Superabsorbent Hydrogel Research Articles

This study presents a novel, circular-economy-driven strategy for valorizing post-consumer denim waste into high-performance hydrogels through a fully integrated and eco-friendly process. Unlike conventional approaches that rely on virgin cellulose or harsh chemical treatments, our method uniquely combines high-energy mechanochemical pretreatment, in situ carboxymethylation to produce carboxymethylcellulose (CMC), and citric acid/urea-based crosslinking, all using recycled denim as the sole cellulose source. High-energy milling effectively reduced particle size and lowered the crystallinity index (CI) from 75.7% to 66.1%, transforming the fibrous structure into a more reactive substrate for etherification. Successful CMC synthesis was confirmed by FTIR (COO− stretch at 1587 cm−1), while citric acid crosslinking generated ester bonds (C=O at ~1724 cm−1), forming a 3D network further tailored by urea, acting as a green porogen. The resulting hydrogels exhibited enhanced thermal stability (TGA) and a tunable porous morphology (SEM), with pore sizes reaching up to 147 µm as the urea content increased. Notably, the hydrogel Hy/CMC/U2/CA achieved an exceptional swelling capacity of 1900%, which is among the highest reported for denim-derived or citric acid-crosslinked systems. The objective of this work is to demonstrate, for the first time, the feasibility of converting waste denim directly into functional hydrogels without intermediate purification steps, offering a scalable and sustainable route for agricultural applications, such as soil water retention, controlled nutrient release, or environmental remediation, within a true circular economy framework.

Polysaccharide-based superabsorbent hydrogels (SAH) as sustainable material alternatives for personal hygiene products

Preparation of sodium allylsulfonate-starch based superabsorbent hydrogel with gamma ray irradiation method and its properties

In this work, the UV-curable superabsorbent hydrogels (SAHs) were synthesized using polyvinyl alcohol, acrylamide and acrylic acid. Then, reinforcement effect of the modified graphitic carbon nitride (g-C3N4) nanoparticles with vinyltrimethoxysilane (VTMS) as a silane coupling agent was studied on the synthesized SAHs properties. By heating a mixture of urea and melamine, g-C3N4 nanoparticles were prepared. g-C3N4 nanoparticles surface was modified by VTMS. Next, g-C3N4/VTMS (CNV) with 0, 0.5 and 1 wt% was added to the SAHs matrix and the SAH/CNV composites were produced. Water absorption and swelling ratio in the SAH/CNV composites were approximately reported to be 1600%. SAH/CNV 0.5 wt% and SAH/CNV 1 wt% composites emitted green fluorescence at 520 nm wavelength led by excitation wavelength at 375 nm. By exposing these samples to UV radiation, absorption bands appeared at 280 and 355 nm, while the neat sample (SAH/CNV 0 wt%) didn’t show UV absorption at the wavelengths higher than 280 nm and also remarkable fluorescence emission. The results of rheological analysis proved that adding CNV to SAHs matrix resulted in improvement of storage and loss moduli of the samples. The SAH/CNV composites also offered self-healing behavior as much as could heal their polymer chains against strain changes.

The safety and efficacy of extended use of an oral shape-shifting superabsorbent hydrogel capsule for weight loss: the ELECT extension study

S788 Oral Super-Absorbent Hydrogel Capsules Double Clinically Meaningful Weight Loss Without Added Serious or GI Adverse Events: A Systematic Review and Meta Analysis of Randomized Controlled Trials

Development of alginate/inulin-based Oral Superabsorbent Hydrogel carrier systems for delivery of white hyacinth bean polysaccharide: Improvement of characteristics and weight management in diet-induced obese mice

Background: Tacrolimus belongs to the BCSclass-IIdrug family and exhibits poor water solubility, which leads to poorbioavailability. Furthermore, since tacrolimus is an immunosuppressant,it is essential to maintain its therapeutic concentration for a greaterperiod of time to confirm its effectiveness against transplant rejection.Therefore, to achieve the objective of the sustained release of thedrug with a suitable amount of entrapment efficiency, pH-sensitivetacrolimus-loaded superabsorbent hydrogels using chitosan have beenprepared. Methodology: The free-radical polymerizationtechnique has been used to develop the hydrogel formulation, wherechitosan served as the polymer, acrylamide served as the monomer, n,n′-methylenebis­(acrylamide) served as the cross-linker,and potassium persulfate served as the initiator. The prepared formulationswere evaluated for their swelling behavior, entrapment efficiency,porosity, in vitro drug release, and kinetics. Theformulation design and optimization have been carried out using astatistical tool, i.e., Design Expert. Results: A goodswelling capacity and porosity of the hydrogel have been observed,advocating a well-interconnected network structure suitable for drugentrapment and release. The porosity of the prepared hydrogel wasfound to be 77.7–232.16%, while the sol–gel fractionranged between 4.65 and 17.71 and 82.29 and 95.35%, respectively.Furthermore, the release of 59.9% of the drug over 8 h of the studieshas assured a good sustained behavior of the formulation. Conclusions: The outcomes of the studies have been advocating the successfulexecution of the research work, where the prepared hydrogel has demonstrateda good entrapment efficiency, followed by a suitable sustained-releasebehavior. Conclusively, the selected combination of the drug and excipients,the adopted method of hydrogel preparation, and the evaluation processwere quite efficient for the delivery of a drug like tacrolimus.

Development and characterization of a carboxymethyl cellulose-alginate hybrid superabsorbent hydrogel designed for water management in agriculture.

Regional sources drive atmospheric microplastic deposition at rural background sites.

Superabsorbent Chitosan-Based Nanocomposite Antibacterial Hydrogel for Biofilm Disruption and Accelerated Healing of Infected Wounds

Abstract In this study, a superabsorbent hydrogel based on Carbopol 940, carboxymethyl cellulose sodium salt (NaCMC), and acrylic acid (C/NaCMC/PAc) was prepared using gamma radiation. This technique serves as a clean and effective method for initiation and crosslinking, intended for agricultural use as a slow-release urea fertilizer. The parameters affecting the gelation percentage, such as Ac and Carbopol contents, as well as different irradiation doses, were studied. The optimal conditions for preparing C/NaCMC/PAc hydrogel were achieved with acrylic acid and Carbopol concentrations of 5 wt% and 3 wt%, respectively, at an irradiation dose of 5 kGy. The swelling rate was enhanced by increasing the Carbopole content, while its degree was enhanced by treating the prepared hydrogel with di-ethanolamine and raising the pH, reaching a swelling degree to 78 g/g. FTIR, XRD, EDX, and SEM were performed to characterize the structure and properties of the fabricated hydrogels. The synthesized hydrogels exhibited excellent urea loading (92 %) and slow release (91 % after 16 days). The extended urea release of Carbopol-co-poly-Ac hydrogels makes them a potential candidate for controlled delivery of urea fertilizer. The data showed that the prepared superabsorbent hydrogel has some advantages and can be used as a slow-release urea fertilizer.

Prolonged drought and soil degradation severely affect soil fertility and limit crop productivity. Superabsorbent hydrogels offer an effective solution for improving water retention in soil and supporting plant growth. In this work, we examined the performance of superabsorbent hydrogels based on sodium alginate, acrylic acid (AA), and poly (ethylene oxide) (PEO) cross-linked with 12.5 kGy using e-beam irradiation. The hydrogels were assessed in various aqueous environments by examining network characteristics, swelling capacity, and swelling kinetics to evaluate the impact of water's electrical conductivity (which ranges from 0.05 to 321 μS/cm). Morphological and chemical structure changes were evaluated using SEM and FTIR techniques. The results demonstrated that water conductivity significantly affected the physicochemical properties of the hydrogels. Swelling behavior showed notable sensitivity to electrical conductivity variations, with swelling degrees reaching 28,400% at 5 μS/cm and 14,000% at 321 μS/cm, following first-order and second-order kinetics. FTIR analysis confirmed that structural modifications correlated with water conductivity, particularly affecting the O-H, C-H, and COOH groups sensitive to the ionic environment. SEM characterization revealed a porous morphology with an interconnected microporous network that facilitates efficient water diffusion. These hydrogels show exceptional swelling capacity and are promising candidates for sustainable agriculture applications.

Carboxymethyl tamarind kernel gum-based superabsorbent hydrogel for release of copper micronutrient.

Investigating polysaccharides role in superabsorbent hydrogel composites with rice husk ash for Pb(II) and Cu(II) adsorption: Experimental and theoretical insights.

Early response (ER) to treatment is predictive of longer-term weight loss. In this post hoc analysis, ER to an oral shape-shifting superabsorbent hydrogel capsule (Epitomee) combined with a lifestyle intervention was compared to placebo combined with a lifestyle intervention. Participants (age = 48.5 ± 12.5 and 48.6 ± 12.4; BMI = 34.1 ± 3.3 and 33.7 ± 3.4, in the Epitomee and placebo groups, respectively) were randomised to Epitomee (N = 138) or placebo (N = 141) with lifestyle intervention. Analyses included body weight measurements taken at baseline, week 8, and week 24. Of the 279 participants enrolled in the study, 250 (90% of the ITT population) provided weight data, including 124 participants in the Epitomee group and 126 in the placebo group. Participants with missing weight data at week 24 were classified as non-responders. Early response (ER) was defined as a weight loss of ≥ 2% at week 8. Weight loss at week 24 was greater in ER to Epitomee compared to placebo (9.3% ± 6.0% vs. 6.9% ± 4.3%; p < 0.0001). The odds ratio for ER to achieve > 5% weight loss at week 24 was 4.10 (95% CI: 1.02, 16.46) for Epitomee and 2.38 (95% CI: 0.62, 9.21) for placebo. A greater proportion of ER to Epitomee, compared to placebo, achieved > 5% (76% vs. 62%; p = 0.0472), ≥ 7% (61% vs. 38%; p < 0.0045) and ≥ 10% (39% vs. 17%; p < 0.0025) weight loss at week 24. ER response to Epitomee was associated with greater weight loss at 24 weeks compared to placebo. Monitoring ER to Epitomee and titrating treatment based on ER may enhance weight loss.

Dyes are significant pollutants in aquatic environments, even at low concentrations. To address this issue, superabsorbent nanocomposite hydrogels were developed using cashew tree gum cross-linked with acrylamide and incorporating laponite as a selective adsorbent for cationic dyes. The hydrogels were characterized through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TG), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive Spectroscopy (EDS), along with assessments of toxicity, swelling capacity, and adsorption parameters. TG and XRD analysis indicated the incorporation of laponite into the polymer matrix. FTIR showed no significant changes due to the low concentration of laponite. SEM revealed a uniform surface in the laponite-containing hydrogel (HGC-LAP). EDS confirmed the presence and good distribution of Mg and Si elements in HGC-LAP. Although hydrogels without laponite (HGC) showed higher swelling capacity, HGC-LAP demonstrated faster adsorption kinetics, with values approaching those of HGC at equilibrium. The addition of laponite improved the adsorption capacity to 2887.5 mg g⁻¹, and the data fitted the pseudo-second order and Langmuir models. The nanocomposite hydrogels proved to be effective as selective adsorbents in dye mixtures.

Hydrogels are soil-conditioning materials capable of absorbing substantial amounts of water relative to their weight. Their use in agriculture is expanding rapidly, but their effects on grapevines at transplanting has until now not been explored. This study compared the localised root-zone application to soil of a potassium polyacrylate hydrogel (SH1) and an organic hydrogel (SH2) at vine transplanting, with an untreated control (C) in two experiments: one on potted vines under semi-controlled conditions and the other in a newly established rainfed vineyard. Both SH1 and SH2 increased soil field capacity and maximum available water. In the potted vines, they improved water status under drought conditions, delaying the decline of stem Ψ (+ 0.25 MPa on the last day before rewatering) and enhancing leaf gas exchange (+ 9 and + 8 µmol m–2 s–1 for SH1 and SH2, respectively, as compared to C). By the end of the second season after transplanting, SH1 and SH2-treated vines exhibited greater leaf area, higher yield (+ 29 % and + 26 % relative to C, respectively), and a lower leaf-to-fruit ratio, resulting in reduced TSS (–2.0 and –2.2 °Brix respectively) and anthocyanin levels. In the field, shoot growth and final leaf area after two years were higher in SH1- and SH2-treated vines (+ 25 %). SH1 accelerated the transition to a productive stage, while SH2 reduced the number of vines requiring two-nodes pruning. Our findings indicate that hydrogels are promising tools for vineyard water management. Their incorporation at transplanting could help shorten unproductive stages and accelerate full crop development.

Effects of Superabsorbent Hydrogel on Soil Porosity, Bulk Density, and Water Productivity of Tomato Grown Under Drought Stress in Clay Loam and Sandy Loam Soils

ABSTRACTIn response to the environmental challenges posed by heavy metals and cationic dyes, superabsorbent hydrogels were prepared using γ‐ray‐induced crosslinking of polyethylene oxide (PEO), starch, and 4‐styrenesulfonic acid sodium salt (SSA). The irradiation dose and composition of starch and SSA were optimized based on gel fraction, swelling, porosity, and crosslink density. The hydrogel's swelling behavior was influenced by pH and ionic strength, following a non‐Fickian process. FTIR confirmed gelation, while TGA and SEM analyses showed enhanced thermal stability and porosity due to SSA incorporation. The hydrogel effectively adsorbed cationic dyes—Basic Fuchsine (BF), Methylene Blue (MB), and Crystal Violet (CV)—with maximum adsorption capacities of 625, 569, and 498 mg/g, respectively. The adsorption was governed by film diffusion, and the isotherms were best fitted to Modified Langmuir, Redlich–Peterson, and Aranovich–Donohue models. After 4 cycles, the hydrogel removed 77%–82% of the dyes. Adsorption kinetics followed pseudo‐first order for MB (98% removal) and CV (91% removal) and pseudo‐second order for BF (92% removal). The slower, pH‐dependent adsorption of Cr3+ (61% removal) was best described by the Freundlich isotherm, intraparticle diffusion, and pseudo‐second‐order kinetics, indicating three adsorption sites per adsorbate.