Concentration Of Sodium Alginate Solution Research Articles

SO3 removal by submicron absorbents synthesized via inhibition method: The product layer grows like parallel peaks

Injecting calcium hydroxide powder into the flue gas is an effective strategy for SO3 removal. However, commercial calcium hydroxide has several disadvantages, including large particle size, low efficiency, and unsuitability for excessive grinding. In this work, sub-micron calcium hydroxide was synthesized by an inhibition method and its performance for SO3 removal from flue gas was investigated on a pilot-scale platform (120 Nm3/h). When the concentration of sodium alginate solution was 100 mg/L, the average particle size of calcium hydroxide decreased from 13.66 µm to 0.84 µm, which improved the SO3 removal (92.1 %) and conversion of the absorbent. The results of the fixed-bed experiments indicate that the absorption kinetics of the reaction is consistent with the Bangham model. In addition, density functional theory verifies that calcium hydroxide captures SO3 by chemisorption. The AFM image shows that the calcium sulfate whiskers produced during the reaction grow like parallel peaks on the adsorbent surface. The calculations suggest that the driving force for SO3 adsorption originates from Ca-p orbital (Ca(OH)2) and O-s orbital (SO3) hybridization. This study complements the island growth mechanism for gas-solid two-phase reactions and provides an effective method for removing SO3 from flue gas in coal-fired power plants. In addition, it will provide an important reference for the development of submicron adsorbents.

Encapsulation of Pomelo Peel Essential oil (Citrus maxima) Using the Alginate/Chitosan complex

Objective: This study aimed to determine appropriate parameters for encapsulating pomelo peel essential oil (Citrus maxima) using the alginate/chitosan complex. Methods: The investigated parameters included the concentration of sodium alginate solution (2 ‒ 3.5% w/v based on the volume of mixture), the concentration of pomelo essential oil (20 ‒ 40% w/w based on dry matter of wall marerials), the concentration of Tween 80 (0 ‒ 20% w/w based on dry matter of wall marerials), the concentration of CaCl2 solution (0.5 ‒ 3.5% w/v based on the volume of mixture), time (10 min – 20 min) and speed of emulsion homogenization (489-4402 × g), the concentration of chitosan solution (0.5 ‒ 2% w/v based on the volume of mixture), and pH of chitosan solution (4 ‒ 6). Results: The results showed encapsulation yield (EY%) and encapsulation efficiency (EE%) of 91.64% and 85.18%, respectively, when using the concentration of sodium alginate solution as 3% (w/v based on the volume of mixture), the concentration of essential oil as 30% (w/w based on dry matter of wall marerials), the concentration of Tween 80 as 15% (w/w based on dry matter of wall marerials), the concentration of CaCl2 solution as 1.5% (w/v based on the volume of mixture), homogenization time as 10 min and homogenization speed as 4402 × g, the concentration of chitosan as 2% (w/v based on the volume of mixture) and pH of Chitosan solution as 5. Conclusion: The alginate/chitosan complex was proven effective in encapsulating pomelo essential oil (Citrus maxima) on a laboratory scale. The resulting encapsulated particles had a relatively uniform size and a high ability to retain essential oils in the core of the particles. Further studies should be conducted to elucidate the mechanism of the encapsulation process and to additionally evaluate the physical and chemical properties of the encapsulated particles.

Encapsulation of Extract from Unused Chokeberries by Spray Drying, Co-crystallization, and Ionic Gelation

The objective of this work is to optimize a new method of unused chokeberries application in food industries, based on the encapsulation by spray drying, co-crystallization, and ionic gelation of their phenolic extract. For each method, the effects of various parameters on efficiency and yield were studied and the optimum operating conditions were predicted. In the spray drying method, the optimum values of encapsulation efficiency (99.6%) and yield (31.9%) were achieved with a ratio of wall to core of 9.0, an air temperature of 190 °C, an air rate of 19.25 m3/h, and maltodextrin:skim milk powder (50:50) as encapsulating agent. The optimum efficiency of co-crystallization (96.3%) was achieved with a solids concentration of extract of 35 oBrix and a ratio of dry extract to sucrose of 0.7. In the ionic gelation, the optimum conditions (efficiency of 94.2%) were: concentration of sodium alginate solution of 2.0% w/w, concentration of calcium chloride solution of 2.5% w/v, and concentration of extract of 20.0% w/w. Powders encapsulated at the optimum conditions were analyzed for moisture content, bulk density, wetting time, hygroscopicity, color, sorption isotherm, release kinetics, and morphology. Furthermore, the antioxidant capacity and stability of the extracts were evaluated during storage.

Slope Stability Evaluation of Reservoir Considering Soil-water Characteristic Curve of the Reinforced Ground Including Alginic Acid Sodium Salt

Alginic acid sodium salt is a type of biopolymer. It is a polysaccharide obtained from the most widely distributed brown algae among marine plants. Its main characteristics are nontoxicity and biodegradability. It is also considered a natural eco-friendly material because it is completely decomposed by microorganisms using only water and carbon dioxide. Moreover, sodium alginate aqueous solution mixed with water has high viscosity; hence, it is expected to effectively saturate and reinforce the soil. The soil-water characteristic curve shows the properties of the capillary pressure according to the water content of the soil. In other words, this curve can predict the shear strength of the soil. In this study, soil-water characteristic curves of soil reinforced with sodium alginate were studied. The stability of the reservoir slope reinforced with sodium alginate was evaluated using the input values of the numerical analysis, and the change in the shear strength of the soil was calculated. The results show that the increased concentration of sodium alginate solution increased the capillary pressure and residual water content of the soil-water characteristic curve, which increased the stability of the reservoir slope. The shear strength of the soil increased as the concentration and capillary pressure of the sodium alginate solution increased.

An investigation of operational parameters of jet cutting method on the size of Ca‐alginate beads

AbstractA rarely used option for reduction the size of Ca‐alginate beads is the jet cutter, a rotating disk coupled to the output of the nozzle, and responsible for cutting the jet in smaller sizes. There are few systematic studies in the literature about this apparatus and its operational effects on the bead size. Therefore, this work aimed to investigate some operational parameters on the size of Ca‐alginate beads produced by dripping and jet cutting methods. First, physicochemical properties of different concentrations of sodium alginate solutions were determined, and the viscosity of 0.92 Pa s, corresponding to 2% (wt/wt), was found to be optimum for bead formation. For the dripping process, the highest flow rate of the alginate solution (49 mL/min) caused a limited reduction of bead size to 2 mm. This study on drop formation demonstrated that models developed for size prediction cannot be used as a tool for determination of size, due to the possible influences of the viscous forces. The jet cutter, adapted to a continuous jet regime, allowed to reduce from 5.2 mm to less than 1 mm in size with the increase of the rotation speed from 200 to 900 rpm. However, this increase resulted in higher tangential velocity of the beads, requiring larger collect recipients. This study developed the basis for broadening the application of the jet cutter to different biopolymers and ensures a better performance of this system.Practical applicationsThe technology of microencapsulation consists in the incorporation of a compound within a matrix, and it has been often used in the food industry by solving several limitations, allowing the immobilization, protection, controlled release of some ingredients, and changing of product properties. The use of biopolymers, such as sodium alginate, associated with the dripping method, enable the preservation even thermolabile compounds, such as drugs, organisms, proteins, and fragrances, since mild conditions are used. However, large beads are produced, which can limit their application. A rarely used and cost‐effective option for size reduction is the jet cutter, a cutting tool that, during its rotation, breaks the jet in smaller sizes, producing very small beads. The results of this study showed that the use of jet cutter was effective in the reduction of bead size and developed some basis for broadening its application for encapsulation using different materials.

Microfluidic fabrication of shape-tunable alginate microgels: effect of size and impact velocity.

We report on a capillary-based microfluidic platform for the fabrication of non-spherical sodium alginate microgels. The sodium alginate droplets were crosslinked off-chip in a mixture of barium acetate and glycerol solution. Novel morphologies such as tear drop, lamp-like, mushroom-like, double-dimpled and bowl-like microgels were fabricated by controlling the size, impact velocity (at the crosslinking solution/oil interface), and concentration of sodium alginate solution. We monitored the microscale deformation process in situ at the interface and proposeed a deformation mechanism resulting in unique morphologies. Additionally, we constructed microgel superstructures by assembling the non-spherical alginate microgels to spherical poly(N-isopropylacrylamide) (pNIPAAm) microgels via electrostatic interaction.

Optimization of Microcapsule Production by Air Atomization Technique using Two-Fluid Nozzle

A method of preparing microcapsules using two-fluid glass nozzle was studied for microencapsulation of food ingredients. In this method, a solution of sodium alginate and starch was sprayed using a two-fluid glass nozzle into a reaction vessel containing calcium chloride gelling bath. The aim of this work was to study the effect of some process variables on particle size of microcapsules. Response Surface Methodology by applying Box-Behnken design was used to optimize four independent variables viz., sodium alginate concentration (% w/v), starch concentration (% w/v), pressure (bar), and flow rate (ml/min) for obtaining target particle size. The ANOVA of the regression model demonstrated that the model was highly significant and adequate (p = 0.0054, R 2 = 0.8837). The microcapsules produced have average particle size ranging from 104.56 to 734.69 μm. The results revealed that concentration of sodium alginate solution and air pressure used for atomization had significant effect on particle size of microcapsules (p < 0.01). The optimized formulation and experimental conditions (sodium alginate concentration (2 % w/v), starch concentration (3 % w/v), air pressure (0.75 bar), and flow rate (80 ml/min)) yielded microcapsules of particle size values very close to predicted particle size. The morphology of microcapsules confirmed the near spherical capsular structure; which indicated that two-fluid glass nozzle can be used for production of spherical microcapsules.

용액 농도에 따른 항균성 알긴산 아연 필름의 제조 및 그 특성

Alginate를 농도 별로 용액상태로 제조한 후 필름 메이커를 이용하여 필름 형태로 만든 후 3 wt%의 <TEX>$ZnCl_2$</TEX> 수용액에 필름을 고화시킨 후 수세하여 <TEX>$60^{\circ}C$</TEX>의 건조기에서 약 20분 동안 건조시켜 zinc alginate 필름을 제조하였다. 필름의 특성을 조사하기 위하여 항균성 및 점도와 FTIR, TGA, SEM, EDS 및 접촉각, 인장측정, 용해도분석 등을 측정하였다. 항균성 시험 결과, zinc alginate 필름에서는 두 균주(포도상구균, 폐렴간균) 모두 우수한 항균력이 나타나는 것을 확인하였다. 9 wt%의 sodium alginate로 제조한 zinc alginate 필름의 표면은 다른 농도별 필름보다 균일한 형태를 나타내었으며, <TEX>$ZnCl_2$</TEX> 응고액에 잘 고화될 때 단단하고 거친 느낌의 단면 형태를 확인하였다. Zinc alginate 필름의 인장강도는 가교결합에 의해 sodium alginate 용액의 농도가 증가함에 따라 증가하였으며, 초기 열 분해 온도가 점차적으로 높아지고 있는 형태를 보였다. Zinc alginate films were prepared by a film maker from sodium alginate solutions of different weight ratios and then they solidified into 3 wt% content <TEX>$ZnCl_2$</TEX> coagulation solution and washed and dried at a <TEX>$60^{\circ}C$</TEX> oven for 20 min. The characteristics were measured by several methods (antimicrobial activity, viscosity, FTIR, TGA, SEM, EDS, contact angle, tensile strength and solubility) and the film properties were investigated. The antimicrobial test showed that the zinc alginate films result in excellent antimicrobial activity in the two strains (Klebsiella pneumonia, Staphylococcus). The surface of zinc alginate film from the solution of 9 wt% sodium alginate showed more uniform shape than any other films and the cross-section were hard and rough when the films were well-solidified by the <TEX>$ZnCl_2$</TEX> solution. The tensile strength of zinc alginate films increased along with the concentration of sodium alginate solution due to the cross-linking, and the initial thermal decomposition temperature increased gradually.

Fabrication and Characterization of Alginate Fibers by Wet-Spinning

Alginate fibers were prepared by extruding a concentrated sodium alginate solution into calcium chloride coagulation bath. The rheological behavior of different concentrations of sodium alginate solutions were investigated to evaluate the spinnability. The effect of dope concentration on the morphologies and mechanical properties of resulting alginate fibers were examined. The results showed that sodium alginate solutions were pseudoplastic fluid and had good spinnability with concentration ranging in 1.5%-3.5%. Moreover, the morphology of obtained fibers became smoother with increasing sodium alginate concentrations. When the sodium alginate concentration was 3.5%, the tensile strength and elongation at break of alginate fibers reach to 13.6±1.2 cN/tex and 8±0.5%, respectively.

Effect of polymer concentration on the depolymerization of sodium alginate by the solution plasma process

Depolymerization of alginate was accessed, for the first time, by the plasma treatment in solution called solution plasma process (SPP). The process was done by applying an electrical discharge into a reactor containing sodium alginate aqueous solution. The key of the production is the generation of reactive species induced by the plasma in a liquid environment that can lead to the scission of polymer chains. Effect of polymer concentration on the SPP processing parameters and the depolymerization efficiency were studied. Three concentrations of sodium alginate solutions, i.e., 0.2, 0.5, and 0.9 %w/v, were prepared. The results showed that increasing concentration of the alginate solution decreased the applied voltage required for the generation of plasma. Optical emission spectra demonstrated that the generation of reactive species was the highest at the lowest alginate concentration (i.e. 0.2 %w/v). Therefore, molecular weight reduction of this concentration after the SPP was more remarkable than the others. The most significant species required for the depolymerization of alginate was the reactive hydrogen species. Molecular weight distributions (MWD) of the obtained low molecular weight alginates (LMALGs) for all concentrations were narrow. Furthermore, reduction trends of molecular weight and viscosity of alginate with varying operation times indicated that the depolymerization of alginate in aqueous solution by the SPP was affected by the combined contribution of two factors: (1) the amount of reactive species generated during the process and (2) the degree of chain entanglement of the polymers.

English

In this&nbsp;study, various concentrations of sodium alginate solutions and calcium chloride solutions were tested in order to optimize the size, shape and texture of alginate synthetic seeds or beads for&nbsp;Acacia&nbsp;hybrid bud-sprouting. The shoot buds and axillary buds from&nbsp;in vitro&nbsp;Acacia&nbsp;hybrids, as explants were encapsulated with 2 to 5% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent and exposed to 25 to 100 mM calcium chloride solution (CaCl2.2H2O). Rounded beads were observed by the encapsulation with alginate 3% and exposed to 75 to 100 mM CaCl2.2H2O combinations and; the encapsulation with alginate 4 to 5% and exposed to any CaCl2.2H2O combinations. The produced synthetic seeds were then tested on the plantlets regeneration ability. The germination rate was within 73.3 to 100% in the duration of 6 to 20 days. It showed that encapsulation at any alginate concentrations and exposed to any of the CaCl2.2H2O concentrations, gave high germination frequency. These plantlets could then be used as the source of explants for the subsequent experiments. The synthetic seeds have the possibility of being an alternative planting material meant for forestry sector in the future, especially for the highly demanded species. &nbsp; Key word:&nbsp;Acacia&nbsp;hybrid, synthetic seeds, encapsulation, alternative planting material.

Evaluation of Alginate-Starch Polymers for Preparation of Enzyme Microcapsules

Flavourzyme® (a protease-peptidase complex) was microencapsulated with sodium alginate and Hi-MaizeTM starch in varying concentrations and proportions for maximising encapsulation efficiency (EE). Seventy two percent EE was achieved for immobilising Flavourzyme® using 1.8% (w/v) sodium alginate and 1% Hi-Maize[TM] starch with 30 min hardening of capsules in 0.1M calcium chloride solution. Hi-MaizeTM starch as a filler material improved EE and reduced the enzyme release during capsular hardening in calcium chloride solution. Increasing the concentration of sodium alginate solution (1.2 to 1.8 %, w/v) and calcium chloride concentration (0.05M to 1.0M) increased the EE. The optimum hardening time for the microcapsules in calcium chloride solution was 30 min. Shrinkage of microcapsules during hardening in calcium chloride was less with higher concentration of alginate. More spherical capsules were produced with up to 1.8% (w/v) sodium alginate and 1% Hi-MaizeTM starch solutions.

Preparation and in vitro evaluation of mucoadhesive properties of alginate/chitosan microparticles containing prednisolone

This study describes the preparation of mucoadhesive alginate/chitosan microparticles containing prednisolone intended for colon-specific delivery. Two methods have been used for the preparation of the particles: the one-step method is the method in which prednisolone was dispersed within sodium alginate solution and this dispersion was then dropped in a solution containing both calcium chloride and chitosan. The two-step method consisted also of the dispersion of prednisolone in alginate solution and then dropping this dispersion into a solution containing calcium chloride, the particles were then transferred to a chitosan solution. The concentration of sodium alginate solution at 2% (w/v), various concentrations of calcium chloride solution (0.5–1.0%, w/v), chitosan solutions (0.5, 1.0 and 1.5%, w/v) and prednisolone drug load (2, 5, 10 and 15%, w/v) have been used. The results for both preparation methods show that the particle size and drug content were mainly depending on the amount of the drug concentration and not the amount of chitosan and calcium chloride. The in vitro mucoadhesive tests for particles prepared from both methods were carried out using the freshly excised gut of pigs. The particles prepared by the one-step method exhibited excellent mucoadhesive properties after 1 h test. Increased chitosan concentrations from 0, 0.5, 1.0 to 1.5% (w/v) resulted in 43, 55, 82 and 88% of the particle remaining attached on the gut surface after 1 h, respectively. However, the particles prepared by the two-step method showed significant less mucoadhesion under the same experimental conditions. At chitosan concentrations of 0, 0.5, 1.0 and 1.5% (w/v) the amount of particles remaining attached to the mucosal surface of the pig gut after 1 h was 43, 3, 11 and 11%, respectively. The prednisolone release at a pH of 6.8 after 4 h was between 63 and 79% for the particles prepared by the one-step method and between 57 and 88% for the particles prepared by the two-step method with a prednisolone drug load of 5 and 10% (w/v), respectively. The results show that depending on the preparation method these chitosan coated alginate particles show different mucoadhesiveness whereas their other properties are not statistically significant different.