Papers by Keyword: Calcium Alginate

Abstract: Water sources in coastal areas are highly susceptible to seawater intrusion, leading to significant environmental and economic losses. Therefore, advanced treatment methods are required to make seawater suitable for clean water production, particularly in addressing water scarcity in coastal regions. One promising approach is seawater desalination using calcium alginate/graphene oxide (GO) beads. In this study, waste coral skeletons were utilized as a calcium source due to their high calcium content. X-ray fluorescence (XRF) analysis revealed that the calcium content in the coral skeletons was 93.4% before calcination and increased to 94.9% after calcination. These findings suggest that coral skeleton waste has potential as an adsorbent for Na⁺ and Cl⁻ ion removal. The synthesis of calcium alginate/GO was conducted using a droplet method and characterized using Fourier-transform infrared spectroscopy (FTIR). The adsorption process for Na⁺ and Cl⁻ ions was investigated at varying CaCl₂ concentrations (0.5 M, 1 M, and 2 M) to determine the optimal conditions for ion removal. Na⁺ ion analysis was performed using atomic absorption spectroscopy (AAS), while Cl⁻ ion concentration was determined via argentometric titration. The optimal Cl⁻ adsorption was observed at a CaCl₂ concentration of 0.5 M with a contact time of 30 minutes, achieving an adsorption efficiency of 99.8% in a standard NaCl solution and 35.9% in seawater. For Na⁺ ion removal, the highest adsorption efficiency was achieved at a CaCl₂ concentration of 2 M with a 30-minute contact time, resulting in 97.3% adsorption in a standard NaCl solution and 61.9% in seawater. These results highlight the potential of calcium alginate/GO composites, derived from waste coral skeletons, as effective adsorbents for seawater desalination.

Abstract: There has been a surge in applying alginate microcapsules in diverse fields due to the numerous advantages of their non-toxicity, simple synthesis, and mechanical and chemical stability. Electrospraying is a simple and excellent technique for producing small microcapsules. This study aimed to analyse the trends in the operational parameters of the electrospraying technique, observed extreme conditions of the electrospraying, and selected the best performing parameters for producing small and spherical microcapsules. Alginate concentration was found to produce smaller microcapsules when kept at a minimum. However, the Implosion of microcapsules formed with less than 2%w/v alginate concentration was observed. Voltage increment produced smaller capsules, and fibre formation began at 21kV. Lower feed rates favoured both smaller microcapsules and better sphericity. Reduction in the needle orifice also favoured the formation of smaller microcapsules with less sphericity. Overall, a needle gauge of 27G, a voltage of 21kV, a flowrate of 0.5ml/h, and 2% w/v calcium chloride concentration were the best parameter combinations for producing small and spherical microcapsules.

Abstract: The key physical and mechanical property is the strength of the capsules, which ensure the implementation of the self-healing technology, in which the capsules are not destroyed during the compaction of the asphalt concrete mixture, but are destroyed during the formation of defects in the asphalt concrete. An increase in the content of the reducing agent in the composition of the alginate emulsion leads to a decrease in the breaking load during compression of the capsules, which is explained by an increase in their diameter. But the change in the content of sodium alginate does not have a significant effect on mechanical properties. As a result of exposure to a temperature of 170 °C, a decrease in the strength of the capsules by 22 % after 1 hour of exposure in the burning oven is observed, and with an increase in the time to 4 hours, the strength decreases by 46.9 %. The maximum decrease in the strength index after 4 hours of exposure at a temperature of 160 °C reaches 29.9 %. A decrease in temperature to 150 °C leads to a decrease in the loss of strength. The strength of the capsules decreases by 4 % after 4 hours of exposure at 150 °C. Exposure of capsules to a temperature of 140 °C has no significant effect on strength.

Abstract: A photocatalyst iron phthalocyanine/calcium alginate gel bead (FePc@SA) was prepared through the mixture including iron tetra (N-carbonylacrylic) aminophthalocyanine (FePc) and sodium alginate dropped into 5 % (w/v) CaCl₂ solution to get gel beads. The color of gel ball was black and the average diameters of gel ball before and after drying were 3.19 mm and 1.20 mm, respectively. Methyl orange was selected as a substrate to investigate the photocatalytic activity of FePc@SA. The results shown that the remaining rate of methyl orange was 19.51 % under the condition of methyl orange 10 mg/L 25 mL, pH value was 3, the dosage of H₂O₂ was 50 μL, FePc@SA was 0.2 g and visible light irradiation for 3 h. The results indicated that FePc@SA/H₂O₂ system had an obvious synergistic effect on photocatalytic oxidative decolorization of methyl orange. The decolorization process conformed to the first order kinetics equation, and the half-life of FePc@SA was 76.7 min. Simple preparation methods and excellent photocatalytic properties made FePc@SA became an ideal high performance photocatalytic material, which was applied to deal with wastewater containing organic pollutants.

Abstract: Stable fluorescent carbon nanoparticles (FCNPs) with excellent water-solubility were prepared firstly by one-step ultrasonic treatment from the blending of glucose and sodium hydroxide. Then, the fluorescence calcium alginate fibers were successfully prepared through wet spinning, using the mixture of FCNPs and sodium alginate solution as the spinning dope. The fluorescent property of FCNPs and fibers were investigated using fluorescence spectrophotometer. Single fiber strength tester was used to measure the strength of the fluorescence fibers. The results showed that both FCNPs and fibers emitted bright blue color under 350nm wavelength UV irradiation. The strength of the fibers was improved when the content of FCNPs in the fibers achieved certain value.

Abstract: The 4-t-octylphenol (4-t-OP) biodegradation by alginate immobilized cells of Acinetobacter sp. was compared with its respective free cells in different media. The effects of different bead densities, pH values and practical applications of artificial seawater and wastewater on the biodegradation rate of 4-t-OP were investigated. Degradation kinetics of 4-t-OP by free and immobilized cells was well fitted with first order kinetic. The immobilized Acinetobacter sp. cells could enhance the efficiency of 4-t-OP degradation. The degradation rate and 4-t-OP half-life were 97.6% and 0.7 d, respectively. Increasing level of bead amount could also improve the degradation effects, when 400 beads per 100 mL were added, the degradation rate and 4-t-OP half-life were 96.5 % and 0.2 d respectively. The immobilized Acinetobacter sp. cells could degrade 4-t-OP both in artificial seawater and wastewater. The degradation rates were 87.7% and 84.3%, respectively, indicating its potential application of removing and biodegrading 4-t-OP under practical environment.

Abstract: In this study, calcium alginate immobilized bean husk powder(CA) beads was used as an adsorbent for the aim of removing Pb(Ⅱ) ions form the aqueous solutions, and the effect of initial solution pH, contact time, temperature, initial metal ion concentrations and ionic strength in the adsorption process were investigated in detail. Experimental results showed that the amount of adsorbed Pb(Ⅱ) increased with the increasing initial metal ion concentration and solution pH in the examined range. The results showed that the optimum adsorption pH for Pb(Ⅱ) was5.5, the uptake was 10. 78 mg/g, the desorption rates of Pb(Ⅱ) by EDTA was calculated as 90 %. The concentration of Pb(Ⅱ)of mine wastewater reach the first class of irrigation water quality standards after the first time of adsorption treatment, and reach the first class of fishery water quality standard after the second treatment.

Abstract: As a natural polymer, alginic acid is widely used in medical fields for its biodegradability, low toxicity and immunogenicity. In this paper, four kinds of cavernous calcium alginate wound dressings were prepared, and physical properties were tested, providing fundamental basis for further study. The results indicate that glycerin is not suitable as a plasticizer for this cavernous wound dressing; a relatively uniform structure of the calcium alginate wound dressing would be obtained as the solution temperature increased; the mechanical properties decrease with the increase of the pre-freezing time.

Abstract: Hydrophilic membranes based on PVP, containing 0.4 and 1% of carboxymethylcellulose staple fibers infused with calcium alginate were obtained and characterized in this study. The main proposal of this study is related to hydrogels based on PVP modified with carboxymethyl cellulose staple fibers infused with calcium alginate. This modified hydrogel is a hydrophilic membrane with better mechanical properties that can incorporate adequate drugs into the fibers for each lesion type. The hydrogels were obtained using ionizing radiation with an electron beam, at a dose of 25 kGy. The membrane’s characterization was performed by tensile and physic-chemical tests (gel fraction and swelling). The results obtained showed that the membranes have higher mechanical strength, a higher swelling degree and a lower gel fraction.

Abstract: Two kinds of new immobilized bio-beads in gel were produced with calcium alginate, polyvinyl alcohol and activated carbon fiber. Scanning electron microscopy was used to detect the microstructure and MB were applied to enhance degradation of benzene. It shows that activated carbon fiber was a excellent carrier material to increase MB stability and enhance the degradation of benzene by changing the microsructure. CA-MB in this study was characteristic of loose interface, intensely homogeneous holes and well-reusability. 80% of benzene could be reduced after120h and removal tallied with one-order knetics.Otherwise,for PVA-MB, it possed more compact ouside and irregular tunnles and poles inside.Benzene removal process was analysed to compose of absorption and biodegradation.The immobilization inoculum of 137.77mg/L was optimal with the most stabilities and the best degradation capability for both CA-MB and PVA-MB. Moreover, it is the addition of ACF as encapsulated carrier that made CA-MB superior to PVA-MB in benzene removal and reutilization.