Calcium Alginate Hydrogel Beads Research Articles

Efficient removal of aqueous Pb(II) ions by magnetic alginate composite microcapsules containing canola straw‐derived biochar as the reinforcing fillers

AbstractWith the rapid development of industry, water pollution caused by lead has caused great harm to human health. In this study, alginate is used as a base and blended with biochar to form calcium alginate hydrogel beads with high mechanical properties through ionic cross‐linking. Besides, the material (BC/MCAC) is prepared by the material (C‐γ‐Fe2O3) as a magnetizing agent and to remove lead. Then, a series of batch experiments and material characterizations are performed to evaluate the adsorption process of the material. The results show that the maximum adsorption capacity of BC/MCAC to Pb(II) is 211.6 mg g−1 at pH = 7. The adsorption process is well described by the Langmuir adsorption isotherm and pseudo‐second‐order kinetic model. This indicates that the lead adsorbed by BC/MCAC is a monolayer chemisorption that occurs on a uniform surface. After three regeneration cycles, BC/MCAC is found to retain 82.37% of the lead adsorption capacity and has good regeneration ability. Lead is removed by BC/MCAC mainly through the complexation of oxygen‐containing functional groups, electrostatic interaction, and ion exchange. BC/MCAC allows for more sustainable use of the wastes and is expected to be a new type of lead adsorbent for industrial wastewater.

Magnetic Fe3O4 nanoparticles loaded guava leaves powder impregnated into calcium alginate hydrogel beads (Fe3O4-GLP@CAB) for efficient removal of methylene blue dye from aqueous environment: Synthesis, characterization, and its adsorption performance

In the present work, a novel Fe3O4-GLP@CAB was successfully synthesized via a co-precipitation procedure and applied for the removal of methylene blue (MB) from aqueous environment. The structural and physicochemical characteristics of the as-prepared materials were explored using a variety of characterization methods, including pHPZC, XRD, VSM, FE-SEM/EDX, BJH/BET, and FTIR. The effects of several experimental factors on the uptake of MB using Fe3O4-GLP@CAB were examined through batch experiments. The highest MB dye removal efficiency of Fe3O4-GLP@CAB was obtained to be 95.2 % at pH 10.0. Adsorption equilibrium isotherm data at different temperatures showed an excellent agreement with the Langmuir model. The adsorption uptake of MB onto Fe3O4-GLP@CAB was determined as 136.7 mg/g at 298 K. The kinetic data were well-fitted by the pseudo-first-order model, indicating that physisorption mainly controlled it. Several thermodynamic variables derived from adsorption data, like as ΔGo, ΔSo, ΔHo, and Ea, accounted for a favourable, spontaneous, exothermic, and physisorption process. Without seeing a substantial decline in adsorptive performance, the Fe3O4-GLP@CAB was employed for five regeneration cycles. Because they can be readily separated from wastewater after treatment, the synthesized Fe3O4-GLP@CAB was thus regarded as a highly recyclable and effective adsorbent for MB dye.

Encapsulation of Concentrated Solution Obtained by Block Freeze Concentration in Calcium Alginate and Corn Starch Calcium Alginate Hydrogel Beads

A model (sucrose and gallic acid) solution was concentrated by block freeze concentration (BFC) at three centrifugation cycles, and the solutions were encapsulated in calcium alginate and corn starch calcium alginate hydrogel beads. Static and dynamic tests determined the rheological behavior, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) established thermal and structural properties, and the release kinetics was evaluated under in vitro simulated digestion experiment. The highest efficiency encapsulation value was close to 96%. As the concentrated solution increased in terms of solutes and gallic acid, the solutions were fitted to the Herschel-Bulkley model. Moreover, from the second cycle, the solutions exhibited the highest values of storage modulus (G') and loss modulus (G″), contributing to form a more stable encapsulation. The FTIR and DSC results demonstrated strong interactions between corn starch and alginate, establishing a good compatibility and stability in the bead formation. The kinetic release model under in vitro conditions was fitted to the Korsmeyer-Peppas model, demonstrating the significant stability of the model solutions inside the beads. Therefore, the present study proposes a clear and precise definition for the elaboration of liquid foods obtained by BFC and its incorporation inside an edible material that facilitates the controlled release in specific sites.

SnLa2O5 wrapped carboxymethyl cellulose mixed calcium alginate nanocomposite beads for efficient reduction of pollutants

In this project, lanthanum oxide doped tin oxide (SnLa2O5) nanomaterial was prepared and characterized morphologically and physiochemically by different techniques. The catalytic performance of SnLa2O5 was assessed toward catalytic reduction of 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), methylene blue (MB) and potassium ferricyanide (K3[Fe(CN)6]). SnLa2O5 was found to be efficient for K3[Fe(CN)6] in the presence of NaBH4, which reduced in only 8.0 min. SnLa2O5 was further wrapped in carboxymethyl cellulose mixed calcium alginate (CMC-Alg) hydrogel beads because the powder catalyst cannot be simply recovered from reaction media to recycle and use again. SnLa2O5 wrapped CMC-Alg (SnLa2O5/CMC-Alg) was assessed for detail analysis of K3[Fe(CN)6] reduction. The effect of NaBH4, K3[Fe(CN)6] concentration and amount of catalyst was optimized using SnLa2O5/CMC-Alg. The amount of catalyst has positive impact on catalytic reduction of K3[Fe(CN)6]. The kinetic study revealed that K3[Fe(CN)6] reduction by SnLa2O5 and SnLa2O5/CMC-Alg was fast, which completed in 8.0 and 4.0 min with rate constant of 0.4283 min−1 and 0.7461 min−1, respectively. These findings indicated that the developed SnLa2O5/CMC-Alg is best and proficient nanocatalyst for K3[Fe(CN)6] reduction. The efficiency along with cost-effective and simple treatment route of the developed nanocatalyst have prospect to compete and replace the reputable commercial catalysts.

Copolymerized Natural Deep Eutectic Solvent Encapsulated in Calcium Alginate Beads: Application as a Green Sorbent for Analysis of Multiclass Pesticides in Nonalcoholic Malt Beverages by GC–MS/SIM

A novel sorbent material consisting of a copolymeric deep eutectic solvent (DES) gel doped in calcium alginate (CA) hydrogel beads was synthesized and used in a green micro-solid phase extraction of 24 pesticides in 8 nonalcoholic malt beverages. The analyses were performed by gas chromatography–mass spectrometry/selective-ion monitoring. The DES was prepared by combining thymol (Thy, thyme oil) and methacrylic acid (MAA, can be obtained from Roman chamomile oil) in a 1:1 molar ratio via the heating-stirring method. Then, it was copolymerized using ammonium persulfate as a polymerization initiator and ethylene glycol dimethacrylate (EGDMA) as a crosslinking monomer through thermally induced free-radical reaction and finally was encapsulated in CA beads. The DES was characterized by Fourier transform infrared, Fourier transform nuclear magnetic resonance, and scanning electron microscopy techniques. A comparison study indicated that t extractionhe efficiency of the modified CA with polymeric DES (CA/[poly(MAA-co-EGDMA)]:[Thy]) was 1.5–3.4-fold higher than unmodified CA hydrogel beads. The influence of significant parameters affecting extraction efficiency was optimized. The method was validated by the matrix effect, specificity, precision, limits of quantifications (0.010–0.230 μg L–1), matrix-matched calibration linearity (0.010–300 μg L–1), and determination coefficients (r2 = 0.990–0.998). The method was successfully utilized for the detection of pesticide residues in nonalcoholic malt beverage samples, and the obtained relative recoveries were 68.2–115.6% (relative standard deviation < 10.2%). The procedure’s greenness was evaluated by the Complex Green Analytical Procedure Index and the Analytical Eco-Scale protocols. This paper is the first report on the preparation and utilization of this novel sorbent for the analysis of pesticides in nonalcoholic malt drinks.

Photobiological production of high-value pigments via compartmentalized co-cultures using Ca-alginate hydrogels

Engineered cyanobacterium Synechococcus elongatus can use light and CO2 to produce sucrose, making it a promising candidate for use in co-cultures with heterotrophic workhorses. However, this process is challenged by the mutual stresses generated from the multispecies microbial culture. Here we demonstrate an ecosystem where S. elongatus is freely grown in a photo-bioreactor (PBR) containing an engineered heterotrophic workhorse (either β-carotene-producing Yarrowia lipolytica or indigoidine-producing Pseudomonas putida) encapsulated in calcium-alginate hydrogel beads. The encapsulation prevents growth interference, allowing the cyanobacterial culture to produce high sucrose concentrations enabling the production of indigoidine and β-carotene in the heterotroph. Our experimental PBRs yielded an indigoidine titer of 7.5 g/L hydrogel and a β-carotene titer of 1.3 g/L hydrogel, amounts 15–22-fold higher than in a comparable co-culture without encapsulation. Moreover, 13C-metabolite analysis and protein overexpression tests indicated that the hydrogel beads provided a favorable microenvironment where the cell metabolism inside the hydrogel was comparable to that in a free culture. Finally, the heterotroph-containing hydrogels were easily harvested and dissolved by EDTA for product recovery, while the cyanobacterial culture itself could be reused for the next batch of immobilized heterotrophs. This co-cultivation and hydrogel encapsulation system is a successful demonstration of bioprocess optimization under photobioreactor conditions.

The viability of cell that encapsulated in calcium alginate hydrogel beads

Abstract Objective To prove that calcium alginate beads can be used as scaffolds during in vitro culture. Methods Mouse preosteoblastic cells (MC3T3-E1) were encapsulated in calcium alginate hydrogel beads. The Cell Counting Kit-8 (CCK-8) assay was used to assess cell viability at 2, 5, 8, 11, 14, and 21 days. Calcein-AM and propidium iodide (PI) were employed for live/dead staining. Results MC3T3-E1 cells were alive on day 21 and had the highest viability on day 14. Conclusion MC3T3-E1 cells could be encapsulated in calcium alginate hydrogel beads and cultured. Calcium alginate hydrogel beads can be used as scaffolds for three-dimensional in vitro culture.

Natural Polymer-Based Graphene Oxide Bio-nanocomposite Hydrogel Beads: Superstructures with Advanced Potentials for Drug Delivery.

The current study sought to create graphene oxide-based superstructures for gastrointestinal drug delivery. Graphene oxide has a large surface area that can be used to load anti-cancer drugs via non-covalent methods such as surface adsorption and hydrogen bonding. To enhance the bio-applicability of graphene oxide, nano-hybrids were synthesized by encapsulating the graphene oxide into calcium alginate hydrogel beads through the dripping-extrusion technique. These newly developed bio-nanocomposite hybrid hydrogel beads were evaluated in structural analysis, swelling study, drug release parameters, haemolytic assay, and antibacterial activity. Doxorubicin served as a model drug. The drug entrapment efficiency was determined by UV-spectroscopy analysis and was found to be high at ⁓89% in graphene oxide hybrid hydrogel beads. These fabricated hydrogel beads ensure the drug release from a hybrid polymeric matrix in a more controlled and sustained pattern avoiding the problems associated with a non-hybrid polymeric system. The drug release study of 12h shows about 83% release at pH 6.8. In vitro drug release kinetics proved that drug release was a Fickian mechanism. The cytotoxic effect of graphene oxide hybrid alginate beads was also determined by evaluating the morphology of bacterial cells and red blood cells after incubation. Additionally, it was determined that the sequential encapsulation of graphene oxide in alginate hydrogel beads hides its uneven edges and lessens the graphene oxide's negative impacts. Also, the antibacterial study and biocompatibility of fabricated hydrogel beads made them potential candidates for gastrointestinal delivery.

Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction.

The development of g-C3N4-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C3N4 nanosheet-coated alginate-based hierarchical porous carbon (g-C3N4@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C3N4 nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C3N4@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH4 system, which included photocatalytic reduction of H+ ions and photocatalytic oxidation of BH4- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.

Carboxymethyl konjac glucomannan-chitosan complex nanogels stabilized double emulsions incorporated into alginate hydrogel beads for the encapsulation, protection and delivery of probiotics

In this study, we developed (W1/O/W2) double emulsions encapsulated by calcium-alginate hydrogel beads system (ACGs) for intestinal-targeted delivery of probiotics (Lactobacillus reuteri). Firstly, the carboxymethyl konjac glucomannan-chitosan (CMKGM-CS) nanogels were successfully fabricated by EDC/NHS initiated crosslinking, as concluded from the TEM images, FTIR spectra, XRD, etc. Then, double emulsions were prepared and encapsulated with various concentrations of alginate to form ACGs hydrogel beads. In vitro probiotic release experiments showed the lyophilized ACG-2 and ACG-3 hydrogel beads had a sustained release in simulated intestinal fluid (SIF), the viability of cells exceeded 107 CFU/mL at 6 h. The lyophilized ACG-3 hydrogel beads exhibited the viable release amount of 8.4 × 107 CFU/mL after storage for 90 d at 4 °C. Besides, the alginate concentration in the ACGs hydrogel beads influences the swelling behavior and structure of hydrogel beads by affecting the hydrogen bonds between alginate and CMKGM-CS, thereby mediating the release of probiotics.

Surface-Enhanced Raman and Surface-Enhanced fluorescence of charged dyes based on alginate silver nanoparticles and its calcium alginate hydrogel beads

This study shows a new SERS (Surface-enhanced Raman Scattering) and SEF (Surface-enhanced Fluorescence) platform approach, in which substrates were constructed from the silver nanoparticles stabilized by alginate polymer (AgALG) and encapsulated in hydrogel calcium alginate beads (AgALGbead). In this regard, the electrostatic repulsion or attraction concerning the charged dyes and the carboxylate groups of the alginate could define the distances between the probe molecules and metallic nanoparticles to determine the SERS or SEF effect. In this sense, the anionic dye named New Indocyanine Green (IR-820) and the cationic dye Rhodamine 6G (Rh6G) were selected to discuss the alginate's ability to quench or enhance the fluorescence and the Raman dyes signals. Furthermore, the SEF effect using the IR-820 dye can be detected for the near-infrared emission (S1 → S0) using the 532 and 633 nm laser lines as well at the visible region (S2 → S0) applying the excitation at 532 nm in the AgALGbead substrates. Nevertheless, the cationic dye provides the Surface-enhanced Resonance Raman Scattering (SERRS) effect and quenching of the fluorescence for the same AgALGbeads substrate at 532 nm laser line.

Student explorations of calcium alginate bead formation by varying pH and concentration of acidic beverage juices

Abstract Teaching experiments involving edible, biodegradable calcium alginate beads serve as an attractive model system to introduce upper secondary age students to core chemistry topics through innovations in sustainable consumer products. A teaching experiment is described that engages students with the synthesis of calcium alginate hydrogel beads from sodium alginate and calcium lactate, two food-safe and renewable materials. The beads’ outer membranes are a result of ionic interactions between carboxylate groups from alginate strands and the divalent calcium cations between them, thus forming cross-linked polymers. Protonation of the carboxylate groups on the alginate strands decreases crosslinking density affecting bead formation. First, various concentrations of citric acid are used to lower the pH of the sodium alginate solution and the effect on the calcium alginate bead formation is observed. A correlation between pH and bead shape and firmness is derived. This information is then used to explore juices with varying natural acidities. The experiment is amenable to implementation in the classroom or as an at-home activity. Learning outcomes include acid-base reactions, chemical bonding, polymer structures, and green chemistry concepts. Students consider the environmental challenges of traditional plastics used in packaging and how innovative new commercial products are attempting to provide solutions.

Highly efficient and reusable BiOCl photocatalyst modulating by hydrogel immobilization and oxygen vacancies engineering

• BiOCl nanosheets are immobilized by calcium alginate hydrogel through a simple crosslinking process. • BOC-CA hydrogel beads can float on the water surface. • The hydrogel beads show enhanced photocatalytic effect during the cycled ultraviolet irradiated degradation process. • The porous structure of the beads provides channels for the transport of ultraviolet induced OVs of BiOCl photocatalysts. • The hydrogel beads have excellent recovery rate and high photocatalytic efficiency over 24 degradation cycles. Photo-induced oxygen vacancies (OVs) are widely introduced as active sites in BiOCl to improve photocatalytic performance. Herein, we propose a strategy to take advantage of OVs of BiOCl nanosheets, which are immobilized in the network of water-rich calcium alginate (CA) hydrogel beads. By modulating the porous structure of the hydrogel, the OVs irradiated by UV light on the surface of BiOCl can be rapidly diffused to the deep inner of the beads, and then they disappear after the beads are immersed into the water for hours, which further enables the regeneration of even better BiOCl-CA beads. This reactive cyclic channel in a water-rich environment improves the transport of photogenerated carriers and achieves excellent cyclic photocatalytic performance. This work not only improves the recovery efficiency of photocatalytic materials but also puts forward a new system of BiOCl based hydrogel beads that can be used repeatedly in wastewater treatment.

Formaldehyde biosensing in air using fluorescent bacterial bioreporter cells

ABSTRACT Formaldehyde is a genotoxic volatile organic pollutant and one of the causative agents of sick building syndrome. Despite of its hazardous carcinogenic effects, it has been still used in daily life products and household materials. Hence, determination of formaldehyde both in ambient air and drinking water sources is crucial to prevent its adverse health effects. Whole-cell biosensors have emerged as bio-sentinels for environmental monitoring to assess pollution in air, water and soil. Herein whole-cell bacterial bioreporter was developed based on a DNA damage response gene promoter and green fluorescent reporter protein, and the cells were entrapped in calcium-alginate hydrogel beads for sensitive detection of formaldehyde in air. Immobilisation enables portability, on-site detection ability and integration into mobile devices. Alginate bead-immobilised bioreporter could successfully detect formaldehyde in gas phase at concentration minimum of 8.1 ppm. This detection limit is useful for monitoring cumulative doses of bioavailable gaseous formaldehyde and taking precaution to avoid acute toxicity of formaldehyde. The developed bioreporter system is simple, low-cost, performable at room temperature and free of sample pre-treatment. The findings of this study will facilitate future research for the creation of portable and user-friendly devices for on-site and real-time environmental formaldehyde gas detection.

Slow-delivery and distributed exchange of cryoprotective agents with hydrogel beads

Intracellular loading of cryoprotective agents (CPAs) into target cells is a critical step for cryopreservation. However, biological membranes are usually much less permeable to CPAs than to water, resulting in high osmotic pressures and osmotic damage during the CPA loading and unloading phases of cryopreservation. Here, we show that calcium alginate hydrogel beads several millimeters in diamater containing CPAs can be admixed with a cell suspension to spontaneously release CPAs in a gradual and distributed manner. We demonstrate that beads containing cell media enable the gradual removal of CPA from Jurkat cells equilibrated in a typical cryopreservation solution of 15% glycerol, protecting the cells from hypotonic damage. We show that the dynamics of CPA exchange are accurately described by a numerical model of free diffusion within the gel. This approach may enable semiautomated and closed methods of gradual CPA exchange from large volume cell suspensions.

Removal of Nitrate Nitrogen by Rhodotorula graminis Immobilized in Alginate Gel for Groundwater Treatment

Groundwater is the source of all tap water in Kumamoto City, Japan. However, the concentration of nitrate nitrogen (NO3−-N) tends to increase every year due to the influences of overfertilization, field disposal of livestock manure, and inflow of domestic wastewater. A heterotrophic nitrification–aerobic denitrification (HN-AD) system is an attractive approach for nitrate-nitrogen removal. In this study, Rhodotorula graminis NBRC0190, a naturally occurring red yeast that shows high nitrogen removal performance in glucose, was immobilized on calcium alginate hydrogel beads. NO3−-N removal efficiency exceeded 98% in the region of NO3−-N concentration below 10 mg/L in the model groundwater. Even after the same treatment was repeated five times, the denitrification performance of the R. gra immobilized alginate hydrogel beads was maintained. Finally, when this treatment method was applied to actual groundwater in Kumamoto City, it was possible to make the water of even higher quality.

Dual-functional calcium alginate hydrogel beads for disinfection control and removal of dyes in water

For the decontamination of both pathogenic microorganism and toxic dye from wastewater, new type of materials should be exploited to fabricate more cost-effective, eco-friendly biosorbent. Herein, a promising hydrogel beads based on the incorporation of nano‑silver/diatomite into calcium alginate (named as Ag-DE@CAH) was designed to disinfect water and remove methylene blue (MB). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM), etc. were utilized for characterization analysis. Compared with nano‑silver/diatomite (Ag-DE), the novel Ag-DE@CAH beads displayed a better sustained release profile for Ag+, and it noteworthy that the concentration of Ag+ in aqueous media is below the limit of the World Health Organization (WHO) standard (100 ppb) for a 30-days release experiment. It was found that Ag-DE@CAH beads exhibited better disinfection ability towards Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus), and the maximum adsorption capacities of Ag-DE@CAH for MB was 128.21 mg/g. In addition, the as-prepared Ag-DE@CAH beads showed superior and reusable performance in the process of adsorption experiments for MB. Overall, the study indicates that the materials with both excellent disinfection and adsorption properties have potential application prospects for water purification.

Preparation and Antimicrobial Properties of Alginate and Serum Albumin/Glutaraldehyde Hydrogels Impregnated with Silver(I) Ions

Calcium alginate (CaALG) hydrogel beads and two sets of composite beads, formed from a combination of calcium alginate/propylene glycol alginate/human serum albumin (CaALG/PGA/HSA) and from calcium alginate with the quaternary ammonium salt, (3-(trimethoxysilyl)propyl)-octadecyldimethylammonium chloride (QA), (CaALG/QA), were prepared. Bovine serum albumin (BSA) was condensed with glutaraldehyde (GLA) to form a BSA/GLA hydrogel. The corresponding Ag+-containing gels of all of the above hydrogels were also formed, and slow leaching of the biocidal transition metal ion from the gels bestowed broad spectrum antimicrobial activity. In the absence of added Ag+, CaALG/QA was the only material to deliver marginal to moderate antibacterial and antifungal effects. The Ag+ impregnated hydrogel systems have the potential to maintain the antimicrobial properties of silver, minimising the risk of toxicity, and act as reservoirs to afford ongoing sterility.

Effective Removal of Cyanide and Heavy Metals from an Industrial Electroplating Stream Using Calcium Alginate Hydrogels.

A real electroplating wastewater, containing 51,190 mg/L of free cyanide (CNf), 4899 mg/L of Ni and 1904 mg/L of Cu, was treated with calcium alginate hydrogel beads (CAB), pure or impregnated with biodegraded grape marc (EBGM) or activated carbon (EAC) in order to reduce the elevated load of toxic pollutants below the regulatory limits. It was evaluated the effect of increasing the amount of bioadsorbent as well as the influence of two successive adsorption cycles in the removal efficiency of pollutants. The most favourable sorption conditions onto CAB provided removal percentages of 85.02% for CNf and between 93.40–98.21% for heavy metals regarding the raw wastewater. The adsorption capacity of each pollutant onto CAB was considerably increased during the first 30 min of contact time, but after achieving the equilibrium, the following sorption capacities were obtained: 1177, 107.3, 39.5 and 1.52 mg/g for CNf, Ni, Cu and Zn, respectively. The kinetic adsorption of pollutants onto the CAB was adjusted to different kinetic models, observing that kinetic data agreed with the pseudo-second-order model. The information about intraparticle diffusion mechanisms in the bioadsorption process was also interpreted.

Formation and characterization of calcium alginate hydrogel beads filled with cumin seeds essential oil

Preparation and characterization of novel encapsulation system based on calcium alginate hydrogels filled with cumin essential oil has been investigated. Firstly, the effect of sodium alginate concentration, CaCl2 level, hardening time, encapsulation and emulsion fabrication methods was studied on loading capacity of the hydrogels using a Resolution-V fractional factorial design (2 V5−1 FFD), followed by response surface methodology (RSM). At the optimum point, the in-vitro release of phenolic compounds in simulated gastric and intestinal mediums were 96.02 ± 0.96% and 10.65 ± 1.23% after 180 min, respectively. The Scanning electron microscopy (SEM) images demonstrated a relatively smooth surface with small pore size. Based on SEM images and Fourier-transform infrared spectrums, the cumin essential oil was encapsulated successfully in calcium alginate beads. Thus, calcium alginate hydrogel could be introduced as a promising carrier for encapsulating biochemical active compounds with favorable features.