Search Results (329)

This work evaluates the CO₂-adsorption relevance and cycling stability of graphene oxide–silica (GO-SiO₂) and reduced graphene oxide–silica (rGO-SiO₂) gels after amine functionalization, demonstrating high-capacity retention under repeated adsorption–desorption cycles: rGO-SiO₂-APTMS retains ≈96.3% of its initial uptake after 50 cycles, while GO-SiO₂-APTMS retains ≈90.0%. The use of surfactants to control the organization of inorganic and organic molecules has enabled the development of ordered mesostructures, such as mesoporous silica and organic/inorganic nanocomposites. Owing to the outstanding properties of graphene and its derivatives, synthesizing mesostructures intercalated between graphene sheets offers nanocomposites with novel morphologies and enhanced functionalities. In this study, GO-SiO₂ and rGO-SiO₂ gels were synthesized and characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), mass spectrometry (MS), N₂ adsorption–desorption isotherms, and transmission electron microscopy (TEM). The resulting materials exhibit a laminar architecture, with mesoporous silica domains grown between graphene-based layers; the silica contents are 83.6% and 87.6%, and the specific surface areas reach 446 and 710 m²·g⁻¹, respectively. The laminar architecture is retained regardless of the surfactant-removal route; however, in GO-SiO₂ obtained by solvent extraction, a fraction of the surfactant remains partially trapped. Together with their high surface area, hierarchical porosity, and amenability to surface functionalization, these features establish amine-grafted graphene–silica gels, particularly rGO-SiO₂-APTMS, as promising CO₂-capture adsorbents. Full article

Nitrate pollution in water bodies has become a global environmental problem, and its excessive presence not only leads to eutrophication of water bodies but also threatens human health through the drinking water pathway. Therefore, it is urgent to develop new adsorbents with high adsorption capacity, good selectivity and excellent regeneration performance to solve the problem of nitrate pollution. In this study, reed straw (RS), trimethylamine-modified reed straw (MRS) and triethylamine-modified reed straw (ERS) were prepared by quaternary amination modification for nitrate removal. The adsorption performance, desorption performance, adsorption characteristics under disturbed environment and dynamic adsorption performance were investigated experimentally, and the adsorption mechanism was analyzed by various characterization means. The adsorption performance followed the order ERS (12.25 mg·g⁻¹) > MRS > RS, demonstrating that quaternary amination modification, particularly with triethylamine, significantly enhanced the NO₃⁻-N adsorption capacity. ERS exhibited excellent regeneration stability (over 80% after nine cycles) and high selectivity towards NO₃⁻-N in the presence of competing anions (Cl⁻, SO₄²⁻, humic acid). In the dynamic adsorption experiment, ERS had a breakthrough time of 290 min at a packing height of 3.3 cm, with an adsorption capacity of 10.74 mg·g⁻¹ and good adaptability to flow rate. In the actual wastewater application, the initial NO₃⁻-N removal rate was over 95%, the dynamic desorption rate reached 99.2% and the peak nitrate concentration of the desorbed solution reached 27 times of the initial value, confirming its high efficiency regeneration and enrichment ability. The study shows that the amine-modified reed straw adsorbent has a good potential for application and provides a new way for wastewater treatment plants to solve the problem of nitrate removal 12.25 mg·g⁻¹. Full article

To address the challenges of low KCl recovery and high collector consumption during flotation at low temperature, a novel approach with utilizing a compound collector consisting of octadecylamine hydrochloride (ODA) and alcohols (butanol, octanol, and dodecanol) to enhance low-temperature KCl flotation recovery was proposed in this study. The flotation performance and underlying mechanisms of this novel amine–alcohol compound collector were investigated through combination of micro-flotation tests, contact angle measurements, and molecular dynamics simulations. The results revealed that KCl flotation recovery decreased with declining temperature using single ODA as the collector, and the maximum KCl flotation recovery was approximately 40% with an ODA concentration of 1 × 10⁻⁵ mol/L at the temperature of 0 °C. Moreover, amine–alcohol compound collector shows different KCl flotation recovery; among them, dodecanol (DOD) presents the best performance at 25 °C with an ODA concentration of 3 × 10⁻⁶ mol/L. The KCl flotation recovery initially increased and then gradually decreased with increasing the DOD concentration, and 90% KCl recovery was achieved with a DOD concentration of 1.5 × 10⁻⁵ mol/L (DOD:ODA = 5:1 in mole) under 25 °C. Furthermore, this compound collector exhibited high selectivity for KCl/NaCl flotation. Mechanism studies indicated that the trend in contact angle changes on the KCl crystal surface closely mirrored the trend in flotation recovery. Molecular dynamics simulations demonstrated that at 0 °C, the presence of DOD resulted in a higher diffusion coefficient for ODA molecules compared to the system without DOD. Additionally, the water molecules in System 3 exhibited a lower diffusion coefficient and a greater number of hydrogen bonds. This novel compound collector offers a potential solution for improving KCl recovery and reducing ODA consumption during low-temperature flotation. It holds significant theoretical and practical implications for advancing low-temperature KCl flotation technology. Full article

The use of organic amine absorbents in CO₂ capture technologies is highly significant. The widespread application of this technique is limited by the heat-stable salts (HSSs) produced during the cyclic absorption–desorption process. This research focused on the HSS removal process using electrodialysis technology and systematically examined the effects of operating voltage, initial concentration, pH, current density, the ratio of liquid volume in the enriched chamber to that in the diluting chamber, and the type of ion-exchange membrane on desalination efficiency, energy consumption, and amine loss. An increase in both voltage and initial concentration significantly enhances the rate of water migration. The rate of ion migration is observed to follow the order of Cl⁻ > ${\mathrm{S}\mathrm{O}}_4^{2-}$> F⁻ in a homogeneous membrane, while in a heterogeneous membrane, the order is ${\mathrm{SO}}_4^{2-}$ > Cl⁻ > F⁻. The optimal operating voltage is 10 V, with a pH level of 8 resulting in the highest ${\mathrm{SO}}_4^{2-}$ removal efficiency. An industrial scenario validated the optimized process conditions, which balanced energy consumption with desalination efficiency. This methodology is essential not only for providing a viable solution for the industrial purification of organic amines but also for promoting the environmentally sustainable development of carbon capture technologies. Full article

Concern over the presence of pharmaceutical waste in the environment has prompted research into the management of emerging organic micropollutants (EOMs). In response, sustainable technologies have been applied as alternatives to reduce the effects of these contaminants. This study investigated the capacity of filamentous fungi isolated from iron mine soil in the Amazon region to biodegrade the drug chloroquine diphosphate. An initial screening assessed the growth of four fungal strains on solid media containing chloroquine diphosphate: Trichoderma pseudoasperelloides CBMAI 2752, Penicillium rolfsii CBMAI 2753, Talaromyces verruculosus CBMAI 2754, and Penicillium sp. cf. guaibinense CBMAI 2758. Among them, Penicillium sp. cf. guaibinense CBMAI 2758 was selected for further testing in liquid media. A Box–Behnken factorial design was applied with three variables, pH (5, 7, and 9), incubation time (5, 10, and 15 days), and chloroquine diphosphate concentration (50, 75, and 100 mg·L⁻¹), totaling 15 experiments. The samples were analyzed by gas chromatography–mass spectrometry (GC-MS). The most effective conditions for chloroquine biodegradation were pH 7, 100 mg·L⁻¹ concentration, and 10 days of incubation. Four metabolites were identified: one resulting from N-deethylation M1 (N4-(7-chloroquinolin-4-yl)-N1-ethylpentane-1,4-diamine), two from carbon–carbon bond cleavage M2 (7-chloro-N-ethylquinolin-4-amine) and M3 (N1,N1-diethylpentane-1,4-diamine), and one from aromatic deamination M4 (N1-ethylbutane-1,4-diamine) by enzymatic reactions. The toxicity analysis showed that the products obtained from the biodegradation of chloroquine were less toxic than the commercial formulation of this compound. These findings highlight the biotechnological potential of Amazonian fungi for drug biodegradation and decontamination. Full article

We present a theoretical model of the hydrogenation and amination of a primal carbon cluster of the tangled polycyclic type. Hydrogen atoms were introduced via H₂, while the nitrogen source was NH₃. The initial chemical processes were modeled using Born–Oppenheimer Molecular Dynamics. Metadynamics was employed to accelerate the saturation. The reactions were characterized in terms of barriers, topology, and intricate changes in the electronic structure. All transition states were identified. Multiple mechanisms for each type of reaction were discovered. Occasional unbiased changes in the carbon skeleton, induced by the guided processes, were observed. The initial addition reactions had no barriers due to the instability and high reactivity of the carbon structure. The final product of barrierless hydrogen saturation was C₂₅H₂₆. This molecule included multiple isolated double bonds, a medium-sized conjugated π system, and no triple bonds. Ammonia additions resulted in quaternary ammonium groups and primary amino groups. In the subsequent amination, a barrier appeared in fewer steps than in repetitive hydrogenation. The final product of barrierless saturation with NH₃ was C₂₅H₂(NH₃)₂NH₂. Further amination was characterized by a forward free-energy barrier of an order of magnitude larger than the reverse reaction, and the product was found to be unstable. Full article

In clinical applications of surface-enhanced Raman spectroscopy (SERS) immunosensors, accurately determining analyte biomarker concentrations is essential. This study presents a non-invasive approach for quantifying various breast cancer biomarkers—including human epidermal growth factor receptor II (HER-II) (2+, 3+ (I), 3+ (II), 3+ (III), and positive IV) and CA 15-3—using a directional, plasmonically active, label-free SERS sensor. Each stage of sensor functionalization, conjugation, and biomarker interaction was verified by UV–Vis spectroscopy. Atomic force microscopy (AFM) characterized the morphology of gold nanourchin (GNU)-immobilized printed circuit board (PCB) substrates. An enhancement factor of ≈ 0.5 × 10⁵ was achieved using Rhodamine 6G as the probe molecule. Calibration curves were initially established using standard HER-II solutions at concentrations ranging from 1 to 100 ng/mL and CA 15-3 at concentrations from 10 to 100 U/mL. The SERS signal intensities in the 620–720 nm region were plotted against concentration, yielding linear sensitivity with R² values of 0.942 and 0.800 for HER-II and CA15-3, respectively. The same procedure was applied to breast cancer serum (BCS) samples, allowing unknown biomarker concentrations to be determined based on the corresponding calibration curves. SERS data were processed using the filtfilt filter from scipy.signal for smoothing and then baseline-corrected with the Improved Asymmetric Least Squares (IASLS) algorithm from the pybaselines.Whittaker library. Principal Component Analysis (PCA) effectively distinguished the sample groups and revealed spectral differences before and after biomarker interactions. Key Raman peaks were attributed to functional groups including N–H (primary and secondary amines), C–H antisymmetric stretching, C–N (amines), C=O antisymmetric stretching, NH₃⁺ (amines), carbohydrates, glycine, alanine, amides III, C=N stretches, and NH₂ in primary amides. Full article

The synthesis of novel biodegradable polymers as non-viral vectors remains one of the challenging tasks in the field of gene delivery. In this study, the synthesis of the polysaccharide-g-polypeptide copolymers, namely, hyaluronic acid-g-polylysine (HA-g-PLys), using a copper-free strain-promoted azide-alkyne cycloaddition reaction was proposed. For this purpose, hyaluronic acid was modified with dibenzocyclooctyne moieties, and poly-L-lysine with a terminal azido group was obtained using ring-opening polymerization of N-carboxyanhydride of the corresponding protected amino acid, initiated with the amino group azido-PEG₃-amine. Two HA-g-PLys samples with different degrees of grafting were synthesized, and the structures of all modified and synthesized polymers were confirmed using ¹H NMR and FTIR spectroscopy. The HA-g-PLys samples obtained were able to form nanoparticles in aqueous media due to self-assembly driven by electrostatic interactions. The binding of DNA and model siRNA by copolymers to form polyplexes was analyzed using ethidium bromide, agarose gel electrophoresis, and SybrGreen I assays. The hydrodynamic diameter of polyplexes was ˂300 nm (polydispersity index, PDI ˂ 0.3). The release of a model fluorescently-labeled oligonucleotide in the complex biological medium was significantly higher in the case of HA-g-PLys as compared to that in the case of PLys-based polyplexes. In addition, the cytotoxicity in normal and cancer cells, as well as the ability of HA-g-PLys to facilitate intracellular delivery of anti-GFP siRNA to NIH-3T3/GFP+ cells, were evaluated. Full article

Stimuli-responsive polymers (SRPs) have garnered significant attention in recent decades due to their immense potential in biomedical and environmental applications. When these SRPs are grafted onto magnetic nanoparticles, they form multifunctional nanocomposites capable of various complex applications, such as targeted drug delivery, advanced separations, and magnetic resonance imaging. In this study, we employed a one-step hydrothermal method using 3-aminopropyltrimethoxysilane (APTES) to synthesize APTES-modified Fe₃O₄ nanoparticles (APTES@Fe₃O₄) featuring reactive terminal amine groups. Subsequently, via two consecutive surface-initiated atom transfer radical polymerizations (SI-ATRP), pH- and temperature-responsive polymer blocks were grown from the Fe₃O₄ surface, resulting in the formation of poly(itaconic acid)-block-poly(N-isopropyl acrylamide) (PIA-b-PNIPAM)-grafted nanomagnetic particles (PIA-b-PNIPAM@Fe₃O₄). To confirm the chemical composition and assess how the particle morphology and size distribution of these SRP-based nanocomposites change in response to ambient pH and temperature stimuli, various characterization techniques were employed, including transmission electron microscopy, differential light scattering, and Fourier transform infrared spectroscopy. The results indicated successful synthesis, with PIA-b-PNIPAM@Fe₃O₄ demonstrating sensitivity to both temperature and pH. Full article

Polymer brushes (PBs) are transformative surface-modifying nanostructures, yet their synthesis via controlled methods like copper-mediated surface-initiated atom-transfer radical polymerization (Cu⁰-SI-ATRP) faces reproducibility challenges due to a lack of understanding of parameter interdependencies. This study systematically evaluates the Cu⁰-SI-ATRP process for polyacrylamide brushes (PAM-PBs), aiming to clarify key parameters that influence the synthesis process. This evaluation followed a step-by-step characterization that tracked molecular changes through infrared spectroscopy (IR) and surface development by contact angle (CA) through two different mixing methods: ultrasonic mixing and process simplification (Method A) and following literature-based parameters (Method B). Both methods, consisting of surface activation, 3-aminopropyltriethoxysilane (APTES) deposition, bromoisobutyryl bromide (BiBB) anchoring, and polymerization, were analyzed by varying parameters like concentration, temperature, and time. Results showed ultrasonication during surface activation enhanced siloxane (1139→1115 cm⁻¹) and amine (1531 cm⁻¹) group availability while reducing APTES concentration to 1 Vol% without drying sufficed for BiBB anchoring. BiBB exhibited insensitivity to concentration but benefited from premixing, evidenced by sharp C–Br (~1170 cm⁻¹) and methyl (3000–2800 cm⁻¹) bands. Additionally, it was observed that PAM-PBs improved with Method A, which had reduced variance in polymer fingerprint regions compared to Method B. Adding to the above, CA measurements gave complementary step-by-step information along the modifications of the surface, revealing distinct wettability behaviors between bulk PAM and synthesized PAM-PBs (from 51° to 37°). As such, this work identifies key parameter influence (e.g., mixing, BiBB concentration), simplifies steps (drying omission, lower APTES concentration), and demonstrates a step-by-step, systematic parameter decoupling that reduces variability. In essence, this detailed parameter analysis addresses the PAM-PBs synthesis process with better reproducibility than the previously reported synthesis method and achieves the identification of characteristic behaviors across the step-by-step process without the imperative need for higher-cost characterizations. Full article

The implantation of bone substitutes is frequently accompanied by inflammation. To reduce the inflammatory response and enhance cell adhesion, proliferation, and differentiation, scaffolds are often loaded with anti-inflammatory drugs. In this study, cellulose and cellulose/hydroxyapatite (1:1 by weight) scaffolds were developed. Structural analysis using SEM and micro-computed tomography revealed that the morphology of the scaffolds met the requirements for bone tissue engineering. The scaffolds were initially loaded with dexamethasone sodium phosphate; however, the drug was released very rapidly. To prolong its release, cationic groups were introduced into the cellulose macromolecules by amination with 2-chloro-N,N-diethylethylamine hydrochloride in an alkaline medium. Dexamethasone sodium phosphate was then immobilised on aminated cellulose and aminated cellulose/HAp scaffolds at concentrations of 157 mg/g and 87 mg/g, respectively. Due to ionic interactions between the cationic groups in the scaffolds and the anionic groups of the drug molecules, drug release was effectively prolonged. After 24 h, only about 6–7% of the drug had been released, with complete release occurring after 170 h. The cationic groups in the scaffold framework facilitated the adsorption and sustained release of dexamethasone sodium phosphate. Full article

High permeance combined with high salt/dye separation efficiency is a prerequisite for achieving zero-liquid-discharge treatment of saline textile wastewater by membrane technology. Thin-film nanocomposite (TFN) membranes incorporating porous nanoparticles offer a promising route to overcome the permeability–selectivity trade-off of conventional polymer membranes. In this study, a vacuum-assisted method was used to co-blend ZIF-67 and SiO₂ nanoparticles, while branched polyethyleneimine (PEI) served as a cross-linking bridge, resulting in a high-performance TFN membrane for salt/dye separation. Acting as a molecular connector, PEI coordinated with ZIF-67 through metal–amine complexation and simultaneously formed hydrogen bonds with surface hydroxyl groups on SiO₂, thereby linking ZIF-67 and SiO₂. The resulting membrane exhibited good hydrophilicity and excellent dye separation performance (water flux = 359.8 L m⁻² h⁻¹ bar⁻¹; Congo Red rejection = 99.2%) as well as outstanding selectivity in dye/salt mixtures (Congo Red/MgCl₂ selectivity of 1094). The optimal ZIF@SiO₂-PEI membrane maintained stable dye rejection over a wide range of trans-membrane pressures, initial concentrations, and pH values. These results reveal the huge potential of applying the ZIF@SiO₂-PEI TFN membranes for resource recovery in sustainable textile wastewater systems. Full article

The precipitation process of rare earth from a rare earth chloride solution using magnesium bicarbonate yields a dilute magnesium chloride (MgCl₂) solution. The dilute MgCl₂ solution can only be concentrated to a maximum concentration of about 70 g/L by conventional reverse osmosis (RO), which is insufficient for recycling. Low-salt-rejection reverse osmosis (LSRRO) allows for a higher concentration of brine while operating at moderate pressures. However, research on LSRRO for the concentration of MgCl₂ solution is still at an initial stage. In this study, polyamide RO membranes were treated with sodium hypochlorite (NaClO) to prepare low-salt-rejection membranes. The effects of NaClO concentration, pH, and chlorination time on the membrane properties were investigated. Under alkaline chlorination conditions, the membrane’s salt rejection decreased, and water flux increased with increasing NaClO concentration and chlorination time. This can be explained by the hydrolysis of polyamide in the alkaline solution to form carboxylic acids and amines, resulting in a decrease in the crosslinking degree of polyamide. The low-salt-rejection membrane was prepared by exposing it to a NaClO solution at a concentration of 15 g/L and a pH of 11 for 3 h, and the salt rejection of MgCl₂ was 50.7%. The MgCl₂ solution with a concentration of 20 g/L was concentrated using multi-stage LSRRO at the pressure of 5 MPa. The concentration of the concentrated brine reached 120 g/L, which is 87% higher than the theoretical maximum concentration of 64 g/L for conventional RO at the pressure of 5 MPa. The specific energy consumption (SEC) was 4.17 kWh/m³, which decreased by about 80% compared to that of mechanical vapor recompression (MVR). This provides an alternative route for the efficient concentration of a diluted MgCl₂ solution with lower energy consumption. Full article

The scarcity of phosphorus resources and the excessive accumulation of phosphates in aquatic environments pose significant threats to ecological systems and human health, while traditional treatment methods often fail to achieve effective resource recovery and reuse. This study aims to develop an efficient method for phosphate removal and resource recycling through the modification of reed straw (MRS) by introducing amine groups. Key operational parameters such as packed bed height, flow velocity, and initial solute concentration were systematically investigated to optimize MRS’s adsorption efficiency. Experimental results demonstrated that under optimized conditions, MRS achieved a maximum phosphate adsorption capacity of 8.337 mg/g and maintained over 80% efficiency after nine adsorption–desorption cycles. Utilizing the desorbed solution as a nutrient solution significantly enhanced maize seedling growth, increasing stem height by 23.8%, fresh weight by 51.3%, and phosphorus content by 80.7%. These findings highlight MRS’s potential, not only as an effective phosphate adsorbent, but also as a means of successful phosphorus resource recovery and recycling, indicating promising applications in environmental remediation and resource management. Full article

Background/Objectives: Colony stimulating factor 1 receptor kinase (CSF1R) is a well-validated molecular target in drug discovery for various reasons. Based on the structure of an early lead molecule identified in our lab and the marketed drug Pexidartinib (PLX3397), we merged fragments of Pexidartinib with our pyrrolo[2,3-d]pyrimidine nucleus, and the idea was supported by initial molecular docking studies. Thus, several new compounds were synthesized with Pexidartinib fragments on C4, C5, and C6 on the pyrrolopyrimidine scaffold using molecular hybridization. Methods: Nine final products were synthesized using a combination of Buchwald-Hartwig and Suzuki-Miyaura cross-coupling reactions in three to four steps and in good yields. The analogues were subsequently profiled as CSF1R inhibitors in enzymatic and cellular assays, and ADME properties were evaluated for some derivatives. Results: N-Methyl-N-(3-methylbenzyl)-6-(6-((pyridin-3-ylmethyl)amino)pyridin-3-yl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine (12b) emerged as the most potent CSF1R inhibitor, showing low-nanomolar enzymatic activity, cellular efficacy, and favorable ADME properties, highlighting its promise as a lead compound for further development. Conclusions: These findings suggest that combining structural elements from previously reported CSF1R inhibitors such as Pexidartinib could guide the development of improved drug candidates targeting this kinase. Full article