Search Results (193)

Dialdehyde crosslinked poly aspartate/alginate hydrogel beads were synthesized by covalently introducing poly aspartate into the alginate network via dialdehyde-mediated crosslinking, and the resulting effects on swelling and adsorption behavior were investigated. Alginate was partially oxidized to form dialdehyde alginate and crosslinked with poly aspartic acid via Schiff base formation, followed by ionic crosslinking with calcium ions. The chemical structure and morphology of the gel beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Incorporation of PAsp significantly altered the swelling behavior of alginate-based gel beads. In saline solution, PAsp-modified gel beads exhibited a swelling ratio of approximately 112 g/g, which was higher than that of calcium alginate gel beads. This behavior is suggested to be associated with changes in the alginate–calcium network structure induced by polymer modification. PAsp-modified gel beads exhibited moderate but distinct adsorption behavior depending on the adsorbate. Removal efficiencies of approximately 40–50% were observed for copper and cobalt ions, while a removal efficiency of around 50% was obtained for the cationic dye crystal violet. In contrast, adsorption of the anionic dye Congo red decreased with increasing PAsp content, indicating charge-dependent adsorption behavior. Overall, this study demonstrates that PAsp modification via dialdehyde-mediated crosslinking influences both the swelling and adsorption properties of alginate-based hydrogel beads. The results provide fundamental insight into how network modification can be used to tune the behavior of alginate-based hydrogels in aqueous environments. Full article

The detailed characterization of antigen-specific serum antibodies is hindered by the lack of efficient, gentle isolation methods. In this context, standard column affinity chromatography, although a powerful purification tool, presents practical challenges, including high antigen consumption and elution conditions that risk inducing antibody polyreactivity, while conventional acidic elution often compromises antibody integrity. This study introduces a novel microscale method for isolating specific immunoglobulins using anionic detergents as mild eluents. We employed antigen-functionalized hydrogel microarrays and magnetic beads as micro-immunosorbents. Among the tested detergents, sodium lauroyl glutamate (SLG) was optimal, achieving up to 78.3% recovery of functional antibodies. The optimized protocol, including recovery via G25-Sephadex gel filtration, effectively isolated specific antibodies from complex serum, retaining 58.5–85.3% of their functional bioactivity. Multiplex immunoassays confirmed the high specificity of the isolated antibodies and the lack of detergent-induced polyreactivity. The method was successfully adapted to isolate both specific antibodies (virus, dietary, and autoimmune) and total IgG, demonstrating versatility across platforms. This work establishes a robust, efficient, and gentle workflow for obtaining high-purity, bioactive antibodies, enabling their subsequent in-depth analysis for research applications. Full article

Pollution by Sb, which is widely used in industry and agriculture, poses serious threats to ecosystems. This study demonstrates, for the first time, that sodium alginate (ALG) modified by polyethyleneimine (PEI) has good adsorption capacity for Sb(III) (the theoretical maximum adsorption capacity was 978 mg/g, and the actual maximum adsorption capacity was 743 mg/g) and can retain 90–98% of the initial removal rate after eight cycles of reuse. The inorganic ions and humic acid in Sb(III)-containing wastewater do not affect the adsorption capacity of PEI/ALG within a certain pH range. However, it was also found that the adsorption was interfered with by Sb(III) precipitation, phosphate ions, and some coexisting cations/metalloids such as Ni, Cd, Pb, and As under higher pH conditions, and the recovery rate of antimony in the desorption process needs to be further improved. Density functional theory calculations reveal that the -OH, -COOH, -NH₂, -NH-, and -N= in PEI/ALG show strong binding with Sb (−56.85, −28.39, −17.98, −25.76, and −17.98 kcal/mol, respectively), enabling these functional groups to easily form stable composite structures with Sb(III). This characteristic enables PEI/ALG to selectively adsorb Sb(III) under certain conditions. Combining these findings with the characterization analysis results indicates that the mechanism of PEI/ALG adsorption of Sb(III) is mainly the formation of H bonds and coordination between -OH, -COOH, and Sb(III). The selective adsorption mechanism of PEI/ALG for Sb(III) has not been investigated previously, and our research results indicate the high potential of this approach. Full article

Background: Isoconazole nitrate (ISN), an antifungal agent that inhibits ergosterol synthesis by blocking lanosterol 14α-demethylation, is widely used to treat candidiasis, and improving its skin retention and permeability can enhance its therapeutic efficacy. Therefore, we developed an ISN nanoparticle (ISN-NP) gel by wet-bead milling in the presence of methylcellulose (MC). Methods: These ISN nanoparticles were incorporated into a carboxypolymethylene hydrogel (Carbopol). The ISN concentration was measured using HPLC, and Wistar rats and Candida albicans were used to evaluate skin absorption and antifungal activity, respectively. Results: The ISN-NP gel exhibited a particle size distribution ranging from 60 to 220 nm, with the nanoparticles remaining stable. In addition, the ISN-NP gel demonstrated superior antifungal activity against Candida albicans. The Carbopol gel maintained appropriate viscosity and physical stability, and the ISN nanoparticles were released from the gel. Compared with microparticle-based gels (ISN-MP gels), the ISN-NP gel showed significantly enhanced drug release and transdermal permeation, with 1.54- and 1.7-fold increases, respectively. Conclusions: These findings indicate that incorporating ISN nanoparticles (nanocrystalline ISN) into a Carbopol-based gel matrix provides a promising strategy to enhance the topical delivery of this poorly water-soluble antifungal drug. Overall, this nanogel system represents a valuable platform for transdermal delivery in clinical applications. Full article

Using Microcystis aeruginosa as the raw material, the microalgae was modified through a potassium permanganate–ferrous sulfate treatment process to prepare Fe-Mn oxide-modified algal powder. Sodium alginate was then combined with this modified powder to create Fe-Mn-modified algal powder gel beads, which were employed for the adsorption of Cd(II) from water. At pH = 9, with dosage of 6 g·L⁻¹ and a contact time of 8 h, the Cd(II) solution at an initial level of 1.0 mg·L⁻¹ achieved a removal efficiency of 96%, and the maximum adsorption capacity is 15.06 mg·g⁻¹. The adsorption behavior conformed to the Langmuir isotherm and obeyed the pseudo-second-order kinetics, and was primarily governed by chemical adsorption. This involved complexation with hydroxyl (-OH) and carboxyl (-COO⁻) functional groups, the ion exchange of Ca²⁺ with Cd(II), and surface complexation on Fe-Mn oxides. This study provides a valuable basis for the resource utilization of algae and the remediation of Cd contamination. Full article

In the field of water treatment, the development of efficient and environmentally friendly antibacterial materials to combat pathogenic contamination is of great significance. This work aimed to synthesize copper nanoparticles (CuNPs) using Rosa roxburghii extract (RRT) and Trichoderma harzianum mycelia-free cell filtrate (MFCF) as reducing agents. It was found that RRT-CuNPs had higher antibacterial ability than MFCF-CuNPs. Therefore, RRT-CuNPs were selected for further study. Through a functionalization modification strategy, polyvinyl alcohol (PVA) and chitosan (CTS) served as carrier matrices, with RRT-CuNPs as the highly efficient antibacterial active component and montmorillonite (MMT) as a reinforcing filler. The CTS/PVA/MMT/RRT-CuNPs composite gel beads were successfully fabricated via a cross-linking and blending method. For RRT-CuNPs-based gel beads, Fourier transform infrared spectroscopy (FTIR) displays that the composite hydrogel particles contain characteristic peaks of PVA, CTS, and MMT. By comparison, it is confirmed that MMT acts as both a reinforcing agent and a molecular structure regulator through interfacial interactions. X-ray diffraction (XRD) shows that MMT and CuNPs are dispersed in the particles. The study illustrates that the optimal initial concentrations of MMT, CTS, and CuNPs added to RRT-CuNPs-based composite gel beads were 4, 30, and 0.5 g/L, respectively. The prepared composite gel beads exhibited significant inhibitory activity towards Gram–positive bacteria (S. aureus) and Gram–negative bacteria (P. aeruginosa and E. coli), acquiring inhibition zone diameters of nearly 21 mm. As the dose of gel beads was 0.3 g/L and the action time was four h, the inhibition rate reached 100% through the plate counting method analysis. In conclusion, RRT-CuNPs-based composite gel beads have excellent antimicrobial activity, showing high potential application in the fields of water treatment. Full article

Profile control is widely employed to improve oil recovery in fractured-vuggy carbonate reservoirs. However, the limitation of current experimental evaluation methods restricts their practical guidance for field applications. In this study, urea-formaldehyde resin gel (URG) is studied using SEM, rheological analysis, FTIR, and Raman spectroscopy. Typical structural models of fractured-vuggy reservoirs are fabricated by 3D printing technology. The distribution patterns of the URG in different fractured-vuggy models are also investigated by using online NMR analysis and core slice characterization. Results show that URG exhibits a kind of 3D mesh structure with a size of 10 μm after gelation at 140 °C. The storage modulus (G′) and loss modulus (G″) of the URG gel are 387.51 Pa and 131.48 Pa, respectively. Chemical composition analysis reveals that URG is mainly composed of amide groups and sulfonate groups, showing excellent thermal stability and salt tolerance. Furthermore, after injecting URG into three types of typical models, URG displays a longitudinally decreasing distribution pattern from the injection side to the outlet side, accompanied by transverse accumulation phenomenon along the fracture walls in the slab fracture model. In the fractured-vuggy model, the gel shows continuous longitudinal distribution and uniform transverse distribution characteristics. In the beaded-vug train model, the gel’s distribution morphology gradually transforms from a “pipeline-filling” pattern at the injection side to a “conduit-dominant” pattern toward the outlet side, with a stepped distribution in the transverse direction. The breakthrough pressures during subsequent water flooding are as follows: beaded-vug train model (11.6 MPa) > fractured-vuggy model (8.1 MPa) > slab fracture model (5.9 MPa). Field application results show that the water cut is reduced from 85% to 30%, with a total incremental oil production of 2416 tons. This study conducts experimental investigations on the distribution patterns of URG in simulated fractured-vuggy models, thereby establishing a novel technical evaluation method for profile control in actual fractured-vuggy carbonate reservoirs. Full article

Antimony (Sb), as a toxic heavy metal, has drawn worldwide attention, and its efficient removal from water has become increasingly urgent. In this study, an iron-modified alkaline lignin chitosan (Fe-ALCS) gel bead is prepared by the freeze-drying method to remove Sb(III) from the aqueous solution. The static adsorption experiment discusses the various environmental influences on the adsorption performance of Fe-ALCS for Sb(III) removal. The adsorption mechanism is explored by combining adsorption kinetics, isothermal adsorption, and characterization methods (such as FTIR, XRD, XPS, etc). The results show that the equilibrium adsorption capacity of Sb(III) decreases with the increase in pH and mass–volume ratio. With the increase in the initial Sb(III) concentration, Q_e showed a rapid increasing trend in the range of 50–100 mg/L and continued to rise with the extension of contact time (t), reaching the maximum value at 3540 min. Under the optimal conditions of pH = 3, m/v = 1.0 g/L, and C₀ = 20 mg/L, the removal efficiency (R_e) value is 95.07%, which is still approximately 86.8% after five adsorption–desorption cycles. The maximum adsorption capacity is 266.58 mg/g fitted by the Langmuir model. The adsorption mechanism is mainly related to the iron-based active site of Fe–O(OH), where the O–H on its surface undergoes ligand exchange with Sb(OH)₃ to form a stable Fe–O–Sb coordination structure. Additionally, C–OH, C–O, and other functional groups in ALCS also contribute to Sb adsorption. Fe-ALCS is an environmentally friendly, renewable, and convenient biomass adsorbent with good potential for wastewater treatment. Full article

The effect of varying sodium alginate (SA) concentrations (1%, 2%, and 3%; SA1–SA3) on the encapsulation of tangerine (Citrus reticulata Blanco ‘Cho Khun’) peel extract (TPE, 0.5% w/v) into hydrogel beads was evaluated. Overall, the results showed that increasing SA concentration significantly altered bead characteristics: lightness (L*) decreased from 56.35 to 45.57, red-green axis (a*) shifted negatively from −1.32 to −6.87, and yellow-blue axis (b*) increased from −17.81 to 6.41. Moisture content (97.85% to 93.16%) and water activity (0.96 to 0.93) declined with higher SA, while hardness increased (4.12 to 5.17 g). ζ-potential values shifted from −29.10 mV (SA1) to −39.10 mV (SA3), confirming enhanced electrostatic stabilization. FTIR spectra revealed characteristic alginate functional groups, and morphological analysis showed smoother, denser beads at higher SA concentrations. Phenolic (47.86–48.51 mg GAE g⁻¹ DW) and flavonoid (34.02–36.68 mg QE g⁻¹ DW) contents were well-retained, supporting antioxidant activities (DPPH 70.34–72.54%; ABTS 65.66–66.91%). Antimicrobial tests demonstrated > 4-log reductions against E. coli and P. aeruginosa. Sensory evaluation revealed that higher SA concentrations improved texture and taste. Overall, SA encapsulation, particularly at 3%, effectively stabilized TPE, preserving its functional properties for potential food and nutraceutical applications. Full article

In this study, red mud (RM) was utilized as an iron and aluminum source, and reed biomass served as a carbon precursor to prepare red mud-modified biochar beads (RM/CSBC) via the gel-calcination method. Under a pyrolysis temperature of 900 °C and an RM/biomass dosage of 3 g each, RM/CSBC exhibited an optimal balance between adsorption performance and cost. Within typical pH range of 6–9 in wastewater, RM/CSBC maintained effective adsorption performance, while metal ion leaching (Fe ≤ 0.3 mg·L⁻¹, Al ≤ 0.2 mg·L⁻¹) complied with Class II surface water standards in China. Kinetic data were well fitted by the pseudo second-order model, supported by the Elovich model, indicating the involvement of both chemical and physical adsorption mechanisms. Isotherm results showed that the Langmuir model provided the best fit, indicating monolayer adsorption, with a maximum capacity of 85.16 mg·g⁻¹ at 25 °C. XPS analysis revealed the formation of AlPO₄ and FePO₄ precipitates, confirming chemical precipitation as a key mechanism, along with electrostatic attraction and physical sorption. This study highlights the feasibility of RM/CSBC as an efficient and low-cost phosphate adsorbent and provides a theoretical basis for phosphorus removal and recovery from wastewater using waste-derived materials. Full article

Infection control and bleeding management in deep wounds remain urgent and unmet clinical challenges that demand innovative, multifunctional, and sustainable solutions. Unlike previously reported sodium alginate and silk fibroin-based gel formulations, the present work introduces a dual-functional system combining antimicrobial and haemostatic activity in the form of conformable aerogel beads. This dual-functional formulation is designed to absorb exudate, promote clotting, and provide localized antimicrobial action, all essential for accelerating wound repair in high-risk scenarios within a single biocompatible system. Aerogel beads were obtained by supercritical drying of a silk fibroin–sodium alginate blend, resulting in highly porous, spherical structures measuring 3–4 mm in diameter. The formulations demonstrated efficient ciprofloxacin encapsulation (42.75–49.05%) and sustained drug release for up to 12 h. Fluid absorption reached up to four times their weight in simulated wound fluid and was accompanied by significantly enhanced blood clotting, outperforming a commercial haemostatic dressing. These findings highlight the potential of silk-based aerogel beads as a multifunctional wound healing platform that combines localized antimicrobial delivery, efficient fluid and exudate management, biodegradability, and superior haemostatic performance in a single formulation. This work also shows for the first time how the prilling encapsulation technique with supercritical drying is able to successfully produce silk fibroin and sodium alginate composite aerogel beads. Full article

Low-temperature dried alginate/silica hybrid aerogel beads with a large specific surface area (160.8 m²/g), low density (0.160 m²/g), and high degree of sphericity were successfully fabricated. Single networks of silica aerogels beads were synthesized via by calcining hybrid aerogel beads in air. Moreover, alginate-derived carbon/silica aerogel beads were also obtained by the thermal treatment of the hybrid aerogel beads in nitrogen, which were indicative of the double networks of the as-synthesized crack-free hybrid aerogel beads for the first time. The adsorption performances of above aerogel beads were also investigated. Meanwhile, using a common silane coupling agent as a modifying agent, a series of hybrid aerogel beads with tunable functional surfaces were obtained. The results showed that the obtained samples adsorbed Pb²⁺ well, and the hybrid aerogel beads modified with KH-590 exhibited an experimental maximum adsorption capacity of Pb²⁺ of 193.73 mg·g⁻¹. Full article

This study investigates the enhancement of nitrogen removal performance in an intermittent biological sponge iron system (BSIS) through the immobilization of aerobic denitrifying bacteria. The aim is to improve the efficiency of simultaneous nitrification and denitrification (SND) in the BSIS by optimizing the microbial community involved in nitrogen conversion. The immobilization technique not only stabilizes the microbial activity and abundance of aerobic denitrifying bacteria, but also promotes a more efficient denitrification process. The optimal material ratio of polyvinyl alcohol–sodium alginate gel beads was determined as 10 g/100 mL PVA, 4 g/100 mL SA, 2 g/100 mL CaCl₂, and 2 g/100 mL of bacterial suspension, achieving a maximum NO₃⁻-N removal rate of 91.73%. A response surface model (RSM), established for the operational conditions, (shaker speed, temperature, and pH) showed a high fitting degree (R2 = 0.9960) and predicted the optimal conditions for maximum NO₃⁻-N removal as 109.24 rpm, 23.6 °C, and pH 7.9. Compared to R1 (47.82%), R3 achieved a higher average total nitrogen (TN) removal rate of 95.49%, following the addition of immobilized aerobic denitrifying bacteria to the BSIS. Full article

Chitosan gel beads represent a promising biopolymer-based delivery system for encapsulating Bacillus subtilis, an effective biocontrol agent in sustainable agriculture. This study investigates the influence of chitosan molecular weight on bead structure, water retention, and swelling behavior, as well as its impact on the viability and antifungal activity of encapsulated B. subtilis. The results demonstrate that chitosan provides a protective microenvironment, enhancing microbial viability, promoting colonization, and ensuring controlled release for prolonged plant protection. Moreover, encapsulation within chitosan gel beads preserved bacterial viability during long-term storage for up to 90 and 180 days. Additionally, the biodegradable and antimicrobial properties of chitosan contribute to pathogen suppression while supporting the plant growth-promoting activities of B. subtilis. The encapsulated bioagent exhibited strong antifungal activity against Fusarium avenaceum and Rhizoctonia solani, highlighting the effectiveness of this eco-friendly approach as an alternative to chemical pesticides. These findings underscore the potential of chitosan-based formulations to enhance the efficacy of bioinoculants, offering a sustainable solution for modern crop management. Full article

Atmospheric water harvesting (AWH) is a promising alternative to address immediate water needs. Desiccant-based AWH could compete effectively with other commercially available AWH technologies. One of the primary challenges facing desiccant-based AWH is the energy required to desorb the captured water vapor from the desiccant. This work presents a multi-faceted approach targeted explicitly at low-humidity and arid regions, aiming to overcome the limitations of the refrigerant-based AWH system. It includes assessing common desiccants (zeolite, activated alumina, and silica gel) and their forms (beads, powdered, or coated on a substrate). A bench-scale test rig was designed to evaluate different types and forms of desiccants for adsorption and desorption cycles and overall adsorption capacity (g/g), kinetic profiles, and rates. Experimental results indicate that beaded desiccants possess the highest adsorption capacity compared to powdered or coated forms. Furthermore, coated desiccants double the water uptake (1.12 vs. 0.56 g water/g desiccant) and improve adsorption/desorption cycling by 52% compared to beaded forms under the same conditions. Additionally, Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and dynamic vapor sorption (DVS) analysis show the pore geometry, morphology, and sorption capacity. The goal is to integrate these performance improvements and propose a more effective, energy-efficient desiccant-based AWH system. Full article