Photocatalytic overall water splitting is an interesting research topic in the field of energy and outer space exploration. Here, we designed a P/MoS2 composite photocatalyst with ...self-water-absorption performance by compositing MoS2 nanosheets and polycrystalline black phosphorus nanosheets. The composite photocatalyst produced a sufficient amount of hydrogen in the absence of any precious metal. This also demonstrated photocatalytic overall water-splitting ability in the absence of any sacrificial agent. More interestingly, it effectively absorbed water and demonstrated good overall water-splitting performance under the simulated Mars conditions; the average hydrogen production rate was 17.68 μmol h−1 g−1, and the oxygen production rate was 7.61 μmol h−1 g−1 over a period of 70 h. A comprehensive investigation of the ability of the composite photocatalyst to absorb water and produce hydrogen was performed.
Here, we designed a P/MoS2 composite photocatalyst with self-water-absorption performance. It demonstrated good water absorption and overall water-splitting properties under simulated Mars conditions. Display omitted
•We designed the first P/MoS2 composite photocatalyst with self-water-absorption performance.•The composite photocatalyst effectively produced hydrogen and absorbed water in the absence of any precious metals.•The ability of the photocatalyst to absorb water and perform overall water splitting was confirmed.
This research aims to develop a multifunctional, water-based product for protecting and consolidating stone materials. A new synthesis strategy using water-diluted silane formulations, composed of ...TEOS and an alkyl monomeric silane (ETES) or a polymeric siloxane (PDMS), homogenized by ultrasonic irradiation was followed to produce hybrid networks and overcome the limitations of current hydrophobic consolidants.
These formulations gave rise to low dry residues and hydrophobic surfaces on various stones, including on low and high porosity stone varieties. Despite some formulations originated cracked films, optimal concentrations of ETES and PDMS showed high protection levels against capillary water absorption with minimal impacts on the color and water vapor permeability of the stones. Besides demonstrating the initial efficacy of these new hybrid materials in modifying the inherent hydrophilic and water-absorbing properties of stones, this work further confirmed their ability to penetrate within the stone pores and their initial efficacy in consolidating porous stones.
Thus, new water-based multifunctional hybrid materials capable of consolidating and protecting various types of stones from water-related damage have been developed. These novel materials align with both technical and environmental requirements.
•New hybrid sonogels were prepared successfully with water-based formulations of silanes.•Different concentrations of ETES and PDMS turn various stones hydrophobic.•Optimal concentrations also reduce drastically the water absorption of very porous stones.•Formulations preserve the original water vapor permeability while offering protection.•A multifunctional role was confirmed, as they also improve the cohesion of porous stones.
Arabinoxylan (AX) is a potential health-promoting fiber ingredient that could be used to improve nutritional properties of bread, but is also known to affect bread and dough quality. To identify the ...role of feruloylation and hydrolysis of wheat bran AX on bread quality and shelf-life, hydrolyzed and unhydrolyzed AX with low and high ferulic acid content were incorporated into wheat bread. Water absorption, visual appearance, specific volume, and crumb structure were evaluated in fresh bread, and texture and moisture content over 14 days of storage. Feruloylated and unhydrolyzed AX breads underwent less moisture loss during storage but none of the AX fractions retarded crumb hardening. Feruloylated and hydrolyzed AX breads were comparable to control bread even at the highest addition level (5%) in terms of volume and crumb structure. The higher quality of these breads was associated with ferulic acid content and lower molar mass based on multivariate analysis. Based on our work, knowledge on specific AX structure can facilitate the use of increased AX levels in breadmaking.
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•Feruloylated and unhydrolyzed AX hindered crumb moisture loss during storage.•Change in moisture content did not lead to hardening of bread crumb.•Increased baking absorption by high molar mass AX reduced bread quality.•Feruloylated and hydrolyzed AX inclusion to 5% gave comparable bread to control.•Optimizing AX structure can facilitate use of increased AX levels in breadmaking.
•Hydrogels are 3D, hydrophilic, polymeric networks linked through physical or chemical bonds.•Hydrogels can present a conformation which allows their use as part of a packaging system.•Moisture ...control and bioactive agent release are their potential application in food products.
Hydrogels are three-dimensional, hydrophilic networks, comprising polymeric chains linked through physical or chemical bonds. In the area of food, hydrogels have great potential to be used in food packaging systems or as carriers of bioactive components. This paper reviews the nature of hydrogels, their 3D network conformation, their functional properties, and their potential applications in food packaging systems. Regarding their potential food packaging applications, hydrogels can present a conformation which allows their use as part of a packaging system to control the humidity generated by food products with high water content. Moreover, the incorporation of nanoparticles into hydrogels may grant them antimicrobial activity. Finally, although the current research in this field is still limited, the results obtained so far are promising for innovative and potential applications in the food field, which also include their integration into intelligent food packaging systems and their direct incorporation into food matrices as a flavor carrier system.
•Effect of the incorporation of RCAs on concrete durability was experimentally investigated.•Amount of absorbed water and salt by RAC with various replacement ratios were obtained.•Quality and ...replacement ratio of RCAs have significant influences on mass penetration in RAC.•Adding RCAs decreases the compressive strength and inversely increases mass transport coefficient.•The linear changing behavior for water and chloride penetration depth in RAC was exhibited.
Knowledge of the transport properties for recycled aggregate concrete (RAC) exposed to chloride environment plays a critical role in assessing its durability and predicting the service life. In this study, the effect of the incorporation of coarse recycled concrete aggregates (RCAs) on the durability of cement-based cementitious materials was experimentally investigated. Two types of RCAs were obtained to produce the RAC with water-to-binder ratio of 0.33 and 0.39, and different substitutions of RCAs ranging from 0%, 30%, 50% and 100% by weight were selected. A series of experiments including compressive strength, water and salt absorption test, and rapid chloride migration (RCM) test for RAC with various replacement ratios of RCAs were conducted. The results indicate that the incorporation of RCAs generally decreases the compressive strength, and inversely increases water and chloride transport coefficient compared to those of the control concrete. An increasing trend can be found in the influence of RCAs replacement ratio on the initial coefficient of capillary water absorption, but it inversely decreases as the quality of RCAs is improved. The chloride content and penetration depth in RAC were remarkably increased as RCA content increases and its quality decreases. The linear changing behavior for the penetration depth between water and chloride ion in RAC with different replacement ratios was well exhibited. This finding reveals the retardation effect that the chloride transport process lags behind water migration for the absorption tests of RAC.
Non-isocyanate polyurethanes (NIPUs) with varying content of secondary amino groups along their chain were studied with respect to water absorption and plasticization. Secondary amino groups promote ...water uptake. Water sorption isotherms in the water activity range 0–0.97 are discussed in terms of various sorption models. Secondary amino groups act as additional hydration sites, increasing monolayer capacity. The red shift of the IR band assigned to the carbonyl of the urethane and the simultaneous blue shift of the urethane N–H bending band show cleavage of the polymer-polymer hydrogen bonds upon water uptake, due to strong interactions between water molecules and hydroxyurethanes constituting the primary hydration sites. A decrease in glass transition temperature (Tg) is observed with increasing water content. The effect is discussed in terms of plasticization and slaving mechanisms, while a peculiar decrease of Tg at very low hydrations is attributed to a mechanism not following common mixing laws.
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•Secondary amino groups along NIPU chain contour act as secondary hydration sites.•Water absorption of NIPUs can be tailored by controlling polar groups concentration.•At low hydrations standard mixing models fail to describe Tg decrease.•This is attributed to scission of inter-segment hydrogen bonds by traces of water.
Chemical modification is a reliable and efficient strategy for designing cellulose-based functional materials. Herein, porous quaternized cellulose beads (QCBs) as cationic superabsorbent were ...fabricated by homogeneous in-situ chemical grafting cellulose molecular chains with glycidyl trimethylammonium chloride (GTAC) in tetraethylammonium hydroxide (TEAOH)/urea aqueous solution followed by acetic acid induced regeneration. The influence of GTAC dosage on the physicochemical-structural properties of cationic QCBs was deeply investigated. Results revealed that cotton liner could well-dissolved in TEAOH/urea aqueous solution, leading to a homogeneous and efficient quaternization medium for cellulose, thereby giving the high DS and positive charge density for quaternized cellulose. NMR results demonstrated the main substitution of GTAC groups at 2-OH and 6-OH positions of the cellulose chains during quaternization reaction. With increasing GTAC dosage, the network skeleton of QCBs gradually transformed from thick fibrils to thin aggregates, as well as enhanced pore volumes and hydrophilicity. Accordingly, QCBs-1.5 with high pore volume (99.70 cm3/g) exhibited excellent absorption capacity and efficiency, absorbing 122.32 g of water and 0.45 g of moisture per gram of the beads in 20 min. This work not only offers a simple strategy for the homogeneous quaternization modification of cellulose, but also provides a porous cellulose-based cationic superabsorbent material.
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•Species mixing improved the water absorption of Pinus massoniana from shallow soils.•Species mixing reduced the water uptake proportion of P. massoniana from deep soils.•Plant rather than soil ...properties mainly regulated P. massoniana water uptake in well-watered conditions.
Tree species mixtures have been identified as an effective strategy to cope with global climate change. Global climate change not only triggers extreme drought, but also stimulates extreme precipitation, resulting in frequent floods and subsequent tree mortality. However, previous studies concentrated primarily on the response of mixed species to extreme drought, with limited studies involving their response to extreme precipitation, especially at the regional scale. Here, we used δD and δ18O coupled with the MixSIAR model to analyze the water use pattern of Pinus massoniana between pure and mixed stands following different magnitudes of rainfall events across southern, central, and northern subtropical China. We further employed partial correlation analysis, variation partitioning analysis and a random forest model to discern the dominant factor affecting plant water absorption. Our results indicated that the proportion of water uptake by P. massoniana from the 0–40 cm soil layers in the mixed stand was significantly higher than that in the pure stand (56.5–81.4 % vs. 44.3–61.7 %), while the proportion of water uptake from the 60–100 cm soil layers exhibited the opposite pattern (9.0–25.0 % vs. 24.1–32.2 %), whether in light, moderate or heavy precipitation. Furthermore, our results revealed that the difference in P. massoniana water absorption between pure and mixed stands was mainly due to the shifts in plant attributes (i.e., root biomass, leaf biomass and predawn leaf water potential). These findings imply that mixed tree species distributions could optimize water uptake patterns by altering plant properties for interspecific niche complementarity, which could effectively increase forest water conservation.
Pervious pavements are efficient in the mitigation of urban heat island effects. Many studies have revealed the water availability of pervious paving materials dominates the evaporative cooling ...effect. However, the water retention capacity of these materials is affected by the water absorption capability, which has scarcely been investigated in relation to evaporation. Therefore, this study investigates the water absorption capability of pervious paving materials and its influence on evaporative cooling performance. We examine the water absorption capability of three similar-coloured materials, including sintered ceramic pervious brick (CB), pervious concrete brick (PB), and open-graded pervious concrete (PC), as well as their evaporative cooling performance under a steady-state hot-humid environment in a climatic wind tunnel. The results indicate that: (1) CB had the highest water absorption coefficient of 2.04 kg/m2·s0.5, which is approximately about 30 and 200 times higher than that of PB and PC, respectively; however, these materials had similar water retention capabilities, with a capillary moisture content of 110 ± 10 kg/m3, revealing that CB could hold more water in a very short time; and (2) CB and PB could effectively reduce the surface temperature by up to 20 °C and 12 °C with a cooling period of 16 h and 12 h, respectively. In comparison, PC demonstrated a weak cooling effect of 2 °C, which only lasted for 4 h. Overall, materials with a high water absorption capability can maintain hydraulic continuity balance for a long time, which is beneficial to enhancing evaporation and further lowering the surface temperature.
•High water absorption of pervious materials helps to retain enough water in a shorter time.•Water absorption capacity of pervious pavement affects the first stage of evaporation.•Materials with higher water absorption rates were more effective at cooling.
•The performance of an integrated solar trigeneration system is investigated.•A concentrating photovoltaic-thermal unit with linear Fresnel is considered.•A water-ammonia absorption refrigeration ...cycle is integrated with the collector.•Performance of the system for providing energy demands of a building is studied.•The system shows a promising result for heating and cooling purposes.
The aim of this study is evaluating the performance of a combined cooling, heating, and power generation system (a trigeneration), composed of a concentrating photovoltaic-thermal unit, coupled with a water-ammonia absorption chiller. In the presented design, an ammonia-water absorption refrigeration cycle with 5 kW of cooling capacity is considered as a part of the trigeneration system. Also, a concentrating photovoltaic-thermal device, equipped with a linear Fresnel collector, is employed as the heat source. The performance of the system is modeled and simulated using TRNSYS. Furthermore, in case of replacing the concentrating collector by a conventional one, the performance of the cycle is investigated. It is revealed that, with the conventional collector type, the system could not provide enough thermal energy for the refrigeration cycle. The annual average of the electrical efficiency of the designed collector and trigeneration system are 12.8% and 58.01%, respectively. By investigating the produced energy from the presented unit, it is concluded that this system could be employed as the heating and cooling source of a typical residential building. However, the electrical energy demand of the building cannot be fully supplied with the presented design, and 6030 kWh of the electrical energy must be provided from the grid.
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