Water Absorption Capability Research Articles

Investigation of functionalized graphene oxide incorporated superabsorbent polymers for enhanced durability, hydration, microstructure and mechanical strength of modified concrete

ABSTRACT This study focuses on enhancing cementitious materials by incorporating silanized graphene oxide (SGO) and superabsorbent polymers (SAPs), aiming to improve their mechanical and durability properties. The primary goal is to evaluate the effects of SGO/SAP composites on the hydration, absorption, shrinkage, and overall performance of concrete. The composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) to understand their microstructure. Mechanical and durability tests revealed that adding SGO/SAP composites significantly increased the mechanical strength and water absorption capabilities of the concrete. The compressive strength, split tensile strength, and flexural strength of the SGO/SAP-modified concrete were measured at 57 MPa, 4.90 MPa, and 8.25 MPa, respectively. Shrinkage tests demonstrated the composite hydrogel’s excellent water-holding capacity at 0.3 wt.% SGO/SAP, facilitating internal curing in concrete structures. FE-SEM analysis indicated a reduction in microcracks due to the presence of SGO/SAP. The improvements are attributed to the synergistic effects of SGO and SAP, which enhance water retention, dispersion, and interfacial bonding within the cementitious matrix. The microstructural studies confirmed the exceptional stability of the SGO/SAP-modified mix, emphasizing its potential as an additive to improve concrete properties. This research underscores the significant potential of SGO and SAP in advancing the performance of cement-based materials, highlighting their applicability in infrastructure development and construction for creating more durable and high-performing concrete structures.

Preparation of Antistatic Polyester Fiber via Layer-by-Layer Self-Assembly

Polyester fibers tend to generate static electricity during the weaving and application processes, posing a threat to their production. Enhancing the water absorbency and electrical conductivity of polyester fibers themselves is an effective approach to improving their antistatic properties. In this study, multifunctional chitosan (CS), sodium phytate (SP), and Cu2+ were loaded on polyester fibers through layer-by-layer (LBL) self-assembly. The antistatic and water absorption capability of the modified polyester fibers was investigated by designing different process parameters combined with a surface resistance test and water contact angle tests. The antistatic property test results confirmed the positive effect of CS and Cu2+ on discharging electrostatic charge. Within a definite scope, with the increase in the number of assembly layers, assembly duration, and the concentration of the assembly substances, the wettability of the modified polyester fibers became more favorable and the antistatic effect became more remarkable.

Application of Antioxidant‐ and Antimicrobial‐Rich Extracts From Hass Avocado Pulp in the Development of Chitosan/Gelatin‐Based Active Packaging Films for Raw Meat Preservation

ABSTRACTIn the present study, the ethanolic extracts derived from Hass avocado pulp were observed to exhibit exceptional bioactive qualities and demonstrate bactericidal efficacy against a wide range of microorganisms, encompassing both gram‐positive and gram‐negative bacteria, as well as fungi. Therefore, this work aimed to develop a biodegradable active film by incorporating the Hass avocado extracts into chitosan/gelatin‐based film (HGCF) for the preservation of beef and pork. The study reveals that the chitosan/gelatin‐based film (GCF) and HGCF exhibit significant water stability and absorption capabilities. HGCF offered the synergy of antimicrobial properties of Hass avocado extracts and high swelling in water of chitosan/gelatin blend to absorb liquid discharged from fresh meat for prolonged storage. HGCF demonstrated a significant effectiveness in controlling microbial density in comparison to uncoated samples and samples coated with plain gelatin/chitosan film. In detail, HGCF was able to partially eliminate Staphylococcus aureus and Escherichia coli during storage, resulting in the densities after 14 days that were similar to those of uncoated meat samples after 6 days. These results demonstrate the potential of HGCF as active packaging for food preservation and advance the sustainable production and preservation of meat products.

A Janus hydrogel that enables wet tissue adhesion and resists abdominal adhesions

Hydrogels have indeed achieved significant advancements, yet their clinical translation has been hampered by their inherent limitations in wet adhesion properties. Furthermore, the design of adhesive hydrogels that can resist postoperative adhesions remains an intricate challenge. In this study, we introduce a Janus hydrogel (JGP) that offers a novel approach to address these challenges. The JGP hydrogel has two asymmetrical sides, consisting of an adhesion layer (AL) and an anti-adhesion layer (AAL). Specifically, the AL incorporates three key components: N-[tris(hydroxymethyl)methyl]acrylamide (THMA), acrylic acid (AAc), and the acrylic acid N-hydroxysuccinimide ester (AAc-NHS). By drying the AL, it has a rapid water absorption capability. The abundance of hydroxyl and carboxyl groups in the AL enables the formation of robust hydrogen bonds with tissues, thereby achieving superior adhesive properties. Additionally, the synergistic effect of THMA's tridentate hydrogen bonding and the covalent bonding formed by AAc-NHS with tissue ensures long-lasting wet adhesion. To realize the anti-adhesion function, one side of the AL was immersed in a solution of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), which undergoes crosslinking to form the AAL. A comprehensive series of tests have confirmed that the JGP hydrogel exhibits exceptional mechanical properties, efficient and enduring adhesion, excellent biocompatibility, and degradability. Moreover, it possesses remarkable hemostatic properties and robust anti-abdominal adhesion characteristics.

Humidity-Controlling Ceramic Bricks: Enhancing Evaporative Cooling Efficiency to Mitigate Urban Heat Island Effect

Passive evaporative cooling technology using the building envelope is a crucial measure to mitigate the urban heat island effect. This study aims to enhance the cooling efficiency of the surface of enclosure structures by utilizing volcanic ash, potassium–sodium stone powder, and silica-based mesoporous oxide (SMO) as primary materials. These components are incorporated into the ceramic brick production process to create innovative humidity-controlling ceramic bricks (HCCTs). This study extensively investigates the impact of SMO and the amount of applied glaze on the physical and mechanical characteristics of these HCCTs. Additionally, it examines the water absorption and evaporative cooling properties of the studied materials under optimal substitution conditions. Numerical calculations are used to determine the heat and moisture transfer properties of HCCTs. The results indicate that incorporating 2% SMO and applying 70 g/m2 of glaze results in a moisture absorption capacity of 385 g/m2 and a moisture discharge capacity of 370 g/m2. These conditions also yield a notable flexural strength of 15.2 MPa. Importantly, the HCCTs exhibit significantly enhanced capillary water absorption and water retention capabilities. Increased water absorption reduces surface temperature by 2–3 °C, maintaining the evaporative cooling effect for 20 to 30 h. It is also found that the temperature of HCCTs decreases linearly with increasing water content and porosity, while the temperature difference gradually decreases with thickness. Water migration in HCCTs with greater thickness is notably influenced by gravity, with water moving from top to bottom. Therefore, it is recommended that brick thickness does not exceed 15 mm.

Influence of chemical treatment of fly ash on mechanical, thermal, and water absorption characteristics of PS/SBC nanocomposite

AbstractThe purpose of this study is to investigate the effective chemical treatment of fly Ash (FA) that affects the mechanical, thermal, and water absorption capabilities of polystyrene/styrene‐butadiene‐copolymer (PS/SBC) nanocomposites. NaOH, H2SO4 and distilled water have been employed to conduct the chemical treatment. Specimens have been prepared using injection molding technique. In order to evaluate the mechanical properties of the material, tensile, flexural, impact, and hardness tests were carried out. thermo‐gravimetric analysis (TGA) and differential thermal analysis (DTA) were employed to gain an understanding of the thermal behavior of the material. Furthermore, to determine the moisture resistance, water absorption experiments were conducted. Experimental results show that, alkali‐treated FA (AL‐FA) demonstrated the maximum values with an ultimate tensile strength of 26.68 MPa, acid‐treated FA (AC‐FA) composite exhibiting the highest flexural strength at 5 MPa whereas water‐treated FA (WA‐FA) composite led to better impact strength of 17.6 kJ/m2. TGA revealed that WA‐FA and AL‐FA composites experienced an 80% reduction in weight at 500°C, while AC‐FA composites exhibited weight reductions of 90%. The significance of treatment methods in interfacial interactions between the polymer and FA has been studied through morphological analysis. These findings provide valuable insights that can be applied to future research and industrial applications in the field of sustainable materials engineering.Highlights Polystyrene/Styrene‐Butadiene‐Copolymer composites were prepared with Fly ash (FA) filler. FA pre‐treated by NaOH (AL‐FA), H2SO4 (AC‐FA) and distilled water (WA‐FA). Injection molding technique was employed to prepare the ASTM standard samples. WA‐FA composite exhibited the highest ductility but lower tensile strength. TGA revealed that AC‐FA composites exhibited weight reductions of 90%.

Rational Design of a Multifunctional Hydrogel Trap for Water and Fertilizer Capture: A Review.

Water scarcity and land infertility pose significant challenges to agricultural development, particularly in arid and semiarid regions. Improving soil-water-retention capacity and fertilizer utilization efficiency through the application of soil additives has become a pivotal approach in agricultural practices. Hydrogels exhibit exceptional water absorption and fertilizer retention capabilities, making them extensively utilized in the fields of agriculture, forestry, and desert control. Currently, most reviews primarily focus on the raw materials, classification, synthesis methods, and application prospects of hydrogels, with limited attention given to strategies for enhancing water-retention performance, mechanisms underlying fertilizer absorption, and environmental risks. This review covers the commonly used cross-linking methods in hydrogel synthesis and the structure-activity relationship between hydrogels and water as well as fertilizer. Additionally, a thorough analysis of the ecological benefits and risks associated with hydrogels is presented. Finally, future prospects and challenges are delineated from the perspectives of material design and engineering applications.

The Development of Edible Straw from Apple and Durian Peel

Over the past few decades, there has been a surge in the demand for plastic utensils, especially plastic straw which contribute to consumption of toxic chemicals. The use of plastic straws has led to plastic pollution crisis due to their non-biodegradability and lengthy decomposition periods. Currently, various kinds of edible straw have been developed to replace traditional plastic straw to reduce the environmental pollution, however the edible straw usually has weak structural integrity and becomes soggy when immersed in beverages. The purpose of this study is to develop the production of edible straw from fruit peel, such as apple and durian peel skin and investigate the physicochemical characteristics of the edible straw at different temperatures. The manufacturing process of edible straw using fruit peel can be categorized into 3 main steps, including preparation of fruit peel paste using fruit peel and distilled water at weight ratio 1:0.3, preparation of edible film as well as drying and demoulding of edible straw. Then, a series of tests including water absorption test, heat resistance test and swelling ratio test have been conducted to investigate the functionality of the edible straw in different kinds of beverages, including hot and cold liquids at temperature ranges from 5 °C to 65 °C. The observation suggests that durian peel edible straw has higher water absorption capability, heat resistance and swelling ratio when soaked in liquids compared to apple peel edible straw. Both the apple and durian peel edible straw are best for use at beverage temperature within 25 °C. Durian peel edible straw has better performance as it can be used for beverage temperature up until 65 °C while only 45 °C for apple peel edible straw.

Synthesis and characterization of biocompatible hydrogel from textile–garment waste for personal hygiene products

The objective of the present study is to synthesise cellulose-based hydrogel from cellulosic waste that is produced in the garment and textile industries. Carboxymethyl cellulose was synthesized via carboxymethylation subsequent to the separation of cellulose. The progress of reaction was monitored by measuring the degree of carboxymethyl cellulose substitution. Carboxymethyl cellulose was graft co-polymerized with acrylic acid and acrylamide in the presence of N,N-methylene-bis-acrylamide to develop a superabsorbent hydrogel. The generated hydrogel was put through several mechanical and physical tests, as well as FTIR, XRD, TGA and SEM investigations, to evaluate its real formation and characteristics. The prepared hydrogel demonstrated favorable swelling properties, as well as excellent adsorption of ions and dyestuffs. The maximum water absorption capability of the superabsorbent material obtained from textile and garment waste was 182 g/g. Furthermore, the prepared hydrogel exhibits exceptional biocompatibility, biodegradability, environmental friendliness, and non-toxicity. These qualities make it an exceptional material for use in personal care items and protective gear.

Enhancing Wound Recovery: A Self-Gelling Powder for Improved Hemostasis and Healing.

A novel self-gelatinizing powder was designed to accelerate wound healing through enhanced hemostasis and tissue recovery. Significantly, this research addresses the critical need for innovative wound management solutions by presenting a novel approach. Carboxymethylcellulose calcium (CMC-Ca) was synthesized using an ion exchange method, and lysine (Lys) was integrated through physical mixing to augment the material's functional characteristics. The prepared powder underwent comprehensive evaluation for its self-gelling capacity, gelation time, adhesion, swelling rate, coagulation efficiency, hemostatic effectiveness, and wound healing promotion. Results indicate that the self-gelatinizing powder exhibited remarkable water absorption capabilities, absorbing liquid up to 30 times its weight and achieving rapid coagulation within 3 min. The inclusion of Lys notably enhanced the powder's gel-forming properties. The gelation time was determined to be within 4 s using a rotational rheometer, with the powder rapidly forming a stable gel on the skin surface. Furthermore, in a mouse skin injury model, near-complete skin recovery was observed within 14 days, underscoring the powder's impressive self-healing attributes and promising application prospects in wound management.

Sustainable mortar reinforced with recycled glass fiber derived from pyrolysis of wind turbine blade waste

Pyrolysis technology has recently made significant progress in recycling millions of tons of wind turbine waste (WTB). Short fibers represent its main product (∼70 wt%), which needs further studies to explore its future applications. In this context, this work aims to the valorization of the recycled glass fiber (rGF) derived from pyrolysis of WTB (at 550 °C) in the production of rGF-reinforced mortar composite (rGF/M) for sustainable building applications. The research began by subjecting the derived rGF to sieving (rGFs), washing (rGFw), and oxidation (rGFo) pretreatments for purification and removing any impurities, organic residues, and char particles. Afterward, the chemical degradation of the treated rGF in a strong alkaline cement solution with pH = 14 was studied for up to 90 days. In parallel, the mortar composite samples were fabricated at 1 wt% of the treated rGF batches (rGFr, rGFw, and rGFo) to study the effect of different pretreatments on their microstructure, dispersion, compressive strength, flexural strength, and water absorption capabilities behavior after different curing periods (28 and 90 days). The results showed that rGFo (7.84%) showed a lower degradation rate versus rGFw (16.41%) and rGFr (30.76%). Meanwhile, the highest curing period (90 days) contributed to improving the properties of the mortar composites in general, especially in the case of using rGFo which led to improved compressive strength (15%) and reduced absorption coefficient (38%) and cumulative water content (32%) with a uniform distribution of short fibers in the matrices and a slight increase in flexural strength compared to control mortar sample (8.6 MPa). While rGFs provides better flexural strength (9.3 MPa) with a 12% improvement. Based on these results it can be concluded that rGFo has high potential in sustainable building materials with high competition with virgin glass fiber.

Durability performance of alkali-activated concrete with pre-treated coarse recycled aggregates for pavements

This study examines the effect of coarse recycled aggregates (CRAs) and processed coarse recycled aggregates (PCRAs) on the behaviour of alkali-activated concrete (AAC) before and after exposure to marine seawater and acidic environments (5% HCl and 5% H2SO4 solutions). Measurements of compressive strength and the microstructure changes were conducted over periods of 56 and 90 days to assess these effects. The experimental design included varying the replacement levels of NAs with CRAs and PCRAs from (0–100%) and using ground-granulated blast furnace slag and fly ash as constant components. In addition to durability tests, sorptivity assessments were conducted to gauge the material’s porosity and water absorption capabilities. Advanced microstructure techniques, such as scanning electron microscopy (SEM) and X-ray diffraction (XRD), were employed to detail the pre and post-exposure mineralogical and microstructural transformations within the AAC blends. The AAC mixtures incorporating PCRAs emerged as durable, showcasing better strength and a denser, more compact matrix facilitated by the synergistic formation of NASH and CASH gels after exposure to aggressive agents compared to untreated CRAs. In addition, the results show that the samples exposed to marine seawater exhibited improved mechanical performance compared to those exposed to acidic environments. The novelty of this study lies in its exploration of the effects of recycling plant-based CRAs and PCRAs on AAC for marine and acid exposure.

Exploring the properties of gelatin/chitosan bioaerogel scaffolds: Toward ultra‐light and highly porous materials

AbstractThis study investigates the development and characterization of chitosan, gelatin, and chitosan/gelatin (Chi/Gel) bioaerogel composites through a facile and eco‐friendly approach. The goal is to optimize their structural and functional properties for potential environmental and biomedical applications. Direct freezing and lyophilization approach were used to prepare the aerogels, the focus was on investigating the effects of blending ratios on the density, porosity, surface area, and water absorption capabilities of the aerogels. The results show that Chi/Gel 60/40 composition achieved an optimal balance of structural robustness and functional performance, characterized by a moderate density of 74.2 mg/cm3, the highest porosity among the samples at 93.5%, an impressive surface area of 184.8 m2/g, and a water absorption capacity of 28.8 g/g. These results suggest that the synergistic effect of chitosan and gelatin at specific ratios significantly enhances the overall properties of the material. Our findings suggest that Chi/Gel bioaerogels, especially the 60/40 composite, hold great promise for diverse applications.Highlights All Gelatin/Chitosan bioaerogels exhibited high porosity and low density. The Chi/Gel 60/40 mix achieved the highest porosity and surface area. Highest water adsorption was observed in the Chi/Gel 60/40 composite. Synergistic effects enhanced properties of the Gelatin/Chitosan scaffolds.

Dextran-Based Antibacterial Hydrogel Dressings for Accelerating Infected Wound Healing by Reducing Inflammation Levels.

Infected wounds pose challenges such as exudate management, bacterial infections, and persistent inflammation, making them a significant challenge for modern dressings. To address these issues in infected wounds more effectively, aerogel-hydrogel biphase gels based on dextran are developed. The gel introduced in this study exhibits antibacterial and anti-inflammatory properties in the process of wound therapy, contributing to accelerated wound healing. The aerogel phase exhibits exceptional water-absorption capabilities, rapidly soaking up exudate from infected wound, thereby fostering a clean and hygienic wound healing microenvironment. Concurrently, the aerogel phase is enriched with hydrogen sulfide donors. Following water absorption and the formation of the hydrogel phase, it enables the sustained release of hydrogen sulfide around the wound sites. The experiments confirm that hydrogen sulfide, by promoting M2 macrophage differentiation and reducing the levels of inflammatory factors, effectively diminishes local inflammation levels at the wound site. Furthermore, the sodium copper chlorophyllin component within the hydrogel phase demonstrates effective antibacterial properties through photodynamic antimicrobial therapy, providing a viable solution to wound infection challenges.

Use of recycled construction and demolition waste as substrate in constructed wetlands for the wastewater treatment of cheese production

Recycled building debris has recently emerged as a suitable wetland infill substrate due to its low density, exceptional water absorption capabilities, and high porosity. This study investigated, for the first time, the use of construction demolition wastes (CDW), and rock processing residues (RPR) as substrate materials in vertical-horizontal flow hybrid constructed wetlands for the treatment of cheese production wastewater. Results showed that the use of both CDW as well as RPR, as substrate material, provided an equal or even better quality of treated wastewater compared to the conventional use of gravel as a substrate. High removal efficiencies were recorded for turbidity (CDW: 91–92%, RPR: 97%), solids (CDW: 85–88%, RPR: 96–97%), organic matter (CDW: 79–84%, RPR: 96–98%), and total phosphorus (CDW: 72–76%, RPR: 87%) for both examined recycled materials. During the experiment, different loadings rates (HLR) were tested: 25 mm d−1 and 37.5 mm d−1. Radiological measurements indicate that, their use did not cause toxic effects on the environment, as the amounts of radioactivity found in the effluent of the systems are not significant. Increasing the hydraulic loading rate appeared to have no negative effect on pollutant removal, as the systems and plants were fully acclimated and mature. This approach offers several advantages, including the use of readily available and abundant waste material, potential cost savings, and the environmental benefits of recycling CDW and RPR instead of disposing of them in landfills.

Multifunctional xanthan gum/wood fibers based hydrogels as novel topsoil covers for forestry and agricultural applications

This study was focused on the development of novel bio-based and biodegradable hydrogels constituted of xanthan gum (XG) reinforced with wood fibers, to be used as eco-sustainable topsoil covers (TSCs) in support of reforestation and agricultural efforts in arid conditions. At this aim, hydrogels were developed by cross-linking XG with citric acid (CA), sodium trimetaphosphate (STMP) or tannic acid (TA) at different concentrations. Samples cross-linked with CA and TA exhibited the highest dimensional stability and exceptional water absorption capability, even after multiple absorption/drying cycles. Hydrogels with 50, 60, and 100 phr of CA displayed water vapor permeance values of about 9.5·10−6 g/(Pa·s·m2), i.e., comparable to commercial woven PP mulching films. The average penetration resistance of the produced hydrogels was twice that of the commercial one. The presence of wood fibers in the hydrogels provided dimensional stability and minimal shrinkage after exposure to outdoor conditions for two months (15.4 % for sample with 60 phr of CA). Furthermore, after 7 months of exposure, more than 60 % of the sample mass was biodegraded. This research demonstrated the potential of xanthan gum/wood fibers based hydrogels as TSCs with superior water-regulating properties, thus offering a simple, cost-effective and scalable technology for forestry and agriculture applications.

Coal gasification slag for preparation of environmentally friendly superabsorbent composites with rapid water absorption and salt tolerance

It is crucial to design the novel low-cost and salt-tolerant superabsorbent for safeguarding food security and achieving sustainable agriculture. Herein, the porous superabsorbent composites with excellent salt tolerance were fabricated by redox-initiated grafting polymerization using water-based Pickering foam template co-stabilized with solid waste of coal gasification slag and plant particles Sapindus mukorossi pericarp. The stabilization mechanism of Pickering foams, swelling performance and salt-resistance of porous superabsorbent composites were studied in detail. Due to the abundant porous structure and the presence of coal gasification slag, the obtained superabsorbent composites exhibited rapid swelling rate and excellent water absorption capability, and the maximum water absorption in distilled water and 0.9 wt% NaCl solution reached 910 g/g and 126 g/g after 30 min, respectively. As 1.5 wt% the optimal superabsorbent composites was added into the saline-alkali soil, the growth of cabbages was significantly improved, and the plant height and chlorophyll content increased by 45.0% and 12.5%, respectively. This work served as a significant reference for preparing novel environmentally friendly water-saving materials for arid saline-alkali soil improvement.

STUDY OF THE EFFECT OF MINERAL ADMIXTURE ADDITION ON PAVING BLOCKS' PHYSICAL AND MECHANICAL PROPERTIES

Paving blocks, concrete bricks made from cement and sand, are a vital alternative to ground cover. Their extensive, precast nature, water absorption capabilities, affordability, and ease of use contribute to their popularity. However, the additional ingredients, particularly mineral admixtures, hold the potential to enhance these blocks' quality and performance significantly. The mineral admixtures used, such as limestone, quartz sand, and gypsum, are instrumental in improving the performance of paving blocks, offering a promising avenue for further research and application. This research, conducted with meticulous scientific rigor, investigated paving blocks' physical and mechanical properties. Paving block test objects were created using sand, cement, and crushed stone with mineral admixtures. The mineral admixtures used in this experiment, including gypsum, quartz sand, and limestone, were crushed before being used in a stone cruiser machine to make them powder and reactive. Compressive strength test, weat resistance test, volume weight test, water absorption test, and visual inspection were conducted experimentally. The research results, derived from a robust experimental setup, revealed that paving blocks with 10% gypsum additives, 6% quartz sand powder, and limestone powder produced a more excellent compressive strength value than standard paving blocks, values of 36,884 MPa, 37,573 MPa, and 38,950 MPa with a regular paving block compressive strength value of 36,119 MPa followed by a decrease in the percentage of absorption. This suggests that using mineral admixtures at a certain percentage as an additional material can improve the quality of paving blocks. However, it is essential to note that adding too many mineral admixtures can also decrease the strength of the paving block, emphasizing the need for careful application of these materials in construction. These findings provide valuable insights for civil engineers, construction professionals, and researchers in materials science and construction technology, enhancing their understanding of the role of mineral admixtures in paving block strength.

Effect and mechanism of biochar-based hydrogel to alleviate drought stress in tobacco

Drought is an important abiotic stressor that adversely affects agricultural production, resulting in decreased crop yields and food insecurity. The objective of this study was to develop a novel hydrogel-based composite (S-B-AA) by incorporating biochar into hydrogel (S-AA) and evaluating its effects on tobacco plants under drought stress. The S-B-AA hydrogel exhibited enhanced water absorption and retention capabilities compared to the S-AA hydrogel. Under drought stress conditions, the S-B-AA hydrogel effectively increased the total water content, relative water content, and free water content of tobacco leaves, while reducing the bound water content and water saturation deficit. Additionally, it improved the stomatal status of tobacco leaves, significantly enhanced the photosynthetic capacity of tobacco seedlings, and promoted biomass accumulation. Moreover, the S-B-AA hydrogel alleviated the excessive accumulation of reactive oxygen species (ROS) induced by drought stress in tobacco seedlings, thereby alleviating ROS damage to cell membranes. It also reduced antioxidant enzyme activity and the levels of the signaling molecule H2S, while minimizing the impact of drought stress on tobacco osmotic regulation. Transcriptome analysis revealed that S-B-AA up-regulated 2826 DEGs and down-regulated 5225 DEGs compared to the control group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis demonstrated that the differentially expressed genes were predominantly enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, plant hormone signaling pathway, and photosynthesis pathway. This study provides a theoretical basis and practical guidance for the application of S-B-AA hydrogel in agriculture and environmental protection.

Super absorbent polymer (SAP) on water‐salt transport in saline alkali soil: Effects of dosage, height and thickness

AbstractSoil salinisation is a pervasive form of land degradation posing a significant threat to the global environment. Saline soil, covering roughly 10% of the total land area, represents a crucial reserve of land resources. The use of super absorbent polymer (SAP) impacts capillary water movement through the soil because of its exceptional water absorption and retention capabilities. SAP is expected to influence the intricate water‐salt migration processes and their redistribution within soil. This study employed soil column experiments to investigate the impacts of varying SAP dosages (A), heights (B) and thicknesses (C) on soil water and salt transport in the Tianjin Binhai New Area, China. The main findings showed that: (1) average capillary water rise rate decreased with SAP dosage increase. The groundwater recharge trend in time was like that of capillary water rise height; (2) SAP usage increased water and salt content on the application layer and reduced surface soil salt accumulation; (3) the best SAP combination for application was 1.1% SAP at 17–18 cm from the groundwater level. This study provides basic effective SAP application strategies for preventing soil salinisation.