Search Results (97)

Developing advanced polysulfone (PSF) membranes for water treatment has garnered significant attention. However, carboxylated polysulfone membranes have shown limited rejection of various ions. This study explores four novel methods for modifying carboxylated polysulfone membranes to enhance their performance: (a) crosslinking of the dicarboxylated membrane surface with polyethylenimine or ethylenediamine, (b) partial hydrolysis of ethylenediamine-crosslinked dicarboxylated membranes to create tailored pores and surface brushes with terminal amine groups, (c) attachment of alkyl brushes to the dicarboxylated membrane surface, and (d) formation of quaternary ammonium moieties at the membrane surface. All modified membranes were fully characterized, and their enhanced functionality was confirmed. For instance, the PSF-PEI membrane exhibited a 28% CaCl₂ rejection and PSF-NH₂ showed improved CaCl₂ rejection up to 37%, compared to 0% for the unmodified PSF-COOH. These methods present practical strategies to modify carboxylated-related membranes further, offering potential pathways to enhance their performance. Full article

Polyethylene terephthalate (PET) is a polyester used in the beverage bottling industry that generates a serious pollution problem. Films were obtained to reuse discarded PET bottles, and their surface was modified to determine their effectiveness in supporting the immobilization of the laccase enzyme applied to a catechol biodegradation assay. Radiofrequency (RF) plasma was used to modify the PET surface using different precursors: (a) with the use of air as precursor, the effect of the etching caused by the air on the greater or lesser immobilization was observed; (b) with the use of ethylenediamine, a mixture of N₂/H_2, or aniline as precursors, it was observed which of these three precursors presented the greater or lesser number of amino groups deposited on the PET surface. After plasma modification, the films were cross-linked with glutaraldehyde to immobilize the laccase enzyme. Finally, the catechol test was performed. It was found that the best etching time using air as a precursor was 90 min, and the precursor that caused a higher insertion of amino groups on the surface was ethylenediamine, which reached a density of amino groups of 3.98 ± 0.10 g·mm⁻². The highest percentage of laccase immobilization achieved on the surface of ethylenediamine-modified PET was 97.30%. In the catechol assay, the highest retention was 86.11%. This research reveals how the effect of plasma increases the surface area on a PET surface and, in conjunction with ethylenediamine as the best precursor of the three precursors evaluated, can immobilize a greater amount of enzyme and oxidize more catechol. There is no scientific evidence from previous studies that used air plasma technology to erode and then used three different precursors to modify a surface to immobilize the laccase enzyme and remove a water contaminant. Full article

The development of sensitive and specific methods for the high-quality analysis of hemin-related drugs is significant in the pharmaceutical field. In this work, a simple and rapid method based on the fluorescent properties of carbon dots (CDs) was established for the determination of hemin in drugs. By taking melamine and ethylenediamine as the reaction materials, the fluorescent CDs were synthesized by a one-step solvothermal method, which can be used for the determination of hemin in drugs by the fluorescent inner filter effect. The as-prepared fluorescent CDs with rich functional groups on the surface displayed good water solubility, strong salt resistance, robust pH stability, and photobleaching resistance. Most importantly, the fluorescent excitation wavelength of fluorescent CDs was very close to the absorption wavelength of hemin, providing the evidence for the fluorescent inner filter effect. When the hemin concentration was in the range of 0.01–1 μM, there was a good linear relationship between the hemin content with the fluorescence intensity of CDs. The linear regression equation was (1 − F/F₀) = 0.0897c + 0.0124, with a correlation coefficient (R²) of 0.9982 and a detection limit of 9 nM. This assay was successfully used to determine the content of hemin in the tablet, which displayed 97.9–105.5% of the labelled amount, with a relative standard deviation of less than 3%. The developed fluorescence method for the detection of hemin content displays the advantages of accurate, rapid, and high sensitivity, which could prove to be a useful tool for the determination of hemin supplement tablets. Full article

In the context of global warming, technologies and studies aimed at mitigating carbon dioxide (CO₂) have become increasingly relevant. One such technology is CO₂ capture by activated and functionalized N-doped carbon from biomasses. This paper explores the ways to find the optimal CO₂ adsorption conditions, based on the carbonization temperature, impregnation rate, and preparation method, considering four different preparation routes in activated and functionalized carbon-N (PCs) of banana peel biomass residues. PCs were produced and chemically activated by K₂C₂O₄ and H₂O and functionalized by ethylenediamine (EDA). Carbon dioxide capture was investigated using functional density theory (DFT). Nitrogen (N) doping was confirmed by X-ray photoelectron spectroscopy (XPS), while the thermal characteristics were examined by thermogravimetric analysis (TGA). Surface morphology was examined by scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) detection, and surface functional groups were characterized using Fourier-transform infrared (FTIR) spectroscopy. In addition, the inorganic components were characterized by X-ray diffraction (XRD). The best performance of CO₂ adsorption of 1.69 mmol/g was achieved at 0 °C and 1 bar over the adsorbent synthesized at 600 °C with 60 min residence time, a 1:1 degree of impregnation, and a dry preparation method (single-stage preparation). This work presents as a great innovation the use of biomass as a raw material in the adsorption of the main greenhouse gases, using easy and accessible products. Full article

This study evaluated the stability and reusability of amino-functionalized nanocellulose aerogels as CO₂-adsorbent materials. The modified aerogels, synthesized via a controlled silylation using N-[3-(trimethoxysilyl) propyl] ethylenediamine (DAMO), demonstrated excellent thermal stability up to 250 °C (TGA) and efficient CO₂ adsorption through chemisorption, which was the main adsorption mechanism. The performance of the aerogels was assessed using both adsorption isotherms and the decay pressure technique, revealing that CO₂ adsorption capacity increased with higher amino group loading (4.62, 9.24, and 13.87 mmol of DAMO). At 298 K and 4 bar, CO₂ adsorption capacity increased proportionally with the amino group concentration, reaching values of 3.17, 5.98, and 7.86 mmol of CO₂ g⁻¹ polymer, respectively. Furthermore, over 20 adsorption/desorption cycles, the aerogels maintained 95% CO₂ desorption at ambient temperature, indicating their potential for industrial use. These findings highlight the aerogels suitability as stable, reusable materials for large scale CO₂ capture and storage technologies. Full article

Flexible perovskite solar cells (F-PSCs) hold great potential for lightweight photovoltaic applications due to their flexibility, bending compatibility, and low manufacturing cost. However, tin oxide (SnO₂), as a common electron transport layer (ETL) used in F-PSCs, typically suffers from high-density surface defects that hinder the charge extraction efficiency and deteriorate the crystallization quality of the upper perovskite film. Additionally, the poor buried interface quality intensifies lattice extrusion and strain residue across the perovskite films, further aggravating the mechanical brittleness in devices. To address the issues, we developed a molecular bridging strategy by introducing the 2,2′-oxybis(ethylenediamine) dihydrochloride (DO) at the perovskite/SnO₂ interface. The diammonium groups of spacer ligands can achieve the bidentate anchoring on the SnO₂ and perovskite films, cooperating with the oxygen atom on the alkyl chain to passivate the charged defects at the buried interface. The tailored interface properties also endow the optimized crystallization quality of perovskite films and significantly alleviate tensile strain to strengthen the perovskite’s pliability. As a result, the F-PSCs achieved a champion efficiency of 23.50%, outperforming the value of 21.87% for the control device. Furthermore, the devices exhibited excellent mechanical robustness, maintaining 90% of the initial PCE after 6000 bending cycles at a radius of 4 mm. This work presents a reliable strategy for the synergistic optimization of the buried contact at the electron extraction interface, contributing to the further development of efficient and stable F-PSCs. Full article

The effective use of polymer carbon dots (PCD) in various fields of science and technology requires a more detailed understanding of the mechanisms of their photoluminescence formation and change as a result of their interaction with the environment. In this study, PCD synthesized via a hydrothermal method from citric acid and ethylenediamine are studied in various solvents using FTIR spectroscopy, optical absorption spectroscopy, and photoluminescence spectroscopy. As a result of the analysis of the obtained dependencies of such PCD spectral characteristics as the photoluminescence FWHM, the photoluminescence quantum yield, the photoluminescence lifetime on the acidity and basicity of the solvent, a hypothesis was formulated on the formation mechanism of hydrogen bonds between the PCD surface groups and the molecules of the environment, and conclusions were made about the donor–acceptor nature of the synthesized PCD. Full article

This study aimed to investigate the effect of aminating waste newsprint paper with different aminating agents (ammonia/ammonia water, ethylenediamine, and diethylenetriamine) for the sorption efficiency of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) dyes. To increase the amination efficiency, the paper material was pre-activated with epichlorohydrin. The scope of this study included the characterization of the sorbents tested (FTIR, elemental analysis, BET surface area, porosity, and pH_PZC), determination of the influence of pH on dye sorption efficiency, sorption kinetics, and the maximum sorption capacity of the dyes. The study results showed that amination with ethylenediamine and diethylenetriamine introduced 87% and 194% more amine groups into the sorbent’s structure compared to the treatment with ammonia. The sorption efficiency of RB5 and RY84 on the sorbents tested was the highest in the pH range of 2–3. The sorption equilibrium time ranged from 90 to 150 min and was longer in the case of the unmodified sorbents. The experimental data from the study were best described by the pseudo-second-order model and the Langmuir 1 and 2 models. Amination had a very strong effect on the sorption capacity of newsprint. For example, the sorption capacity of newsprint paper towards RB5 (Q_max = 7.12 mg/g) increased after amination with ammonia, ethylenediamine, and diethylenetriamine to the value of Q_max = 182.78 mg/g, Q_max = 202.7 mg/g, and Q_max = 231.5 mg/g, respectively. Full article

(1) Background: Bond strength between repair and restorative materials is crucial for endodontic success. This study assessed the effects of the following final irrigation solutions on the bond strength of mineral trioxide aggregate (MTA) to a bulk-fill composite: (1) 17% Ethylenediamine tetraacetic acid (EDTA); (2) 2% Chlorhexidine (CHX); (3) 0.2% chitosan; (4) 0.2% chitosan with 2% CHX; 5) 0.2% chitosan with AgNPs. (2) Methods: Sixty MTA samples were divided into six groups (n = 10) based on the final irrigation solution: 1. EDTA, 2. CHX, 3. Chitosan, 4. Chitosan-CHX, 5. Chitosan-AgNP, and 6. distilled water (control). After a 5-min solution exposure, each sample was restored with the bulk-fill composite, and the shear bond strength (SBS) was measured. Structural changes in MTA were analyzed using SEM and EDS, and failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed by one-way ANOVA with Tamhane’s T2 and Tukey’s tests (α = 0.05). (3) Results: EDTA exhibited the lowest SBS (p < 0.001), while Chitosan-CHX showed the highest. SEM showed a spongy, void-rich surface in EDTA-treated MTA, with significant Ca depletion per EDS. Chitosan-CHX showed no structural change. Cohesive fractures within MTA were predominant. (4) Conclusions: EDTA significantly reduces SBS, while chitosan with CHX enhances bond strength. Full article

Background/Objectives: Fluoroquinolones (FQs) are topoisomerase II inhibitors with antibacterial activity, repositioned recently as anti-cancer agents. Glutamic acid (GLA) is an amino acid that affects human metabolism. Since an anti-cancer mechanism of FQs is human topoisomerase II inhibition, it is expected that FQ-GLA hybrids can act similarly. Methods: We designed 27 hypothetical hybrids of 6 FQs and GLA through amide bonds at the 3- and 7-position groups of FQs or via ethylenediamine/ethanolamine linkers at the carboxyl group of the FQ. Hydroxamic acid derivatives were also theoretically formulated. Computational methods were used to predict their physicochemical, pharmacokinetic, or toxicological properties and their anti-cancer activity. For comparison, etoposide was used as an anti-cancer agent inhibiting topoisomerase II. Molecular docking assessed whether the hybrids could interact with the human topoisomerase II beta in the same binding site and interaction sites as etoposide. Results: All the hybrids acted as potential topoisomerase II inhibitors, demonstrating possible anti-cancer activity on several cancer cell lines. Among all the proposed hybrids, MF-7-GLA would be the ideal candidate as a lead compound. The hybrid OF-3-EDA-GLA and the hydroxamic acid derivatives also stood out. Conclusions: Both FQs and GLA have advantageous structures for obtaining hybrids with favourable properties. Improvements in the hybrids’ structure could lead to promising results. Full article

In recent years, graphene oxide (GO)-based two-dimensional (2D) laminar membranes have attracted considerable attention because of their unique well-defined nanochannels and deliver a wide range of molecular separation properties and fundamentals. However, the practical application of 2D GO layered membranes suffers from instability in aqueous solutions as the interlayer d-spacing of GO membranes is prone to expansion caused by the hydration effect. In this study, the effects of the ethylenediamine (EDA) addition amount on the structure, crosslinking mechanism and separation performance of GO membranes were investigated systematically, and membrane performance was evaluated using water permeability and dye/salt rejection tests. The experimental results show that the amine groups of EDA chemically bond with the hydroxyl functional group (O=C–OH) of GO after intercalation, as evident from Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). By further controlling the amount of the intercalated EDA, the as-prepared GO composite membranes show nanoscale-tuned d-spacing promising for downstream applications. In the demonstrated dye/salt nanofiltration scenario, the EDA intercalated and crosslinked GO membrane has enhanced permeability by over five times and a better dye rejection rate of over 96% compared with pure GO membranes. These findings highlight a facile strategy for controlling nanochannels by tuning the amounts of reactive intercalants. Full article

To improve the potential of lupeol against cancer cells, a privileged structure, thiazolidinedione, was introduced into its C-3 hydroxy group with ester, piperazine-carbamate, or ethylenediamine as a linker, and three series of thiazolidinedione-conjugated compounds (6a–i, 9a–i, and 12a–i) were prepared. The target compounds were evaluated for their cytotoxic activities against human lung cancer A549, human breast cancer MCF-7, human hepatocarcinoma HepG2, and human hepatic LO2 cell lines, and the results revealed that most of the compounds displayed improved potency over lupeol. Compound 12i exhibited significant activity against the HepG2 cell line, with an IC₅₀ value of 4.40 μM, which is 9.9-fold more potent than lupeol (IC₅₀ = 43.62 μM). Mechanistic studies suggested that 12i could induce HepG2 cell apoptosis, as evidenced by AO/EB staining and annexin V-FITC/propidium iodide dual staining assays. Western blot analysis suggested that compound 12i can upregulate Bax expression, downregulate Bcl-2 expression, and activate the mitochondria-mediated apoptotic pathway. Collectively, compound 12i is worthy of further investigation to support the discovery of effective agents against cancer. Full article

Dynamic polymer networks combine the noteworthy (thermo)mechanical features of thermosets with the processability of thermoplastics. They rely on externally triggered bond exchange reactions, which induce topological rearrangements and, at a sufficiently high rate, a macroscopic reflow of the polymer network. Due to this controlled change in viscosity, dynamic polymers are repairable, malleable, and reprocessable. Herein, several dynamic polyurethane networks were synthetized as model compounds, which were able to undergo thermo-activated transcarbamoylation for the use in rebondable adhesives. Ethylenediamine-N,N,N′,N′-tetra-2-propanol (EDTP) was applied as a transcarbamoylation catalyst, which participates in the curing reaction across its four -OH groups and thus, is covalently attached within the polyurethane network. Both bond exchange rate and (thermo)mechanical properties of the dynamic networks were readily adjusted by the crosslink density and availability of -OH groups. In a last step, the most promising model compound was optimized to prepare an adhesive formulation more suitable for a real case application. Single-lap shear tests were carried out to evaluate the bond strength of this final formulation in adhesively bonded carbon fiber reinforced polymers (CFRP). Exploiting the dynamic nature of the adhesive layer, the debonded CFRP test specimens were rebonded at elevated temperature. The results clearly show that thermally triggered rebonding was feasible by recovering up to 79% of the original bond strength. Full article

The stability of slurries used for chemical mechanical polishing (CMP) is a crucial concern in industrial chip production, influencing both the quality and cost-effectiveness of polishing fluids. In silicon wafer polishing, the conventional use of commercial neutral silica sol combined with organic bases often leads to slurry instability. To address this issue, this study proposes organic amines—specifically ethanolamine (MEA), ethylenediamine (EDA), and tetramethylammonium hydroxide (TMAOH)—as catalysts for synthesizing alkaline silica sol tailored for silicon wafer polishing fluids. Sol–gel experiments and zeta potential measurements demonstrate the efficacy of this approach in enhancing the stability of silica sol. The quantitative analysis of surface hydroxyl groups reveals a direct correlation between enhanced stability and increased hydroxyl content. The application of the alkaline silica sol in silicon wafer polishing fluids improves polishing rates and enhances surface flatness according to atomic force microscopy (AFM). In addition, electrochemical experiments validate the capability of this polishing solution to mitigate corrosion on silicon wafer surfaces. These findings hold significant implications for the advancement of chemical mechanical polishing techniques in the field of integrated circuit fabrication. Full article

In recent decades, cellulose (Cel) and its modified forms have emerged as a new class of versatile adsorbents for removing dyes from aqueous solutions. This work reports the immobilization of macromolecules obtained from reactions between ethylenediamine (N) and ethylene sulfide (S) in three molar proportions (1:1, 1:2, and 1:4) on the surface of chlorinated cellulose (Cl-Cel), aiming to increase the adsorption capacity of dyes. The materials obtained (NS-Cel, N2S-Cel, and N4S-Cel) were characterized by elemental analysis, which demonstrated immobilization of macromolecules with a ratio of 12 ethylene sulfides to 1 ethylenediamine in the materials NS-Cel and N4S-Cel and a ratio of 10 ethylene sulfides to 1 ethylenediamine in NS-Cel. Intense C-H stretching bands of CH₂ groups at 2900 cm⁻¹ in the FT-IR spectra suggest a large amount of the functional group, corroborating the ¹³C NMR spectra, which presented a signal at 33 ppm referring to methylene carbons. The materials obtained had excellent performance in removing the dyes studied, with the adsorption capacity of the Remazol yellow GR dye being approximately 24 times greater than the raw material (87.70 ± 2.63 mg g⁻¹) for the best-hyperbranched cellulose N4S-Cel and 3.60 ± 0.18 mg g⁻¹ for Cel, and about ten times higher for the dye Remazol red RB (57.84 ± 1.73 mg g⁻¹) for N4S-Cel compared to previously published work for Cel. Full article