Current Research in Green and Sustainable Chemistry最新文献

TiO₂ nanomaterial photocatalysts for energy and environmental applications have attracted the interest of researchers in recent decades. The broad bandgap (3–3.2 eV), which limits the quantity of light absorption, and the relatively high charge-carrier recombination, which limits photocatalytic activity, are the key bottlenecks. The discovery of black TiO₂ in 2011 sparked global research attention and renewed optimism for solving this challenge. The presence of defects such as Ti³⁺ species and oxygen vacancies at the surface of black TiO₂ nanostructures – so called due to the color assumed by the oxide following a reduction process - is responsible for enhancing the optical absorption of UV to visible light. This review focuses on recent advancements in the development of black TiO₂ nanomaterials, including description of the synthesis processes, focused on plasma and thermal methods to convert TiO₂ to black TiO₂, discussion of black TiO₂ properties, and diverse applications of black TiO₂, and concludes by addressing some essential concerns that must be tackled to unleash the desired future developments, particularly for solar energy production and pollutants decomposition.

In this study, the choice of supercritical fluid extraction as a renewable alternative for extracting orange peel essential oil (OPEO) was motivated by concerns about sustainability with conventional solvent extraction methods. The physical and chemical characteristics of OPEO were examined to assess its potential as a sustainable resource. The extraction process was optimised, and the ideal conditions determined were 317.51 min of extraction time at 74.85 °C with a solvent-to-sample ratio of 4. Analysis of the extracted OPEO revealed significant values for saponification (121.67 mg KOH/g), acid (4.13 mg KOH/g), ester (117.54 mg KOH/g), and free fatty acid (1.56 mg KOH/g) content, demonstrating its composition. Notably, key ingredients such as Limonene (43.96%), α-pinene (15.60%), β-myrcene (10.21%), γ-terpinene (5.00%), and α-terpineol (4.15%) were found in high proportions according to chemical composition analysis. Furthermore, OPEO exhibited excellent antioxidant properties with an IC50 value of 7.73 ± 2.00 mg/mL and displayed notable antimicrobial activity against various microorganisms, including P. aeruginosa (17.7 ± 0.6 mm), E. coli (11.0 ± 0.0 mm), K. pneumoniae (10.7 ± 0.6 mm), and S. aureus (10.3 ± 0.6 mm). These findings have significant implications for the flavor and fragrance sector, as well as for the food preservation industry.

Disposing wastewater from textile industries and dyes into water bodies has aesthetic effects on the nature of water, it can also cause serious adverse environmental impacts on the water ecosystem by reducing sunlight penetration and photosynthetic reactions. Adsorption is one of the most common methods for removal of toxic pollutants due to its easy and cheap operation. Using agricultural waste to prepare cheap and simple adsorbents is an alternative method for commercial carbons. In this research, a cost-effective adsorbent was fabricated from palm leaf agricultural waste during two stages of carbonization and modification with acid. XRD and FTIR analyses were used to characterize the carbon-based adsorbent. The funding indicated that the removal performance of methylene blue at an initial concentration of 25 mg/L is about 99.6 % after 60 min of reaction at solution pH 7. However, the highest adsorption capacity of 175.6 mg/g was achieved at the adsorbent dose of 25 mg. The adsorption isotherm and kinetics evaluation indicated that the adsorption of methylene blue on the adsorbent prepared from palm leaf waste is chemical heterogeneous adsorption. The findings of the present research promise the development of a cost-effective adsorbent from agricultural waste to remove dye compounds from industrial wastewater at near-neutral conditions.

Silica aerogels are outstanding insulation materials, and applying them as building insulation could significantly enhance the energy efficiency of dwellings. However, the current high price of aerogels hinders their use on large scales, in part due to the embedded costs of production such as raw materials and their energy-intensive drying process. This study proposes a method relying on the upcycling of waste mixed fine soda lime glass as a silica source for subsequent aerogel synthesis via ambient pressure drying (APD). The optimal conditions for the dissolution of silica from waste glass were found to be a 24-h reaction with a 4 M NaOH solution under 80 °C and a liquid-to-solid ratio of 10. The investigation of silica dissolution considers the balance between the yield of silica and the practical scalability. The resulting aerogel is hydrophobic, has a thermal conductivity of 26 mW m⁻¹ K⁻¹, a specific surface area of 608 m² g⁻¹, and a density of 121 kg/m³. These properties are comparable to commercial aerogel, and to a reference aerogel made from commercial sodium silicate. Additionally, the heat treatment of aerogel at 500 °C for 4 h further improved its properties, suggesting a potential for targeted property enhancements.

Corrosion has produced unprecedented disintegration of metals, constituting an imminent danger to mankind and triggering catastrophic global economic losses. The effectiveness of expired clindamycin (ECLI) as a low-cost corrosion control agent for mild steel was investigated utilising response surface methodology (RSM), artificial neural network (ANN), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), quantum chemical computation (QCC), and molecular dynamic simulation (MDS) studies in conjunction with thermometric and gasometric protocols at different HCl concentrations. The RSM model demonstrated an outstanding level of accuracy in predicting the mild steel corrosion inhibition efficiency (IE), the volume of hydrogen gas (VHG), reaction number (RN), and corrosion rate (CR). The model was significantly influenced by the operational parameters that were investigated, such as temperature (299–333 K), ECLI concentrations (100–500 mg/L), immersion time (1–6 h), and acid concentration (0.5–2.5 M). It was observed that as ECLI concentration increases, the VHG, RN, and CR decreased per time as well as % IE increased. The thermometric, gasometric, PDP, and EIS results showed percentage inhibition efficiency of 69.10, 69.49, 83.17, and 77.87 %, respectively. PDP revealed that ECLI operates as a mixed type of inhibitor, and EIS indicated that the inhibition process involves charge transfer. The Langmuir isotherm suits better and accurately describes the ECLI adsorption process on mild steel. The electron transfer propensity of the ECLI on the metal surface is measured by QCC using the DFT approach. MDS was implemented to establish the optimal adsorption orientation between ECLI and Fe (110). The inspection of surface morphology by SEM displayed the formation of a blanket-like layer on the steel by ECLI. To validate the experimental results, RSM and ANN prediction models were utilised, which were evaluated using a normal plot of residual, predicted versus actual, and residual versus run, and were found to be effective modelling tools. This study illustrates that ECLI can be utilised as a potent and affordable mild steel inhibitor, even at high acid concentrations.

In this study, iron oxide biochar nanocomposites made from khat leftover (KL) and coffee husk (CH) are investigated as possibly useful adsorbents for the removal of Cr (VI) from water. Biochar-based iron oxide nanocomposites were synthesized by pretreating 25 g of biomass with a 1:1 M ratio of FeS to FeCl₃ and pyrolyzing at 300 °C for 1 h. Pristine biochar, synthesized through biomass pyrolysis of CH and KL at 300 °C, removed 74.98% and 84.78% of Cr (VI) from aqueous solutions containing 20 mg L⁻¹, respectively. The corresponding nanocomposites showed a maximum removal efficiency for Cr (VI) of 99.83% with the iron oxide-coffee husk biochar nanocomposite (Fe₃O₄–CHBNC) and 99.86% with the iron oxide-khat leftover biochar nanocomposite (Fe₃O₄-KLBNC). A pseudo-second-order model and the Langmuir isotherm are both well-fitted by the adsorption process, suggesting advantageous monolayer adsorption. The Fe₃O₄–CHBNC and Fe₃O₄-KLBNC demonstrated satisfactory removal efficiencies even up to six cycles, indicating their potential effectiveness for large-scale use for treating wastewater contaminated by Cr (VI).

Electroorganic synthesis is a powerful sustainable tool for achieving greener and more efficient chemical processes across various industries. By adhering to the principles of green chemistry, atom economy, and resource efficiency, electroorganic synthesis can play a pivotal role in addressing environmental concerns and promoting a more sustainable future for chemical production. This review focuses on the latest advancements in the emerging application of electrochemistry in C-N bond formation through C-H/N-H cross-coupling. The first part of the review describes the electrochemical amination of arenes using metal catalysis (Cu, Co, Ni) with directing groups on the arene moiety. The next section addresses the same type of electrochemical C-N bond formation on arenes without directing groups, which represents a more general strategy enabling the synthesis of anilines and various heterocyclic-bound arenes in high yields. Further developments on benzylic systems are also discussed. This is followed by developments in the combination of photocatalysis and electrochemistry to activate C-H bonds in arenes, alkanes, and benzylic systems, including the use of flow reactor configurations for these reactions.