A new hydrogel nanocomposite, sodium alginate-g-poly(acrylic acid)/montmorillonite (SA-g-P(AA)/MMT), was created using free radical polymerization. The purpose was to test its ability to remove Azur B dye. Detailed analysis using techniques like FTIR, XRD, FESEM, and EDX confirmed the synthesis of the material, revealing characteristic functional groups, a change in the MMT's crystalline structure, and a porous surface morphology. The poly(acrylic acid) was effectively grafted onto sodium alginate, and montmorillonite was incorporated. This process resulted in a porous and amorphous structure ideal for adsorption. Adsorption tests yielded excellent results, with a maximum removal efficiency of 97.13% achieved. The material demonstrated capacity of 1942.80 mg/g. Optimal conditions were found to be pH 1.2, 30 °C, and a 180 min. Kinetic studies determined that the adsorption process followed a pseudo-second-order mechanism. Thermodynamic analysis indicated that the process was spontaneous (ΔG = −14.35 kJ/mol) and endothermic (ΔH = 18.88 kJ/mol). The Temkin model (R² = 0.986) provided the best fit for the adsorption isotherm, indicating a heterogeneous surface with consistent binding energy. The nanocomposite also exhibited pH-responsive swelling, which enhanced its performance in acidic environments (swelling of 590% at pH 10). These findings confirm that SA-g-P(AA)/MMT nanocomposite is a pH-sensitive adsorbent, making it a promising material for water treatment. KEY WORDS: Azur B dye, Hydrogel, Clay, Nanocomposite, Adsorption, Water treatment Bull. Chem. Soc. Ethiop. 2026, 40(3), 533-550. DOI: https://dx.doi.org/10.4314/bcse.v40i3.4

Abstract Emerging contaminants pose significant risks to environmental and human health, warranting detailed investigation. Among these contaminants, pharmaceuticals and their metabolites are of particular concern, as they are widely released into the ecosystem. Their chemical and biological stability contributes to their persistence in aquatic systems and limits the effectiveness of conventional water treatment technologies. Adsorption is one of the most commonly used advanced treatment techniques for removing pharmaceuticals due to its favorable operation and cost-effectiveness. The use of adsorbents obtained through biotechnological processes has emerged as a promising approach due to their efficiency and environmental sustainability. Promising biotechnological adsorbents include live microorganisms such as fungi, bacteria, and microalgae. Dead or inactive biomass also shows applicability, being considered lower in cost. Additionally, algae and adsorbents based on natural polymers obtained through biotechnological processes, such as sodium alginate, bacterial cellulose, and chitosan, stand out. Biocomposites enable the combination of desirable characteristics from more than one material, resulting in adsorbents with better performance and lower environmental impact compared to conventional alternatives. Moreover, adsorption processes employing biocomposites often operate under mild conditions, such as neutral pH and ambient temperature, further increasing their applicability. Thus, this literature review aims to explore the application of adsorption processes for the removal of pharmaceuticals from water using adsorbents derived from biotechnological processes.

Nonspecific adsorption remains a persistent obstacle in biosensing applications, as it adversely impacts key performance indicators of biosensors such as sensitivity, specificity, and operational stability. Although conventional antifouling peptides have achieved much success, their practical utility is often constrained by susceptibility to enzymatic hydrolysis as natural enzymes exist in biological fluids. Herein, a robust nonfouling biosensor is proposed based on a newly designed peptide (δ-P) with both antifouling, antienzymatic degradation and recognition capabilities, functionalized with a δ-L-lysinyl-L-glutamic acid dimer. Crucially, the antifouling domain of the peptide is composed of a δ-L-lysinyl-L-glutamic acid dimer (glutamic acid with the lysine side chain), and the recognition domain specific for the protein ANXA1 is composed of D-type amino acids, and both of them are capable of resisting enzymatic degradation. Two types of proteases (alkaline protease and trypsin), which represent less site-specific and site-specific cleavage proteases, respectively, were tested to illustrate proteolysis. Taking advantages of the designed peptide, a highly sensitive and low-fouling electrochemical biosensor (with a linear range of 0.001-1000 ng mL-1 and a detection limit of 0.32 pg mL-1), capable of assaying protein ANXA1 in human sera, was prepared by attaching the peptide onto the electrode modified with a poly(3,4-ethylenedioxythiophene)-sodium alginate (PEDOT@SA) film and gold nanoparticles. More interestingly, the biosensor showed satisfactory accuracy for the detection of ANXA1 in undiluted clinical serum samples (verified by the ELISA method). It is anticipated that the peptide designing strategy presented in this work can be easily extended to the development of various robust antifouling biosensors capable of assaying targets in complex biological environments.

Because polyamide-cured epoxy resin (EP) can be cured at room temperature or at low temperatures (<100 °C), it brings great convenience to practical applications. However, the structure makes it have poorer thermal properties and is more prone to combustion. Herein, the bio-based intumescent flame retardant alginate derivative (SAPM) was synthesized using biomass sodium alginate reacting with phosphate and melamine, and it was applied to EP. The results show that the modified EP containing 16 wt% SAPM can pass the UL-94 V-0 level, and its limiting oxygen index (LOI) increases from 22.0% for pure EP to 28.2%. Thermogravimetric results indicate that SAPM significantly improves the thermal stability of EP composites at high temperatures. Compared to pure EP, the modified EP exhibits a 62% reduction in peak heat release rate and a 42% decrease in total heat release. Meanwhile, both the total smoke release and smoke release rate also show a significant decrease, while CO and CO2 emissions are effectively suppressed. The char residues reveal that the EP with SAPM could form a dense, continuous, and smooth outer char shell. This work offers novel perspectives on the efficient utilization of alginate and the development of green and effective intumescent flame retardants.

Enhancing structural, optical and electrical properties of carboxymethyl cellulose/sodium alginate hybrid polymer films with CoCl2 for solid-state battery applications.

Sodium alginate-immobilized epoxide hydrolase: A multifaceted strategy for enhanced stability, reusability, and catalytic performance.

Nanogel therapy for chronic and post-surgical wounds: a bioengineered Lactoferrin-Acacia-Alginate system enhancing tissue regeneration and inflammatory resolution.

α-Cyclodextrin mediated 3D printed ceramic/polymer composite scaffolds for immunomodulation and osteogenesis in bone defect repair.

Although Tremella fucitormis is a kind of nutritious edible fungi, wildly accepted by the public, its original elastic texture and appearance are not suitable for the growing elderly people with dysphagia. This work aimed to use microwave drying to fabricate suitable appearance and textural properties of 4D printed nutritious Tremella fucitormis-based food with high shape fidelity for the elderly people with dysphagia, considering the amount of sodium alginate addition (0.86%, 0.97%, 1.08%, 1.18% and 1.29%), and the microwave drying duration (0, 10, 20, 30 and 40 s). Results showed that sodium alginate addition obviously increased the apparent viscosity, hardness, elasticity, chewiness, adhesion, cohesion and shape stability of such foods; however, higher flow behavior showed negative impact. The sample with 1.08% sodium alginate exhibited the best shape fidelity (>95%). As the microwave drying duration increased, the deformation degrees of the printed flower with four petals simultaneously increased, showing an expected deformable 4D printing “blooming” behavior. Morphological differences between printed and cast samples suggested that, to the preparation of such highly viscoelastic materials, microwave drying and 4D food printing was helpful. International dysphagia diet standardization initiative (IDDSI) tests indicated that such food could be classified as level 5-minced and moist diet, which was suitable for people with dysphagia.

Pinus sylvestris var. mongolica is a naturally susceptible host for the pine wood nematodes (PWNs, Bursaphelenchus xylophilus) and a dominant afforestation tree species in northeastern China. With the continuous northward expansion of PWNs, P. sylvestris var. mongolica may become a critical conduit for their further expansion. To prevent pine wilt disease (PWD) from spreading via P. sylvestris var. mongolica in northeastern China, it is essential to elucidate its defense mechanisms against PWN and enhance its resistance. Transcriptome analysis of P. sylvestris var. mongolica following inoculation with PWNs revealed the involvement of chalcone synthase (chs) genes in the flavonoid biosynthesis pathway, indicating their crucial role in the interaction between P. sylvestris var. mongolica and PWN. Treatment with elicitors known to induce chs gene expression-chitosan (CTS), chitosan oligosaccharide (COS), and sodium alginate (NaAlg)-delayed the progression of PWD, with NaAlg exhibiting the strongest protective effect. Differentially expressed genes (DEGs) enriched in the pathways related to flavonoid biosynthesis were observed following treatment with 100 mg/L NaAlg, and upregulated expressions of chs genes. This treatment also increased the abundance of key flavonoid pathway metabolites, including phloretin, chrysoeriol, and L-tyrosine. However, inoculation with PWN following 100 mg/L NaAlg treatment downregulated expressions of chs genes and consumed phloretin, chrysoeriol, and L-tyrosine, while promoting the accumulation of p-coumaryl alcohol. The expression of chs genes plays a critical role in the defense of P. sylvestris var. mongolica against PWN infection. Spraying 100 mg/L NaAlg solution before PWN infection activates chs genes in P. sylvestris var. mongolica, regulating the levels of L-tyrosine, phloretin, chrysoeriol, and p-coumaryl alcohol to enhance self-resistance against PWN, thereby delaying the progression of PWD in P. sylvestris var. mongolica. © 2025 Society of Chemical Industry.

Multifunctional sodium alginate/nanocellulose fibers/chitosan edible coating: A sustainable strategy for prolonged fruit preservation and reduced cold-chain dependency.

Sequence-dependent assembly of whey protein‑sodium alginate-steviol glycoside ternary complexes: Mechanistic insights and functional modulation.

Development and characterization of a novel polymeric nanocomposite based on sodium alginate and polycaprolactone with green magnesium nanoparticles: In vitro safety profile, antibiofilm activity, phytotoxicity and UV photodegradation

Tailoring the structure and functionality of Akebia trifoliata seed protein through Maillard-mediated conjugation with polysaccharide in aqueous media.

Biodegradable and osteoconductive sodium alginate-gelatin/amorphous magnesium phosphate 3D-printed scaffolds for craniofacial bone regeneration.

Machine learning-assisted sensing platform for simultaneous and visual detection of tetracycline hydrochloride and ofloxacin.

Hydrophobic derivatization of sodium alginate for use in fucoxanthin delivery

Layer-by-layer polyvinyl alcohol intercalated graphene oxide membrane with sodium alginate for ethanol dehydration via pervaporation

Study on the dust suppression performance of sodium alginate hydrogel modified with gallic acid in open-pit coal mines

Mechanistic insights into ginsenoside Rd nanoparticles-mediated protection against memory impairment: From preparation and physicochemical characterization to in vivo efficacy.