A novel eco-friendly procedure was developed to produce safer, stable and highly pure zinc oxide nanoparticles (ZnO NPs) using microalgae Chlorella extract. The ZnO NPs were synthesized simply using ...zinc nitrate and microalgae Chlorella extract which conducted at ambient conditions. In this recipe, microalgae Chlorella extract acted as the reducing agent and a stabilizing layer on fresh ZnO NPs. UV-visible spectrum was confirmed the formation of ZnO NPs showing an absorption peak at 362 nm. XRD results demonstrated that prepared ZnO NPs has a high-crystalline hexagonal (Wurtzite) structure, with average size about 19.44 nm in diameter. FT-IR spectral analysis indicated an active contribution of algae-derived biomolecules in zinc ions bioreduction. According to SEM and TEM observations, ZnO NPs are well dispersed and has a hexagonal shape with the average size of 20 ± 2.2 nm, respectively. Based on gas chromatography analyses, the optimum 0.01 g/L dosage of ZnO catalyst revealed an effective photocatalytic activity toward the degradation (97%) of Dibenzothiophene (DBT) contaminant as an organosulfur model in the neutral pH at the mild condition. Rapid separation and facile recyclability at five consecutive runs were demonstrated high efficiency and durability of green ZnO nanophotocatalyst. The possible mechanisms of green ZnO NPs formation and the photo-desulfurization of DBT were also proposed.
This contribution presents the biosynthesis, physiochemical properties, toxicity and photocatalytic activity of biogenic CeO
NPs using, for the first time, marine oyster extract as an effective and ...rich source of bioreducing and capping/stabilizing agents in a one-pot recipe. CeO
NPs formation was initially confirmed through the color change from light green to pale yellow and subsequently, their corresponding absorption peak was spectroscopically determined at 310 nm with an optical band-gap of 4.67 eV using the DR-UV technique. Further, XRD and Raman analyses indicated that nanoceria possessed face-centered cubic arrangements without any impurities, having an average crystallite size of 10 nm. TEM and SEM results revealed that biogenic CeO
NPs was approximately spherical in shape with a median particle size of 15 ± 1 nm. The presence of various bioorganic substances on the surface of nanoparticles was deduced by FTIR and TGA results. It is found that marine-based nanoceria shows no cytotoxic effect on the normal cell, thus indicating their enhanced biocompatibility and biosafety to living organisms. Environmentally, due to energy band gap, visible light-activated CeO
nanocatalyst revealed superior photocatalytic performance on degradation of methylene blue pollutant with removal rate of 99%. Owing to the simplicity, cost-effectiveness, and environmentally friendly nature, this novel marine biosynthetic route paves the way for prospective applications of nanoparticles in various areas.
The present study reports the synergistic antibacterial activity of biosynthesized silver nanoparticles (AgNPs) with the aid of a combination of chitosan and seaweed-derived polyphenols as a green ...synthetic route. Under optimum synthesis conditions, the rapid color change from yellowish to dark brown and UV-visible absorption peak at 425 confirmed the initial formation of AgNPs. DLS, TEM, XRD, and EDX analyses revealed the spherical shape of pure biogenic AgNPs with a mean diameter size of 12 nm ± 1.5 nm, and a face-centered cubic crystal structure, respectively. FTIR and TGA results indicated the significant contribution of chitosan and polyphenol components into silver ions bioreduction and thermal stability of freshly formed AgNPs. Long-term colloidal stability of AgNPs was obtained after 6-month storage at room temperature. The bio-prepared AgNPs possessed a negative surface charge with a zeta potential value of - 27 mV. In contrast to naked chemical silver nanoparticles, the green Ag nanosamples demonstrated the distinct synergistic antibacterial in vitro toward all selected human pathogens presumably due to the presence of high content of biomolecules on their surface. The results show that synergy between chitosan and polyphenol results in the enhancement of bactericidal properties of biogenic AgNPs. We also highlighted the underlying mechanism involved in AgNPs formation based on nucleophile-electrophile interaction.
This research presents a novel biological route for the biosynthesis of nickel oxide nanoparticles (NiO NPs) using marine macroalgae extract as a reducing and coating agent under optimized synthesis ...conditions. XRD and TEM analyses revealed that phytosynthesized NiO NPs are crystalline in nature with a spherical shape having a mean particle size of 32.64 nm. TGA results indicated the presence of marine-derived organic constituents on the surface of NiO NPs. It is found that biogenic NiO NPs with BET surface area of 45.59 m
g
is a highly efficient catalyst for benign one-pot preparation of pyridopyrimidine derivatives using aqueous reaction conditions. This environmentally friendly procedure takes considerable advantages of shorter reaction times, excellent product yields (up to 96%), magnetically viable nanocatalyst (7 runs), low catalyst loadings, and free toxic chemical reagents.
A facile novel green methodology is presented for the synthesis of highly stable and well-dispersed copper oxide nanoparticles using aqueous wheat seed extract. Under optimal reaction conditions, the ...wheat seed extract-derived electron-rich biomolecules were functioned as a reducing and capping/ stabilizing agent. The ultraviolet-visible absorption peak at 300 nm was confirmed the formation of copper oxide nanoparticles. Fourier-transform infrared spectroscopy analysis determined Cu–O bonds in nanosample, indicating the active role of functional groups in the wheat seed extract in bio-reduction of Cu cations. X-ray diffraction pattern results demonstrated the monoclinic structure of highly pure biosynthesized copper oxide nanoparticles with a crystallite size of 20.76 nm. The stability of copper oxide nanoparticles was confirmed after 3 months’ storage of product with no sedimentation or suspension. Transmission electron microscopy results showed the spherical shape of nano-particle with an average size of 22 ± 1.5 nm. X-ray photo-electron spectroscopy analyses revealed only copper and oxygen elements in the sample, confirming the purity of copper oxide nanoparticles. Bio-assisted copper oxide nanoparticles demonstrated significant catalytic efficiency and reusability toward 4-nitrophenol removal by an average of 97.6% from aqueous solutions after successive 5 days’ exposure to UV irradiation.
In this study, we investigate the adsorption behavior of three benzophenone derivatives, namely 2,4-Dihydroxybenzophenone (benzophenone-1; BP-1), 2,2′,4,4′-tetrahydroxybenzophenone (benzophenone-2; ...BP-2), and 2-hydroxy-4-methoxybenzophenone (benzophenone-3; BP-3) on the surfaces of graphene oxide (GO) using density functional theory method. The geometric optimization of the unaltered structures of GO adsorbent, benzophenone derivatives, and their respective complexes was conducted via the M052X/6-311 + G* level of theory. The optimal temperature for the interaction between the GO adsorbent and BPs pollutants in the aqueous phase was found to be 298.15 K. The adsorption process was found to be spontaneous, exothermic, and irreversible based on the calculated values of adsorption energy, Gibbs free energy (Δ
G
ad
), and enthalpy (Δ
H
ad
). The negative values of the calculated chemical potential for all structures indicated that the studied structures were thermodynamically stable. The adsorption of BP-2 pollutant on the surface of GO results in a highest dipole moment (
μ
d
= 28.22 D) compared to the corresponding unadsorbed molecule (
μ
d
= 7.93 D). The adsorption efficiency of GO–BPs complexes follows an increasing trend of GO–BP-2 (−1009.75 kcal/mol) > GO–BP-3 (−1006.31 kcal/mol) > GO–BP-1(−1000.65 kcal/mol). Moreover, infrared (IR) frequency calculations confirmed the feasibility of the structures, showing true local minima. The recovery time values indicate that GO is a highly effective adsorbent in removing organic BP-2 pollutants (
τ
=
3.158 ms) from aqueous media rather than BP-3 (
τ
=
2.120 ms) and BP-1 (
τ
=
1.831 ms) counterparts. Other key parameters engaged in the adsorption behavior of considered molecules, including charge capacity, electrophilicity, band gap, chemical potential, and chemical hardness, were also deliberated.
This study reports the synthesis and potential application of biocompatible silica nanoparticles for subgrade soil stabilization. Nanosilica preparation as a major component from wheat husk ash is ...systematically studied and confirmed by FTIR, ICP, XRD, and TEM analyses. The produced biogenic nanosilica showed an amorphous structure with an average size of 20 nm. Upon loading various green nanosilica contents, our results show an improvement in the key parameters including Atterberg's limits, maximum dry density, optimum water content, and shear strength of treated soil. Under optimal loading condition, the nanosilica-mediated soil analyses reveal a significant increase in the plastic and liquid limits by factors of 1.60 and 1.24 whereas plasticity index is declined by a factor of 0.78 rather than untreated soil specimen. The treated soil demonstrates a superior increase in the angle of internal friction, cohesion, shear strength, and maximum dry unit weight by factors of 2.17, 3.07, 2.21 and 1.5, respectively. The California Bearing Ratio (CBR) strength of nanosilica-cured soil presents a substantial increase by a factor of 5.83 higher than the corresponding original subgrade soil. We obtained the maximum increase in strength parameters of modified soil at the optimum biogenic nanosilica content of 1.5%.
Abstract
The present study reports the synergistic antibacterial activity of biosynthesized silver nanoparticles (AgNPs) with the aid of a combination of chitosan and seaweed-derived polyphenols as a ...green synthetic route. Under optimum synthesis conditions, the rapid color change from yellowish to dark brown and UV–visible absorption peak at 425 confirmed the initial formation of AgNPs. DLS, TEM, XRD, and EDX analyses revealed the spherical shape of pure biogenic AgNPs with a mean diameter size of 12 nm ± 1.5 nm, and a face-centered cubic crystal structure, respectively. FTIR and TGA results indicated the significant contribution of chitosan and polyphenol components into silver ions bioreduction and thermal stability of freshly formed AgNPs. Long-term colloidal stability of AgNPs was obtained after 6-month storage at room temperature. The bio-prepared AgNPs possessed a negative surface charge with a zeta potential value of − 27 mV. In contrast to naked chemical silver nanoparticles, the green Ag nanosamples demonstrated the distinct synergistic antibacterial in vitro toward all selected human pathogens presumably due to the presence of high content of biomolecules on their surface. The results show that synergy between chitosan and polyphenol results in the enhancement of bactericidal properties of biogenic AgNPs. We also highlighted the underlying mechanism involved in AgNPs formation based on nucleophile–electrophile interaction.
A novel biological method is proposed for producing ceramic alpha aluminum oxide nanoparticles using an extract of the algae Sargassum ilicifolium. The algal extract functions as a bioreducing as ...well as a stabilizer agent. The presence of an absorption peak at 227 nm, confirmed the formation of the aluminum oxide nanoparticles using a UV–visible spectroscopy. FTIR analysis indicated that bioreduction of aluminum ions and nanoparticle stabilization probably occurred by interactions between aluminum and the biofunctional groups of algal extract. The XRD pattern revealed that after calcination at ~ 1200 °C, the Al2O3 nanoparticles were alpha crystalline in nature with a diameter of 35 nm and had a rhombohedral structure. TEM indicated that the alumina nanoparticles were well-dispersed and spherical in shape with an average size of 20 ± 2.1 nm. EDX spectroscopy revealed that the sample contained only aluminum (46.31%) and oxygen (53.69%), confirming the high purity of the alumina nanopowder. The results demonstrated that alpha alumina NPs has an optical band gap of 5.46 eV.
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