Strong Hydrophilicity Research Articles

Highly sensitivity and wide-range flexible humidity sensor based on LiCl/cellulose nanofiber membrane by one-step electrospinning

Cellulose is considered an ideal material for flexible electronic humidity sensors due to its green renewable nature, rich surface groups and strong hydrophilicity. However, the traditional cellulose-based humidity sensor cannot simultaneously have wide detection range, high sensitivity and fast response time, which seriously hinder their development and application. Here, an ultrathin Lithium chloride (LiCl)/cellulose nanofiber membrane as moisture sensitive materials was prepared by one-step electrospinning and used to assemble a high-performance humidity sensor. N, N-Dimethylacetamide/Lithium chloride (DMAc/LiCl) solvent system was used to dissolve the cellulose, and DMAc volatilized into the air while LiCl remained in the cellulose nanofibers during the electrospinning process. LiCl as a highly moisture-sensitive inorganic salt has strong hydrophilicity and enhances the moisture sensing detection limit of cellulose fiber (especially under low humidity conditions), thus giving the cellulose moisture sensor excellent sensitivity (up to 4191 %) and a wide detection range (5–98 % RH). The nanometer size of cellulose fibers, the extremely low thickness and large pores of cellulose membranes accelerate the mass exchange of moisture between the air and the membrane, thus giving cellulose humidity sensor a fast response/recovery time (99/110 s) and low hysteresis (2.9 %). Moreover, the performances of humidity sensors didn’t degrade even after being subjected to long-term application (>30 days), high/low temperatures (73.6/0.1 ℃) and thousands of bending cycles. The proposed LiCl/cellulose nanofiber humidity sensor brings innovative solutions for the design of cellulose based sensor with great potential for use in non-contact humidity detection, respiratory monitoring and sleep apnea detection applications.

Preparation and Characterization of Bio-Fibre Based on the Biological Properties of Bougainvillaea, Loofah, and Aloe Vera

This study is based on environmental sustainability and aims to explore the preparation and evaluation of biodegradable bio-fibre materials using discarded bougainvillaea, loofah, and aloe. After sorting and analyzing the existing literature, it is found that research on bougainvillaea, loofah, and aloe primarily focuses on environmental science, horticulture, biology, light industry, and pharmacy, while research on bio-fabric combining bougainvillaea, loofah, and aloe in two or three combinations remains unexamined. This study adopts both observational and experimental methods to identify candidate varieties suitable for natural dyeing by observing the characteristics of bougainvillaea and by preparing and testing bio-fibre materials through experimentation. Notably, the beet pigment found in bougainvillaea serves as a natural dye, the α-cellulose and hemicellulose in loofah sponge provide strong hydrophilicity, and the caffeic acid and rhamnolipids in aloe exhibit antioxidant and antibacterial properties, thereby improving the fabric’s safety. Experimental results and final bio fibre performance tests indicate that fibres made from these three plants have a stable internal structure, abrasion resistance of over 30,000 cycles, colour fastness concentrated at level 4, and a contact angle of less than 90°, thereby showing good stability, abrasion resistance, colour fastness, and hydrophilicity. Consequently, this study finds that bio-fibres prepared from bougainvillaea, loofah, and aloe demonstrate promising performance and are expected to contribute to the development of sustainable fibres in the future.

Self-Etching Synthesis of Superhydrophilic Iron-Rich Defect Heterostructure-Integrated Catalyst with Fast Oxygen Evolution Kinetics for Large-Current Water Splitting.

Developing catalysts with rich metal defects, strong hydrophilicit, and extensive grain boundaries is crucial for enhancing the kinetics of electrocatalytic water oxidation and facilitating large-current water splitting. In this study, we utilized pH-controlled etching and gas-phase phosphating to synthesize a flower-like Ni2P-FeP4-Cu3P modified nickel foam heterostructure catalyst. This catalyst features pronounced hydrophilicity and a high concentration of Fe defects. It exhibits low overpotentials of 156 mV and 210 mV at current densities of 10 and 100 mA cm-2 respectively, and maintains stability for up to 200 h at 100 mA cm-2 with only 7.3% degradation, showcasing outstanding electrocatalytic water oxidation performance. Furthermore, when integrated into a Ni2P-FeP4-Cu3P/NF||Pt-C/NF electrolyzer, it achieves excellent overall water splitting performance, reaching current densities of 10 and 400 mA cm-2 at just 1.47 V and 1.73 V, respectively, and operates stably for 60 h at 500 mA cm-2 with minimal degradation. Analysis indicates that high-valence oxyhydroxides/phosphides of Ni, Fe, and Cu act as the primary active species. The presence of abundant Fe defects enhances electron transfer, strong hydrophilicity improves electrolyte contact, and numerous grain boundaries synergistically modulate the activation energy between active sites and oxygen-containing intermediates, significantly improving the kinetics of water oxidation.

Creating smart chlorine-resistant polyamide reverse osmosis membranes via self-healing temperature-responsive nanocontainer functionalization

We present an innovative solution for improving the chlorine resistance of polyamide RO membranes. Our method involves the design of temperature-specific (70 ℃) responsive nanocontainers (T-RNC) through layer-by-layer self-assembly on a monodisperse SiO2 nanoparticle core. These nanocontainers, measuring 25 nm in size, are embedded within a thin film nanocomposite (TFN) membrane, resulting in a homogeneous surface structure with increased roughness and strong hydrophilicity. The precise temperature-responsive properties of T-RNC enable the dissolution of the encapsulated shell material, releasing SS molecules containing amino and carboxyl groups. These molecules effectively bind to broken amid bonds within the PA layer, repairing structural damage caused by chlorination and significantly enhancing the membrane’s chlorine resistance. Extensive testing revealed that the temperature-responsive TFN membrane maintained over 90 % NaCl rejection, even after exposure to 18,000 ppm.h of chlorination. In contrast, the control group lacking temperature-responsive TFN and TFC membranes exhibited reduced rejection rates of 62.15 % and 71.24 %, respectively. Additionally, the TFN membranes exhibited excellent water permeability and resistance to contamination. Our findings offer promising avenues for researchers to explore the development of intelligent and chlorine-resistant polyamide RO membranes, with a particular focus on chlorination-remediation techniques.

3D reconfigurable hydroxylated carbon nanotubes-based water evaporators with long-distance transportation for continuous vapor generation

Utilizing solar-thermal power for water purification through interfacial solar steam generation represents an environmentally friendly approach to secure a clean water source. However, it is still challenging to simultaneously overcome short transport distances, low transport rates, and unsatisfactory solar-thermal energy conversion efficiency, as well as the salt accumulation problem. In this work, three-dimensional (3D) reconfigurable water evaporators are developed based on commercial fabric strings and hydroxylated carbon nanotubes. The specifically designed 3D architecture enables the fabric strings to have a long water transport distance and localized focusing of solar light that benefits the fabrication of 3D evaporators and water isolation with low heat loss. Besides, the hydroxylated carbon nanotubes with strong hydrophilicity as well as their inherent black color show high solar-heat conversion efficiency. A high evaporation rate of 3.234kg m-2h−1 is found and a solar-to-vapor efficiency of 123.21 % is also achieved by using a vertical evaporation structure due to the enlarged surface area allowing absorption of heat from the environment. Meanwhile, the accumulated salts do not block the water transport pathway and they can be easily removed in high-salinity water evaporation by employing the assembled rotating evaporator. The results suggest that the fabric rope is a good platform for exploring highly efficient evaporation structures. Combined with hydroxylated carbon nanotubes, as-designed 3D reconfigurable evaporators are promising for efficient freshwater generation.

Solid-liquid phase microextractive adsorption of bio-lactic acid by a novel microextractor immobilizing ionic liquid A336

The separation of biochemicals poses significant challenges, such as complex product composition, strong hydrophilicity, and high boiling point, which leads to laborious procedures, low yield, and high energy consumption. These obstacles have become bottlenecks for the industrialization of biochemicals. To enhance the efficient separation of bio-lactic acid, a novel microextractor, PS-A336, was synthesized through the copolymerization of ionic liquid (IL) A336 onto a polystyrene (PS) skeleton and further employed to investigate the solid–liquid phase microextractive adsorption (SLPMA). Extensive analysis of PS-A336 microstructure and chemical composition demonstrated its exceptional performance with a rapid (< 20 min) adsorption capacity (1150 mg/g) for LA in the batch system, which is the highest value reported and 11.0 times higher than that of the pristine supports. PS-A336 maintained its stability even after 15 cycles of column chromatography. Its adsorption behavior also fits the common thermodynamic and kinetic models, and it is better for the SLPMA kinetic model established on Fick diffusion law. Additionally, PS-A336 exhibited high adsorption capacity and selectivity for LA from the fermentation broth, achieving above 98 % removal ratios to proteins, inorganic salts, and pigments. The double hydrogen bonds between PS-A336 and LA were identified as the primary driving forces for SLPMA following theoretical and structural investigations. Notably, the immobilized IL in PS-A336 exhibited a remarkable microextraction effect, i.e., an increase in extractive capacity at least 16.6 times due to 59.8-fold improvement in the interface area compared with the bulk IL, which is 28.6 times higher than the adsorption capacity of PS skeleton. Our findings provided new insights into the combination of extraction and adsorption, as well as valuable guidance for the efficient separation of bio-based chemicals.

Fabrication of norepinephrine and ε-polylysine engineered magnetic nanocomposites tailored for phosphopeptides analysis

Protein phosphorylation is a highly prevalent post-translational modification that holds a vital position in numerous physiological processes. Prior to mass spectrometry detection, the enrichment of phosphopeptides is critically significant due to their susceptibility to interference from abundant non-phosphopeptides. In this study, the magnetic nanocomposite (Fe3O4@NE@PL) was successfully synthesized and characterized. Fe3O4@NE@PL exhibited strong hydrophilicity, electrophilicity and intermolecular interactions through hydrogen bonds, enabling it to effectively enrich phosphopeptides with excellent sensitivity (0.4 fmol β-casein) and selectivity (β-casein:BSA=1:1000). In addition, Fe3O4@NE@PL was successfully applied to enrich phosphopeptides from complex real biological samples such as human serum and saliva, achieving up to 4 recycles with favorable stability and reusability. This study demonstrates that Fe3O4@NE@PL is a promising adsorbent for phosphopeptides enrichment in proteomics research, providing new ideas for the construction of magnetic enrichment materials.

Insights into the wetting mechanisms in low-permeability sandstone reservoirs and its evolution processes: The shahejie formation in the Dongying Depression, Bohai Bay basin

During the accumulation and development processes of low-permeability oil, wettability plays a crucial role in the percolation capacity of fluids. In particular, the evolution of low-permeability sandstones involves complex changes in formation fluid properties and mineral types, leading to a deficient understanding of wetting mechanisms in low-permeability sandstones. This gap significantly impedes research on the accumulation mechanisms of low-permeability oil. Focusing on the low-permeability sandstones in Shahejie formation of Dongying Depression, Bohai Bay Basin, tests like Casting thin section, scanning electron microscope, contact angle measurement, molecular dynamics simulation and the Amott method based on nuclear magnetic resonance technology were performed to comprehensively investigate sandstone wettability and its evolutionary process. The results indicate that the adsorption capacity of hydroxyl groups or monovalent cations (K+and Na+) for water molecules causes residual intergranular pores, feldspar dissolution pores, quartz dissolution pores, clay mineral intercrystalline pores and micro-cracks to exhibit hydrophilicity; while the adsorption capacity of divalent cations (Ca2+and Mg2+) for oil molecules causes the surface of dissolution pores of carbonate minerals to exhibit neutrality or lipophilicity. Additionally, changes in formation conditions (temperature, pressure, ion types, and ion concentration) significantly control the wettability of pore surfaces, further determining the overall wettability of low-permeability sandstone reservoirs. Throughout the evolutionary process of low-permeability sandstones, the Amott-Harvey index of low permeability sandstone is greater than zero, and the wettability exhibited hydrophilic or neutral. From A-stage eodiagenesis to B-stage mesodiagenesis, the Amott-Harvey index is 0.82, 0.12, 0.37, 0.03, and 0.49, and the wettability of reservoirs transitions through phases of strong hydrophilicity, weak hydrophilicity, hydrophilicity, neutrality, and hydrophilicity, respectively. Finally, an evolutionary model of the wettability of low-permeability sandstone reservoirs was established, which is of great significance for predicting the quality of low-permeability sandstone reservoirs.

Adsorption of methyl orange and methylene blue on activated biocarbon derived from birchwood pellets

This study explored the adsorption capacity of a physically activated biocarbon derived from the pyrolysis of birchwood pellets (ABPB) towards two dyes - methyl orange (MO, anionic) and methylene blue (MB, cationic), at pH 2, 7 and 11. Compared to mineral commercial activated carbon (CACmineral), ABPB exhibited lower SSA, pores volume and surface; higher external surface and average pore diameter, similar ash content and aromaticity, and stronger hydrophilicity and polarity. The maximum adsorption capacity on ABPB was equal to 220 mg/g for MO and 91 mg/g for MB after 17 h. Batch tests with variable adsorbent amount (0.5–2.5 g/L) showed for both ABPB and CACmineral better results for lower adsorbent dose. Under all tested conditions, ABPB showed higher or analogous adsorption capacity compared to CACmineral. Based on the pKa of MB (3.80) and MO (3.46) and on the pHPZC of ABPB (5.3), the adsorption was favored at pH 2 for MO and at pH 11 for MB. Kinetics analysis and isotherm modelling revealed that, although many different physicochemical interactions occurred between ABPB and the dyes molecules, chemisorption is the rate-controlling step and prevalent mechanism. In conclusion, this study may provide support to further research aimed at exploring the effect of ABPB's physicochemical properties on the efficiency and mechanisms of dyes adsorption.

Synergistic effect of reinforced cellulose nanofibrils/polyethylene glycol embedded particles in ammonia nitrogen wastewater: An in-depth microbial denitrification analysis

The encapsulation and immobilization technology provide a good growth environment for bacteria, strong protection ability, improved survival rate, and resistance to adverse environmental factors. Cellulose nanofibrils (CNF) with polyhydroxyl structure improve the elasticity, tensile properties, mechanical strength and gel strength of embedded particles through non-covalent forces. Polyethylene glycol (PEG) is a water-soluble polymer with unique carbon‑oxygen chain as the core skeleton. The ether bonds present in each unit give PEG extremely strong hydrophilicity and solubility. CNF and PEG to reinforce SA (sodium alginate) and PVA (polyvinyl alcohol)-SA embedded particle were adopted to treat ammonia nitrogen wastewater. The ammonia diffusion coefficients and oxygen diffusion coefficients of the CNF/PEG/SA and CNF/PEG/PVA-SA were 0.454 × 10−9, 0.286 × 10−9, 0.672 × 10−9 and 0.493 × 10−9 m2/s, respectively. The physicochemical properties of embedded particles were characterized by mass transfer characterization, SEM, XRD, FTIR, and BET analysis. The specific surface areas of CNF/PEG/SA and CNF/PEG/PVA-SA increased to 2.583 m2/g and 3.962 m2/g, respectively. The removal efficiency of NH4+-N, COD and TN in the CNF/PEG/PVA-SA system was 90 %, 74 % and 80 % at 30 °C. By HRT 8 h, the removal efficiency of NH4+-N, chemical oxygen demand (COD)and total nitrogen (TN) by the reinforced system was 94.35 %, 63.07 % and 73.84 %, respectively. The neutral to weakly alkaline pH range showed the highest removal efficiencies of NH4+-N, COD, and TN, at 88.51 %, 74.95 %, and 77.56 %, respectively. The half-saturation constant K was 82.98 mg/L, and the maximum ammonia oxidation rate (Vmax) was 358.92 mgN/(L-particles-h). The reinforced system showed zero-order reaction kinetics. Nonlinear fitting of each initial NH4+-N concentration and ammonia oxidation rate was carried out using the Michaelis-Menten equation. In reinforced embedded particles, microbial genomic data (KEGG; MetaCyc database annotation) analysis was conducted. The reinforced system demonstrated enhanced strength, specific surface area, mass transfer properties, resistance to adverse external environmental factors, and microbial survival rate for the effective treatment of NH4+-N wastewater.

Correlation between sewage sludge pore structure evolution and water filtration performance: Effect of thermal hydrolysis with or without carbonaceous skeleton-assisted

Municipal sewage sludge contains a high water content and strong hydrophilicity, making mechanical dewatering a critical step in sludge treatment and disposal. To clarify the collapse of filtration channels within the sludge cake under high pressure and to develop more precise targeted conditioning methods, this study focused on the direct correlation between pore structure evolution and sludge dewatering performance. A self-designed online system was used to compare the dewatering processes of raw sludge, thermal hydrolyzed (TH) sludge, and carbonaceous skeleton-assisted thermal hydrolyzed (CSkel-TH) sludge. In-depth analysis was conducted on the structure scanning data of the filter cake at different time intervals and the corresponding filtrate mass data. The results showed that during the press filtration process, the raw sludge gradually transformed into a filter cake, with larger pores trapping the water. In the upper and bottom layers, regions with a porosity higher than 10 % appeared, forming a “water-locking layer” even with continued pressure, it became impossible to remove additional water. After separate hydrolysis, the porosity and pore connectivity of the sludge decreased, and the thickness of the “water-locking layer” increased as press filtration progressed, inhibiting water discharge and making cake formation difficult. Following CSkel-TH treatment, the number of pores with diameters ranging from tens to over a hundred micrometers increased, and the connectivity between pores was enhanced. In this case, the channels formed by interconnected small pores continuously transported the water trapped in the large pores outward, facilitating water discharge. This work provided a basis for further targeted regulation of pore structures to enhance the effectiveness of high-pressure dewatering of sludge.

Nano-structured urchin-like photothermal covalent organic frameworks for efficient Solar-Driven interfacial water evaporation

Solar-driven interfacial water evaporation is a promising sustainable technology to alleviate the global energy crisis and clean water shortage. The design of advanced photothermal materials play the critical role to utilize photothermal heat for water evaporation. Covalent organic frameworks (COFs) as a new class of crystalline porous polymer semiconductor materials have been deemed as an ideal nanoscale platform for designing photothermal materials with notable features like highly ordered structures, porous open channels, and tunable structure and functionality. In this work, we focus on the regulation of the multi-scale structure of COFs and design hierarchically nano-structured photothermal COFs for efficient solar-driven interfacial water evaporation. At the molecular scale, we synthesize a photothermal functionalized COF-366-OH using photosensitive 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) and 2,5-dihydroxyterephthalaldehyde (DHTA) as building blocks. At the micro-nano scale, we introduce the π-conjugated catechol molecule 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) to regulate COF polycondensation and assembly, which enable the shaping of COF-366-OH into urchin-like nano-morphologies (namely UCOF-366-OH). The synthesized UCOF-366-OH exhibits high crystallinity, large surface area, excellent photothermal conversion capacity, and strong hydrophilicity. Furthermore, UCOF-366-OH is processed into a photothermal composite membrane. With localized solar heating and optimized water transport at the water evaporation interface, a high evaporation rate of 2.51 kg m−2h−1 with solar-to-vapor efficiency of 97.3 % is achieved. This work paves a new way for the multi-scale structural design of COF-based photothermal materials and highlights their innovative application in solar water evaporation.

Specific isolation and quantification of PD-L1 positive tumor derived exosomes for accurate breast cancer discrimination via aptamer-functionalized magnetic composites and SERS immunoassay

PD-L1 positive tumor derived exosomes (TEXsPD−L1) play a significant role in disease progression, tumor metastasis and cancer immunotherapy. However, the overlap of PD-L1 between TEXs and non-tumor derived exosomes (non-TEXs) restricts the specific isolation and quantification of TEXPD−L1 from clinical samples. Herein, a new aptamer-functionalized and hydrophilic immunomagnetic substrate was designed by decorating generation 5 polyamidoamine dendrimers (G5 PAMAM), zwitterionic trimethylamine N-oxide (TMAO) and EpCAM (Epithelial cell adhesion molecule) aptamers on magnetic cores sequentially (Fe3O4@PAMAM@TMAO@Aptamer, named as FPTA) for rapid target and efficient capture of TEXs. The FPTA substrate gathered excellent characters of strong magnetic responsiveness of Fe3O4, abundant affinity sites of PAMAM, strong hydrophilicity of TMAO and enhanced affinity properties of EpCAM aptamers. Because of these advantages, FPTA can isolate TEXs quickly within 30min with high capture efficiency of 90.5 % ± 3.0 % and low nonspecific absorption of 8.2 % ± 2.0 % for non-TEXs. Furthermore, PD-L1 (Programmed cell death-ligand 1) positive TEXs (TEXsPD−L1) from the captured TEXs were recognized and quantitatively analyzed by utilizing SERS (surface-enhanced Raman spectroscopy) reporter molecules 4-NTP (4-Nitrothiophenol) on PD-L1 aptamers-functionalized gold immunoaffinity probe. The signal of TEXsPD−L1 was converted to SERS signal of 4-NTP at 1344 cm−1 which exhibited a linear correlation to concentration of TEXsPD−L1(R2 = 0.9905). With these merits, this strategy was further applied to clinical plasma samples from breast cancer (BC) patients and healthy controls (HC), exhibited an excellent diagnosis accuracy with area under curve (AUC) of receiver operating characteristic (ROC) curve reaching 0.988. All these results demonstrate that the FPTA immunomagnetic substrate combined with SERS immunoaffinity probe may become a generic tool for specific isolation and quantitative analysis of PD-L1 positive tumor-derived exosomes in clinics.

Inorganic porous carbon as the supporter of H2TiO3 via in-situ polymerization synchronous conversion for lithium recovery from aqueous solutions

The extraction of lithium from liquid minerals, such as salt lake brines and underground brines, has garnered extensive interest due to its eco-friendly and cost-effective properties. However, the effectiveness of this method is constrained by the stability and capacity of the materials. Herein, a new-type inorganic carbon-supported H2TiO3 adsorbent was developed by a novel in-situ polymerization synchronous conversion strategy. It was found that when resorcinol and formaldehyde containing Li2CO3 and TiO2 were polymerized in-situ and then calcined at 973.15 K, the resin was successfully carbonized to obtain the carbon supporter with a low degree of disorder, and the Li2CO3 and TiO2 in the supporter were synchronously converted into Li2TiO3 and uniformly dispersed in the carbon matrix. Because of the large specific surface area and strong hydrophilicity of the carbon supporter, the material exhibited a maximum Li+ adsorption capacity of 52.14 mg·g−1, which was far higher than that of inorganic composite materials reported at present. Even the equilibrium adsorption capacity for Li+ at a low concentration of 29.26 mg·L−1 reached 28.51 mg·g−1. Following adsorption, the Li+ in the material was easily eluted by 0.25 mol·L−1 HCl, and the elution rate was more than 90 % within 2 h. Dynamic adsorption using a fixed-bed was also performed at 298.15 and 343.15 K, and the adsorption capacity for the same concentration of Li+ was 7.08 and 9.44 mg·g−1, respectively. Because of the high capacity for low-concentration Li+ and the promoting effect of temperature on adsorption, the material is well-suited for recovering Li+ from liquid resources, particularly from geothermal water with high temperatures and low Li+ concentrations.

Regiocontrollable B(2/3)-H Alkenylation of nido-Carboranes.

Anionic nido-carboranes, as open-cage analogues of closo-carboranes with strong hydrophilicity and higher potential in the development of biomedicines, have been notably more challenging because of their strong interaction with transition metals. While the exo-cage B-H activation reactions of nido-carboranes have been widely studied, there are few reports on the direct functionalization of B-H bonds located on a closed polyhedral sphere. Here, we report an efficient palladium-catalyzed regioselective B(2/3)-H alkenylation of nido-carboranes with various alkenes and alkyne coupling partners, enabled by 3-methylpyridine directing groups, to achieve a regiocontrollable functionalization of B(2/3)-H vertices over highly reactive exo-cage B11-H vertex in nido-carboranes.

Solid amine adsorbent with surfactant modification for Direct Air Capture (DAC) under different temperature and humidity conditions

Direct air capture (DAC) technologies have been vigorously pursued to achieve the goal of net-zero CO2 emissions due to the dramatic increase in atmosphere CO2 concentrations and global temperatures. In practical DAC conditions, variations in temperature and humidity can lead to different CO2 adsorption outcomes. Current studies lack comprehensive information on the optimal temperature and humidity conditions for DAC. In this study, a comparison between PMSU-F (impregnating polyethyleneimine (PEI600) on MSU-F support) and PPMSU-F (co-impregnating polyethylene glycol (PEG200) with PEI600 on MSU-F support) under different temperature and relative humidity conditions were conducted. Under dry conditions, the addition of PEG200 effectively enhanced the adsorption capacity, adsorption rate, and amine efficiency and decreased the energy consumption for desorption depending on the comparison of the two absorbents. Under the popular atmospheric temperature ranges (−5 °C–45 °C), an increase in temperature favors CO2 adsorption. Under humid conditions, the presence of PEG200 had a negative effect due to its strong hydrophilicity. By comparing dry and humid conditions, the introduction of moisture generally enhanced overall CO2 adsorption performance, and the adsorption capacity interestingly further increased under low-temperature conditions. The highest CO2 adsorbing capacity of PMSU-F (3.82 mmol/g) and PPMSU-F (3.76 mmol/g) appeared at −5 °C and 75% relative humidity, indicating that low temperature and relatively high relative humidity were more favorable for DAC, which is possibly attributed to the thermodynamic control under low temperatures with moisture. The results indicate that the adsorbents chosen in this study are promising for DAC under low temperatures and relatively high humidity conditions. The performances of modified DAC adsorbents, e.g., adsorption capacity, stability, antioxidant property for industrial-grade DAC system should be evaluated in the next work.

Facile preparation of graphene oxide/Poly (N‐Isopropylacrylamide‐co‐acrylic acid) composite thin film and its quartz crystal microbalance humidity sensing property

AbstractThe composite microgels were synthesized from N‐Isopropylacrylamide (NIPAM) and acrylic acid (AA) monomers in the presence of graphene oxide (GO) using an in situ radical copolymerization method. The successful preparation of these composite microgels was investigated through Fourier transform infrared spectroscopy (FTIR), ultraviolet visible absorption spectroscopy (UV–vis), and Raman spectroscopy. Due to the hydrophilic properties of GO and the microgels containing oxygenated groups (OH, COOH, and CONH2), quartz crystal microbalance (QCM) sensors can be fabricated by spraying the GO/P(NIPAM‐co‐AA) dispersion onto QCM sensors as sensitive coating materials. The results indicate a notable enhancement in the performance of GO/P(NIPAM‐co‐AA) modified QCM humidity sensor, compared to QCM sensors modified with either GO or P(NIPAM‐co‐AA) microgels alone. This improvement is mainly evidenced by higher sensitivity and reduced moisture hysteresis. The humidity sensing mechanism is based on the combined effect of GO and P(NIPAM‐co‐AA) microgels, which synergistically enhance the sensor's performance. Additionally, the results from water contact angle measurements, laser scanning confocal microscopy (LSCM), and scanning electron microscope (SEM) show that GO/P(NIPAM‐co‐AA) exhibits greater roughness and stronger hydrophilicity than either GO or P(NIPAM‐co‐AA) microgels alone. These properties make GO/P(NIPAM‐co‐AA) an effective moisture‐sensitive material for QCM sensors.

Three birds with one stone: Sewage sludge deep-drying in 1 hour using secondary aluminum ash to fabricate bricks

Due to the high moisture, strong hydrophilicity, and hard compressibility of sewage sludge (SS), it is difficult to realize the high-efficiency drying. Herein, a novel SS drying technology was developed to quickly and deeply reduce the moisture of SS from 75.6% to 38.5% in 1 h. During the process, secondary aluminum ash (SAA), a solid waste, was added to SS and acted as skeletons to form plenty of channels. Subsequently, NaOH was added and reacted with SAA to produce a lot of heat, resulting in a rapid temperature rise of the system from 20 to 105°C in 60 s. The heat could effectively remove water from these channels, which could be proved by the T1-T2 maps of in-site Low-Field 1H nuclear magnetic resonance. In addition, the extracellular polymeric substances were decomposed by SAA/NaOH successfully, and thus the SS became hydrophobic, favoring the drying. Finally, the dried SS could be used to fabricate unburned bricks. Thus, this work provides a promising method to realize the rapid SS deep drying and high-efficiency utilization of SAA and dried SS.

Sulfonated electrospinning nanofibrous membranes for high-efficient removal of cationic dyes

Wastewater containing dyes is generated in diverse industrial processes, and its treatment has become more crucial owing to increasing environmental concerns recently. Herein, we report a versatile strategy to fabricate a sulfonated electrospinning nanofibrous membrane for high-efficient removal of cationic dyes from their aqueous solution via electrostatic adsorption. The resulting sulfonated polyetherketone-cardo (SPEK-C) membranes have controllable sulfonation degree (SD), uniform nanofibrous structures, large specific surface areas and strong hydrophilicity. Particularly, they show excellent adsorption efficiency for cationic dyes, outstanding sustainability and renewability in filterable adsorption-desorption experiments. For example, the membrane consisting of ∼150 nm-thick SPEK-C nanofibers with the SD of 78 % has the specific surface area of 40.2 m−2 g−1, water contact angle of 35.8°, and high adsorption capacity for cationic dyes, such as 171.9 mg g−1 for methylene blue (MB). Moreover, the membrane keeps over 90 % adsorption percentage and over 80 % desorption percentage after several circulations in filterable adsorption-desorption experiments. The presented strategy has great potential in the fabrication of nanofibrous membranes for high-efficient removal of charged contaminants.

Octadecylamine modified gelatin-based biodegradable packaging film with good water repellency and improved moisture service reliability

Industrial gelatin is a good candidate for fabricating biodegradable packaging film, but the strong hydrophilicity of gelatin-based film lowers its moisture service reliability. Herein, we demonstrated a low surface energy water repellency surface design combined with covalent cross-linking for decreasing the water absorption and improving the moisture service reliability. Biodegradable octadecylamine (ODA) was chosen as the low surface energy providing material to fabricate the water repellency surface through a dehydration condensation reaction between the amine groups of ODA and gelatin chains via tetra-hydroxymethyl phosphonium chloride (THPC) in an aqueous phase. THPC also was employed as the cross-linking agent to form covalent bonding between the gelatin chains. The results determined that ODA modification and covalent cross-linking endowed the gelatin-based film with good water repellency and improved moisture service reliability. But high dose of ODA would result in phase separation and mechanical strength loss of the fabricated film. Additionally, ODA modification did not change the biodegradability of gelatin-based film, all the modified films were completely biodegradable in natural soil. Considering the sustainable modification process and abundant raw materials, the proposed strategy facilitates the effective utilization of low value industrial gelatin and provides a facile way for gelatin-based film as biodegradable packaging film.