitic Acid from Sweet Sorghum Plant Extract Using a Solvent Mixture, and Its Potential Use as a Nematicide

Trans-aconitic acid (TAA) is naturally present in sweet sorghum juice and syrup, and it has been promoted as a potential biocontrol agent for nematodes. Therefore, we developed a process for the extraction of aconitic acid from sweet sorghum syrup. The process economics were evaluated, and the extract was tested for its capability to suppress the motility of the nematodes Caenorhabditis elegans and Meloidogyne incognita. Aconitic acid could be efficiently extracted from sweet sorghum syrup using acetone:butanol:ethanol mixtures, and it could be recovered from this solvent with a sodium carbonate solution, with an overall extraction and recovery efficiency of 86%. The estimated production cost was USD 16.64/kg of extract and this was highly dependent on the solvent cost, as the solvent was not recycled but was resold for recovery at a fraction of the cost. The extract was effective in reducing the motility of the parasitic M. incognita and causing over 78% mortality of the nematode when 2 mg/mL of TAA extract was added. However, this positive result could not conclusively be linked solely to TAA. An unidentified component (or components) in the acetone:butanol:ethanol sweet sorghum extract appears to be an effective nematode inhibitor, and it may merit further investigation. The impact of aconitic acid on C. elegans appeared to be entirely controlled by pH.

Isoelectric point isolation and characterization of proteins from lupine cultivars as influenced by chemical and thermal treatments

Pulses provide a significant nutritional potential for the large proportion of the population in developing countries. Lupine is among the underutilized legume crops for human food in Ethiopia and globally concomitant to its contents of bitter alkaloids. This research was initiated to investigate the effects of soaking lupine seeds of bitter and sweet varieties in water and 2% sodium carbonate (Na2CO3) solutions as grain softener on the protein extraction efficiency and its sensory acceptability. It was hypothesized that the soaking treatment results in the removal of characteristic bitterness when coupled with thermal treatment (roasting). The result showed that soaking in Na2CO3 significantly increased the protein extraction efficiency (both protein yield and quality (purity)) in the two lupine cultivars. The roasting treatment did not help much. The bitter variety of lupine soaked in Na2CO3 with no roasting treatment gave the highest protein yield (39.45%), while the sweet variety soaked in water followed by roasting exhibited the least protein yield (23.25%). The purity of the protein isolates from the lupine samples soaked in 2% Na2CO3 followed by roasting was the highest (92.29%). The non-soaked samples of the sweet variety after roasting resulted in the lowest purity (75.05%). The water holding, and oil absorption capacity, as well as the emulsification activity and foaming capacity of the protein isolates were significantly varied for the lupine varieties, and by the soaking and roasting treatments. Higher (314.38%) WHC was recorded for the protein isolates from sweet variety soaked in Na2CO3, where the bitter variety, when soaked in 2% Na2CO3 without roasting gave protein isolates of higher emulsion and foaming capacities. The research revealed also that soaking of lupine seeds in grain softeners shows a great potential as a pretreatment for enhanced protein extraction and functional desirability (in terms of emulsion and foaming capacities) as well as sensory acceptability and can be recommended for scaling up at industrial level.

Viability of melon seeds using the pH testing of exudate

Abstract: Melon is one of the most consumed cucurbits and commercially significant cucurbits in the world. It is planted predominantly through seedlings, and seed quality is essential in this process. Among the rapid tests used in seed analysis, the pH testing of exudate has shown promise for several cultivated species. Thus, this study aimed to verify the viability of melon (Cucumis melo L.) seeds through the pH testing of exudate. For this, seeds of the hybrids Premier and Supreme (three lots each) were subjected to germination and vigor tests (first germination count, tetrazolium, accelerated aging, emergence speed index, and emergence). The pH testing of exudate was evaluated using phenolphthalein and sodium carbonate solutions. The results indicated the possibility of classifying the lots into three quality levels for both hybrids, similar to most tests used to assess initial quality. Therefore, the pH testing of exudate was effective in determining the viability of lots of melon seeds and can be conducted with a soaking period of 120 minutes at 25 or 30 °C.

Mass Transfer from a Drop in Fall into the Fluid Thickness

High-speed videorecording is used to trace the fine structure evolution in the case of freely falling drop matter propagation beneath the deformed surface of a fluid, initially at rest. The coalescence of a water drop with ammonium rhodanide solution and drops of sodium chloride solution, sodium carbonate, and ink with water is studied. In the initial stage of the coalescence process occurring in the impact regime with rapid cavity formation the drop loses the continuity. Short thin jetlets penetrating the cavity bottom are visualized for the first time. The earlier-observed drop disintegration into thin fibers that form linear or reticular structures on the cavity and crown surfaces is confirmed.The jetlets that contain the drop matter merge gradually and form an intermediate fibrous layer embracing the cavity; this layer possesses a well-defined outer boundary. As the cavity enlarges, the intermediate layer homogenizes and becomes thinner. Further on, in the process of cavity collapse new fiber groups are formed in the target fluid; they penetrate the cavity boundary beneath the grid nodes. In the experiments performed the fibrous layer embracing the primary cavity was observable, when a fluid of greater density (ink, sodium carbonate, or sodium chloride solution drops) intruded into a less dense medium (water) or when a fluid of smaller density (water droplets) was introducedinto a heavier fluid (ammonium rhodanide solution). The fibrous shell of the primary cavity becomes thicker with increase in the drop velocity.

Synthesis of NiFe layered double hydroxides with varied layer charge densities: the templating effect of dioctyl sulfosuccinate.

NiFe layered double hydroxides (LDHs) intercalated with dioctyl sulfosuccinate with varied Fe3+/(Ni2+ + Fe3+) ratios (0.04-0.25) were prepared by constant-pH co-precipitation from an aqueous solution of Ni and Fe perchlorates at room temperature. The interlayer dioctyl sulfosuccinate was exchanged with carbonate by the reaction of the product with an aqueous solution of sodium carbonate. The basal spacing of the NiFe-LDHs containing carbonate varied (0.80-0.90 nm) depending on the Fe3+/(Ni2+ + Fe3+) ratio; larger basal spacing was attained from the LDH with smaller Fe3+/(Ni2+ + Fe3+) due to the weaker attractive force between the LDH layer and the interlayer anion, proving that the Fe3+/(Ni2+ + Fe3+) ratios were associated with the layer charge density of NiFe-LDHs.

Carbon Capture From Coal Power Plants And Algae Farming With Technical-Economic Analysis

CO2 is a major cause of global warming, one of the world's most critical environmental problems and responsible for about 55% of global warming. According to research, the quantity of CO2 in the atmosphere corresponds well with the growth in the average global temperature of the planet's surface. The main aim of this work is to investigate different emerging Technologies for the carbon capture from power plants and its atmosphere. After capturing of CO2, it is used for the injecting in raceway ponds for micro algae cultivation. Mathematical and experimental analysis for the carbon capture and Sequestration from the coal power plant have been performed in the RKDF University and proposed the microalgae production using captured CO2. For that total 24 experiments were performed to get the efficiency of the CCS plant. The result shows that Input of 250 kg/ hr of flue gasses has been used to capture the CO2. Sodium Carbonate solution of 10% will be sprinkled on top of the packing in tower-A to increase the contact area. The gases are now subject to the counter-current of MEA solution of 30% contained with 1 kg of CO2. MEA - CO2 mixture is heated up to 155°C with the help of a Scheffler dish collector. CO2 gas released from the MEA - CO2 mixture when heated above 130°, the maximum efficiency of the CCS plant of 87.58 % on 04 Jan 2021 at 1200 Noon.

Degradable MXene-Doped Polylactic Acid Textiles for Wearable Biomonitoring.

Degradable wearable electronics offer a promising route to construct sustainable cities and reduced carbon society. However, the difficult functionalization and the poor stability of degradable sensitive materials dramatically restrict their application in personalized healthcare assessment. Herein, we developed a scalable, low-cost, and porosity degradable MXene-polylactic acid textile (DMPT) for on-body biomonitoring via electrospinning. A combination of polydimethylsiloxane templating and MXene flake impregnation methods endows the fabricated DMPT with a sensitivity of 5.37/kPa, a fast response time of 98 ms, and a good mechanical stability (over 6000 cycles). An efficient degradation of as-electrospun DMPTs was observed in 1 wt % sodium carbonate solution. It is found that the incorporation of MXene nanosheets boosts the hydrophilicity and degradation efficiency of active polylactic acid nanofibrous films in comparison with the pristine counterpart. Furthermore, the as-received DMPT demonstrates great capability in monitoring physiological activities of wrist pulse, knuckle bending, swallowing, and vocalization. This work opens up a new paradigm for developing and optimizing high-performance degradable on-body electronics.

The Development and Evaluation of Phase Transition Microemulsion for Ocular Delivery of Acetazolamide for Glaucoma Treatment

The aim of this study was to develop microemulsion (ME) formulation with possible phase transition into liquid crystals upon ocular application to enhance acetazolamide bioavailability. Pseudoternary phase diagrams were constructed using olive oil or castor oil (oily phase), Tween 80 (surfactant), and sodium carbonate solution (aqueous phase). Microemulsion and liquid crystal (LC) formulations were selected from the constructed phase diagrams and were evaluated for rheological properties and in vitro drug release. The efficacy of the developed formulations in reducing intraocular pressure (IOP) was assessed in vivo. In vitro release study showed slower release rate from LC and ME compared with drug solution with the release from LC being the slowest. Ocular application of acetazolamide ME formulations or aqueous solution resulted in significant reduction in IOP from baseline. The recorded Tmax values indicated faster onset of action for acetazolamide aqueous solution (1 h) compared with ME systems (3 h). However, the duration of action was prolonged and the reduction in IOP continued for up to 10 h in case of MEs, while that of aqueous solution was only for 4–5 h. The study suggested ME formulations for ocular delivery of acetazolamide with enhanced efficacy and prolonged duration of action.

In-situ leaching of molybdenum and uranium by percarbonate and chloride-hypochlorite solutions

In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.

Polysaccharides of Salsola passerina: Extraction, Structural Characterization and Antioxidant Activity.

The above-ground part of the Salsola passerine was found to contain ~13% (w/w) of polysaccharides extractable with water and aqueous solutions of ammonium oxalate and sodium carbonate. The fractions extracted with aqueous sodium carbonate solutions had the highest yield. The polysaccharides of majority fractions are characterized by similar monosaccharide composition; namely, galacturonic acid and arabinose residues are the principal components of their carbohydrate chains. The present study focused on the determination of antioxidant activity of the extracted polysaccharide fractions and elucidation of the structure of polysaccharides using nuclear magnetic resonance (NMR) spectroscopy. Homogalacturonan (HG), consisting of 1,4-linked residues of α-D-galactopyranosyluronic acid (GalpA), rhamnogalacturonan-I (RG-I), which contains a diglycosyl repeating unit with a strictly alternating sequence of 1,4-linked D-GalpA and 1,2-linked L-rhamnopyranose (Rhap) residues in the backbone, and arabinan, were identified as the structural units of the obtained polysaccharides. HMBC spectra showed that arabinan consisted of alternating regions formed by 3,5-substituted and 1,5-linked arabinofuranose residues, but there was no alternation of these residues in the arabinan structure. Polysaccharide fractions scavenged the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical at 0.2-1.8 mg/mL. The correlation analysis showed that the DPPH scavenging activity of polysaccharide fractions was associated with the content of phenolic compounds (PCs).

Effective Cu/ZnO/Al2O3 Catalyst for Methanol Production: Synthesis, Activation, Catalytic Performance, and Regeneration

A precursor CuO/ZnO/Al2O3 catalyst for methanol synthesis has been prepared at room temperature by introducing a ternary salt solution into the excess of sodium carbonate solution following the reverse co-precipitation method. The catalyst was tested for the synthesis of methanol from synthesis gas. The composition (vol. %) has been presented: CO, 22; CO2, 5.8; N2, 5.5; H2, balance. The methanol productivity was recorded to be 2.7 kg kgcat–1 h–1 at a temperature of 260 °С, a pressure of 3 MPa, and a space velocity of 61,700 l (kgcat)–1 h–1. The possibility of regenerating the activity of a catalyst subjected to conditions of artificial aging (overheating in a syngas environment) has been tested: approximately 92% of the initial activity could be restored. Physicochemical studies were conducted using the thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), the scanning electron microscopy (SEM), and the X-ray diffraction (XRD) techniques using the Cu, Zn, and Al oxides obtained following the co-precipitation method. X-ray studies revealed that an amorphous phase was obtained from the Al oxide that was synthesized following both the direct and reverse co-precipitation methods. The calcination temperature was 300 °C. Individual oxides of Cu and Zn obtained following the reverse co-precipitation method form crystalline phases when calcined at 300 °C. When all three ingredients are present, calcination of the sample at 300 °C helps obtain an X-ray amorphous structure of the catalyst characterized by a high specific surface area. High-temperature carbonates are formed from samples prepared using a ternary mixture of nitrate salts when these are calcined at 300 °C.

A freestanding dual-cross-linked membrane with robust anti-crude oil-fouling performance for highly efficient crude oil-in-water emulsion separation

Hydrogel membranes generally possess weak mechanical properties, and the membrane surface is susceptible to abrasion, which results in the loss of superwetting properties and oil/water separation ability. Therefore, we prepared a flexible freestanding membrane using a dual-cross-linking approach. A mixed solution of sodium alginate (SA) and polyvinyl alcohol (PVA) was covalently and ionically cross-linked with borax and calcium chloride (CaCl2) to form a hydrogel, and sodium carbonate (Na2CO3) solution was then added to synthesize calcium carbonate (CaCO3) in situ. The combination of covalent and ionic cross-linking improves the tensile strength. The prepared SA/PVA/borax/CaCO3 (SPBC) membrane maintained excellent superwetting properties and oil/water separation ability, even after abrasion. The SPBC membranes have broad application prospects in the oily wastewater purification owing to their numerous advantages, such as cost effectiveness, high separation efficiency, and improved mechanical strength.