Calcium Alginate Membrane Research Articles

Cost-effective production of density-controllable monodisperse spheres for experiments in fluids

Cost-effective production method for making density-controllable monodisperse spheres is demonstrated. A sodium alginate aqueous solution containing gelatin is emulsified with canola oil. The droplet surface is covered with a calcium alginate membrane by dropping the emulsion into a calcium lactate aqueous solution. The content of the canola oil can control the sphere's density. To demonstrate the applicability of the spheres to experimental research, rheological measurements of the suspensions of the spheres were performed. The effective viscosity agrees with the theoretical formula at volume fractions of 0.7%–11.7%. The demonstration highlights that the spheres can function as neutrally buoyant solid particles in studies for the physics of fluids.

TiO2/CMWCNT/CaAlg composite membrane used for dye desalination and its rapid cleaning under ultraviolet light and advanced oxidation activated by monopersulfate

Membrane separation technology holds tremendous potential in treating dye wastewater. However, the widespread issue of membrane fouling leads to a significant decline in separation efficiency and lifespan. In this paper, titanium dioxide (TiO2)/carboxyl multi-walled carbon nanotube (CMWCNT)/calcium alginate (CaAlg) membranes were prepared by blending and simple cross-linking methods. The influence of TiO2 and CMWCNT concentrations on membrane performance, especially the anti-swelling performance, was explored. Additionally, the mechanical properties, filtration performance, fouling resistance, and dye/salt separation performance of the composite membrane were investigated. Notably, the rejection rate of dye molecules (Mw > 696 Da) was greater than 98 %, while the rejection rate of salt was less than 11.0 %. Furthermore, two methods for environmental-friendly cleaning membrane, photocatalytic degradation and advanced oxidation activated by monopersulfate, were performed. Finally, the photocatalytic degradation process and mechanism of Congo red (CR) were investigated by electron spin resonance (ESR).

Addition of chitosan to Calcium-Alginate Membranes for Seawater NaCl Adsorption

<abstract> <p>Initial research was focused on the production of calcium-based alginate-chitosan membranes from coral skeletons collected from the Gulf of Prigi. The coral skeleton's composition was analyzed using XRF, revealing a calcium oxide content ranging from 90.86% to 93.41%. These membranes showed the significant potential for salt adsorption, as evidenced by FTIR analysis, which showed the presence of functional groups such as -OH, C = O, C-O, and N-H involved in the NaCl binding process. SEM analysis showed the particle size diameter of 185.96 nm, indicating a relatively rough and porous morphology. Under optimized conditions, the resulting calcium-based alginate-chitosan membrane achieved 40.5% Na<sup>+</sup> and 48.39% Cl<sup>-</sup> adsorptions, using 13.3 mL of 2% (w/v) chitosan and 26.6 mL of 2% (w/v) alginate with a 40-minutes contact time. The subsequent we applied for the desalination potential of calcium alginate, revealing the efficient reduction of NaCl levels in seawater. The calcium of coral skeletons collected was 90.86% and 93.41% before and after calcination, respectively, affirming the dominant calcium composition suitable for calcium alginate production. We identified an optimal 8-minute contact time for calcium alginate to effectively absorb NaCl, resulting in an 88.17% and 50% for Na<sup>+</sup> and Cl<sup>-</sup> absorptions. We applied the addition of chitosan into calcium-alginate membranes and its impact on enhancing salt adsorption efficiency for seawater desalination.</p> </abstract>

Insight of multifunctional Cu-alginate hydrogel membrane for precise molecule/ion separation applications

Membrane technology has garnered significant attention for its role in addressing the challenges of molecule/ion separation processes, yet it remains hindered by issues such as membrane fouling, including organic and biofouling. While calcium alginate (CaAlg) membranes have demonstrated remarkable antifouling and molecule/ion separation properties, they suffer from high swell ability and poor mechanical performance. This study introduces a one-step ion-crosslinking method to fabricate a series of copper alginate (CuAlg) hydrogel membranes. These membranes are then assembled into a dual-layer structure with a modified hydrophilic and mechanically robust microfiltration fiber support layer (MHSL). Notably, the CuAlg/MHSL membrane exhibits excellent separation performance, characterized by high selectivity and flux recovery rate. This membrane significantly enhances the long-term molecule/ion separation performance through improved mechanical strength, anti-swelling properties, and antimicrobial capabilities. In addition, the decreased thickness of the CuAlg/MHSL membrane enables higher flux rates, proving beneficial in cases of CaAlg membranes' inability to perform well under high-salt conditions. To further investigate the pore structure and anti-swelling mechanism of the CuAlg membrane, molecular dynamics (MD) simulations are conducted. Additionally, a life cycle analysis comparing the CuAlg hydrogel with various traditional polymers assesses their respective environmental impacts, highlighting the eco-friendliness of the hydrogel as a membrane substrate. These findings provide valuable insights for developing sustainable hydrogel membranes with stable performance and high separation efficiency in molecular/ion separation applications.

High-strength and anti-bacterial BSA/carboxymethyl chitosan/silver nanoparticles/calcium alginate composite hydrogel membrane for efficient dye/salt separation

In order to solve the problems of poor mechanical property, non-antibacterial and low flux of calcium alginate (CaAlg) membrane, silver nanoparticles (AgNPs) were synthesized with bovine serum albumin (BSA) and carboxymethyl chitosan (CMCS) for improving CaAlg membrane in this paper. Meanwhile, the dispersion property of silver nanoparticles and the mechanical property, thermal stability, antibacterial property and filtration efficiency of the composite membrane were explored. The results illustrated CMCS observably strengthened the mechanical property and thermal stability of the composite membrane, and AgNPs endowed the composite membrane with excellent antibacterial property. The flux of the BSA/CMCS/AgNPs/CaAlg composite membrane was raised compared to CaAlg membrane. Finally, the viscose fiber/polyethylene terephthalate fiber (VF-PET) nonwoven fabric was introduced as the support layer to further improve the filtration flux and mechanical property of the composite membrane. VF-PET/BSA/CMCS/AgNPs/CaAlg membrane had a rejection rate of over 99.0 % for dye molecules and <9.0 % for salt ions, while the flux maintained 38.5 L·m−2·h−1. Furthermore, VF-PET/BSA/CMCS/AgNPs/CaAlg membrane also had excellent separation effect on actual dye wastewater. The separation of dye and salt by the membrane mainly depended on the screening mechanism of membrane pore size, rather than adsorption. The composite membrane had an outstanding performance on the separation of dye molecules and inorganic salt ions.

Viability of Mesenchymal Stem Cells from Stromal Vascular Fraction to Tissue Engineering Scaffold Collagen, Calcium Alginate, Oxidized Cellulose, Gelatin, And Amnion Membrane (Primary Cell Culture in Vitro Study)

Introduction: Soft tissue engineering strategies targeting volume loss restoration has been developed as the current management of soft tissue defects. Important components of this method are cell sources, scaffold, and bioreactor. Adipose-derived mesenchymal stem cell (ADMSC) from a stromal vascular fraction (SVF) attached to scaffold and differentiated into defect tissue through cell communication. This study was aimed to investigate the viability of ADMSC from SVF combined with collagen, calcium alginate, oxidized cellulose, gelatin, and amnion membrane in vitro. Method: This true experimental done in the laboratory using 24 samples of SVF ADMSC that had been cryopreserved for 5 months and already get through the thawing process. Result: Based on the descriptive analysis with 4 repetition each group and control, gelatin shows average 90.928 and deviation standard 1,053, oxidized cellulose average 19,528 and deviation standard 2,543, collagen average 93,273 and deviation standard 1,195, calcium alginate average 92,953 and deviation standard 1,257, amnion membrane average 92,068 and deviation standard 2,467, control 95,995 and deviation standard 0,428. Conclusion: The use of gelatin, collagen, calcium alginate, and amnion membrane as scaffold show high viability results of ADMSC from SVF. Otherwise, oxidized cellulose scaffold has the lowest amount of viable cell. However, the most recommended scaffold material is amnion membrane because of the easiness of the production process, high availability, high potency of cell growth, and low cost.

One-step fabrication of hydrophilic lignosulfonate-decorated reduced graphene oxide to enhance the pervaporation performance of calcium alginate membranes

In this study, a reduced graphene oxide (rGO)@sodium lignosulfonate (NaLS) composite material was fabtricated using a one-step method and then mixed with natural polysaccharide calcium alginate (CaAlg) to prepare the [email protected]/CaAlg pervaporation membrane. The appearance and physical properties of the [email protected]/CaAlg membrane were characterized by scanning electron microscopy and water contact angle. The swelling performance of the membrane and its dehydration performance to organic solvents were evaluated. The results indicate that the addition of [email protected] can increase the hydrophilicity of the [email protected]/CaAlg membrane and reduce its degree of swelling in the ethanol solution. The membrane incorporated with 6 wt% [email protected] exhibits the best pervaporation performance, and ethanol can be purified to 99.8%.

Bioremediation of oily seawater by Bacteria immobilization on a novel carrier material containing nutrients

A novel carrier material was obtained by coating puffed rhubarb rice (PRR) with calcium alginate (CA) membrane. The carrier material was prepared to contain oil-degrading bacterial strains and inorganic nutrients through entrapping them in different locations. This formulation possessed floatability, biodegradability and nutrient slow-release properties. Therefore, it could be applied for oil biodegradation on seawater surfaces. For controlling the release rate of nutrients, the optimal preparation technique was established. The number of viable cells immobilized on the carrier material reached 2 × 109 CFU/g. This formulation could be stored at −20 °C for three months without a significant decrease in the number of viable immobilized cells (4 × 108 CFU/g). Scanning electron microscope (SEM) results showed that the cells were immobilized on the outer CA membrane, and the inorganic nutrients were entrapped in the inner PRR and CA membrane. The immobilized cells were able to remove 86% of the diesel oil at an initial diesel oil concentration of 1% (v/v), an incubation temperature of 37 °C, during three days of incubation. Gas chromatography-mass spectrometry (GC–MS) analysis results showed that most components of diesel oil were degraded by the formulations.

Evaluation of Calcium Alginate-Based Biopolymers as Potential Component of Membranes for Recovering Biosurfactants from Corn Steep Water

Corn steep water (CSW) is a complex agro-food stream that is used as a source of cost-competitive biosurfactants, since they are produced spontaneously in the steeping process of corn, avoiding production costs. Nevertheless, the extraction of biosurfactants from CSW using sustainable processes is still a challenge. Consequently, the use of calcium alginate membranes could present a novel and sustainable technology for recovering biosurfactants from aqueous streams. Therefore, the aim of this work is to evaluate calcium alginate-based biopolymers, without and with the presence of grape marc as an additive, as a key component of membranes for the recovery of biosurfactants in corn steep water. Biosurfactants are present in CSW, together with other inorganic solutes and biomolecules, such as organic acids, sugars, cations, anions as well as metals. Hence, the competition of these mentioned compounds for the active sites of the calcium alginate-based biopolymers was high. However, they showed a good adsorption capacity for biosurfactants, recovering around 55 ± 2% and 47 ± 1%, of biosurfactants from CSW using both calcium alginate-based biopolymers, with and without biodegraded grape marc. Regarding adsorption capacity, it was 54.8 ± 0.6 mg biosurfactant/g bioadsorbent for the biopolymer containing grape marc, and 46.8 ± 0.4 mg biosurfactant/g bioadsorbent for the calcium alginate-based biopolymer alone. Based on these results, it could be postulated that the formulation of green membranes, based on calcium alginate-based polymers, could be an interesting alternative for the recovery of biosurfactants from aqueous streams including CSW.

Tailorable regulation of mass transfer channel in environmentally friendly calcium alginate membrane for dye removal

Environmentally friendly polymer membranes for dye contamination removal were prepared from edible calcium alginate. The stable gel structure was formed by molecular chains of sodium alginate cross-linked by chelate-formation with calcium ions. To improve the water permeability of the membranes and make them suitable for membrane separation processes, their mass transfer channels were precisely regulated to form fine voids via the addition of oligoethylene glycol (OEG) or polyethylene glycol (PEG) to a casting polymer solution and subsequent removal of the OEG or PEG from the membranes by a washing process after cross-linking. Fourier transform infrared spectroscopy confirmed that the chemical properties of the membranes with voids formed by OEG or PEG were the same as the properties of the original calcium alginate membrane without void forming. Despite their same chemical properties, the performance of the membranes clearly differed. The effect of the different void structures on the mass transfer channels was investigated using pure water permeation, Methyl Orange dye rejection, and volumetric void fraction measurements, as well as morphological observations by field-emission scanning electron microscopy. The membrane with voids formed by OEG exhibited to an increase in water permeability compared with the original membrane, whereas the molecular separation performance was maintained within the nanofiltration region. Meanwhile, the membrane with voids formed by PEG was suitable for use in high-flux ultrafiltration processes for pretreating wastewater. The biocompatible membranes with tailorable separation ability presented herein are candidates for use in purification processes for recovering dye-polluted water resources.

Polypropylene non-woven supported calcium alginate hydrogel filtration membrane for efficient separation of dye/salt at low salt concentration

Calcium alginate hydrogel is an eco-friendly material, but its wide application as a self-supporting filtration membrane is severely limited by the weak mechanical properties, which makes it difficult for the large scale preparation and the fixation of the membrane in filtration equipment. In this work, a fiber-reinforced calcium alginate membrane (CaAlg-PP) was prepared by coating calcium alginate (CaAlg) hydrogel on the polypropylene (PP) non-woven fabric treated with ethanol/water (v:v = 1:1) solution. The CaAlg-PP filtration membrane was characterized and used for dye/salt separation under a series of operating conditions. The membrane exhibited the co-operativity of the porous support layer and the CaAlg hydrogel in the compositing process, and also exhibited good pressure resistance, pollution resistance and low anionic dye adsorption efficiency. The optimized CaAlg-PP membrane had a high permeance (e.g. 20.3 L·m−2·h−1 for methyl blue at 0.1 MPa) and high dye rejection (e.g. methyl blue 99.5%), while low salt rejection (e.g. NaCl 7.5%), and the selectivity of methyl blue/NaCl was up to 185. The CaAlg-PP membranes made with simple processes and low-cost materials may provide new strategies for environmentally-friendly and economical low salts-containing wastewater treatment and dye recycling.

Multiphase calcium alginate membrane composited with cellulose nanofibers for selective mass transfer

A multiphase calcium alginate membrane composited with cellulose nanofibers (CNF) was successfully prepared by using the method. The maximum stress and strain, water content, water permeability, and mass transfer characteristics were examined according to the addition ratio of CNF. Increasing of the amount of CNF enhanced the maximum stress and reduced the maximum strain, thereby suggesting that CNF impart flexibility and stiffness to the composite membrane. The CNF in the calcium alginate noticeably increased the water flux at the same pressure. The permeability of the composite of the CNF membrane was higher. The effective diffusion coefficient dramatically decreased 2.5 × 103 times when the molecular weight increased ten-fold (from 60 to 604 Da). Moreover, stronger dependency was observed in the CNF composite membrane. The morphology of the cross-section of the membrane was observed using scanning electron microscopy. The appearance of the CNF composite membrane became rougher when the amount of CNF increased.

Capsule membranes encapsulated with smart nanogels for facile detection of trace lead(II) ions in water

A novel method based on capsule membranes encapsulated with smart nanogels is successfully developed for facilely detecting trace lead(II) (Pb2+) ions, which are hazardous to both human health and the environment because of their toxicity. The capsule membrane system is composed of a semi-permeable calcium alginate membrane and encapsulated poly(N-isopropylacrylamide-co-acryloylamidobenzo-18-crown-6) (PNB) nanogels. The semi-permeable membrane allows Pb2+ ions and water to pass through quickly, but rejects the encapsulated nanogels and polymers totally. As soon as Pb2+ ions appear in the aqueous environment and enter into the capsule, they can be specifically recognized by encapsulated PNB nanogels via forming 18-crown-6/Pb2+ complexes that cause a Pb2+-induced phase transition of PNB nanogels from hydrophobic to hydrophilic state. As a result, the osmotic pressure inside the capsule membrane increases remarkably, and thus the elastic capsule membrane isothermally swells upon the presence of Pb2+ ions in the environmental aqueous solution. The Pb2+-induced swelling degree of the capsule membrane is dependent on the concentration of Pb2+ ions ([Pb2+]) in water. Thus, the [Pb2+] value in water is able to be easily detected by directly measuring the Pb2+-induced isothermal swelling ratio of the capsule membrane, which we demonstrate by using 15 prepared capsule membranes arranged in a line. The Pb2+-induced swelling ratios of the capsule membrane groups are easily observed with the naked eye, and the detection limit of the [Pb2+] in water is 10-9 mol L-1. Such a proposed method provides an easy and efficient strategy for facile detection of trace threat analytes in water.

Mechanical Properties and Water Absorption of Alginate/hydroxypropyl Methyl Cellulose Blend Membranes with Semi-interpenetrating Network

Sodium alginate (SA) is a renewable material with broad application prospects in textiles, medicine, and other fields. However, the disadvantage of poor strength and brittleness limited its future application. In this work, the SA was reinforced by the hydroxypropyl methyl cellulose (HPMC) with a semi-interpenetrating network which leverages the favourable properties. The structure and surface morphology of SA/HPMC blend membranes after Ca ion cross-linking were examined by FTIR, Raman, XRD and SEM. The mechanical properties and water absorbency of the blend membranes were also studied. The results indicated that the hydrogen bond was found in SA/HPMC blend membranes, which improved the SA/HPMC blend membranes stability. Compared with calcium alginate membrane, the tensile strength and elongation at break of SA/HPMC blend membranes were improved to 57 % and 400 %, respectively.

Filtration and adsorption properties of porous calcium alginate membrane for methylene blue removal from water

Porous sodium alginate membrane was first prepared by vacuum freeze-dry method, then, sodium ions were substituted by calcium ions through cross-linking reaction to obtain the porous calcium alginate membrane via natural drying. The filtration and the adsorption properties of methylene blue on the porous calcium alginate membrane were studied through investigating the experimental parameters such as the pH, contact time, temperature and dosage. The data of the adsorption equilibrium were described by the Langmuir and Freundlich isotherms. The pseudo-first order, pseudo-second order, and intra-particle diffusion equation were used to evaluate the kinetic data. Thermodynamic analysis indicated that the adsorption of methylene blue on to the porous calcium alginate membrane was an exothermic reaction.

Selective diffusion of glucose, maltose, and raffinose through calcium alginate membranes characterized by a mass fraction of guluronate

Glucose was selectively separated from an aqueous solution of mixed sugars (glucose 180Da, maltose 342Da, and raffinose 504Da) by static diffusion, and not ultrafiltration, without the driving force of pressure. The calcium alginate membrane described in this study provides a simple technical medium for sugar separation. Excellent selectivity based on the molecular size of sugar was realized. The mass fraction of homopolymeric blocks of guluronate in alginate polymer chains (FGG) was defined as a gravimetric ratio of homopolymeric blocks of α-l-guluronate in sodium alginate to the total mass of the sodium alginate polymer. FGG was a key factor for regulating the mass transfer characteristics of the calcium alginate membrane. Two different FGG membranes were employed to assess the selective separation of glucose. The effective diffusion coefficient in the membrane (Deff) was determined from the mass transfer flux through the calcium alginate membrane. The effective diffusion coefficient in the FGG 0.56 membrane exhibited a 38-fold decrease in the mixed system of the three sugars, even when the molecular weight showed only a 2.8-fold increase from glucose to raffinose. In the FGG 0.18 membrane, the effective diffusion coefficient exhibited a 14-fold decrease. The mass fraction of guluronate blocks was a dominant factor that regulated the selective diffusion of the sugars. The design of a calcium alginate membrane based on the mass fraction of guluronate blocks is promising for desirable selective sugar separation in industrial applications.

Improved Water Barrier Properties of Calcium Alginate Capsules Modified by Silicone Oil

Calcium alginate films generally offer poor diffusion resistance to water. In this study, we present a technique for encapsulating aqueous drops in a modified calcium alginate membrane made from an emulsion of silicone oil and aqueous alginate solution and explore its effect on the loss of water from the capsule cores. The capsule membrane storage modulus increases as the initial concentration of oil in the emulsion is increased. The water barrier properties of the fabricated capsules were determined by observing the mass loss of capsules in a controlled environment. It was found that capsules made with emulsions containing 50 wt% silicone oil were robust while taking at least twice the time to dry completely as compared to capsules made from only an aqueous alginate solution. The size of the oil droplets in the emulsion also has an effect on the water barrier properties of the fabricated capsules. This study demonstrates a facile method of producing aqueous core alginate capsules with a modified membrane that improves the diffusion resistance to water and can have a wide range of applications.

Effects of process variables on the encapsulation of oil in ca-alginate capsules using an inverse gelation technique

The objective of this study was to investigate the effects of process variables on the encapsulation of oil in a calcium alginate membrane using an inverse gelation technique. A dispersion of calcium chloride solution in sunflower oil (water-in-oil emulsion) was added dropwise to the alginate solution. The migration of calcium ions to the alginate solution initiates the formation of a ca-alginate membrane around the emulsion droplets. The membrane thickness of wet capsules and the elastic modulus of dry capsules increased following first-order kinetics with an increasing curing time. An increase in the calcium chloride concentration increased the membrane thickness of wet capsules and the elastic modulus of dry capsules. An increase in the alginate concentration decreased the mean diameter of wet capsules but increased the elastic modulus of dry capsules.

Impact Factors to Regulate Mass Transfer Characteristics of Stable Alginate Membrane Performed Superior Sensitivity on Various Organic Chemicals

Calcium alginate membrane has great potential for membrane separation technology. The polymer frameworks of the membrane were successfully regulated by the mass fraction of homopolymeric blocks of α-L-guluronic acid ( FGG ) in the entire molecular chain of alginate and the additive CaCl2 as a cross-linker. The mechanical strength can be controlled by regulated the FGG and CaCl2 concentration. Selected mass transfer of saccharides (Glucose,G, 180 Da; Maltose,M, 324 Da; Raffinose,R, 504 Da) was achieved. The mass transfer flux of saccharides was strongly changed and inversely proportional to the 4.4 th power of molecular volume. The mass transfer flux of saccharides was inversely proportional to the 2 nd power of FGG at prepared 1 M CaCl2. The mass transfer flux of urea (60 Da) was clearly decreased with increasing CaCl2 concentration. Especially, in higher FGG range, effect of CaCl2 concentration remarkably appeared on its effective diffusion coefficient ( Deff ). The volumetric water fraction with calcium concentration was very slight, regardless of FGG . The tortuosity increased linearly with increasing additive CaCl2 concentration. In higher CaCl2 concentration, the effect of FGG on the tortuosity remarkably appeared. Obtained empirical equation was anticipated as a guideline to estimate the effective diffusion coefficient of the alginate membrane. High permeability was performed by low FGG (0.18) membrane performed high permeability than high FGG (0.56) membrane. The water permeation mechanism was obeyed by Hagen-Poiseuille flow regardless of FGG .

Dominant impact of the &agr;-L-guluronic acid chain on regulation of the mass transfer character of calcium alginate membranes

The dominant impact of the &agr;-L-guluronic acid chain on regulation of the mass transfer character of calcium alginate membranes was investigated. The polymer frameworks of the membranes were successfully regulated by altering the mass fraction of homopolymeric blocks of &agr;-L-guluronic acid (FGG) in the entire molecular chain of alginate. Sodium alginate is well-known as a hydrophilic polysaccharide. Its molecular chain is composed of &agr;-L-guluronic acid and &bgr;-D-mannuronic acid. The polymeric structure of calcium alginate is mainly constructed by intermolecular ionic bonds with homopolymeric blocks of the &agr;-L-guluronic acid junction zone. The entire alginate polymer chain then forms into a swollen gel and a membrane. The water fraction of the swollen membrane and the mechanical strength changed with FGG. The volumetric water fraction based on the swollen state of the membrane was evaluated from the gravitational water content (HM). The change in the mass transfer mechanism of the membrane was evident in the effective diffusion coefficient, especially for the smaller molecules (e.g., urea). Good correlation between the volumetric water fraction and the effective diffusion coefficient strongly suggested that the mass transfer channels in the alginate membrane were dominantly regulated by the mass fraction of homopolymeric blocks of &agr;-L-guluronic acid (FGG). The relationship between the effective diffusion coefficient and the volumetric water fraction agreed with Yasuda’s free volume theory. The tortuosity was markedly increased and the effective d iffusion coefficient was reduced. In conclusion, the homopolymeric blocks of &agr;-L-guluronic acid have a dominant impact on the mass transfer character in the calcium alginate membrane.