Hygroscopic Performance Research Articles

Development of Biodegradable and Recyclable FRLM Composites Incorporating Cork Aggregates for Sustainable Construction Practices

Reducing energy consumption in the building sector has driven the search for more sustainable construction methods. This study explores the potential of cork-modified mortars reinforced with basalt fabric, focusing on optimizing both mechanical and hygroscopic properties. Six mortar mixtures were produced using a breathable structural mortar made from pure natural hydraulic lime, incorporating varying percentages (0–3%) of cork granules (Quercus suber) as lightweight aggregates. Micro-computed tomography was first used to assess the homogeneity of the mixtures, followed by flow tests to evaluate workability. The mixtures were then tested for water absorption, compressive strength, and adhesion to tuff and clay brick surfaces. Adhesion was measured through pull-off tests, to evaluate internal bonding strength. Additionally, this study examined the relationship between surface roughness and bond strength in FRLM composites, revealing that rougher surfaces significantly improved adhesion to clay and tuff bricks. These findings suggest that cork-reinforced mortars offer promising potential for sustainable construction, achieving improved hygroscopic performance, sufficient mechanical strength, internal bonding, and optimized surface adhesion.

Investigations of Silica/MOF composite coating and its dehumidification performance on a desiccant-coated heat exchanger

Desiccant materials have an important impact on the dehumidification performance of desiccant-coated heat exchanger (DCHE). In this paper, a desiccant-coated heat exchanger based on a composite desiccant material of metal organic frameworks (MOFs) and silica gel was proposed. The coating was experimentally prepared and tested for its hygroscopic performance under different binder types (PVP, PVA, and PVB), different binder mass concentrations, and different MOF mass concentrations in the composite adsorbent. Further simulations were performed to investigate the effects of key structural and operational parameters on the performance of DCHE. Experimentally, the optimal hygroscopic performance of the composite adsorbent was obtained at 15 wt% PVP and 20 wt% MOF, which was 51.71 % higher than that of silica coating, and the cost of the composite adsorbent drops 78.04 % by comparing to the pure MOF for laboratory fabrication, and based on the novel economic efficiency index proposed in this paper, the mass concentration of the MOF should not exceed 32.8 wt%. Simulation results showed that under the conditions as follows: 1.2 mm (fin spacing), 25 mm (fin height), 0.28 mm (coating thickness), 25 °C (cooling water temperature), and 0 % (initial moisture content), the corresponding moisture removal capacity (MRC) and of DCHE was 6.740 g/kg, which was 149.63 % higher than that of silica coating.

Eco-efficient plastering mortars for improved indoor comfort − The influence of A. dealbata bark addition

The passive contribution of indoor coatings to improve interior comfort is an eco-efficient challenge nowadays. Gypsum is one of the more eco-efficient binders available to produce plasters. Acacia dealbata is an invasive plant species in many countries, and the management of its wood waste for fires prevention is imperative. This study intends to evaluate the effect of using Acacia dealbata bark waste, directly after milling (raw) or with additional thermal treatment (1 h at 250 ⁰C), as an addition to an industrial gypsum-based plastering mortar to passively improve indoor comfort. To prevent the biological colonization, air lime is also added. Two clay-based plasters are used for comparison, as this type of plaster is known for being highly hygroscopic, together with a reference gypsum plaster. Results show that both the gypsum-bark mortars fulfill the standard requirements and do not show biological vulnerability. They doubled the moisture buffering of the reference gypsum plaster and got closer to the hygroscopic performance of the clay plasters. The very similar results between the two gypsum-bark mortars suggest that the thermal treatment of bark is not an eco-effective choice. So, the raw bark-added gypsum mortar is selected as a promising coating material to passively contribute for indoor comfort in an innovative, eco-efficient, way.

Research Progress on Hygroscopic Agents for Atmospheric Water Harvesting Systems.

Adsorptive atmospheric water harvesting systems (AWHs) represent an innovative approach to collecting freshwater resources from the atmosphere, with a hygroscopic agent at their core. This method has garnered significant attention due to its broad applicability, strong recycling capacity, and sustainability. It is being positioned as a key technology to address global freshwater scarcity. The core agent's hygroscopic properties play a crucial role in determining the performance of the AWHs. This article provides a comprehensive review of the latest advancements in hygroscopic agents, including their adsorption mechanisms and classifications. This study of hygroscopic agents analyzes the performance and characteristics of relevant porous material composite polymer composites and plant composites. It also evaluates the design and preparation of these materials. Aiming at the problems of low moisture adsorption and desorption difficulty of the hygroscopic agent, the factors affecting the water vapor adsorption performance and the method of enhancing the hygroscopic performance of the material are summarized and put forward. For the effect of hygroscopic agents on the volume of water catchment devices, the difference in density before and after hygroscopicity is proposed as part of the evaluation criteria. Moisture absorption per unit volume is added as a performance evaluation criterion to assess the effect of hygroscopic agents on the volume of water collection equipment. The article identifies areas that require further research and development for moisture absorbers, exploring their potential applications in other fields and anticipating the future development direction and opportunities of moisture-absorbing materials. The goal is to promote the early realization of adsorptive atmospheric water harvesting technology for large-scale industrial applications.

Cement Pastes with Hygroscopic Polymeric Additions for Potential Building Applications

The development of highly predictive analysis for designing cementitious composite with improved thermal and hygroscopic performance for building and construction poses a significant challenge. To investigate new potential applications, cement pastes have been prepared using a cement, sand, and crystallization admixture, with highly hygroscopic polymer additions (SA-PA) of sodium polyacrylate and/or recycled polyamide fibers. The porosity evolution was investigated at different curing stages and after heat treatment at 200 °C, the temperature at which the paste dehydrates quickly without structural changes. Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), cyclic shear tests, thermal conductivity, and diffusivity measurements were carried out on the cement pastes to assess their microstructure. The behavior of the cement pastes varied with polymer additions and thermal treatments; ka−0.5 must be maximized in heat storage applications, where a and k are thermal diffusivity and conductivity, respectively. In contrast, the product a0.5k−1 must be maximized in energy-efficient insulation. Cement pastes with SA-PA exhibited the highest values of both 9.191 102 m−2 K−1 s0.5 W and 1.088 10−3 m2 K s−0.5 W−1, respectively. After the thermal treatment at 200 °C, SA-PA samples maintained the highest heat-storing performance of 6.258 102 m−2 K−1 s0.5 W, while the samples with SA-PA and polyamide fibers performed better in energy-efficient insulation, demonstrating performance of 2.552 10−3 m2 K s−0.5 W−1. These results, discussed in terms of pore size distribution, suggest potential applications in the building field and are valuable for designing plaster and concrete for applications such as thermal and hygroscopic control.

Impact of microencapsulated phase change material on a bio-based building composite, hygrothermal and mechanical behavior

Among the promising solutions to reduce the ecological impact of construction materials is the promotion and development of local natural materials, such as the valorization of agricultural by-products. These bio-based materials offer interesting thermal and acoustic characteristics while significantly reducing the consumption of fossil energy (grey energy) and greenhouse gas emissions associated with their manufacturing process. Moreover, due to their permeable nature, these materials ensure stable hygrothermal exchanges with the surrounding environment.This work aims to develop a new bio-based composite thermally reinforced by incorporating organic and non-paraffinic phase change materials (PCMs) into hemp concrete. Different PCM contents, namely 5%, 10% and 15% of the binder mass, are considered.In this study, an extensive hygrothermal and mechanical experimental analysis was carried out on hempcrete-PCM composites. The incorporation of PCMs in hemp concrete resulted in a degradation of the mechanical strength, an enhancement of the thermal storage capacity, and no significant impact on the hygroscopic performance.

Static, fatigue and hygroscopic performance of steel-reinforced resins under various temperatures

Resins are essential structural materials predominantly used in load-bearing connections such as adhesively bonded joints and resin-injected bolted connections. In an effort to improve the latter, a new injection material, Steel Reinforced Resin (SRR), has been developed, consisting of spherical steel particles embedded in a resin. SRR's applicability has been explored in injection bolts used in composite steel-to-concrete floor systems and as an injection material in Fibre Reinforced Polymer (FRP) sandwich web-core panels of highway bridges. While the short-term and creep performance of SRR has been researched, its fatigue behaviour remains unexplored. From joint-level cyclic experiments with SRR, it was observed that joint endurance is dominated by SRR's fatigue performance. There is currently no research on the influence of temperature on SRR's mechanical properties and moisture uptake. This paper fills this gap, by investigating the static and fatigue performance of epoxy, unsaturated polyester polyurethane hybrid (UPE + PU), and vinyl ester based SRRs under ambient and elevated temperatures. Water absorption assessments were conducted on the three resins with and without steel particles to evaluate their durability and corrosion resistance. The results show that temperature significantly impacts tensile stiffness, tensile splitting strength, and fatigue life. Epoxy based SRR endured 20 times more tensile splitting stress cycles to failure compared to the UPE + PU resin based SRR at the same stress range. However, after 200 days of water exposure at maximum temperature, the epoxy resin (with and without steel shot) exhibited a weight increase of 4.0% and 0.50% respectively, suggesting that despite its superior fatigue performance, it may not be suitable for SRR applications in high moisture environments. In contrast, UPE + PU resin and its corresponding SRR displayed substantially lower water absorption.

Facile and efficient chitosan-based hygroscopic aerogel for air dehumidification

Sorption dehumidification, as an energy-saving and eco-friendly approach, has been emerging in application for air dehumidification. Here, a prospective method is proposed to prepare biomass-based hygroscopic aerogels that are easily applicable, sustainable, high-efficient, and recyclable. The chitosan-based aerogel with a porous and hydrophilic network acts as the carrier and water reservoir for the uniformly distributed lithium chloride hygroscopic salt, and provides the hygroscopic salt with more liberal water channels to facilitate moisture capture and transfer. As a consequence, the prepared chitosan/polyvinyl alcohol@lithium chloride (chitosan/PVA@LiCl) hygroscopic aerogel exhibits an excellent moisture absorption capacity of up to 2.77 g g−1 at a relative humidity of 90 %. Meanwhile, as the chitosan/PVA@LiCl aerogel is set in a closed space about 2200 times larger than its own volume, the relative humidity can be reduced from 90 % to 32 % within 2 h, and further lower to 25 % after 4 h. Furthermore, combined with multi-walled carbon nanotubes, the photothermal hygroscopic aerogel is obtained that can rapidly desorb water under sunlight, thus to realize energy-free cycle. Overall, the renewable biomass-based aerogel materials with the advantages of simple preparation and excellent hygroscopic performance provides a new path for the development of sorption dehumidification technology.

Study on Preparation and Properties of PNIPAm/PPy Hydrogel Hygroscopic Material for Solid Dehumidification System

Air-conditioning systems account for 40–60% of the energy consumption of buildings, and most of this figure corresponds to the cooling and dehumidification process of air-conditioning units. Compared with traditional compressed air-conditioning systems, solid adsorption dehumidification systems possess good potential to improve indoor air quality and reduce buildings’ energy consumption. However, there are still some problems that prevent the use of solid adsorption dehumidification systems, such as their complexity and high regeneration temperatures. The key to solving the above problem is the discovery of more suitable adsorbents. In this paper, poly N-isopropylacrylamide/polypyrrole (PNIPAm/PPy) hydrogel was selected as the research object, and the performance of the dehumidification material and its potential for application in solid dehumidification systems were studied. It was found that the pore structure of PNIPAm/PPy was relatively complex and that there were abundant pores with uneven pore sizes. The minimum pore size was about 4 μm, while the maximum pore size was about 25 μm, and the pore sizes were mostly distributed between 8 and 20 μm. Abundant and dense pores ensure good hygroscopic and water-releasing properties of the resulting hydrogel. The PPy inside the hydrogel acts as both a hygroscopic and photothermal agent. In an environment with a relative humidity of 90%, 60%, and 50%, the hygroscopic efficiency of PNIPAm/PPy reached 80% in about 75, 100, and 120 min, and the corresponding unit equilibrium hygroscopic capacity values were 3.85 g/g, 3.72 g/g, and 3.71 g/g, respectively. In the initial stage, the moisture absorption increased with the increase in time; then, the increase in moisture absorption decreased. When the temperature was below 40 °C, the hygroscopic performance of PNIPAm/PPy was almost temperature-independent. The PNIPAm/PPy with different thicknesses showed similar moisture absorption efficiency. The lowest desorption temperature of PNIPAm/PPy was 40 °C, which indicates that low-grade energy can be used for material desorption. And the higher the temperature, the faster the desorption rate of PNIPAm/PPy and the higher the desorption amount. It can be seen that the PNIPAm/PPy hydrogel presents good desorption performance and can be used repeatedly.

Thermal comfort and passive survivability in earthen buildings

Earthen building materials have been regaining popularity due to their environmental, economic, and health advantages. Furthermore, given projected thermal survivability in the face of climate change, passive strategies that minimize use of fossil fuels for operational space conditioning are becoming increasingly necessary. Using the lens of passive survivability, this research investigates the abilities of four earthen wall assemblies (cob, light straw clay, unstabilized rammed earth, insulated unstabilized rammed earth) and three conventional assemblies (concrete masonry unit (CMU), insulated CMU, insulated wood frame) to provide adaptive thermal comfort in six distinct climates, with and without passive heating and cooling systems. Residential dwellings were evaluated through simulation with heat and moisture transport algorithms, showing that passive conditioning is especially beneficial with earth assemblies, bringing 25–70% of uncomfortable annual hours into the adaptive comfort zone, alongside strikingly lower diurnal temperature swings in all examined climates, and in all seasons, than conventional walls. Further investigation into the heat and moisture fluxes reveals that the thermal stability of the earth dwellings is provided in part by moisture sorption and evaporation. Together, for the first time, these results show that the thermal performance of earth assemblies can, with well-designed passive heating and cooling strategies, equal or outperform conventional assemblies in a range of U.S. climates, supporting their expanded inclusion in U.S. building codes. This research provides a novel contribution to the thermal performance optimization of earth construction, critically linking thermal and hygroscopic performance with passive design strategies such as shading, natural ventilation, and movable insulation.

Comfort and functional evaluation of silk/profiled antibacterial polyester fabric

In this study, a novel multifunctional woven silk fabric characterized by quick-drying and bacteriostasis was developed through the addition of modified polyester filaments. The effect of fabric structure and filament proportion on the properties of multifunctional silk fabrics was investigated to determine the optimal weaving parameters for optimizing the overall fabric manufacturing process. Moreover, the fabric’s basic wearing properties, hygroscopic performance (e.g. wicking height, drip diffusion, and permeability), and antibacterial performance against Escherichia coli and Staphylococcus aureus were examined. Subsequently, the optimum parameters and weave structures were analyzed and evaluated using AHC (Analytic Hierarchy Process)-TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) method. The novel fabric exhibits great wearability, antibacterial properties, dyeing properties, and hand feeling, and it shows great commercial potential and takes on a vital significance in future silk product development.

Mechanical and Hygroscopic Characteristics of Unidirectional Jute/Glass and Jute/Carbon Hybrid Laminates

ABSTRACT Physical and mechanical performance of natural fiber composites can be tailored by hybridizing with synthetic fibers. Jute fibers are promising and highly available at a low cost in some countries, and they have been used in several applications, with the extra benefit of helping socially depressed people who commonly explore this plant. This work investigates the effect of hybridization on the properties of jute/glass and jute/carbon laminates with polyester resin. Nine different laminates were manufactured by vacuum infusion using unidirectional jute, E-glass, and carbon fabric reinforcements. Tensile, flexural, and short beam tests were performed in accordance with ASTM standards. The hybrid composites showed generally intermediate properties compared to the non-hybrid two-component laminates. The mechanical properties of the hybrid composites were 50–75% smaller than those of their respective pure glass and pure carbon composites, but 30–300% higher compared to the pure jute composite. Among the hybrids, the number of layers of the synthetic fiber played the most important role on properties, rather than the layup. That is, the variation in the number of jute fabrics may produce the required combination of stiffness and strength for different applications. Besides, the hybrid laminates, with more layers of synthetic fibers showed better hygroscopic performance.

Enhancement Mechanism of Minerals on Lignite-Water Molecule Interactions.

Five coal samples were prepared by deashing Shengli lignite in distinct phases, which consisted of residual ash from spontaneous combustion. The effects of removal and introduction of inherent minerals on the water reabsorption performance of coal samples were systematically investigated in three aspects: pore structure, oxygen-containing functional groups, and lignite materials. Low-field nuclear magnetic resonance spectroscopy was employed to investigate the changes in the water molecular adsorption tendency of coal samples with the variation in the mineral content. The study elucidates that the hygroscopic performance of the coal samples is significantly reduced due to the massive removal of inherent minerals. However, the pore structure of the coal samples after HCl/HF washing becomes more developed, and the oxygen-containing functional groups on the surface are more exposed, leading to an increase in the equilibrium adsorbed moisture content (EMC) of the coal samples. The binding force between coal samples and water molecules is reduced by the removal of the inherent minerals, which weakens the interaction forces between lignite and water molecules. The oxygen-containing functional groups on the surface of lignite interact with the residual ash from spontaneous combustion to enhance the binding force between lignite and surface water molecules, thus leading to the improved tendency of lignite to adsorb water molecules. The formation of intermediate complexes between minerals and oxygen-containing functional groups, in particular, carboxyl functional groups, on the surface of lignite enhances the acting force of polar sites, which improves the interaction of lignite-water molecules.

Experimental investigation of the effect of salt on the hygroscopic properties of autoclaved aerated concrete

The hygroscopic properties of autoclaved aerated concrete (AAC) significantly affect building energy consumption. However, the impact of salt on the hygroscopic properties of AAC in buildings in marine environments has not been sufficiently investigated. Thus, we tested the hygroscopic performance of AAC specimens with different salt contents at various humidity levels. The results show that the equilibrium moisture content (EMC) of the AAC is 0.98–1.25 (0.99–3.68) times higher in the presence of salt than in the absence of salt at low (high) relative humidity (RH) (RH threshold of 75.5%). Furthermore, an equation to predict the EMC of salt-containing materials was proposed based on existing adsorption equations and the results of this study. A comparison with related studies indicates that the reason for the high prediction value of the proposed prediction model may be an insufficient moisture absorption time. The proposed model can be used to calculate the EMC of building materials with different salt contents.

Enhanced thermal, safety and anti-hygroscopicity performance of core-shell ammonium perchlorate with a double coating layer.

A new core-shell structure AP/Cu-DABT/Cu(Pa)2 (10 wt% each) (AP = ammonium perchlorate, DABT = 3,3'-diamino-5,5'-bis(1H-1,2,4-triazole), Pa = palmitic acid) with two coating layers was synthesized through two self-assembly reactions to improve the thermal decomposition performance, safety performance and moisture absorption resistance of AP. The results show that the surface of AP particles is uniformly and densely covered by Cu-DABT and Cu(Pa)2 coatings successively. Compared with pure AP, the HTD (high-temperature decomposition) peak temperature and activation energy of the AP/Cu-DABT/Cu(Pa)2 (10 wt% each) composite material were reduced by 74.7 °C and 117.67 kJ mol-1, respectively, and the heat release increased by 1421.02 J g-1. In addition, the burning rate and maximum flame temperature of the propellant containing the AP/Cu-DABT/Cu(Pa)2 (10 wt% each) composite were increased by 8.7 mm s-1 and 815.8 °C, respectively, compared with the propellant containing pure AP. Moreover, compared with pure AP, the contact angle of the AP/Cu-DABT/Cu(Pa)2 (10 wt% each) composite with water increased by 89.15°, and the water content decreased by 0.38 wt%. The impact sensitivity and friction sensitivity of the composite material were reduced by 16.9 cm and 96%, respectively. Analysis shows that the Cu-DABT coating plays a major role in improving the thermal properties of the composite material, the burning rate and flame temperature of the propellant, while the Cu(Pa)2 coating plays a major role in improving the hygroscopic performance and safety performance of the composite material. The composite material has good thermal decomposition properties, anti-hygroscopic properties and safety properties, so the composite material is very promising as a potential additive for solid propellants.

Optimization of minor-LiCl-modified gypsum as an effective indoor moisture buffering material for sensitive and long-term humidity control

Porous gypsum materials buffer indoor humidity autonomously by adsorbing/desorbing moisture but are limited by poor adsorption capacity. Adding hydrophilic salt, such as lithium chloride (LiCl), is known to improve the capacity; however, the hydrophilic salt may block moisture desorption when overused, which is detrimental to moisture buffering and materials durability, particularly on humid days. This paper investigates the effects of minor LiCl addition on the fundamental (thermal conductivity, etc.), hygroscopic (adsorption/desorption), and moisture buffering performance of gypsum in daily and weekly humidity fluctuations. Results showed that minor addition of LiCl (1%–8%) substantially improves the gypsum board's fundamental properties and hygroscopic performance but avoids significant microstructure alteration. The improvement is reinforced with increasing LiCl ratio but then leveled off. The minor-LiCl-modified composites absorbed and desorbed moisture repeatedly without hysteresis for daily and weekly humidity fluctuations. The composite's moisture buffering effects on indoor air and the resulting energy-saving potentials were then modeled with study cases set in Shanghai and Paris; the composites effectively controlled indoor humidity, yielding a good energy-saving on dehumidification. Based on the results, a LiCl-mixing-ratio of ∼4% was proposed to serve as the optimum, under which the composited gypsum presented a remarkable capacity of 0.16 kg/kg and marked energy-saving by lowering indoor latent load from 7.8 W/m2 to 3.4 W/m2 and compensating for the investment increase in 1–2 years. These findings emphasize that implementing minor LiCl to porous gypsum materials enables distinct moisture buffering ability for sensitive and long-term humidity control on indoor air.

Study on influence of geometric characteristics of cracks on HAM coupling transfer and thermal performance of multi-layer cellular concrete wall

The effect of concrete cracks on the evaluation of the thermal performance of walls has not been effectively considered within the assessment of the thermal and hygroscopic performance of buildings. Based on the dual permeability model, a conjugate method is proposed to reconstruct the PDE equation of unsaturated porous materials with cracks. The reliability of the model is verified from three angles: the heat-moisture coupling benchmark of matrix material, the analytical solution of two-dimensional single fracture heat flow coupling problem and the moisture absorption problem of unsaturated cracks. The reliability of the model is verified from three perspectives: the benchmark of thermal and hygroscopic coupling of matrix materials, the analytical solution to the two-dimensional single-break thermal flow coupling problem, and the hygroscopic problem of unsaturated cracks. The effect of heat and moisture transfer in cracked concrete was quantified by detailed modeling of cracks in terms of the probability of over-penetration, crack roughness, crack density, length, and angle of a two-dimensional discrete crack network, showing that cracks contribute to moisture transfer. This is followed by a 10 day experimental simulation of the meteorological environment, comparing the quantities of moisture accumulation, thermal performance, internal surface temperature and humidity within the fractured and non-fractured wall structures, illustrating the potential adverse effects of cracks on thermal performance and moisture transfer in walls under characteristic conditions. Finally, the necessity of applying moisture-proof layer to the damaged wall is demonstrated by comparing the results before and after the application of the moisture-proof layer.

Earthen construction materials as enabler for circular construction

The construction sector in Germany is one of the largest contributor to climate change. The majority of waste generation, resource consumption as well as CO2 emissions relate to the construction and operation of buildings [1][2][3]. In order to tackle such negative impacts, the construction industry has to undergo a major transformation. Circular construction is the most promising answer to close effectively material cycles and to reduce CO2 emissions related to the manufacturing of construction materials. Stakeholders involved in construction have to review the entire life cycle of building products and buildings and develop new approaches that address such shortcomings to turn the linear way of construction into a circular one. Nowadays the strong focus on economic considerations, lacking knowledge as well as unresolved warranty issues amongst others impede this transformation process. To demonstrate the benefits of earthen materials with regards to circular construction, this study analyses the potential of two different internal partition wall systems, based on earthen as well as conventional building materials in a holistic way. Several aspects have been taken into consideration, evaluated through the physical dismantling of both wall systems as well as a LCA assessment. Construction cost as well as other material benefits, such as the hygroscopic performance of construction materials have been investigated as well. The results demonstrate that earthen materials reduce both, construction and demolition waste as well as CO2 emissions and demonstrate a much higher water vapour sorption capacity, a material parameter relevant for the reduction of mechanical ventilations systems. Although the economical assessment shows expectable lower construction cost for the wall system based on conventional materials such figures have to be placed in relation with the other results. In fact, the analysis demonstrates clearly that a holistic approach is needed in order to achieve the necessary shift.

Comprehensive Chemical Dust Suppressant Performance Evaluation and Optimization Method.

Chemical dust suppression is an effective dust control technology. A dust suppressant component evaluation method that facilitates a complete selection of safe, efficient, and economical chemical materials has not been explored. Considering dust suppression performance, environmental safety, and cost-effectiveness of chemical dust suppressant technology, this study constructs a comprehensive evaluation index system of chemical dust suppressant performance, including the wetting performance, hygroscopic performance, bonding performance, annual cost per unit area, pH value of dust suppression solution, chemical toxicity, and chemical corrosion. Among them, the index characterizing the wetting performance of the solution is the sedimentation wetting time, which is determined by the dust sedimentation experiment; the index characterizing the hygroscopic performance of the solution is the evaporation stability time, which is determined by the evaporation experiment of the solution on the dust surface; the index to characterize the bonding performance of the solution is the surface wind erosion rate, which is determined by the wind erosion experiment of the solution on the dust surface; the toxicity of the solution is evaluated by the LD50 of the solution; the index to characterize the corrosion performance of the solution is the Q235 monthly steel corrosion rate, which is determined by the Q235 steel corrosion test. Corresponding evaluation parameters are determined including sedimentation wetting time, evaporation stabilization time, surface wind erosion rate; annual average use cost per unit area; solution pH value, chemical acute toxicity classification, monthly corrosion rate of Q235 steel, and corresponding standard test methods are also provided. In order to evaluate the comparability of the results, according to the specific requirements of the evaluation index system and the distribution characteristics of the measurement data, the data of each evaluation and detection index are standardized by linear transformation, range transformation and other methods, so that the obtained results are comparable. Considering the differences in the actual performance requirements of dust suppressants in different usage scenarios, the weights of evaluation indicators at all levels can be set independently and flexible. The experimental test data obtained through the example shows that: among the four chemicals selected to participate in the experiment, the comprehensive dust suppression performance score of Triton X-100 solution is in the poor-grade category. The comprehensive dust suppression performances of calcium chloride solution, water, and polyacrylamide solution scored high in the average-grade category. The comprehensive evaluation process is logically correct, and the results are consistent with the phenomena observed in the experiment, consistent with conventional understanding, and have strong credibility. This method can provide a standardized evaluation technique and test process for the comprehensive performance evaluation and comparison of chemical materials and dust suppressants.

Study on the hygroscopic performances of poplar wood fiber biomass brick

Poplar fiber biomass brick is an energy-saving and environmentally friendly biomass building material developed in recent years. It has good hygroscopic performance, can adjust indoor air humidity, helps reduce building energy consumption for dehumidification and humidification, and improves indoor air comfort. This paper studies the hygroscopic performance of poplar fiber brick from the microscopic pore structure experiment, nitrogen physical adsorption experiment, equilibrium moisture content experiment, moisture sorption and desorption cycle experiment, and water vapor transmission experiment. The model of the sorption-desorption curve of poplar fiber biomass brick at 23 °C is established. Moreover, the ideal moisture buffering value (MBV) of poplar fiber brick and the ideal and practical MBV values under the experimental procedures of this article are calculated. The results show that the Peleg model is most suitable for poplar fiber brick's moisture absorption and desorption curve at 23 °C. The MBV value is the “Excellent” level and has good moisture sorption and desorption performance. The obtained data and models provide potent data support for promoting and applying biomass bricks and theoretical model research.