Chemical Papers最新文献

Carbon fiber exhibits weak interfacial adhesion with the matrix due to its nonpolar nature, which subsequently limits the mechanical strength of the resulting composites. This research examines the chemical surface modification via oxidation, reduction, and silane functionalization to enhance the fiber-matrix adhesion in carbon fiber-reinforced polymer composites. Carbon fiber was treated using HNO₃ and H₂SO₄:HNO₃ mixture, followed by reduction and silane functionalization with tetraethyl orthosilicate (TEOS). The presence of hydroxyl (–OH) and silanol (–SiOH) groups on TEOS-grafted fiber was confirmed by Fourier transform infrared spectroscopy. This modified fiber, along with epoxy matrix, was used to fabricate the composite using hand lay-up along with compression molding. The resultant composite was investigated for tensile strength, Young’s modulus, and impact strength. The CFRC-4 composite (sample modified with HNO₃ and TEOS) showed highest tensile strength and stiffness, depicting improved interfacial adhesion. Moreover, based on experimental data, the artificial neural network (ANN) model was developed to predict the mechanical performance. At a specific hidden layer size, the optimal performance of stress and strain was precisely predicted by ANN. The experimental validation along with data-driven modeling was combined in this hybrid methodology, providing deeper knowledge of the relation between surface chemistry and composite performance. This approach enables the faster prediction of material characteristics for cutting-edge engineering applications and future research work.

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In the present work, the inhibition performance of sulfaguanidine (SG) as a corrosion inhibitor of iron was investigated mathematically via regression and statistical analysis and theoretically via quantum chemical calculations. Four models were proposed, including a linear model (LM), a linear model with interaction (LIM), a quadratic model with interaction (QIM), and a kinetics model (KM). Among the mathematical models, the QIM was the most accurate one, with a 0.9943 correlation coefficient. The kinetics model demonstrated a correlation coefficient of 0.9954. These models showed that the effect of temperature on the corrosion was more significant than the effect of inhibitor concentration. On the other hand, quantum chemical calculations indicate that the difference between HOMO–LUMO (ΔE) was 0.199 eV, which indicates a high reactivity of SG. The strong adsorption is due to a donor–acceptor bonding connection between the Fe surface and the SG molecules, which has been studied in more detail.

This study focuses on developing an oral drug delivery system for the sustained release of the anti-diabetic drug sitagliptin. The system is designed using a polyelectrolyte complex formed by combining anionic brown algae alginate and sulfated red seaweed ĸ-carrageenan with cationic chitosan. The primary objective is to enhance drug retention in the acidic environment of the gastrointestinal tract, thereby improving its bioavailability in the intestine, where absorption is most effective. In vitro, studies conducted in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) indicated that coating an alginate–chitosan core with ĸ-carrageenan (CA20) resulted in favorable properties for oral drug delivery. The composite effectively controlled drug diffusion at pH 1.2, characteristic of the stomach, ensuring that a significant portion of the drug reached the intestine. The sitagliptin-loaded composite (CA20) exhibited approximately 36% of the drug release in SGF at pH 1.2, followed by a sustained release over 4 h in SIF at pH 7.4. Mathematical modeling of the drug release kinetics showed that the Higuchi model provided the best fit, with an R² value of 0.964 or higher. Structural integrity assessments using FT-IR, XRD, DSC, and SEM confirmed the stability of the composites. These findings suggest that the developed composites hold promise as effective drug delivery systems for intestinal absorption and extended release, with potential applications in targeting the colon.

In this article, more than fifty publications (2021–2025) have been reviewed to analyze the adsorption behaviors of ionic liquid-based materials for different water contaminants under varied environmental conditions. Thus, the trends observed across the removal performances for different pollutant classes are depicted, and the common interaction mechanisms related to material reusability as an adsorbent are discussed. The main observations we drew from this review are as follows: (i) Ionic liquid-based materials show significant promise as effective scavengers of aqueous pollutants by adsorption because they have relatively high adsorption capacities and good recyclability of five cycles of reuse and more, (ii) support-immobilized ionic liquid-based materials show enhanced material stability, reusability, and adsorption efficiency for aqueous adsorbates, (iii) however, there are key challenges that persist, and these cover aspects related to ionic liquid stability, environmental safety, and real-water applicability of these ionic liquid-based materials under harsh environmental conditions, and (iv) lifecycle-based techno-economic studies of ionic liquid-based adsorption units is necessary if ionic liquid-based materials are being contemplated for industrial water treatment processes. This review also identifies current research gaps around the development of more efficient, durable, and sustainable ionic liquid-based adsorption systems for water purification. The major implication of developing ionic liquid-based aqueous-phase adsorbents is to promote green chemistry at the laboratory scale and aspire for green chemical process engineering in real-world water remediation systems using such a material that has the requisite selectivity and durability.

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To promote environment-friendly hydrogen generation through water electrolysis, high-performance, inexpensive electrocatalysts abundant in earth elements that do not depend on valuable metals and expensive materials are required. In the present work, the hydrothermal procedure was utilized to prepare CoS/MnO₂ composite and physical characterization methods were applied to study the crystal structure, shape and textual characteristics as well. The increased surface area and smaller crystallite size of CoS/MnO₂ composite demonstrate increased active sites for the oxygen evolution process. Nevertheless, electrocatalytic efficiency and stability for OER under basic medium have been demonstrated by different electrochemical studies. The produced catalyst revealed an overpotential η (261 mV), a low Tafel gradient (39 mV/dec) to acquire 10 mA/cm² current density (j) and low solution resistance (R_s) value (2.45 Ω) for CoS/MnO₂ composite than the distinct CoS and MnO₂. Additionally, the CoS/MnO₂ composite displayed outstanding stability, exhibiting an oxygen evolution reaction (OER) efficiency for over 50 h and maintaining a low reduction in activity even after 2500th CV cycles. These outcomes promote their capability in energy conversion as well as storage techniques.

Environmentally, different types of adsorbents were investigated for the removal of organic substrate in aqueous solution. The adsorption of acetone (AC, CH₃)₂CO) by nano-zero iron supported onto zeolite (NZIZ) and supported onto carbon zeolite (NZICZ) was directed through batch adsorption process. The new adsorbents were prepared via the reduction method for the ferric sulfate hex hydrate by using sodium borohydride as reducing agent. Both of the adsorbents were described by the Fourier transform infrared spectroscopy (FTIR), the Brunner–Emmett–Teller (S_BET), and X-ray powder diffraction (XRD). The (S_BET) surface area of the adsorbents was viewed with values of 118.54 m²/g and 183.63 m²/g for NZI/Z and NZI/CZ, respectively. The adsorption process accomplished after 60 min and 100 min for NZI/Z and NZI/CZ, respectively, with initial concentration of 20 mg/l of (AC) solution. The pH for the adsorption process was ranged from 2 to 10. The uptake of the (AC) evacuation was higher for the carbon-coated adsorbent with a value of 57.84 mg/g in comparison with non-coated adsorbent with uptake value of 47.28 mg/g. The isotherm studies were performed at different concentrations of AC ranging from 10 to 40 mg/l. The Langmuir and Freundlich isotherm models were used to fit the adsorption studies of the process. The higher value of the adsorption coefficient (R²) is 0.9987 for Freundlich rather than Langmuir for fixing the result of multilayer adsorption as a result for the carbon layer development. The kinetic studies were carried out via the pseudo-second and pseudo-first order which were more fitting the adsorption of AC onto NZI/CZ. Subsequently, the adsorption of AC onto the carbon-covered adsorbent was demonstrated as well-accepted and an affected adsorbent for the removal of AC from the aqueous solution.

The eye is one of the most important and sensitive organs of the human body that is naturally protected by the membrane and vascular barriers. Although these barriers protect the eye effectively, different types of diseases such as age-related macular degeneration (AMD), diabetic macular edema (DME), cataract, proliferative vitreoretinopathy (PVR), uveitis, cytomegalovirus (CMV), and glaucoma and other physiological factors affect the posterior and anterior portions of the eye. Effective ocular drug delivery is still a major and serious challenge in the medical field. Conventional methods are not efficient due to many limitations including low ocular bioavailability of drugs, low levels of drugs in the ocular tissue and washed-off drugs from the eye in a very short period of time. The use of nanotechnology to design drug delivery systems to achieve controlled release as well as penetration of protective barriers has been promising. In the past decades, different types of nano-scaled ocular drug delivery systems have been developed. Some of these nano-systems are effective for drug delivery to the anterior and some of them to the posterior segment. In this article, the authors reviewed and discussed the efficiency and effectiveness of different types of nanoscale ocular drug deliveries with their advances and challenges.

Here, we conducted the synthesis of carbon-based adsorbents derived from an expired instant noodle product for the removal of sulfadiazine. ZnCl₂ was used as an effective activator at different impregnation ratios (1:4, 1:2, 1:1, and 3:2, w/w) to create activated carbons. We found that ZnCl₂ activation brought a porous structure and increased structural defect. Batch adsorption was performed to evaluate the effect of contact time (0–120 min), dosage (0.25–1.0 g/L), pH (3–9), and SDZ concentration (2.5–20 mg/L). Equilibrium sulfadiazine adsorption was mostly achieved at 60 min and pH 7. Chemisorption and monolayer adsorption might play key roles in sulfadiazine adsorption. The adsorbent activated at an impregnation ratio of 1:1 showed a Q_m of 51 mg/g. Thus, this work suggests that the strategy of converting expired food waste into adsorbents can be feasible to alleviate water contamination caused by pharmaceuticals.