Journal of The Chinese Chemical Society最新文献

Rice husk (RH), an abundant agricultural byproduct in rice-producing countries, has emerged as a renewable and cost-effective bioadsorbent for pollutant removal. This study developed an optimized approach to synthesize rice husk-based biochar (RHB) for the adsorption of Cu(II) and Mn(II) ions in aqueous solutions. The obtained adsorbent was characterized using SEM-EDS and Brunauer–Emmett–Teller (BET) analysis. The effects of three independent variables—RH particle size (X₁), pyrolysis temperature (X₂), and pyrolysis time (X₃)—on the physicochemical properties of RHB were indirectly studied through the adsorption capacity of Cu(II) and Mn(II) using response surface methodology (RSM) combined with central composite design (CCD). The optimum synthesis conditions were achieved at X₁ = 0.88 mm, X₂ = 444°C, and X₃ = 140 min, resulting in the highest removal efficiencies for Cu(II) of 73.1% and Mn(II) of 61.3%. The large values of R² (≥0.9792), R² adjusted (≥0.9605), R² predicted (≥0.9035), and small probability values (p-value < 0.0001) demonstrated a strong agreement between the experimental data and the quadratic model predictions. The main effects ranked were pyrolysis temperature (p-value < 0.0001), and pyrolysis time (p-value ≤ 0.0001), followed by RH particle size (p-value ≤ 0.0525).

Focus of the Picture: To advance chemical research and foster international collaboration, the “Taiwan-Japan Bilateral Symposium on the Architecture of Functional Organic Molecules” was co-initiated by Professors Tahsin J. Chow (Academia Sinica, Taiwan) and Teruo Shinmyozu (Kyushu University, Japan). To commemorate its 20th anniversary, 16 past symposium lecturers were invited to share advances in organic materials, covering synthesis, spectroscopy, optical and photophysical studies, supramolecular interactions, and photoelectronic devices. This special issue highlights cutting-edge developments and honors the symposium's role in fostering rich academic exchanges, supporting ongoing collaboration and future breakthroughs in organic materials research.

Although Carbon Fiber Reinforced Polymers (CFRPs) are recognized for their remarkable strength-to-weight ratio, their overall performance is sometimes limited by the thermal and mechanical constraints of traditional epoxy resins. This study directly targets these deficiencies by developing a next-generation composite based on an advanced epoxy-phenolic resin matrix. This complicated matrix functions as the high-performance basis of our system, chosen expressly for its superior heat stability, chemical resistance, and toughness relative to conventional epoxies. Initiating with a more substantial matrix yields a more durable composite from the beginning. We are using wood-derived biochar as a sustainable, useful filler to enhance this system. This work examines the potent synergistic interactions among three essential components: the reinforcing carbon fibers, the durable epoxy-phenolic matrix, and the multifunctional biochar. Our study entails precisely regulated pyrolysis to generate superior biochar and a comprehensive examination of its effects on the composite's interfacial dynamics and overall efficacy. This study seeks to illustrate how biochar, incorporated inside a meticulously chosen epoxy-phenolic matrix, may substitute industrial carbon black. The objective is to develop ecologically friendly, high-performance composites with improved mechanical properties and functions, aiding in the achievement of net-zero carbon emission goals.

Li⁺ adsorption from brine water by lithium manganese oxide ion sieve (LMO) has become one of the most promising methods due to the high efficiency and selectivity towards lithium ion. However, the dissolution loss of Mn affects its structural stability and thus seriously limits its practical application. In this study, a novel approach of two-step hydrothermal oxidation technique where H₂O₂ and NaClO as the oxidants for the first step and the second step oxidation, respectively, is developed to fabricate nanostructured LMO (N-LMO) with particle size of 20–45 nm. Influences of synthesis conditions in the first-step H₂O₂ oxidation and the second-step NaClO oxidation on the lithium adsorption of N-HMO prepared by N-LMO acid leaching were investigated. Selectivity behavior towards lithium ion of N-HMO was also studied. FTIR, FESEM, XPS, and XRD were used to characterize the structure and morphology of N-LMO. Porous and nanostructures produced by two-step hydrothermal oxidation increase the exposure of adsorption sites, which significantly accelerates the deintercalation and intercalation of Li⁺ from vacancies in the framework. N-HMO has high Li⁺ adsorption capacity of 31.5 mg/g. Adsorption capacity for Li⁺ remains at 85.7% after 5 recycles, indicating stable structure and good cycling performance of N-HMO in the process of adsorption–desorption, due to the fact that the second-step NaClO oxidation can transform some Mn³⁺ into Mn⁴⁺. The distribution coefficient (K_d) of Li⁺ (874.21) is significantly higher than those of other competing metal ions (Na⁺: 23.17, K⁺: 22.51, Ca²⁺: 30.89, Mg²⁺: 70.22). Moreover, the concentration factor C_F of Li⁺(608.3) is much higher than that of other metal ions, indicating that lithium adsorption is hardly interfered by other competitive metal ions, and thus lithium is recovered from brine with high selectivity. This research develops an efficient and novel strategy for the synthesis of nanostructured LMO with simple and mild conditions via a two-step hydrothermal oxidation method, eliminating the requirement for complicated, time-consuming and high-energy consumption for conventional calcination method, and the prepared N-HMO has great potential application in recovering lithium ion from brine sources due to its high structural stability and high selectivity towards lithium ion.

Deep-red emitters have attracted considerable attention in the biomedical field owing to their strong tissue penetration, good biocompatibility, and potential to promote cellular activation and repair. However, many deep-red molecules suffer from low photoluminescence quantum yields (PLQYs) due to dipole–dipole quenching, which limits their performance. To address this, we employed an aggregation-induced emission (AIE) strategy, which offers high brightness, large Stokes shifts, and resistance to aggregation-caused quenching (ACQ). Four donor–acceptor (D–A)- type compounds (5a–5d) were synthesized, featuring carbazole as the electron donor, which enhances molecular rigidity by restricting bond rotation, and 2-oxo-4-phenyl-2,5-dihydrofuran-3-carbonitrile as the electron acceptor to achieve red-shifted emission. The four molecules differ in their π-conjugated linkers, enabling investigation of the effect of molecular planarity on photophysical properties. In solution, their maximum emission wavelengths were 535.0, 638.4, 652.0, and 643.0 nm, respectively, while in thin films, 5a–5c exhibited further red shifts to 654, 699, and 738 nm. Among them, 5a showed the highest fluorescence intensity under UV excitation in the solid state. All compounds displayed twisted intramolecular charge transfer (TICT) behavior in high-polarity solvents, and AIE measurements revealed that only 5a and 5c possessed distinct AIE characteristics. Single-crystal analyses of 5a and 5b indicated that AIE activity correlates with the dihedral angle between the carbazole and the adjacent aromatic ring; larger dihedral angles reduce π–π stacking upon aggregation and restrict intramolecular bond rotation, thereby promoting AIE. These results provide valuable structural insight for the rational design of high-performance AIE-active deep-red emitters for biomedical and optoelectronic applications.

Meloxicam (MEL) is a nonsteroidal anti-inflammatory medication with antipyretic, anti-inflammatory, and analgesic properties. Establishing a sensitive and reliable method to monitor MEL in pharmaceutical formulations is critical to ensure dosing accuracy and guarantee therapeutic efficacy. Herein, a simple electrochemical method was developed for the determination of MEL levels using a TiO₂-Ag-reduced graphene oxide (TiO₂-Ag-rGO) nanocomposite-modified electrode in pH 3.0 Britton–Robinson (BR) buffer via the differential pulse voltammetric (DPV) technique. The prepared TiO₂-Ag-rGO nanocomposite was characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) to analyze its morphology, structure, and composition. It was then coated onto a glassy carbon electrode (GCE) surface to construct the TiO₂-Ag-rGO/GCE. On this modified electrode, the oxidation peak current of MEL centered at 0.65 V showed a notable improvement and was linear with MEL concentrations ranging from 0.5 to 150 μM using optimal parameters. The detection limit calculated for MEL was 15.2 nM (S/N = 3). Application of the method for the assay of MEL in the commercially available tablets form, acceptable deviation from the stated concentration and satisfactory accuracy were obtained.

Chloramphenicol (CAP) is a potent antibiotic banned in many countries due to its serious health risks. Its illicit use in livestock feed can lead to contamination of meat and environmental matrices, underscoring the need for early-stage monitoring in feed and soil. In response, we developed a green electrochemical sensing method based on cyclic voltammetry and disposable screen-printed electrodes (t-SPEs) for the direct detection of CAP. This system achieved a detection limit of 4.0 μg/mL (80 ng) with 85% recovery and demonstrated strong selectivity. To enhance performance, the electrodes were modified with nitrogen-doped graphene quantum dots (N-GQDs), resulting in the SPCE*-(N-GQD) sensor. This modification significantly improved sensitivity, lowering the detection limit to 0.83 μg/mL and increasing recovery rates to 95%–103%. The electrochemical characteristics of the SPCE*-(N-GQD) electrodes were further analyzed to elucidate the mechanisms underlying their enhanced detection capabilities. While the sensitivity of this platform is slightly lower than that of some advanced electrochemical systems, it remains sufficiently robust for routine screening of CAP in livestock feed. Overall, this simple, low-cost, selective, and environmentally friendly approach provides a practical tool for on-site CAP monitoring in agricultural environments.

Fly ash, an industrial by-product generated from coal combustion, poses significant environmental and health hazards. However, its remarkable adsorption behavior for various toxic pollutants can be further enhanced through physical and chemical modifications. Converting fly ash into zeolites not only mitigates disposal challenges but also transforms waste into valuable materials for industrial applications. In this study, fly ash-derived zeolite was modified with poly(ethyleneimine) (PEI) and subsequently used as a template for loading Fe₃O₄ nanoparticles (NPs). The synthesized Fe₃O₄ NPs-decorated PEI-modified zeolite was incorporated with polymeric materials, including polystyrene sulfonate (PSS), polyvinyl alcohol (PVA), and chitosan, to fabricate a magnetic thin film (Fe₃O₄ NPs@PEI-zeolite film). The resulting magnetic and non-magnetic films demonstrated excellent functionality and durability in removing para-nitrophenol (p-NP), a toxic and carcinogenic contaminant. The adsorption mechanism primarily involved electrostatic interactions between protonated functional groups, such as amino groups from chitosan and PEI (N, NH, NH₂), and hydroxyl groups from FeOH, facilitating efficient p-NP removal. Notably, the films exhibited high adsorption efficiency over a broad pH range, indicating their practical applicability. Kinetic studies revealed that the magnetic film followed a pseudo-second-order kinetic model, with faster sorption kinetics than previously reported materials. Furthermore, the adsorption behavior conformed to the Langmuir isotherm model, suggesting a homogeneous monolayer adsorption process. The magnetic film exhibited superior sorption capacity compared to earlier studies, highlighting its potential for effective p-NP treatment.