Search Results (26)

Water pollution is a global concern, especially due to iron and manganese, which, at high concentrations, affect water quality by altering taste, odor, and color. This work explores the sustainable synthesis of hydrochar from orange peel and bagasse using hydrothermal carbonization (HTC) and a 2³ factorial design to optimize Fe²⁺ and Mn²⁺ removal for water treatment polishing. HTC was performed by varying (1) temperature (100–200 °C), (2) residence time (8–14 h), and (3) activation agent (H₃PO₄ or NaOH), with a central point at 150 °C for 11 h without activation. Characterization was performed using FTIR, TGA, SEM, nitrogen adsorption (BET) for surface area determination, elemental analysis, Brønsted acidity measurements, and zeta potential analysis. The hydrochar synthesized at 100 °C for 14 h with NaOH (HC6) showed the best Fe²⁺ and Mn²⁺ removal performance. The equilibrium time was 400 min, with pseudo-first-order kinetics best fitting the Fe²⁺ adsorption data, while pseudo-second-order kinetics provided the best fit for Mn²⁺ adsorption. The adsorption process was best described by the Freundlich and Langmuir isotherms, with maximum adsorption capacities (q_max) of 21.44 and 33.67 mg g⁻¹ for Fe²⁺ and Mn²⁺, respectively. It can be concluded that HTC-derived hydrochars offer a sustainable and efficient solution for Fe²⁺ and Mn²⁺ removal. This strategy presents a potentially valuable approach for sustainable water treatment, offering advantages for industrial application by operating at lower temperatures and eliminating the need for biomass drying, thereby reducing energy consumption and environmental impact. Full article

As a traditional Chinese medicine, the adverse hepatotoxicity effects of Pleuropterus multiflorus (Thunb.) Nakai (PM) have been documented. However, nephrotoxicity has been neglected as studies related to kidney toxicity mechanisms are limited. Our previous research reported that extract D [95% ethanol (EtOH) elution, PM-D] in a 70% EtOH PM extract showed more significant hepatotoxicity than other extracts. In the current study, PM-D was continuously administered to mice for 7 days at a dose of 2 g/kg (equivalent to a human dose of 219.8 mg/kg), which increased renal biochemical indexes and caused pathological kidney injury, suggesting renal toxicity. Therefore, network pharmacology and spatially resolved metabolomics were conducted to explore nephrotoxicity mechanisms underpinning PM-D. Network pharmacology indicated that BCL2, HSP90, ESR1, and CTNNB1 genes were core targets, while the phosphoinositide 3-kinase (PI3K)/protein kinase B(AKT)/signaling pathway was significantly enriched. Spatially resolved metabolomics indicated heterogeneous metabolite distribution in the kidney, further indicating that PM-D nephrotoxic metabolic pathways were enriched for α-linolenic acid and linoleic acid metabolism, pyrimidine metabolism, carnitine synthesis, and branched-chain fatty acid oxidation. Our comprehensive analyses highlighted that nephrotoxicity mechanisms were related to oxidative stress and apoptosis induced by disordered energy metabolism, lipid metabolism issues, and imbalanced nucleotide metabolism, which provide a platform for further research into PM nephrotoxicity mechanisms. Full article

Polyurethanes (PUs) are one of the most versatile polymeric materials, making them suitable for a wide range of applications. Currently, petroleum is still the main source of polyols and isocyanates, the two primary feedstocks used in the PU industry. However, due to future petroleum price uncertainties and the need for eco-friendly alternatives, recent efforts have focused on replacing petrol-based polyols and isocyanates with counterparts derived from renewable resources. In this study, waste cooking oil was used as feedstock to obtain polyols (POs) for new sustainable polyurethane foams (PUFs). POs with various hydroxyl numbers were synthesized through epoxidation followed by oxirane ring opening with diethylene glycol. By adjusting reagent amounts (acetic acid and H₂O₂), epoxidized oils (EOs) with different epoxidation degrees (50–90%) and, consequently, POs with different OH numbers (200–300 mg KOH/g) were obtained. Sustainable PUFs with high bio-based content were produced by mixing the bio-based POs with a commercial partially bio-based aliphatic isocyanate and using water as the blowing agent in the presence of a gelling catalyst and additives. Various water (4, 8, 15 php) and gelling catalyst (0, 1, 2 php) amounts were tested to assess their effect on foam properties. PUFs were also prepared using EOs instead of POs to investigate the potential use of EOs directly in PUF production. Characterization included morphological, chemical, physical, thermal, and mechanical analyses. The rigid PUFs exhibited high density (150–300 kg/m³) and stability up to 200 °C. The combined use of bio-based polyols with partially bio-based isocyanate and water enabled PUFs with a bio-based content of up to 77 wt.%. EOs demonstrated potential in PUF production by bypassing the second synthesis step, enhancing sustainability, and significantly reducing energy and costs; however, PUF formulations with EOs require optimization due to lower epoxy ring reactivity. Full article

Utilizing MgO as the precursor and deionized water as the solvent, this study synthesized nanoparticles of Mg(OH)₂ via hydrothermal methods, aiming to control its purity, particle size, and morphology by understanding its growth under non-uniform nucleation. Characterization of crystal morphology and structure was conducted through scanning electron microscopy and X-ray diffraction, while laser particle size detection assessed the secondary particle size distribution. The study focused on how MgO’s hydrothermal process conditions influence Mg(OH)₂ crystal growth, particularly through ion concentration and release rate adjustments to direct crystal growth facets. These adjustments shifted the dominant growth plane, enhancing the peak intensity ratio I001/I101 from 1.03 to 2.14, thereby reducing surface polarity and secondary aggregation of crystals. The study of the physicochemical properties of the same sample at different times revealed the pattern of crystal dissolution and recrystallization. A 2 h hydrothermal reaction notably altered the particle size distribution, with a decrease in particles sized 0.2~0.4 μm and an increase in those sized 0.4~0.6 μm, alongside new particles over 1 μm, indicating a shift toward uniformity through dissolution and recrystallization. Optimal conditions (6% magnesium oxide concentration, 160 °C, 2 h) led to the synthesis of highly dispersed, uniformly sized magnesium hydroxide, showcasing a simple, eco-friendly, and high-yield process. Full article

A rapid, eco-friendly, and simple method for the synthesis of long-lasting (2 years) silver nanoparticles (AgNPs) is reported using aqueous leaf and petal extracts of Tagetes erecta L. The particles were characterized using UV-Visible spectrophotometry and the analytical and crystallographic techniques of transmission electron microscopy (TEM). The longevity of the AgNPs was studied using UV-Vis and high-resolution TEM. The antibacterial activity of the particles against Erwinia amylovora was evaluated using the Kirby–Bauer disk diffusion method. The results were analyzed using ANOVA and Tukey’s test (p ≤ 0.05). Both the leaf and petal extracts produced AgNPs, but the leaf extract (1 mL) was long-lasting and quasi-spherical (17.64 ± 8.87 nm), with an absorbance of UV-Vis λ_max 433 and a crystalline structure (fcc, 111). Phenols, flavonoids, tannins, and terpenoids which are associated with -OH, C=O, and C=C were identified in the extracts and could act as reducing and stabilizing agents. The best antibacterial activity was obtained with a nanoparticle concentration of 50 mg AgNPs L⁻¹. The main contribution of the present research is to present a sustainable method for producing nanoparticles which are stable for 2 years and with antibacterial activity against E. amylovora, one of most threatening pathogens to pear and apple productions. Full article

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using plants has grown in significance in recent years. ZnO NPs were synthesized in this work via a chemical precipitation method with Jasminum sambac (JS) leaf extract serving as a capping agent. These NPs were characterized using UV-vis spectroscopy, FT-IR, XRD, SEM, TEM, TGA, and DTA. The results from UV-vis and FT-IR confirmed the band gap energies (3.37 eV and 3.50 eV) and the presence of the following functional groups: CN, OH, C=O, and NH. A spherical structure and an average grain size of 26 nm were confirmed via XRD. The size and surface morphology of the ZnO NPs were confirmed through the use of SEM analysis. According to the TEM images, the ZnO NPs had an average mean size of 26 nm and were spherical in shape. The TGA curve indicated that the weight loss starts at 100 °C, rising to 900 °C, as a result of the evaporation of water molecules. An exothermic peak was seen during the DTA analysis at 480 °C. Effective antibacterial activity was found at 7.32 ± 0.44 mm in Gram-positive bacteria (S. aureus) and at 15.54 ± 0.031 mm in Gram-negative (E. coli) bacteria against the ZnO NPs. Antispasmodic activity: the 0.3 mL/mL sample solution demonstrated significant reductions in stimulant effects induced by histamine (at a concentration of 1 µg/mL) by (78.19%), acetylcholine (at a concentration of 1 µM) by (67.57%), and nicotine (at a concentration of 2 µg/mL) by (84.35%). The antipyretic activity was identified using the specific Shodhan vidhi method, and their anti-inflammatory properties were effectively evaluated with a denaturation test. A 0.3 mL/mL sample solution demonstrated significant reductions in stimulant effects induced by histamine (at a concentration of 1 µg/mL) by 78.19%, acetylcholine (at a concentration of 1 µM) by 67.57%, and nicotine (at a concentration of 2 µg/mL) by 84.35%. These results underscore the sample solution’s potential as an effective therapeutic agent, showcasing its notable antispasmodic activity. Among the administered doses, the 150 mg/kg sample dose exhibited the most potent antipyretic effects. The anti-inflammatory activity of the synthesized NPs showed a remarkable inhibition percentage of (97.14 ± 0.005) at higher concentrations (250 µg/mL). Furthermore, a cytotoxic effect was noted when the biologically synthesized ZnO NPs were introduced to treated cells. Full article

This work investigates the potential synthesis of cost-effective polyaluminum chloride (PACl) coagulant from waste household aluminum foil and utilization for treating petroleum wastewater (PWW), especially dissolved organic compounds (DOC, like octanol–water mixture) and nonsettleable suspended (NSS-kaolin) mineral particles. Based on the Standard Practice for Coagulation–Flocculation Jar Test, the efficiency of PACl for DOC and NSS removal was evaluated in relation to the effects of the operational parameters. The results demonstrated that the as-prepared PACl has an amorphous morphology with a Keggin-type e-Al13 molecular structure {Na[AlO₄(OH)₂₄(H₂O)]·xH₂O and good thermal stability up to 278 °C. PACl coagulant also exhibited a higher efficiency for NSS removal than DOC by around 1.5- to 1.9-fold under broad pH (5–7), while a higher acidic/alkaline pH disrupts the sweep floc formation. An increased PACl dosage (over 25 mg/L) also caused a decrease in the coagulation efficiency by 11.7% due to Al species’ transformation and pH depression (from 6.8 to 4.9) via increased PACl hydrolysis. With a fast rotating speed of 280 rpm for 2 min, the minimum dose of PACl (10–25 mg/L) can maximize the removal efficiency of NSS (~98%) and DOC (~69%) at pH 6.5 ± 0.5 and 35 °C after 30 min of settling time. Treating actual saline PWW samples (salinity up to 187.7 g/L) also verified the high efficacy of PACl coagulation performance in reducing the turbidity and dissolved hydrocarbons by more than 75.5% and 67.7%, respectively. These findings verify the techno-economic feasibility of the as-prepared PACl coagulant in treating PWW treatment at different salinity levels. Full article

This paper presents a novel family of jarosites with the molecular formula MFe₃(SO₄)₂(OH)₆·xH₂O; M = Na, K, NH₄ that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. The jarosites have been prepared by conventional heating at temperatures close to 95 °C for 3 h. The synthesis method was improved and optimized to reduce the time and energy consumption. The improved conventional heating method allowed for the synthesis of Na− and K−jarosites with a yield of up to 97.8 wt.% at 105 and 150 °C, respectively, in 3 h. The Na−, K−, and NH₄−jarosites were synthesized at 150 °C in 5 min via a microwave-assisted method, which yielded jarosite crystalline agglomerates with more uniform topography, shape, and size than the conventional method. Both methods allowed the selective synthesis of jarosites. Chemical decomposition of jarosites suspended in water occurred at a pH less than 2 and higher than 10 and temperatures up to 150 °C. In the solid state, the jarosites were thermally stable at least to 300 °C. The Na−jarosite presented a maximum adsorption capacity (Q_max) of 65.6 mg g⁻¹ for As(V) and 94 mg g⁻¹ for Pb(II). The jarosites are considered promising bifunctional adsorbents for the remediation of contaminated water due to their improved synthesis method, stability, and high adsorption capacity for ions of different natures. Full article

The synthesis, structure and photophysical properties of two polynuclear zinc complexes, namely [Zn₆L₂(µ₃-OH)₂(OAc)₈] (1) and [Zn₄L₄(µ₂-OH)₂](ClO₄)₂ (2), supported by tridentate Schiff base ligand 2,6-bis((N-benzyl)iminomethyl)-4-tert-butylphenol (HL) are presented. The synthesized compounds were investigated using ESI-MS, IR, NMR, UV-vis absorption spectroscopy, photoluminescence spectroscopy and single-crystal X-ray crystallography. The hexanuclear neutral complex 1 comprises six-, five- and four-coordinated Zn²⁺ ions coordinated by O and N atoms from the supporting ligand and OH- and acetate ligands. The Zn²⁺ ions in complex cation [Zn₄L₄(µ₂-OH)₂]²⁺ of 2 are all five-coordinated. The complexation of ligand HL by Zn²⁺ ions leads to a six-fold increase in the intensity and a large blue shift of the ligand-based ¹(π-π)* emission. Other biologically relevant ions, i.e., Na⁺, K⁺, Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺ and Cu²⁺, did not give rise to a fluorescence enhancement. Full article

Zero-valent iron nanoparticles (ZVI-NPs) are utilized for the indemnification of a wide range of environmental pollutants. Among the pollutants, heavy metal contamination is the major environmental concern due to their increasing prevalence and durability. In this study, heavy metal remediation capabilities are determined by the green synthesis of ZVI-NPs using aqueous seed extract of Nigella sativa which is a convenient, environmentally friendly, efficient, and cost-effective technique. The seed extract of Nigella sativa was utilized as a capping and reducing agent for the generation of ZVI-NPs. UV-visible spectrophotometry (UV-vis), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared spectroscopy (FTIR) was used to investigate the ZVI-NP composition, shape, elemental constitution, and perspective functional groups, respectively. The biosynthesized ZVI-NPs displayed a peak of plasmon resonance spectra at 340 nm. The synthesized NPs were cylindrical in shape, with a size of 2 nm and (-OH) hydroxyl, (C-H) alkanes and alkynes N-C, N=C, C-O, =CH functional groups attached to the surface of ZVI-NPs. Heavy metals were successfully remediated from industrial wastewater collected from the various tanneries of Kasur. During the reaction duration of 24 h, different concentrations of ZVI-NPs (10 μg, 20 μg and 30 μg) per 100 mL were utilized for the removal of heavy metals from industrial wastewater. The 30 μg/100 mL of ZVI-NPs proved the pre-eminent concentration of NPs as it removed >90% of heavy metals. The synthesized ZVI-NPs were analyzed for compatibility with the biological system resulting in 87.7% free radical scavenging, 96.16% inhibition of protein denaturation, 60.29% and 46.13% anti-cancerism against U87-MG and HEK 293 cell lines, respectively. The physiochemical and exposure mathematical models of ZVI-NPs represented them as stable and ecofriendly NPs. It proved that biologically synthesized NPs from a seed tincture of Nigella sativa have a strong potential to indemnify heavy metals found in industrial effluent samples. Full article

In this paper, electrochemical degradation of Reactive Black 5 (RB5) textile azo dye was examined in regard to different synthesis procedures for making PbO₂–graphitic carbon nitride (g-C₃N₄) electrode. The reaction of $\mathrm{Pb}{\left(\mathrm{OH}\right)}_3^{-}$ with ClO⁻ in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium phosphate (TBAP), under conventional conditions, resulted in the formation of PbO₂ with varying morphology. The obtained materials were combined with g-C₃N₄ for the preparation of the final composite materials, which were then characterized morphologically and electrochemically. After optimizing the degradation method, it was shown that an anode comprising a steel electrode coated with the composite of PbO₂ synthesized using CTAB as template and g-C₃N₄, and using 0.15 M Na₂SO₄ as the supporting electrolyte, gave the best performance for RB5 dye removal from a 35 mg/L solution. The treatment duration was 60 min, applying a current of 0.17 A (electrode surface 4 cm², current density of 42.5 mA/cm²), while the initial pH of the testing solution was 2. The reusability and longevity of the electrode surface (which showed no significant change in activity throughout the study) may suggest that this approach is a promising candidate for wastewater treatment and pollutant removal. Full article

A rapid, cheap and feasible new approach was used to synthesize the Mg_0.375Fe_0.375Al_0.25-LDH in the presence of tetramethylammonium hydroxide (TMAH), as a nontraditional hydrolysis agent, applying both mechano-chemical (MC) and co-precipitation methods (CP). For comparison, these catalysts were also synthesized using traditional inorganic alkalis. The mechano-chemical method brings several advantages since the number of steps and the energy involved are smaller than in the co-precipitation method, while the use of organic alkalis eliminates the possibility of contaminating the final solid with alkaline cations. The memory effect was also investigated. XRD studies showed Fe₃O₄ as stable phase in all solids. Regardless of the alkalis and synthesis methods used, the basicity of catalysts followed the trend: mixed oxides > parent LDH > hydrated LDH. The catalytic activity of the catalysts in the Claisen–Schmidt condensation between benzaldehyde and cyclohexanone showed a linear dependence to the basicity values. After 2 h, the calcined sample cLDH-CO₃²⁻/OH⁻-CP provided a conversion value of 93% with a total selectivity toward 2,6-dibenzylidenecyclohexanone. The presence of these catalysts in the reaction media inhibited the oxidation of benzaldehyde to benzoic acid. Meanwhile, for the self-condensation of cyclohexanone, the conversions to mono- and di-condensed compounds did not exceed 3.8%. Full article

In this study, a homogenizer in conjunction with a two-stage process was utilized to facilitate biodiesel production from waste edible oil (WEO). This paper contributes to the improvement of the yield and the shortening of the reaction time for biodiesel synthesis. Sulfuric acid was used in the first stage which was the esterification of the free fatty acids (FFA) of the WEO; then the transesterification reaction of triglycerides took place in the second stage with an alkaline catalysis. The present investigation aimed to explore the parameters affecting the reactions, including homogenizer speed, alcohol/oil molar ratio, catalyst dosage, reaction temperature, and reaction time. Under the operating conditions of the first stage (the reaction temperature was 65 °C, the homogenizer speed was 8000 rpm, the methanol/oil molar ratio was 15:1, and the amount of sulfuric acid was 4 wt%), the acid value fell to below 2 mg KOH/g after 10 min. The best base-catalyzed conditions in the second stage were: homogenizer speed of 8000 rpm, NaOH catalyst concentration of 1 wt%, methanol/oil molar ratio of 9:1 (mol/mol), reaction temperature of 65 °C, and reaction time 10 min. Consequently, the conversion rate from WEO to biodiesel achieved 97% after only 20 min, in line with the EU EN14214 standard, which requires a biodiesel production rate of at least 96.5%. Full article

In this study, using the Box–Behnken model, we optimized the ethanolic extraction of phytochemicals from Enantia chloranta bark for the first time, assessed the composition with HPLC-MS/MS, performed the green synthesis of silver nanoparticles (AgNPs) and characterized them with UV-Vis spectrophotometry, photon cross-correlation spectroscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. The antibacterial and antibiotic-resistance reversal properties of optimized extract (O-ECB) and AgNPs were assessed on various microorganisms (15 Gram−, 7 Gram+, and 2 fungi) using the well diffusion method and microbroth dilution assay. The mechanism of action was investigated on growth kinetic and proton pumps of Escherichia coli. The in vivo antimicrobial activity and toxicity were assessed on Galleria mellonella larvae. The optimal mass yield (14.3%) related to the highest antibacterial activity (31 mm vs. S. aureus ATCC 6538) was obtained with the following operating conditions: % EtOH—100%; ratio m/v—20 g/mL; and extraction time—6 h. All the compounds identified in O-ECB were alkaloids and the major constituents were palmatine (51.63%), columbamine +7,8-dihydro-8-hydroxypalmatine (19.21%), jatrorrhizine (11.02%), and pseudocolumbamine (6.33%). Among the minerals found in O-ECB (S, Si, Cl, K, Ca, Mn, Fe, Zn, and Br), Br, Fe, and Cl were the most abundant with mean fluorescence intensities of 4.6529, 3.485,4, and 2.5942 cps/uA, respectively. The synthesized AgNPs revealed a strong absorption plasmon band between 430 and 450 nm and an average hydrodynamic diameter ×50 of 59.74 nm, and the presence of Ag was confirmed by a characteristic peak in the spectrum at the silver Kα line of 22.105 keV. Both O-ECB and AgNPs displayed noteworthy and broad-spectrum antimicrobial activities against 20/24 and 24/24 studied microorganisms, respectively, with recorded minimal inhibitory concentrations (MICs) ranging from 8 to ≥1024 µg/mL and 2 to 64 µg/mL. O-ECB and AgNPs showed antibiofilm properties and significantly enhanced the efficacy of conventional antibiotics against selected multidrug-resistant bacteria, and the mechanistic investigations revealed their interference with bacterial growth kinetic and the inhibition of H+-ATPase proton pumps. LD50s were 40 mg/mL and 0.6 mg/mL for O-ECB and AgNPs, respectively. In conclusion, the current study provides a strong experimental baseline to consider Enantia chlorantha bark and their green synthetized AgNPs as potent antimicrobial compounds in this era of antimicrobial resistance. Full article

The aim of this work is the reduction and decoration of graphene oxide (GO) with magnesium oxide (MgO). In this work, GO was synthesized using modified Hummers’ protocol with (1:2), (1:3) and (1:4) graphite:potassium permanganate mass ratios. Subsequently, all GO samples (GO1:2, GO1:3, GO1:4) were reduced and decorated with magnesium oxide nanoparticles using a reflux technique at 100 °C for 2 h. Sample characterization using X-ray diffraction (XRD) reveals the presence of peaks relative to two different magnesium (Mg) phases: magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)₂). The presence of these spectral features, although characterized by a remarkable broadening, confirms the successful synthesis of Mg(OH)₂-rGO-MgO nanocomposites. X-ray photoelectron spectroscopy (XPS) spectra indicate the presence of peaks assigned to C, O and Mg. The analysis of the high-resolution XPS spectra of these elements confirms once again the presence of Mg(OH)₂-rGO-MgO compounds. The low temperature synthesis of Mg(OH)₂-rGO-MgO nanocomposite exhibiting superior catalytic properties compared to MgO–rGO nanoparticles is an important step forward with respect to the current state of the art. The antioxidant activity of six nanocomposites, namely GO1:2, GO1:3, GO1:4, MgO–rGO1:2, MgO–rGO1:3 and MgO–rGO1:4, was determined using standard protocols based on a DPPH radicals scavenging assay, an H₂O₂ scavenging assay, and a phosphomolybdate assay. All our samples exhibited dose-dependent antioxidant activity. Interestingly, among the different synthesized nanoparticles, GO1:4 and MgO–rGO1:4 showed the best performances. Full article