Search Results (23)

As eco-friendly processes become central to modern organic synthesis, plant-based materials are emerging as attractive alternatives for both nanoparticle fabrication and catalysis. In this study, we explore the use of clove extract, a natural and renewable resource, for the green synthesis of copper oxide (CuO) nanoparticles and their subsequent application in organic transformations. Clove extract was employed to reduce copper chloride via a simple co-precipitation method under mild conditions, yielding CuO nanoparticles characterized by XRD, FTIR, and SEM-EDX techniques. These nanoparticles were then used as catalysts in the copper-catalyzed azide–alkyne cycloaddition (CuAAC) to afford eugenol-based 1,2,3-triazoles in excellent yields. This dual use of clove extract exemplifies a sustainable approach that merges natural product valorization with efficient catalysis for triazole synthesis. Full article

Organic soil pollution poses a persistent threat to environmental sustainability by disrupting nutrient cycling and ecosystem functioning. The biochar-activated persulfate (PS)-based advanced oxidation process (AOP) has emerged as a promising strategy for the sustainable remediation of organic-contaminated soils. This review provides a comprehensive overview of the recent progress in the PS-based degradation of organic pollutants, with a particular focus on the role of biochar as an efficient and environmental activator. This review further summarizes advancements in the design of modified biochars, including metal (Fe, Cu, Co, Mn, Zn, and La), non-metal (N, S, B, P), and functional group modifications, aimed at enhancing the PS activation efficiency while minimizing secondary environmental risks. Importantly, the overlooked contributions of soil microorganisms in PS/biochar systems are discussed, highlighting their potential to complement chemical oxidation and contribute to eco-compatible remediation pathways. This review emphasizes the sustainability-oriented evolution of PS/biochar technology, highlighting the importance of a cost-efficient implementation, ecological compatibility, and the rational engineering of smart, regenerable catalysts. These insights support the advancement of PS/biochar-based AOPs toward scalable, intelligent, and environmentally sustainable soil remediation. Full article

Contaminants of emerging concern (CECs) in water, including pharmaceuticals and personal care products, represent a significant threat to environmental and human health. In this context, the electro-Fenton (EF) process has emerged as a highly effective technique for the removal of such pollutants. This study investigates the innovative use of tea waste material (TWM) in combination with copper-iron nanoparticles (FeCuNPs) to degrade a mixture of CECs. A central aspect of this research is the sustainable reuse of organic waste material, such as TWM, to support catalytic nanoparticles. This approach not only utilizes a resource that would otherwise be discarded but also promotes sustainability in the treatment of contaminated water, aligning with the principles of the circular economy. The as-prepared FeCuNPs@TWM catalyst was fully characterized, and critical parameters influencing the pollutant removal were assessed, including adsorption capacity, catalyst load, and applied current. Under optimized conditions, the EF process, enhanced by FeCuNPs@TWM, achieved complete degradation of the contaminants within 15 min of the electrochemical process, and the activity remained after five catalytic cycles. Results demonstrate that using tea waste functionalized with FeCu nanoparticles as a catalyst not only improves the efficiency of the EF process but also offers an eco-friendly and cost-effective alternative. Full article

Microwave plasma-driven nitrogen fixation can occur at atmospheric pressure without complex processing conditions. However, this method still faces the challenge of high energy consumption and low production. Combined plasma–catalyst systems are widely used to increase production and reduce energy consumption in nitrogen fixation. However, the efficacy of currently used catalysts remains limited. In this paper, the metal–organic framework materials (MOFs) copper benzene-1,3,5-tricarboxylate (Cu-BTC) and zeolitic imidazolate framework-8 (ZIF-8) are combined with atmospheric microwave plasma for nitrogen fixation. The experimental results show that they have a better catalytic effect than the ordinary catalyst zeolite socony mobil-5 (ZSM-5). The maximum nitrogen oxide concentration reaches 33,400 ppm, and the lowest energy consumption is 2.05 MJ/mol. Compared to no catalyst, the production of nitrogen oxides (NO_x) can be increased by 17.1%, and the energy consumption can be reduced by 14.6%. The stability test carried out these catalysts demonstrates that they have a stable performance within one hour. To the knowledge of the authors, this is the first effort to study the synergistic effects of atmospheric microwave plasma and MOFs on nitrogen fixation. This study also introduces a potentially eco-friendly approach to nitrogen fixation, characterized by its low energy consumption and emissions. Full article

Recalcitrant compounds resulting from anthropogenic activity are a significant environmental challenge, necessitating the development of advanced oxidation processes (AOPs) for effective remediation. This study explores the synthesis of cuprous oxide nanoparticles on cellulose-based paper (Cu₂O@CBP) using Eucalyptus globulus leaf extracts, leveraging green synthesis techniques. The scanning electron microscopy (SEM) analysis found the average particle size 64.90 ± 16.76 nm, X-ray diffraction (XRD) and Raman spectroscopy confirm the Cu₂O structure in nanoparticles; Fourier-transform infrared spectroscopy (FTIR) suggests the reducing role of phenolic compounds; and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis DRS) allowed us to determine the band gap (2.73 eV), the energies of the valence band (2.19 eV), and the conduction band (−0.54 eV) of Cu₂O@CBP. The synthesized Cu₂O catalysts demonstrated efficient degradation of methylene blue (MB) used as a model as recalcitrant compounds under LED-driven visible light photocatalysis and heterogeneous Fenton-like reactions with hydrogen peroxide (H₂O₂) using the degradation percentage and the first-order apparent degradation rate constant (k_app). The degradation efficiency of MB was pH-dependent, with neutral pH favoring photocatalysis (k_app = 0.00718 min⁻¹) due to enhanced hydroxyl (·OH) and superoxide radical (O₂·⁻) production, while acidic pH conditions improved Fenton-like reaction efficiency (k_app = 0.00812 min⁻¹) via ·OH. The reusability of the photocatalysts was also evaluated, showing a decline in performance for Fenton-like reactions at acidic pH about 22.76% after five cycles, while for photocatalysis at neutral pH decline about 11.44% after five cycles. This research provides valuable insights into the catalytic mechanisms and supports the potential of eco-friendly Cu₂O nanoparticles for sustainable wastewater treatment applications. Full article

Hydrotalcite-derived materials are eco-friendly, cheap, and efficient catalysts of different reactions. However, their application in liquid-phase hydrogenation could be more extensive. Hence, this work concerns the application of three hydrotalcite-derived materials with different CuZnAl molar ratios in the liquid-phase continuous-flow hydrogenation of 2-methyl-2-pentenal (MPEA) at a wide range of temperature (298–378 K) and pressure (1 × 10⁶–6 × 10⁶ Pa). The catalytic investigations were supported by catalysts characterization by ICP-OES, TPR, in situ XRD, XPS, NH₃-TPD, CO₂-TPD, and TEM measurements on different stages of their biography. It was shown that the catalytic activity of these samples is related to the Cu⁰/Cu⁺ ratio. Depending on the reaction conditions, selectivity control is possible. All catalysts were 100% selective to 2-methylpentanal (MPAA)—sedative drug precursor, with low conversion, at temperatures ≤ 338 K at every pressure. However, the selectivity of the second desired product, fragrance intermediate, 2-methyl-2-penten-1-ol (MPEO), increased significantly at higher temperatures and pressures. It reached the unique value of 54% with 60% substrate conversion at 378 K and 6 × 10⁶ Pa for the catalyst with the highest Cu loading. It was revealed that the production of significant amounts of MPEO is related to the reaction conditions, the Cu⁺ predominance on the surface, the hydrogen spillover effect, and the acid–base properties of these systems. Full article

This study explores an eco-friendly method for recovering platinum group metals from a synthetic automotive three-way catalyst (TWC). Bioleaching of palladium (Pd) using the thiosulfate-copper-ammonia leaching processes, with biogenic thiosulfate sourced from a bioreactor used for biogas biodesulfurization, is proposed as a sustainable alternative to conventional methods. Biogenic thiosulfate production was optimized in a gas-lift bioreactor by studying the pH (8–10) and operation modes (batch and continuous) under anoxic and microaerobic conditions for 35 d. The maximum concentration of 4.9 g S₂O₃²⁻ L⁻¹ of biogenic thiosulfate was reached under optimal conditions (batch mode, pH = 10, and airflow rate 0.033 vvm). To optimize Pd bioleaching from a ground TWC, screening through a Plackett–Burman design determined that oxygen and temperature significantly affected the leaching yield negatively and positively, respectively. Based on these results, an optimization through an experimental design was performed, indicating the optimal conditions to be Na₂S₂O₃ 1.2 M, CuSO₄ 0.03 M, (NH₄)₂SO₄ 1.5 M, Na₂SO₃ 0.2 M, pH 8, and 60 °C. A remarkable 96.2 and 93.2% of the total Pd was successfully extracted from the solid at 5% pulp density using both commercially available and biogenic thiosulfate, highlighting the method’s versatility for Pd bioleaching from both thiosulfate sources. Full article

The chemical recycling of used motor oil via catalytic cracking to convert it into secondary diesel-like fuels is a sustainable and technically attractive solution for managing environmental concerns associated with traditional disposal. In this context, this study was conducted to screen basic and acidic-aluminum silicate catalysts doped with different metals, including Mg, Zn, Cu, and Ni. The catalysts were thoroughly characterized using various techniques such as N₂ adsorption–desorption isotherms, FT-IR spectroscopy, and TG analysis. The liquid and gaseous products were identified using GC, and their characteristics were compared with acceptable ranges from ASTM characterization methods for diesel fuel. The results showed that metal doping improved the performance of the catalysts, resulting in higher conversion rates of up to 65%, compared to thermal (15%) and aluminum silicates (≈20%). Among all catalysts, basic aluminum silicates doped with Ni showed the best catalytic performance, with conversions and yields three times higher than aluminum silicate catalysts. These findings significantly contribute to developing efficient and eco-friendly processes for the chemical recycling of used motor oil. This study highlights the potential of basic aluminum silicates doped with Ni as a promising catalyst for catalytic cracking and encourages further research in this area. Full article

ZIF-8 and ZIF-67 containing various percentages of copper were successfully synthesized through a green in-situ thermal (IST) approach based on 2-methylimidazole (2-MIM) as the organic linker. The IST method has several advantages over previously reported studies, including solvent and additive-free reaction conditions, a mild reaction temperature, a single-step procedure, no activation requirements, and the use of the smallest precursor ratio (M/L). The high catalytic performance of Cu/ZIF-8 and Cu/ZIF-67 in click chemistry is attributed to their high specific surface area, excellent porosity, and structural stability. To achieve these features, a range of parameters—such as time, temperature, gas atmosphere, and precursor ratio—were optimized. Several characterization methods were used to confirm the features of the produced catalysts. Overall, the synthesis strategy for achieving the targeted ZIFs with unique features is “green” and does not require further activation or treatment to eliminate side products. This method has great potential for manufacturing metal-organic frameworks on a large scale. Moreover, water was used as a solvent during the click reaction, resulting in high yields and making this an attractive, green, and eco-friendly procedure. Full article

In this study, oxidized maltodextrins with a high concentration of carboxyl groups were produced using CuSO₄ as a catalyst and H₂O₂ as an eco-friendly oxidant. Infrared spectroscopy, proton-nuclear magnetic resonance spectroscopy, and thermogravimetric analysis were utilized to examine the structure and properties of oxidized maltodextrins. The reaction conditions were optimized in terms of oxidant content, catalyst content, temperature, pH, and reaction time. The prepared oxidized maltodextrin had a carboxyl group content of 105% under the conditions of 200% molar H₂O₂, 1% molar catalyst, 55 °C, initial pH = 9.7, and 2 h reaction time. In comparison to the commonly used sodium hypochlorite oxidation process, the carboxyl group content was increased by 58%. Full article

Herein, the aqueous extract of Portulaca oleracea has been used as a safe, cheap, eco-friendly, and applicable scale-up method to bio-fabricate copper oxide nanoparticles (CuO-NPs). The character of CuO-NPs were determined using UV-vis spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray(EDX), Dynamic light scattering (DLS), and zeta potential. Spherical and crystalline CuO-NPs with a size range of 5–30 nm at a maximum surface plasmon resonance of 275 nm were successfully fabricated. The main components of the green-synthesized particles were Cu and O with weight percentages of 49.92 and 28.45%, respectively. A Zeta-potential value of −24.6 mV was recorded for CuO-NPs, indicating their high stability. The plant-based CuO-NPs showed promising antimicrobial and catalytic activity in a dose-dependent manner. Results showed that the synthesized CuO-NPs had the efficacy to inhibit the growth of pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans with low MIC values in the ranges of 6.25–25 µg/mL. The highest decolorization percentages of tanning wastewater were attained under sunlight irradiation conditions at a concentration of 2.0 mg/mL after 200 min with percentages of 88.6 ± 1.5% compared to those which were recorded under dark conditions (70.3 ± 1.2%). The physicochemical parameters of tanning wastewater including total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), biological oxygen demand (BOD), and conductivity under optimum conditions were significantly decreased with percentages of 95.2, 86.7, 91.4, 87.2, and 97.2%, respectively. Interestingly, the heavy metals including cobalt (Co), lead (Pb), nickel (Ni), cadmium (Cd), and chromium (Cr (VI)) decreased with percentages of 73.2, 80.8, 72.4, 64.4, and 91.4%, respectively, after treatment of tanning wastewater with CuO-NPs under optimum conditions. Overall, the plant-synthesized CuO-NPs that have antimicrobial and catalytic activities are considered a promising nano-catalyst and environmentally beneficial to wastewater treatment. Full article

Transfer hydrogenation (TH) is considered as one of the most promising ways to convert biomass into valuable products. This study aims to demonstrate the performance of high-loaded Ni-based catalysts in the TH of phenolic compounds such as guaiacol and dimethoxybenzenes. The experiments were carried out under supercritical conditions at 250 °C using 2-PrOH as the only hydrogen donor. Ni-SiO₂ and NiCu-SiO₂ were synthesized using the eco-friendly original method based on supercritical antisolvent coprecipitation. It has been found that guaiacol is rapidly converted into 2-methoxycyclohexanol and cyclohexanol, while the presence of Cu impedes the formation of the latter product. Transformations of dimethoxybenzene position isomers are slower and result in different products. Thus, 1,3-dimethoxybenzene loses oxygen atoms transform into methoxycyclohexane and cyclohexanol, whereas the saturation of the aromatic ring is more typical for other isomers. The Cu addition increases specific catalytic activity in the TH of 1,2-and 1,3-dimethoxybenzene compared to the Cu-free catalyst. Full article

Using a semiconductor catalyst with sunlight can make the photodegradation of pollutants an economically viable process since solar energy is an abundant natural energy source. Solar photocatalysis can provide clean and green eco-friendly technology for the analysis of industrial effluents. Photocatalytic deterioration of the aqueous solution of malachite green oxalate dye (MGO dye) was studied using gelatin–cerium–copper sulphide (Ge-Ce-CuS) nanoparticles under the sunlight source. The nanoparticles were synthesised by a hydrothermal process. The structural properties of the nanoparticles have been characterised by XRD, SEM, EDS, HR-TEM, and XPS. The effects of the initial concentration of dye, dosage of photocatalyst, reaction time, and pH on dye removal efficiency were studied. The mineralisation of MGO dye has been confirmed by chemical oxygen demand (COD) measurements. The reusability of the catalyst was proved. The antibacterial activity has been studied for the synthesised nanoparticles. The higher photocatalytic degradation efficiency of Ge-Ce-CuS is explained by its reduced electron-hole recombination and sunlight activity. Full article

In this study, a biosorption system for nickel (Ni²⁺) and copper (Cu²⁺) removal by selected exopolymeric substance-producing bacterial strains was evaluated from the perspective of water remediation. A preliminary screening in a biofilm-based filtration system allowed the selection of two best-performing Serratia plymuthica strains for specific Ni²⁺ and Cu²⁺ removal from synthetic solutions, as well as the definition of the optimal growth conditions. Further tests were conducted in a planktonic cell system in order to evaluate: (i) the effect of contact time, (ii) the effect of initial metal concentration, and (iii) the effect of biomass dose. S. plymuthica strain SC3I(2) was able to remove 89.4% of Ni²⁺ from a 50 mg L⁻¹ solution, and showed maximum biosorption capacity of 33.5 mg g⁻¹, while S. plymuthica strain As3-5a(5) removed up to 91.5% of Cu²⁺ from a 200 mg L⁻¹ solution, yielding maximum biosorption capacity of 80.5 mg g⁻¹. Adsorption equilibria of both metals were reached within 30 min, most of the process occurring in the first 2–4 min. Only Ni²⁺ biosorption data were adequately described by Langmuir and Freundlich isothermal models, as Cu²⁺ was in part subjected to complexation on the exopolymeric substances. The capability of the exopolymeric substances to stably coordinate a transition metal as Cu²⁺ offers the possibility of the eco-friendly re-use of these new hybrid systems as catalysts for application in addition reaction of B₂(pin)₂ on α,β-unsaturated chalcones with good results. The systems formed by biomass and Ni²⁺ were instead evaluated in transfer hydrogenation of imines. The biosorption performances of both strains indicate that they have the potential to be exploited in bioremediation technologies and the obtained organo–metal complexes might be valorized for biocatalytic purposes. Full article

Dimethyl carbonate is a generally used chemical substance which is environmentally sustainable in nature and used in a range of industrial applications as intermediate. Although various methods, including methanol phosgenation, transesterification and oxidative carbonylation of methanol, have been developed for large-scale industrial production of DMC, they are expensive, unsafe and use noxious raw materials. Green production of DMC from CO₂ and methanol is the most appropriate and eco-friendly method. Numerous catalysts were studied and tested in this regard. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. Electron-assisted activation of CO₂ and membrane reactors which can separate products in real-time giving a maximum yield of DMC are also being used in the quest to find more effective production method. In this review paper, we deeply addressed green production methods of DMC using Zr/Ce/Cu-based nanocomposites as catalysts. Moreover, the relationship between the structure and activity of catalysts, catalytic mechanisms, molecular activation and active sites identification of catalysts are also discussed. Full article