Liquid Absorption Research Articles

Exergy-economic based multi-objective optimization and carbon footprint analysis of solar thermal refrigeration systems

The increasing carbon footprint associated with conventional cooling methods underscores the urgent need for sustainable alternatives. This study investigates the economic and environmental advantages of various solar-thermal cooling systems, with a focus on optimizing their performance across different climate conditions. Employing a multi-objective approach, the research emphasizes exergy-economic indices to optimize selected cycles. The analysis covers multiple refrigeration technologies, including liquid absorption, solid adsorption, and solid desiccant cycles. Results indicate that the liquid absorption cycle performs optimally in hot, arid climates, reducing the payback period to approximately 8 years when optimized. In hot and humid regions, the solid desiccant cycle proves most effective due to its superior humidity control, yielding a payback period of 5.3 years. For cold and mountainous areas, the solid adsorption cycle is preferred, with a payback period of 13.5 years, while moderate and humid climates benefit from the solid desiccant cycle for both cooling and humidity regulation. The exergy-economic factors for the solar refrigeration systems across semi-arid, hot and arid, hot and humid, cold and mountainous, and moderate and humid climates are 0.758, 0.602, 0.698, 0.74, and 0.575, respectively.

Physicochemically modified polymer-based fluidic gates with tunable wetting properties for intelligent liquid manipulations

The creation of a selective flow path and the regulation of a flow rate are of critical importance for polymer-based devices that manipulate liquid at the microscale. The formation of a 3D interconnected network of voids (i.e., physical volumetric modification) and the addition of a nonionic surfactant, Silwet L-77, (i.e., chemical volumetric modification) are expected to affect the wetting properties of polymers, thereby achieving selective gating effect in the polymer-based devices as an appropriate technology. Here, a set of polydimethylsiloxane (PDMS)-based fluidic gates (F-gates) were developed to enable selectivity for liquids and flow-rate control of the liquids by tuning the wetting properties of PDMS with the physicochemical volumetric modifications. For water and oil with different surface tensions (STs), the effects of the physical and chemical volumetric modifications on the fluidic gating of PDMS were quantitatively characterized in terms of contact angle, mass flow rate, and liquid absorption speed. The applicability of PDMS-based F-gates to the selective separation of oil and water even from oil-in-water emulsion was demonstrated by fabricating Janus PDMS-based F-gates. Our physicochemical volumetric modifications were also extensively analyzed to examine whether they satisfy the technological, economic, and ecological requirements of appropriate technology. This is the first effort to tailor the wetting properties of PDMS through physicochemical volumetric modifications, thus configuring a set of PDMS-based F-gates that act both as a separator for liquids of different STs and as a switch for fluid flows.

Highly efficient CO2 capture by a non-aqueous amine-based absorbent of 3 aminopropanol/polyethylene glycol 200: Experimental and computational simulation

In the present work, a novel non-aqueous 3-aminopropanol/polyethylene glycol 200 (3AP/PEG200) absorbent for efficient carbon dioxide (CO2) capture was designed using environment-benign and non-toxic polyethylene glycol 200 (PEG200) as an alternative to water. The mechanism, physical, thermodynamic, and kinetic properties of absorption process was investigated through a combination of experimental and multi-scale computational simulation approaches including molecular dynamics (MD) simulation and quantum chemical (QC) calculations. It was found that the addition of PEG200 not only enhanced the thermal stability of the absorbent, but also did not significantly increase the viscosity. In addition, kinetic studies revealed that the absorption process conforms to a pseudo-first-order equation, with the activation energy (Ea) value of 20.40 kJ/mol, significantly lower than that of the benchmark 30 % monoethanolamine (MEA) aqueous solution used in industrial CO2 capture. Furthermore, the enthalpy change (ΔH) and entropy change (ΔS) values were found to be more negative than those of other liquid absorption systems, indicating that the 3AP/PEG200 absorbent is favorable for CO2 absorption even at low partial pressures. Most importantly, the absorption system exhibited good regeneration capability, as demonstrated by five absorption–desorption cycle experiments. In conclusion, the non-aqueous 3AP/PEG200 absorbent exhibits low viscosity, high thermal stability, enhanced absorption capacity, and excellent cyclic performance, positioning it as a promising candidate for CO2 absorption in industrial applications.

Chondroitin sulfate sponge scaffold for slow-release Mg2+/Cu2+ in diabetic wound management: Hemostasis, effusion absorption, and healing

The management of diabetic wounds presents significant challenges due to persistent inflammation, microenvironmental disruptions, and impaired angiogenesis. To address these issues, this study developed a multifunctional chondroitin sulfate sponge (CSP@Cu-Mg) with anti-inflammatory properties, hemostatic effects, effusion absorption, and enhanced healing promotion. Through ion crosslinking, MgO and CuO were incorporated into the interpenetrating network structure of chondroitin sulfate and acellular dermal matrix, resulting in a sponge with impressive liquid absorption capacity (3450 %) and porosity (83 %). This sponge enabled sustained release of Mg2+/Cu2+ ions, with approximately 40 % cumulative release over 7 days. This release helped reduce inflammation, promote the proliferation and migration of skin repair-related cells, and stimulate angiogenesis. In vivo studies demonstrated that the CSP@Cu-Mg sponge significantly improved diabetic wound healing by modulating inflammation and accelerating collagen deposition, angiogenesis, and re-epithelialization. This extracellular matrix sponge, which synergistically releases Mg2+/Cu2+, presents a promising strategy for comprehensive diabetic wound management with substantial clinical implications.

Fabrication of a Polyglycolic Acid Porous Microneedle Array Patch Using the Nonsolvent Induced Phase Separation Method for Body Fluid Extraction

ABSTRACTTraditional blood sampling is essential for early diagnosis and subsequent analysis, but the methods using hypodermic needles are painful and burdensome. Recently, a minimally invasive approach utilizing porous microneedles has been developed and various porous microneedle array patches (MAPs) composed of biodegradable polymers have been investigated. To address issues about low mechanical strength and liquid absorption with porous MAPs, we used polyglycolic acid (PGA) as it is a biodegradable and hydrophilic polymer with high mechanical properties. In this study, we established a nonsolvent‐induced phase separation (NIPS) method for the fabrication of PGA porous MAPs, as the porous MAPs can be fabricated by simply immersing the molds injected with PGA‐hexafluoro‐2‐propanol (HFIP) solution in nonsolvents. We achieved the maximum liquid absorption rate of 16 ± 8.2 × 10−2 µL/min per one microneedle using the PGA porous MAPs fabricated by using ethanol as nonsolvent and PGA concentration of 10% (w/w). Our study provides a comprehensive understanding of porous MAPs fabricated using PGA material as well as its characteristics regarding the structural and mechanical properties of PGA MAPs, with potential as a diagnostic device to substitute conventional hypodermic needles for interstitial fluid (ISF) sampling and diagnosis.

The Weathering of the Beech and Spruce Wood Impregnated with Pigmented Linseed Oil

This research aimed to examine the effects of a deep impregnation technique (Royal process) and surface coating using a linseed oil-based product, enhanced with small amounts of brown and grey pigments, on the natural and artificial weathering of wood. The treated and reference samples underwent natural weathering for five years and artificial weathering for 1900 h. Changes in color and surface roughness were assessed during weathering. For the artificially weathered samples, liquid water absorption was measured both before and after exposure. The impregnated and coated samples gradually lost their brown color, turning grey over time. More pronounced differences were observed during natural weathering, with the coated samples showing greater structural changes on the wood surface. In contrast, impregnated samples slowed down structural alterations compared to the reference samples. Both treatments effectively reduced water absorption before weathering, although this effect diminished after exposure. The treatments did not significantly impact the fire resistance of spruce and beechwood.

Investigating the influence of CaCO3 nanoparticles on the performance of CO2 absorption in the PVC membrane contactors

The membrane contactor application to purify acid gases is a significant advancement in environmental protection and engineering processes. Notwithstanding the numerous privileges of membrane contactors, the wetting of the polymeric membrane is considered the main worry in developing the mentioned technology. The polymeric membrane wetting by liquid absorbents increases the membrane mass transfer resistance and decreases the gas absorption. In this study, hydrophobic PVC membranes including various amounts of CaCO3 nanoparticles were manufactured to reduce the wetting problem. The prepared membranes were evaluated using AFM, TEM, XRD, contact angle, SEM, and tensile strength measurements. The contact angle results illustrated that adding the nanoparticles enhanced the membrane contact angle; so that for nanocomposite membranes comprising 1.5 wt.% nanoparticles, the contact angle increased from about 77°–94°. Investigating the tensile strength results showed that the nanoparticle presence in the membrane structure raised the tensile strength by 10 MPa. Finally, the nanocomposite and pure membrane performance in CO2 absorption was evaluated in the system of membrane contactors. The findings exhibited that after 25 days of the gas absorption process, the permeate flux of pure membranes significantly decreased. However, the gas absorption flux in nanocomposite membranes containing 1.5 wt.% nanoparticles remained constant during this period.

Effect of Pempek Vinegar on Composite Resin Hardness Nanohybrid

Background: Nanohybrid composite resin is a dental restorative material that is widely used in modern dental practice. However, the interaction of these materials with acidic foods and drinks, such as pempek vinegar, can affect their mechanical properties. Materials and Methods: This research is laboratory experimental research with pretest-posttest with only group design. In this study, nanohybrid composite resin was used in the form of a circle on a mold with a thickness of 2 mm and a diameter of 10 mm which was immersed in a solution of pempek vinegar. The number of samples used is 6 samples with 4 test groups. The 4 test groups were divided into immersion times of 1,3,5,7 days. Results: After immersion, the results of the hardness of the composite resin were taken. Using the normality and homogeneity tests, the hardness test results data were processed. It was found that the data were normally distributed and not homogeneous for each data group. After that an analysis was carried out using independent t-test (p <0.005) it was found that there was a significant effect of the hardness of the composite resin on immersion in Pempek vinegar solution which was soaked for 3 days, 5 days and 7 days. Conclusion: Pempek vinegar solution affects the surface hardness of the nanohybrid composite resin which is probably influenced by pH, liquid absorption ability, and soaking time.

Liquid absorbent bamboo fiber foams: Towards 100% ligno-cellulosic menstrual absorbent pads

Traditional menstrual absorbent pads typically combine cellulose fiber fluff pulp with non-biodegradable, petroleum-based superabsorbent polymers (SAPs). To eliminate the need for SAPs, this study explores foaming as a method to create a highly porous lignocellulosic fiber network capable of storing large amounts of fluid. Bamboo fibers were chosen due to their high lignin content, which is expected to help maintain the structural integrity of the porous network during liquid absorption and preventing collapse compared to 100% cellulose fibers. The bamboo fiber foams demonstrated remarkable porosity and superior absorbency compared to commercial pads, but they exhibited lower water retention when subjected to compression. Refining the fibers and incorporating microfibrillated cellulose offer promising opportunities to enhance water retention.

Investigation into the Liquid Absorption Performance of MSNs@CTS-g-P(AA-co-AM) Absorbent Resin

Investigation into the Liquid Absorption Performance of MSNs@CTS-g-P(AA-co-AM) Absorbent Resin

Synthesis and Characterization of CL-PA Ionic Liquid

Caprolactam is most commonly used in the production of Nylon 6 in industry and is generally produced from cyclohexanone by the Beckmann rearrangement. Orthophosphoric acid is generally used in fertilizer production and is produced through two processes: wet and dry. In this study, detailed characterization of CL-PA was carried out by synthesizing CL-PA ionic liquid from orthophosphoric acid (PA) and caprolactam (CL). FTIR, Raman and UV-Vis spectroscopic analyses reveal that a bond is formed between CL and PA. The thermal behavior of CL-PA ionic liquid was inspected by TGA and DSC. It has been observed that the decomposition temperature of CL-PA ionic liquid is different from that of the starting materials (CL and PA). It was disclosed by DSC analysis that CL-PA ionic liquid only has a glass transition temperature. The room-temperature CL-PA ionic liquid synthesized from solid CL with melting point of 70.34 ℃ and 85 wt.% PA did not show any melting or freezing point and the glass transition temperature was found to be −27 ℃. It was revealed that CL-PA ionic liquid was more thermally stable than CL which alone almost completely evaporated at about 197 ℃. As a result of FTIR analysis of CL-PA ionic liquid and its constituents, it was demonstrated that –NH peaks of CL disappeared in the CL-PA spectrum and the peak of C=O group shifted to a lower frequency (i.e., 1604 cm⁻1). In the Raman analysis of CL-PA and its constituents, it was observed that the asymmetric C=O bending vibration and C=O stretching vibration of CL disappeared in the CL-PA spectrum. In the UV spectrum, it was observed that the maximum absorbance of CL-PA ionic liquid varied with respect to that of CL.

Enhancing leachate management with antibacterial nanocomposites incorporating plant-based carbon dots and Satureja Khuzestanica essential oils

Landfill leachate, a complex mixture of pollutants, poses a significant environmental hazard. This study reports the synthesis and characterization of superabsorbent nanocomposites (SANs) designed for enhanced performance in waste management applications. SANs were prepared using carboxymethyl cellulose (CMC) and sodium polyacrylate (SPA) as the main components, carbon dots (CDs) to improve absorption, and Satureja Khuzestanica essential oil (SEO) for antibacterial performance. The results demonstrated that the addition of CDs significantly increased the absorption capacity and liquid retention of the samples, with a water absorption capacity reaching up to 8621 %. Furthermore, the samples exhibited high mechanical strength, with tensile strength improving by over 100 % in the presence of CDs. The inclusion of SEO provided strong antibacterial activity against Escherichia coli and Staphylococcus aureus, with inhibition zones measuring up to 26 mm. These SANs, with their high absorption capacity, mechanical robustness, and antibacterial properties, show great potential for improving waste management practices, particularly in leachate absorption strategies.

Modeling selective absorption of H2S from a gas mixture containing CO2 within rotating packed bed based on surface renewal theory

Compared to conventional packed beds (PBs), the rotating packed beds (RPBs) demonstrate superior selectivity for H2S. RPBs can selectively absorbing more than 99 % of H2S in CO2-rich gas mixtures, while the co-absorption rate of CO2 in RPBs is only 1/9 of that in PB columns. Therefore, RPBs have been well applied in the gas purification for natural gas, blast furnace gas, and refinery gas. While, modeling the selective reaction process in RPBs under conditions of rapid liquid film renewal remains challenging. Here, a diffusion–reaction mass transfer model based on surface renewal theory is established. The model elucidates the mechanism behind the selective absorption of H2S, and also demonstrate how RPBs enhance liquid film absorption. Experimental data collected from an RPB operating under actual conditions were used to validate the model. The model demonstrates high precision in predicting the removal efficiency of H2S and CO2.

Ultralight 3D silk nanofiber scaffolds with enhanced hemostatic properties and biocompatibility for rapid hemostasis

Developing an effective hemostatic material that combines excellent biocompatibility with high blood absorption capacity remains a critical clinical challenge. In this study, ultralight three-dimensional (3D) silk fibroin (SF) scaffolds, composed of continuously interconnected nanofibers, are introduced as a novel hemostatic material. The distinctive fluffy nanofiber architecture endows the scaffolds with a remarkable porosity of 78.9 % and exceptional liquid absorption capacity. The integration of montmorillonite (MMT) further enhances the hemostatic properties of the scaffolds, while SF naturally promotes the intrinsic coagulation pathway. The scaffolds exhibit an impressive blood absorption capacity of 1687.7 %. In vitro evaluations indicate that the SF nanofiber scaffolds exhibit a blood clotting index rate of 24.6 %, a hemolysis ratio of less than 4 %, and outstanding biocompatibility. The blood coagulation time is significantly reduced from 449 s to 230 s. Additionally, the scaffolds show adhesion rates to erythrocytes and platelets of 52 % and 45.9 %, respectively. The nanofiber scaffolds aggregate and activate platelets extensively, accelerating the formation of platelet emboli, which collectively contribute to their superior hemostatic performance. Consequently, these nanofiber scaffolds hold substantial promise as absorbable hemostatic agents for achieving rapid hemostasis in clinical applications.

An environmentally friendly and superhydrophobic melamine sponge self-roughened by in-situ controllably grown polydopamine nanoparticle for efficient oil-water separation

The preparation of conventional superhydrophobic sponges inevitably requires the involvement of noxious and non-degradable raw materials，thus threatening ecosystems. As reported herein, an environmentally friendly and superhydrophobic melamine sponge is facilely prepared for efficient oil-water separation, which is completely derived from eco-friendly substances. The formation of a hierarchical structure on the sponge skeleton was achieved via the in-situ controllable growth of polydopamine nanoparticles in mildly alkaline solution. In addition, octadecyl amines (ODA) with long chains of hydrophobic alkyl groups were grafted onto the polydopamine coating to reduce the surface energy through Schiff base or Michael addition reactions. Ultimately, the resulted sponge possessed extreme water repellency with a water contact angle (WCA) of 153.21 ± 1.31° and could retain its superhydrophobicity when it was exposed to solutions with different pH values and high temperature. Moreover, the resultant sponge exhibited fully reversible compressibility with up to 80% strain and excellent structural stability after 200 cyclic compression tests. Meanwhile, distinct organic liquid absorption experiments were conducted to confirm the resulted sponge with excellent oil absorption capacity (73.46 - 119.66g/g) and oil-water separation properties. Therefore, the as-prepared superhydrophobic sponge provides valuable insight into efficient oil-water separation.

3D nanofiber sponge based on natural insect quaternized chitosan/pullulan/citric acid for accelerating wound healing

Extensive traumatic injuries and difficult-to-heal wounds, induced by many circumstances, impose a significant social and economic burden on an annual basis. Thus, innovative wound dressings that encourage wound healing are greatly needed. In this work, we prepared a novel insect chitosan (MCS) using waste pupal shells from housefly (Musca domestica L.) culture. After conducting comparative investigations with commercially available chitosan, it was shown that MCS exhibited comparable qualities and may be used as a substitute source of commercial chitosan. A quaternized chitosan/pullulan/citric acid three-dimensional nanofiber sponge (3D-NS) of natural origin was prepared by electrostatic spinning and gas foaming techniques after MCS was quaternized. In vitro, tests showed that the 3D-NS had a higher liquid absorption capacity than the two-dimensional nanofibrous membrane (2D-NM). Additionally, the 3D-NS showed improved hemostatic, pro-cell proliferation, antibacterial, and anti-inflammatory qualities. In vitro, tests demonstrated that 3D-NS could inhibit the release of inflammatory factors, promote angiogenesis, accelerate collagen deposition, and promote wound contraction. These effects considerably facilitated the healing process of wounds in rats with full-thickness skin damage. In conclusion, the great bioactivity and physicochemical properties of 3D-NS render it an optimal candidate for developing novel wound dressings.

Binary Biomass-Based Electrolyte Films for High-Performance All-Solid-State Supercapacitor.

Solid-state electrolytes have received widespread attention for solving the problem of the leakage of liquid electrolytes and effectively improving the overall performance of supercapacitors. However, the electrochemical performance and environmental friendliness of solid-state electrolytes still need to be further improved. Here, a binary biomass-based solid electrolyte film (LSE) was successfully synthesized through the incorporation of lignin nanoparticles (LNPs) with sodium alginate (SA). The impact of the mass ratio of SA to LNPs on the microstructure, porosity, electrolyte absorption capacity, ionic conductivity, and electrochemical properties of the LSE was thoroughly investigated. The results indicated that as the proportion of SA increased from 5% to 15% of LNPs, the pore structure of the LSE became increasingly uniform and abundant. Consequently, enhancements were observed in porosity, liquid absorption capacity, ionic conductivity, and overall electrochemical performance. Notably, at an SA amount of 15% of LNPs, the ionic conductivity of the resultant LSE-15 was recorded at 14.10 mS cm-1, with the porosity and liquid absorption capacity reaching 58.4% and 308%, respectively. LSE-15 was employed as a solid electrolyte, while LNP-based carbon aerogel (LCA) served as the two electrodes in the construction of a symmetric all-solid-state supercapacitor (SSC). The SSC device demonstrated exceptional electrochemical storage capacity, achieving a specific capacitance of 197 F g-1 at 0.5 A g-1, along with a maximum energy and power density of 27.33 W h kg-1 and 4998 W kg-1, respectively. Furthermore, the SSC device exhibited highly stable electrochemical performance under extreme conditions, including compression, bending, and both series and parallel connections. Therefore, the development and application of binary biomass-based solid electrolyte films in supercapacitors represent a promising strategy for harnessing high-value biomass resources in the field of energy storage.

Enhancing mechanical properties of cellulose acetate/carbon black nanofibers for oil spill cleanup

Oil contamination caused by various oil-related industries and domestic usage is one of the major global challenges that threaten the environment. Therefore, employing efficient and environmentally friendly methods for oil removal from oily water is crucial. Nanofibers offer suitable mediums for such applications due to their low fiber diameter and high surface area. Herein, mechanically enhanced carbon black (CB) loaded-cellulose acetate (CA) nanofiber mats were developed for oil removal applications. Initially, CA/CB nanofibers were fabricated from 15% wt. CA solutions containing 2% wt. CB. To improve the mechanical properties, the samples were treated in an ethanol:acetone bath for 2 and 4h. Increasing post-treatment duration increased the nanofiber diameters from 438 nm to 601 nm and decreased porosities from 75% to 66%. The post-treatments improved the mechanical properties of the samples and the highest modulus was achieved as 20.85 MPa. The water and oil contact angles increased from 86° to 102° and 61° to 80°, respectively. The liquid absorption and retention capacities of the samples were evaluated by immersing them in water, seawater, waste oil, and their emulsions. Despite their lower initial oil absorption compared to the non-treated one, post-treated samples still retained large amounts of oil at the end of 24 h.

Study on Plasma Surface Modification of Hydrophobic Materials

The hydrophobic materials were treated by plasma continual treater to achieve its surface modification and improve its wettability. The influences of treating time, discharge power, working gases and gas pressure on the surface modification of the materials have been investigated. The chemical states and species on the surface of materials have been investigated by some technologies such as contact angles. After plasma surface treatment, the contact angles of PTFE sharply decrease, and the alkali liquid absorption of PE increased to three times of its weight. The contact angles of silicon rubber and polyester decreased remarkably after surface modification. PTFE films were grafted with crylic acid to evaluate the ageing. The effect of vacuum ultraviolet radiation to surface modification was initially described. The results of experiment demonstrate that the better wettability of hydrophobic material can be achieved. The technique and the equipment have the promotional value for industrial application.

Surfactant-mediated enhancement of liquid permeability in scots pine wood

Scots pine (Pinus sylvestris L.) is a widely-used wood species in construction and exterior applications. However, inherently low liquid permeability of wood presents substantial challenges to processing efficiency. In order to improve the liquid permeability in Scots pine, the effect of two different surfactants including dodecyl dimethyl ammonium chloride (DDAC) and primary alcobol ethoxylate (JFC-U) were investigated in this study. The mechanism was unveiled by microscopic observation, chemical analysis of extractive composition, and molecular dynamics (MD) simulations. The results demonstrated that both surfactants increased the liquid absorption in Scots pine by 14.7–46.3 % within 0.5 h. This effect was mainly attributed to the surfactants' capability to enhance surface wetting and dissolve extractives deposited on pit membrane in Scots pine wood. DDAC outperformed JFC-U in dissolving extractives. The MD simulations between DDAC and stearic acid (a representative extractive) illustrated that DDAC could envelope stearic acid molecules and form micellar structures through the strong intermolecular forces between them. These findings provide valuable insights into the effect and mechanisms by which surfactants enhance liquid permeability in extractive-rich wood, therefore, to support the development of efficient wood treatment technologies.