Fabrication of chitosan-based fluorescent hydrogel membranes cross-linked with bisbenzaldehyde for efficient selective detection and adsorption of Fe2.

Chitosan, as a natural biomass material, is green, recyclable, sustainable and well biocompatible. The molecular chain is rich in active groups such as amino and hydroxyl groups, and its preparation of fluorescent probes has the advantages of biocompatibility and efficient detection performance. In this study, a bis(benzaldehyde) (BHD) fluorescent functional molecule was designed. Then a series of fluorescent chitosan-based hydrogel films (CSBHD) were prepared using chitosan as raw material and BHD as cross-linking agent. As a fluorescent probe for metal ions, CSBHD was able to efficiently detect Fe2+ with a linear correlation of fluorescence intensity in the range of 0-160 µM, and the limit of detection (LOD) was 0.55 µM. Moreover, it has excellent adsorption performance for Fe2+ ions, with a maximum adsorption capacity of 223.5 g/mg at 500 mg/L Fe2+ concentration. Finally, we characterised the structure and microscopic morphology of CSBHD films and found that CSBHD as a hydrogel film has a high cross-linking density, good water resistance, excellent thermal stability, strong resistance to swelling, and excellent stability in cycling tests. Hence, it has great potential for application in adsorption and detection of Fe2+ ions. It also provides a good strategy for the application of chitosan based fluorescent probe materials in environmental monitoring and heavy metal ion adsorption.

Covalently surface-grafting α­zirconium phosphate nanoplatelets enables collagen fiber matrix with ultraviolet barrier, antibacterial, and flame-retardant properties.

Manipulating the dispersibility and reactivity of two-dimensional nanomaterials in collagen fibers (CFs) matrix has aroused attention in the fabrication of multifunctional collagen-based nanocomposites. Here, α­zirconium phosphate nanoplatelets (ZrP NPs) were surface-functionalized with gallic acid (GA) to afford ZrP-GA NPs for engineering CFs matrix. The influence of ZrP-GA NPs on the ultraviolet barrier, antibacterial, and flame-retardant properties of resultant CFs matrix were investigated. Microstructural analysis revealed that ZrP-GA NPs were dispersed and bound within the collagen fibrils and onto the collagen strands in the CFs matrix. The resultant CFs matrix also maintained typical D-periodic structures of collagen fibrils and native branching and interwoven structures of CFs networks with increased porosity and enhanced ultraviolet barrier properties. Inhibition zone testing presented excellent antibacterial activities of the CFs matrix owing to surface grafting of antibacterial GA. Thanks to enhanced dispersion and binding of ZrP NPs with the CFs matrix by surface-functionalization with GA, the resultant CFs matrix reduced the peak heat release rate and the total heat release by 42.9 % and 39.0 %, respectively, highlighting improved flame-retardant properties. We envision that two-dimensional nanomaterials possess great potential in developing reasonable collagen-based nanocomposites towards the manufacture of emergent multifunctional collagen fibers-based wearable electronics.

Preparation and performance study of rhodamine B naphthylamide, a fluorescent probe, for the detection of Fe3.

Fe3+ is essential for humans, and its deficiency or excess can be harmful to human health; thus, it is crucial to detect Fe3+. Herein, a novel 1,8-naphthylimide rhodamine-based fluorescent probe (NA-RhBEA) was prepared from rhodamine B, anhydrous ethylenediamine, and 1,8-naphthoic anhydride. This fluorescent probe complexes Fe3+ with N and O on the carboxyl groups of its spironolactam structure and part of the 1,8-naphthalenedicarboxylic anhydride structure, which results in spironolactam ring-opening and fluorescence. NA-RhBEA has high selectivity for Fe3+ in ethanol/buffer solution (4 : 1, v/v), and fluorescence is detected at an excitation wavelength λEX = 500 nm, an absorption peak appears at 585 nm, and a significant color change appears. The effect of the fluorescence intensity of Fe3+ under a series of different concentration conditions was investigated, and it was concluded that the fluorescence intensity increased with increasing Fe3+ concentration in the range of 0-500 µmol, and its detection limit was 0.84 µmol L-1. In addition, we explored the detection ability of NA-RhBEA in solutions with different pH values, mixed metal ions, and different solvents, and the results showed that the fluorescent sensor also has good anti-interference properties and some practical applicability.

Fabrication of 1,8-naphthalimide modified cellulose derivative composite fluorescent hydrogel probes and their application in the detection of Cr(VI).

The design and development of a rapid and quantitative method for the detection of heavy metal ions is of great importance for environmental protection. We have prepared a 1,8-Naphthalimide modified cellulose composite fluorescent hydrogel (CENAEA/PAA) with a stereo double network structure. Characterized by excellent hydrogel functional structure and fluorescence detection performance, it can efficiently and selectively identify and detect Cr(VI) with linear quenching in the range of 0-400 µmol/L and detection limit of 0.58 µmol/L for Cr(VI). The results show that the CENAEA/PAA can effectively adsorb Cr(VI) with a maximum adsorption capacity of 189.04 mg/g. Finally, the morphological characteristics, chemical structure, fluorescence properties and adsorption behavior of CENAEA/PAA were analyzed and fitted well with the pseudo-second-order model and Freundlich model. Thus, the present work provides a green and sustainable approach for the synthesis of a functional material that can be used for the detection and adsorption of heavy metal ions.

Light-Propelled Super-Hydrophobic Sponge Motor and its Application in Oil-Water Separation.

Self-propelled separation materials, that is, motor, are one of the keys to realizing smart oil-water separation. Although three-dimensional sponges such as commercial melamine sponge (MS) exhibit excellent oil-water separation ability, they cannot move by themselves on water. Aiming at solving this problem, a polydimethylsiloxane (PDMS) and molybdenum disulfide (MoS2) modified MS motor (PDMS@MS/MoS2) with an asymmetric multilayer structure was prepared, in which the photothermal layer MoS2 provided the propelling force for the motor under infrared light irradiation, and the middle layer PDMS was used as the superhydrophobic modified agent and adhesive agent between commercial MS and MoS2 powder. PDMS coated MS (PDMS@MS) as the superhydrophobic layer showed good superhydrophobic ability (153.1°) and oil-water separation capacity (52.33 g/g to liquid paraffin). Furthermore, the introduction of MoS2 made the speed of the sponge motor reach 8.27 mm s-1 with a removal quantity of 12.20 g/g for cyclohexane. After recycling 8 times, the contact angle, cyclohexane capturing amount, and average velocity of the motor were 150.3°, 11.40 g/g, and 8.41 mm/s, respectively. Meanwhile, PDMS@MS/MoS2 kept a similar light-propelling velocity (∼8 mm) at different pH values and in simulated seawater, demonstrating that the light-propelling motor possessed a good cycle and practical performance, which provides a possibility for the directional light propulsion of a sponge motor in oil-water separation.

Photothermal Conversion of Hydrogel-Based Biomaterial.

Traditional energy from fossil fuels like petroleum and coal is limited and contributes to global environmental pollution and climate change. Developing sustainable and eco-friendly energy is crucial for addressing significant challenges such as climate change, energy dilemma and achieving the long-term development of human society. Biomass hydrogels, which are easily synthesized and modified, have diverse sources and can be designed for different applications. They are being extensively researched for their applications in artificial intelligence, flexible sensing, biomedicine, and food packaging. The article summarizes recent advances in the preparation and applications of biomass-based photothermal conversion hydrogels, discussing the light source, photothermal agents, matrix, and preparation methods in detail. It also explores the use of these hydrogels in seawater desalination, photothermal therapy, antibacterial agents, and light-activated materials, offering new ideas for developing sustainable, efficient, and advanced photothermal conversion biomass hydrogel materials. The article concludes with suggestions for future research, highlighting the challenges and prospects in this field and paving the way for developing of long-lasting, efficient energy materials.

Thermal and mechanical properties of coal gasification slag based foam concrete.

Foam concrete possesses low density and excellent thermal insulation properties and has been widely used in construction industry. Considering the recycling and reusing of coal gasification slag (CGS), a solid waste product in the coal chemical industry, CGS was used as the supplementary cementations material to prepare foam concrete (CGS-FC) in this work. The influence of the CGS content and water-binder ratio on the pore structure, mechanical and thermal properties was investigated. The results show that the CGS content and water-binder ratio directly impact the fluidity of the slurry, which affects the internal pore structure of the specimens after molding. And a CGS-FC with a compressive strength of 6.89 MPa, thermal conductivity of 0.24 W/m K, and a bulk density of 867 kg/m3 was successfully produced when the CGS content was 30% and water-binder ratio was 0.5. In particular, the utilization of CGS to prepare foam concrete product has recycling efficiency and environmental benefit.

Resourceful Utilization of Cow Hair in the Preparation of Iron Tailing-Based Foam Concrete.

Cow hair, a by-product of tannery waste, is usually stockpiled on a large scale as waste, which leads to serious environmental impacts. In this paper, cow hair was used as a reinforcement fiber to improve the mechanical strength of iron tailing-based foam concrete. The effects of the amount of cow hair fiber on the apparent density, compressive strength, and flexural strength of foam concrete were investigated by a series of characterization methods. Meanwhile, Image-Pro Plus software was used to analyze the porosity, average pore size, roundness, and other parameters of the specimens with different amounts of cow hair fiber. Results revealed that a proper amount of cow hair fiber can form a stable three-dimensional network structure inside the foam concrete and promote a uniform distribution and size of the pore structure inside the test piece. This could effectively improve the compressive strength, flexural strength, and crack resistance of the foam concrete, and when the fiber content was 0.2 wt%, the foam concrete exhibited the best mechanical properties, with a compressive strength of 11.19 MPa and a flexural strength of 3.58 MPa. The present work was in agreement with the strategic objective of resource recycling and solid waste utilization, which was conducive to the development of the circular and green economy.

Fabrication, Structure, Performance, and Application of Graphene-Based Composite Aerogel.

Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.

Biochar/struvite composite as a novel potential material for slow release of N and P.

For soil and environmental remediation, biochar/struvite composites are prepared by the crystallization-adsorption method. The recovery rates of N, P, and Mg in the solution increase to 99.02%, 97.23%, and 95.22%, respectively, by forming 10% biochar/struvite composite. X-ray diffraction (XRD) patterns acquired from the 10% biochar/struvite composite show a crystalline structure of MgNH4PO4·6H2O (PDF no. 15-0762) and release of the main nutrient elements (N, P, Mg) from the 10% biochar/struvite composite increases significantly compared to struvite. The solubility of the biochar/struvite composite is the highest in 0.5 mol/L HCl, second in 20 g/L citric acid, and lowest in water. The power function equation describes more precisely the cumulative release of N, P, and Mg from the biochar/struvite composite in distilled water, whereas it follows the simple Elovich equation in 20 g/L critic acid and first-order kinetics equation in 0.5 mol/L HCl. Leaching experiments are performed on the biochar/struvite composite in soil, and the results indicate that the biochar/struvite composite has a longer cycle of release of nutrients than traditional chemical fertilizers and has large potential as a slow-release fertilizer.

Investigation of the Effects of Polymer Dispersants on Dispersion of GO Nanosheets in Cement Composites and Relative Microstructures/Performances.

This study focused on the uniform distribution of graphene oxide (GO) nanosheets in cement composites and their effect on microstructure and performance. For this, three polymer dispersants with different level of polar groups (weak, mild, and strong) poly(acrylamide-methacrylic acid) (PAM), poly(acrylonitrile-hydroxyethyl acrylate) (PAH), and poly(allylamine-acrylamide) (PAA) were used to form intercalation composites with GO nanosheets. The results indicated that GO nanosheets can exist as individual 1⁻2, 2⁻5, and 3⁻8 layers in GO/PAA, GO/PAH, and GO/PAM intercalation composites, respectively. The few-layered (1⁻2 layers) GO can be uniformly distributed in cement composites and promote the formation of regular-shaped crystals and a compact microstructure. The compressive strengths of the blank, control, GO/PAM, GO/PAH, and GO/PAA cement composites were 55.72, 78.31, 89.75, 116.82, and 128.32 MPa, respectively. Their increase ratios relative to the blank sample were 40.54%, 61.07%, 109.66%, and 130.29%, respectively. Their corresponding flexural strengths were 7.53, 10.85, 12.35, 15.97, and 17.68 MPa, respectively, which correspond to improvements of 44.09%, 64.01%, 112.09%, and 134.79%.