Effects Of Superabsorbent Polymers Research Articles

Effect of In Situ Polymerization of Super Absorbent Polymers on the Protection of Earthen Heritage Sites in Semi-Arid Regions

As precious cultural heritage, earthen sites are susceptible to various natural factors, leading to diverse forms of degradation. To protect earthen sites, the effects of super absorbent polymers (SAPs) on soil water retention, physical properties, and color compatibility at different concentrations were studied. After applying SAP treatment to an earthen site with different degrees of weathering, we drew the following conclusions. SAP-2 improved soil water retention capacity, increased soil water content, and slowed down the precipitation of soluble salts. At the same time, SAP-2 had the least effect on soil color difference and reduced the development of cracks by filling soil pores and enhancing the cohesion between soil particles, thus giving the earthen sites better weathering resistance. Therefore, the results provide a useful reference for the surface cracking of earthen sites in semi-arid areas and the degradation caused by flaking and block spalling.

Synergistic Effects of SAP, Limestone Powder and White Cement on the Aesthetic and Mechanical Properties of Fair-Faced Concrete

In this investigation, a comprehensive assessment was conducted on the cooperative effects of Super Absorbent Polymers (SAP), limestone powder, and white cement within the realm of fair-faced concrete. We discerned that while white cement augments the color vibrancy of the concrete, its accelerated hydration rate potentially induced early-stage cracks and compromised performance. To mitigate these challenges, SAP was incorporated to regulate early hydration, and limestone powder was introduced as a fortifying agent to bolster the mechanical robustness of the concrete. Our findings highlighted not only the capability of SAP to enhance concrete workability and longevity but also the pivotal role of limestone powder in amplifying its mechanical attributes. Microscopic evaluations, undertaken via Scanning Electron Microscopy (SEM), unveiled the potential of both SAP and limestone powder in refining the microstructure of the concrete, thereby elevating its performance metrics. Synthesizing the research outcomes, we pinpointed an optimal amalgamation of SAP, limestone powder, and white cement in fair-faced concrete, offering a valuable reference for prospective architectural applications.

Effects of superabsorbent polymers (SAPs) incorporated with organic and inorganic fertilizer on the water and nutrient retention of soil in rare earth mine tailing areas

Effects of superabsorbent polymers (SAPs) incorporated with organic and inorganic fertilizer on the water and nutrient retention of soil in rare earth mine tailing areas

Effects of superabsorbent polymers (SAP) on the rheological behavior of cement mortars: A rheological study on performance requirements for 3D printable cementitious materials

While the potential of incorporating superabsorbent polymers (SAP) as an additive in 3D printing cementitious materials has been a subject of interest recently, little research has been conducted on the effects of SAP incorporation on the rheological properties of cement mortars and the required performance of 3D printable cementitious materials when no other additives, such as superplasticizer (SP), are present or when SAP is added up to 1.0% by weight of the binder. Accordingly, the effects of SAP on the rheological behavior of cement mortar were analyzed in this study from the perspective of the performance requirements for 3D printable material with the SAP dosage (0%, 0.5%, and 1.0% by weight of cement), SAP particle size (100–180 and 355–425 μm), and superplasticizer (SP) presence (polycarboxylate-ether) as variables. The rheological properties of cement mortars with the same initial slump flow (180 mm ± 5 mm) were measured using a vane rotational rheometer, and their conformance to the performance requirements for 3D printable cementitious materials was studied. Static yield stress, dynamic yield stress, and plastic viscosity were calculated for each specimen using measured torque data obtained from the stress growth and flow curve experiments. The ratios of static to dynamic yield stress, plastic viscosity, and thixotropic areas were analyzed from the perspective of pumpability and extrudability, whereas the yield stress evolution and structural build-up rate were analyzed from the perspective of buildability. The results demonstrated that although the rheological properties of the SAP-incorporated cement mortar with a low water–cement ratio were similar to those of the SAP-incorporated cement mortar with a high water–cement ratio when SP was incorporated, the change in rheological properties with time and shear differed. SAP incorporation promoted the structuration of the mixtures without SP that have a high water–cement ratio due to the physical effects of SAP particles, but the effect was reversed in the mixtures with SP and a low water–cement ratio due to the water migration kinetics associated with SAP. Because a low water–cement ratio with SP is commonly applied for 3D printable materials, the findings of this study indicate that the water migration kinetics of SAP critically determines the printability of cementitious materials mixed with SAP. Given that observed effects are substantial, SAP arguably has potential as a rheology modifier for 3D printable cementitious materials.

Almond (Prunus sp.) Growth and Morphological Properties Affected by Super Absorbent Polymers and Phosphorus and Iron Fertilization

Almond (Prunus sp.) is produced in large amounts in the province of ChaharMahal and Bakhtiari, Iran. The effects of super absorbent polymers (SAPs, potassium acrylamide, KC3H5NO) singly, or in combination with phosphorus (P) and iron (Fe), on the growth and morphological properties of 20-year old almond orchards were tested in a two-year field experiment. It was a three-way factorial on the basis of a complete randomized block design testing almond growth affected by SAPs (control and 100 g), P (control and 750 g) using triple super phosphate, and Fe (control and 250 g) using FeSO4, placed at 70 cm depth of each tree shadow zone. The plant samples were collected and measured in July, four months after flowering. The trees used for sampling were similar in terms of age and cultivar. The green and woody nuts were collected in August and September, respectively. The perimeter of trunk environment (PTT), branch length (BL), branch length after three months (BLT), difference of branch length (DBL), number of almond fruits (NAF), weight of green, woody, and fresh nuts (GWN), and weight of woody and fresh nuts (WN) were determined. The tested treatments singly or in combination significantly improved plant morphological properties including BL, BLT, and WN. The important conclusion about the present research is the gradual release of water by SAPs, which makes the plant roots absorb water along with the essential nutrients including the tested P and Fe at the right time for a higher tree branch and nut production.

Effect of Cement Types and Superabsorbent Polymers on the Properties of Sustainable Ultra-High-Performance Paste.

This study focuses on the effects of superabsorbent polymers (SAP) and belite-rich Portland cement (BPC) on the compressive strength, autogenous shrinkage (AS), and micro- and macroscopic performance of sustainable, ultra-high-performance paste (SUHPP). Several experimental studies were conducted, including compressive strength, AS, isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), attenuated total reflectance (ATR)–Fourier-transform infrared spectroscopy (FTIR), ultra-sonic pulse velocity (UPV), and electrical resistivity. The following conclusions can be made based on the experimental results: (1) a small amount of SAP has a strength promotion effect during the first 3 days, while BPC can significantly improve the strength over the following 28 days. (2) SAP slows down the internal relative humidity reduction and effectively reduces the development of AS. BPC specimens show a lower AS than other specimens. The AS shows a linear relationship with the internal relative humidity. (3) Specimens with SAP possess higher cumulative hydration heat than control specimens. The slow hydration rate in the BPC effectively reduces the exothermic heat. (4) With the increase in SAP, the calcium hydroxide (CH) and combined water content increases, and SAP thus improves the effect on cement hydration. The contents of CH and combined water in BPC specimens are lower than those in the ordinary Portland cement (OPC) specimen. (5) All samples display rapid hydration of the cement in the first 3 days, with a high rate of UPV development. Strength is an exponential function of UPVs. (6) The electrical resistivity is reduced due to the increase in porosity caused by the release of water from SAP. From 3 to 28 days, BPC specimens show a greater increment in electrical resistivity than other specimens.

Effects of superabsorbent polymers on moisture migration and accumulation behaviors in soil

Superabsorbent polymer (SAP) is an eco-friendly material in soil and water conservation, agricultural production, and the performance enhancement of cement-based materials. It is well known that moisture migration and accumulation is a prerequisite for the performance deterioration of soil. In this study, SAPs were introduced as an admixture for soil expecting to enhance its ability of accommodating moisture variations. Compaction and dynamic triaxial tests were first conducted to the soil with various contents of SAPs to evaluate their compaction characteristics and mechanical performances. Furthermore, novel moisture migration tests utilizing a self-developed system were performed to quantitatively evaluate the effects of SAPs on improving the moisture migration and accumulation behaviors of soil. Two situations regarding the moisture migration manners typically occur in soil were taken into account: 1) the moisture migration in the formation of liquid state caused by the moisture inside of the soil, and 2) the moisture migration due to the intrusion of external moisture in the formation of liquid and gaseous phase. The findings from the tests showed that within a proper adding content, SAPs could not only improve the uniformity of water distribution in the soil, but improve its workability and compactability. SAP-water gels formed by SAPs also showed potentials on enhancing the cohesion and dynamic modulus of the soil samples under repeat stresses. Due to the water absorption and retention ability, SAPs could significantly restrain the moisture migration and accumulation in the soil; and with an increased content of SAPs, although their moisture contents were higher in the unfrozen zone, smaller moisture contents and less ice lenses/grains could be detected in the frozen zone.

Effects of Super Absorbent Polymers and Gibberellin on Germination and Growth of alfalfa

For proven effects of eco-friendly super absorbent polymer and gibberellin on germination and growth of alfalfa, taking the germination and growth test in the artificial climate box by adding the different amount of super absorbent polymer and gibberellin. Observed the germination potential, germination rate, shoot length, root length, fresh weight and dry weight, under the different experiment conditions. The test showed that the super absorbent polymer had a promoting effect on alfalfa. The property of slowly release water, water supply on super absorbent polymer could keep plants prolonging the survival rate in the case of insufficient water supply. It could improve the germination rate of the seed of alfalfa. Adding super absorbent polymer and gibberellin not only improved the survival rate, but also promoted the growth of root and shoot on alfalfa.

Effects of superabsorbent polymers on the vertical infiltration of soil water with sand mulching

Superabsorbent polymer (SAP) is a kind of polymer with advantages like high water absorption and conservation. We studied the effect of various concentrations of SAPs on the infiltration of soil water with sand mulching. Five soil columns with surface sand mulch and evenly distributed SAPs at concentrations of 0, 0.1, 0.2, 0.5 and 1.0% were tested. The SAPs slowed the migration of the wetting front and thus the rate of infiltration of water, and the higher the SAP concentration, the slower the migration. The relationship between the wetting front displacement and time could be described by a logarithmic function, [Formula: see text]. The amount of cumulative infiltration was inversely proportional to the amount of SAPs. The final cumulative infiltration was proportional to the amount of SAPs, within a limited range. The relationship between cumulative infiltration and time was described by a power function, [Formula: see text]. The relationship between wetting front displacement and cumulative infiltration could be characterized by a linear equation, [Formula: see text], indicating that the rate of cumulative infiltration increased with the amount of SAPs for the same infiltration depth, which satisfied the Kostiakov model ([Formula: see text]). High concentrations of SAPs strongly inhibited the infiltration of water. The infiltration rate of soil water was optimal at a SAP concentration of 0.2%, which effectively increased the amount of water in the soil.

Effects of super-absorbent polymers with different granularities on the physicochemical properties of substrate and the growth of lettuce seedlings

Effects of super-absorbent polymers with different granularities on the physicochemical properties of substrate and the growth of lettuce seedlings

Establishing and validating a root water uptake model under the effects of superabsorbent polymers

AbstractIn‐depth understanding of the patterns of root water uptake (RWU) is the key to improving the water‐use efficiency of plants. Superabsorbent polymers (SAPs) can repeatedly absorb and then release water to plants when needed, which substantially increases the water‐use efficiency of plants in arid and semiarid farming. However, it also creates a challenge in modeling RWU due to unstable soil hydraulic parameters and the unclear response of root growth to SAP application. A controlled soil column experiment was conducted to investigate the response of two important root indexes, that is, root length density (RLD) and root nitrogen mass density (RND), to SAP application, as well as their relationships with RWU. The results showed that the use of the SAP caused a steady increase in RND, and it also substantially increased the RLD in the early stage, but the rate of increase gradually slowed over time. The effect of unstable soil hydraulic parameters on RWU was analyzed in a numerical experiment, which indicated that the time‐dependent effect of SAP on soil hydraulic parameters should be considered to avoid errors in calculating RWU. A specific method for calculating the RWU source/sink term in the Richards equation was proposed and ultimately used as the theoretical value of RWU to verify the RWU models based on RLD and RND to ensure the best one was selected. The results showed that RND was better able to be used for development of the RWU model to simulate the patterns of RWU under SAP application.

Effects of superabsorbent polymers on the abundances of antibiotic resistance genes, mobile genetic elements, and the bacterial community during swine manure composting

Superabsorbent polymers (SAPs) are considered suitable amendments for reducing the selection pressure due to heavy metals and the abundances of antibiotic resistance genes (ARGs) during composting. In this study, three SAP (sodium polyacrylate) levels (0, 5, and 15mgkg−1 of compost) were applied and their effects on the abundances of ARGs, mobile genetic elements (MGEs), and the bacterial community were investigated. After composting, the abundances of ARGs and MGEs decreased to different extent, where the removal efficiencies for tetW, dfrA7, ermX, aac(6′)-ib-cr and MGEs exceeded 90%. The high SAP concentration significantly reduced the abundances of ARGs and MGEs, and changed the microbial community. Redundancy analysis indicated that the moisture content mainly explained the changes in ARGs and MGEs. Network analysis determined the potential hosts of ARGs and MGEs, and their co-occurrence. The results suggested that applying 15mgkg−1 SAP is appropriate for reducing ARGs in compost.

Growth characteristics of Artemisia sieberi influenced by super absorbent polymers in texturally different soils under water stress condition

ABSTRACTThe effects of super absorbent polymers (SAPs) on growth characteristics and seedlings survival of Artemisia sieberi (under two soil textures, three irrigation levels and seven hydrogel compositions with three replications) were investigated. The studied traits were shoot height, shoot dry weight, root dry weight, ratio of root/shoot, root length, root perimeter, root area and root volume. SAPs successfully enhanced growth capability of A. sieberi in two soil textures compared to the controls. Ideally, 5 g kg‒1 Aquasorb™ (SNF Company, France) with 100% irrigation and 10 g kg‒1 Stockosorb® (Evonik Corporation, Germany) with 75% irrigation in a sandy loam texture and 10 g kg‒1 Boloorab A™ (Boloorab Company, Iran) with 75% irrigation in a loamy texture significantly affected all traits, resulting in 100% survival for A. sieberi seedlings. Aquasorb™ and Stockosorb® showed the best results in the sandy loam texture and preferable outputs were obtained by Boloorab A™ application in the loamy texture. In other words, because of the basic differentiation among soils in terms of mineralogy, temperature and moisture content, different SAPs should be applied. Production of dense root network and root aggregation stimulated by SAPs increased root contact with moisture. Therefore, improving the growth and survival of the plants is accessible using SAPs under water stress condition.

Response of super absorbent polymers under different water gradient on growth characteristics of Parthenocissus quinquefolia seedlings

In order to study effects of super absorbent polymers and future rainfall change on growth characteristics of Parthenocissus quinquefolia seedlings, and search for a way to improve ecological environment conditions. The experiment about response of super absorbent polymers under different water gradient on growth characteristics of Parthenocissus quinquefolia seedlings was examined at Zheng Lanqi cultivating grass station in Inner Mongolia, China. The results showed that super absorbent polymers treatment can increase soil water content obviously, and keep it for quite a long time; Stem length, branch number, leaf number and biomass increment of stem, leaf, root and plants are all increased with increasing water supply, and the effect of super absorbent polymers treatment is larger than that of water gradient, especially W3 and W4 had obvious differences while comparing to contrast; Biomass allocation was significantly influenced by super absorbent polymers treatment, especially leaf weight ratio and root weight ratio, while branch weight ratio and root / shoot have little differences.

Effects of Superabsorbent Polymers on the Hydraulic Parameters and Water Retention Properties of Soil

Superabsorbent polymers (SAPs) are widely applied in dryland agriculture. However, their functional property of repeated absorption and release of soil water exerts periodic effects on the hydraulic parameters and water-retention properties of soil, and as this property gradually diminishes with time, its effects tend to be unstable. During the 120-day continuous soil cultivation experiment described in this paper, horizontal soil column infiltration and high-speed centrifugation tests were conducted on SAP-treated soil to measure unsaturated diffusivityDand soil water characteristic curves. The experimental results suggest that the SAP increased the water retaining capacity of soil sections where the suction pressure was between 0 and 3,000 cm. The SAP significantly obstructed water diffusion in the soil in the early days of the experiment, but the effect gradually decreased in the later period. The average decrease in water diffusivity in the treatment groups fell from 76.6% at 0 days to 1.2% at 120 days. This research also provided parameters of time-varying functions that describe the unsaturated diffusivityDand unsaturated hydraulic conductivityKof soils under the effects of SAPs; in future research, these functions can be used to construct water movement models applicable to SAP-treated soil.

The effects of superabsorbent polymers on the microstructure of cementitious materials studied by means of sorption experiments

Superabsorbent polymers (SAPs) are a promising additive to be used in the building industry but may induce microstructural changes. Water vapour sorption may be used to characterize the change in pore structure of cementitious materials, but the technique is difficult to interpret. In the present paper, static and dynamic vapour sorption (DVS) measurements were performed and compared to nitrogen adsorption experiments. The models of Dubinin-Radushkevich and Barrett-Joyner-Halenda were hereby applied to study pores in the micro- and mesopore range. The results show that cement pastes with SAPs and without additional water show a slight decrease in porosity in the micro- and mesopore range. Cement pastes with SAPs and with additional water show no significant change of porosity in the micropore range and a slight increase in the larger mesopore range. These new findings give insight into the effects of SAPs on the microstructure and strength of cementitious materials.

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

AbstractThe application of superabsorbent polymers (SAPs) in agriculture can enhance water use efficiency and ease water shortage in agriculture. In this study, by applying SAPs to the middle layer of the soil root zone, the effects of SAPs on moisture distribution during infiltration and evaporation under the condition of point source irrigation were investigated. The results show that during infiltration, the wetting front formed an accident change zone in the horizontal direction; in the bottom layer, the horizontal infiltration rate is greater than the vertical infiltration rate due to the effect of SAPs from the middle layer; the soil water content in the middle layer increased remarkably by 23.6%, higher than that in the surface and bottom layers; during evaporation, the soil water content changed significantly in the surface layer due to strong evaporation on the surface, it was largest and quite even in the SAP–soil mixture layer, and decreased the least in the bottom layer due to water storage in the mixture layer. Therefore, SAP application in the crop root layer is helpful to conserve soil water content in the crop root zone, inhibit evaporation of soil water in the lower layer and facilitate moisture conservation. Copyright © 2015 John Wiley & Sons, Ltd.

Effects of super-absorbent polymers on a soil–wheat (Triticum aestivum L.) system in the field

Super-absorbent polymers (SAPs) have been established as a soil conditioner to reduce soil water loss and increase crop yield. However, there are few studies about how SAPs affect the soil microbial community. In this study, two types of SAPs, Jaguar C (JC) and Jaguar S (JS), were applied at 200kgha−1 by bulk and spraying treatments in a field trial to investigate their effects on winter wheat growth, the soil's physical properties and microbial abundance and activity. It was found that the addition of SAPs promoted the formation of macro soil aggregates (particle size >0.25mm) and soil bacterial abundance under winter wheat cultivation. SAPs also significantly increased the soil water content (SWC) and soil maximum hygroscopic moisture (SMHM) in the booting and filling stages but had no effects on the soil available water-holding capacity (AWC) compared with the control in the filling stage. The effects of SAPs depended on the application strategy, as only the bulk JC treatment improved the wheat yield, soil microbial biomass carbon (MBC) and soil microbial respiration (SMR). The results showed that the application of SAPs did not lead to detectable adverse effects on the soil microbial community and might even enhance soil microbial activity. This study should serve as a useful complementary exploration for the assessment of the environmental effects of soil additives.

Effects of super absorbent polymers on soil microbial properties and Chinese cabbage (Brassica chinensis) growth

New water retention materials, super absorbent polymers (SAPs), have shown the potential to improve some soil physicochemical properties and promote growth of some crop species in arid and semi-arid areas. However, the impacts of SAPs on soil microbial properties are unclear. This study was conducted to clarify the effects of two SAPs on soil microbial properties and Chinese cabbage (Brassica chinensis) growth under different water conditions in the greenhouse. Experimental conditions included different irrigation conditions and different quantities of SAPs. Chinese cabbage was harvested after 1-month growth in the greenhouse. Meanwhile, soil samples were collected and sieved (<2-mm mesh). Some of the soils were kept at −4 °C for analysis of soil physicochemical properties, and some at −20 °C for analysis of soil microbial properties. Chinese cabbage samples were thoroughly washed with deionized water for the measurement of fresh weight, shoot length, and root length. The effects from SAPs were not obvious under water sufficient (WC1, watered every 2 days, and WC2, watered every 4 days) since plant properties were smaller in some SAP treatments than those in control. However, under water deficit (WC3, watered every 8 days), there were significant differences in plant shoot length and fresh weight between SAP treatments. There were also significant differences in relative soil water content between water condition (WC) or SAP treatments. The SAPs were beneficial for the formation of large aggregates. Under WC3, the soil organic matter (SOM) increased by 16.9 and 11.5 %, soil microbial biomass C (SMBC) by 32.5 and 19.3 %, and soil microbial respiration (SMR) by 52.1 and 37.2 % with Jaguar C (JC) and Jaguar S (JS), respectively. Under WC1 and WC2, significantly higher copy numbers of AOA in bulk treatment of JC were found compared with control treatment in this study. Under water deficit, the abundance of bacteria was significantly increased by application of SAPs. For almost every property of soil and plant, JC was showing better effects than JS. Our results showed that cabbage growth was restricted under water-deficit conditions and the application of SAPs could conserve soil water and be useful for increasing cabbage growth under water deficit, improving SOM, SMBC, and SMR under different WC, and stimulating amoA gene AOA copy numbers and bacterial gene copy numbers. Thus, there should be no adverse effects of SAP application on soil microbial environment and Chinese cabbage growth.

Effects of super‐absorbent polymers on the physical and chemical properties of soil following different wetting and drying cycles

AbstractSuper‐absorbent polymers (SAPs), a group of new water‐saving materials and soil conditioners, have been widely adopted in agriculture, but little is known about their effects on soil physical and chemical properties under alternating dry and wet conditions. This study assesses soil moisture, bulk density, pH, electrical conductivity (EC) and available P and K after different wetting and drying cycles. Four types of SAPs, labelled BF, JP, BJ and WT, with organic macromolecules were mixed with sandy soils to give concentrations of 0%, 0.05%, 0.1%, 0.2% and 0.3%, with the aim of determining water retention and soil properties after amendment with the SAPs. Soil moisture increased by 6.2–32.8% with SAP application, while soil bulk density was reduced by 5.5–9.4% relative to the control, especially with a moderate water deficit when the relative soil moisture contents were about 40–50%. The largest increase in soil moisture and the greatest reduction in bulk density resulted from the WT treatment. The effects of SAPs on soil pH and EC were contrary. Soil available P increased slightly while available K significantly decreased, except following the first wetting and drying cycle. Available K increased with drying, but the opposite effect was observed for available P. Particular SAPs (JP and WT) seem more suitable under alternating dry and wet conditions. The effects on soil‐water retention and other soil properties varied according to the structure of the SAP and soil moisture.