Inhibition of Fusarium oxysporum by AgNPs biosynthesised using Cinnamomum camphora fruit extract

Cinnamomum camphora fruit extract was used to biosynthesise silver nanoparticles (AgNPs), and the optimised synthesis system was ascertained through solution colour change and ultraviolet–visible absorption spectra. It contained 20 ml of fruit extract, 4 mM Ag nitrate, and pH 7. AgNPs obtained based on such conditions were spherical and finely dispersed, with an average size of 20.3 nm. As‐synthesised AgNPs exhibited excellent antifungal effect against Fusarium oxysporum. At a dose of 400 μg/ml of AgNPs, the inhibition rate of colony growth reached 61.00% and an IC₅₀ value of 154.39 μg/ml. In addition, the conidia germination was totally inhibited at 100 μg/ml of AgNPs. Results of this study provide a new approach for biological control of plant pathogenic fungi, and it makes that possible for developing a brand new fungistat.Inspec keywords: nanoparticles, microorganisms, agricultural products, nanobiotechnology, silver, antibacterial activity, nanomedicine, pharmaceutical technologyOther keywords: fusarium oxysporum, cinnamomum camphora fruit extract, biosynthesis, silver nanoparticles, antifungal effect, conidia germination, plant pathogenic fungi, Ag     

Photocatalytic degradation for methylene blue using zinc oxide prepared by codeposition and sol-gel methods

Zinc oxide nanoparticle was obtained by zinc hydrate deposited on the silica nanoparticle surface and zinc hydrate was dispersed in starch gel. The structure of zinc oxide particle was characterized by nitrogen adsorption-desorption and XRD, the morphology was observed by TEM. The result showed that the zinc oxide nanoparticle deposited on the silica nanoparticle surface was well-dispersed and less than 50nm, displayed higher photocatalytic activity for methylene blue degradation. However, the zinc oxide nanoparticle in a size of 60nm was derived from starch gel and showed poorer photocatalytic activity. It provided a simple and effective route to prepare zinc oxide nanoparticle with higher photocatalytic activity through depositing zinc oxide on the silica particle surface, moreover, the catalyst is easier to recover due to its higher density.     

High-efficiency photocatalytic degradation of methylene blue using electrospun ZnO nanofibers as catalyst

In this work, ZnO nanofibers (ZNFs) were successfully prepared via a simple electrospinning technique using polyvinylpyrrolidone (PVP) and zinc acetate dihydrate (Zn(CH3COO)2 2H2O) as precursors. The obtained ZNFs have an average diameter of ca. 95 nm and are composed of crystalline wurtzite phase. Methylene blue (MB) dye was used to investigate the photocatalytic performance of pure ZNFs. The study confirms that ZNFs have favorable catalytic activity, and the best degradation efficiency of MB can exceed 90% under UV light irradiation for 3 hours. In addition, we propose a possible photodegradation mechanism.     

凹凸棒土负载CeO2催化氧化处理亚甲基蓝染料废水

采用均相沉淀法,以Ce(NO3)3·6H2O为原料,HMT为沉淀剂,制备了ATP/CeO2纳米复合材料.并以H2O2为氧化剂,利用该复合材料对亚甲基蓝(MB)染料模拟废水进行了催化氧化处理,分别考察了催化剂的投加量及CeO2的负载量对MB降解的影响规律.研究结果表明,负载CeO2凹凸棒土纳米复合催化剂的催化活性明显高于相同条件下制备的纯的CeO2,CeO2负载量及ATP/CeO2的投加量分别为40%和0.2g时,最大降解率可达96%,对亚甲基蓝表现出较强的催化活性.     

Studies on the properties of copper tin hydroxide-based catalysts prepared by co-precipitation method for photocatalytic degradation of methylene blue dye

Journal of Materials Science: Materials in Electronics - In this work, we report the enhanced photocatalytic behaviour of copper tin hydroxide (CuSn(OH)6)-based catalyst materials for the...     

Antibacterial potential of silver nanoparticles biosynthesised using Canarium ovatum leaves extract

Silver nanoparticles (AgNPs) have been extensively used as antibacterial agents, owing to their ease of preparation. In the present study, leaves extract of Canarium ovatum have been employed for the biosynthesis of silver nanoparticles (CO‐AgNPs). CO‐AgNPs were synthesised under very mild, eco‐friendly manner where the plant extract acted both as reducing and capping agent. These AgNPs were synthesised by taking into account several parameters, that included, time of reaction, concentration of AgNO₃, amount of extract and temperature of reaction. The optimisation studies suggested efficient synthesis of CO‐AgNPs at 25°C when 1.5 mM AgNO₃ was reduced with 1:20 ratio of plant extract for 40 min. Size determination studies done on dynamic light scattering and scanning electron microscope suggested of spherical shape nanoparticles of size 119.7 ± 7 nm and 50–80 nm, respectively. Further, characterisations were done by Fourier transform infrared and energy‐dispersive X‐ray spectroscopy to evaluate the functional groups and the purity of CO‐AgNPs. The antibacterial efficacy of CO‐AgNPs was determined against the bacterial strain Pseudomonas aeruginosa. As evident from disc diffusion method studies, CO‐AgNPs remarkably inhibited the growth of the tested microorganism. This study suggested that C. ovatum extract efficiently synthesises CO‐AgNPs with significant antibacterial properties and can be good candidates for therapeutics.Inspec keywords: antibacterial activity, nanoparticles, silver, nanofabrication, particle size, light scattering, scanning electron microscopy, Fourier transform infrared spectra, X‐ray chemical analysis, microorganisms, biomedical materials, nanomedicineOther keywords: antibacterial potential, silver nanoparticles, biosynthesis, Canarium ovatum leave extract, plant extract, reducing agent, capping agent, antibacterial agents, reaction time, reaction temperature, dynamic light scattering, scanning electron microscopy, spherical shape nanoparticles, Fourier transform infrared spectroscopy, functional groups, bacterial strain Pseudomonas aeruginosa, disc diffusion method, microorganism, energy‐dispersive X‐ray spectroscopy, temperature 25 degC, time 40 min, Ag     

Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder

The ability of an unconventional bio-adsorbent, pineapple leaf powder (PLP) for the adsorption of methylene blue (MB) from aqueous solution was studied. It was observed that intra-particle diffusion was involved in the adsorption process and that the kinetic data fitted well with a pseudo-second-order equation. Fitting parameters revealed that the rate of adsorption increased with decrease in dye concentration and decrease in ionic strength while the mixing speed did not have a significant effect on adsorption. The adsorption was favorable at higher pH and lower temperature, and the equilibrium data were well fitted by the Langmuir isotherm. The maximum adsorption capacity varied from 4.68 × 10⁻⁴ to 9.28 × 10⁻⁴ mol/g when pH increases from 3.5 to 9.5. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. The results revealed that this agricultural waste has potential to be used as an economical adsorbent for the removal of methylene blue from aqueous solution.     

ZnAlTi型层状双氢氧化物光催化降解亚甲基蓝的性能研究

利用动态尿素水解法制备了3种不同比例的ZnAlTi型层状双氢氧化物,取部分样品分别在温度为500、600、700和900℃条件下煅烧4h,制得具有光催化性能的材料。研究催化剂不同摩尔比、催化剂用量、煅烧温度等不同因素对光催化降解亚甲基蓝过程的影响。结果表明,紫外光照射下,在反应温度为30℃、催化剂中Ti和Al的摩尔比为2、催化剂投加浓度为1.0g/L、亚甲基蓝初始浓度为10mg/L、煅烧温度为600℃的反应条件下,催化剂对亚甲基蓝的降解效果最好,光照反应12h后亚甲基蓝的降解率为94.4%。     

Oxidative decolorization of methylene blue using pelagite

Pelagite generally has large surface area and high adsorbing and oxidizing reactivity due to highly amorphous nature, and high reducing potential of Mn (hydro)oxide phases present in it. In the present study, pelagite, collected from the East Pacific Ocean, was tested as a potential oxidant for decolorization of methylene blue (MB) in a batch system under air-bubbling and motor-stirring conditions. The effects of suspension pH (3.0-10.0), MB concentration (10-100 mgL(-1)) and loading (0.2-3.0 gL(-1)), and particle size (100-200 mesh) of pelagite on kinetics of MB decolorization were assessed. Results show that in typical concentration range of dye wastewaters (10-50 mgL(-1)), pelagite can be used as a highly efficient material for oxidative degradation of MB. MB decolorization was through a surface mechanism, that is, formation of surface precursor complex between MB and surface bound Mn(III, IV) center, followed by electron transfer within the surface complex. Iron (hydro)oxide phases present in the pelagite did not play an important role in MB decolorization. Suspension pH exerted double-edged effects on MB decolorization by influencing the formation of surface precursor complex, and reducing potential of the system. Kinetic rate of MB decolorization is directly proportional to saturation degree of available reaction sites by MB adsorption. At the initial and later stages, the kinetics for MB decolorization with respect to MB concentration, pelagite loading, and particle size could be described separately using two pseudofirst rate equations, except at very high pelagite loading (3.0 mgL(-1)). Accumulation of Mn(2+) and probably some organic intermediates exerted marked inhibitory effect on MB decolorization. Vigorous dynamic condition was favorable for MB decolorization. The presence of oxygen could enhance MB decolorization to a limited extent.     

Photocatalytic degradation of methylene blue with Co alloyed CdZnS nanoparticles

In our present study, firstly; cadmium zinc sulfide (CdZnS) nanoparticles (NPs) with 1, 2, 5, 10% of Zn concentration were synthesized in aqueous solution by simple chemical co-precipitation method and their photocatalytic activity was investigated using the degradation of methylene blue under visible light in air at room temperature. It was found that CdZnS NPs with 2% of Zn concentration indicates the highest degradation efficiency compare to other Zn concentrations. CdZnS NPs with 2% of Zn concentration was symbolized as CdZnS_1. Later; 0.1, 0.2, 0.5, 1, 5, 10% of cobalt (Co) concentration was separately alloyed on the CdZnS_1 NPs. It was oberved that Co(5%):CdZnS NPs has the highest degradation efficiency. Structure, surface morphology, elemental analysis and optical properties of CdZnS_1 and Co (5%): CdZnS NPs 0were analyzed using X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and UV–Vis absorption measurements, respectively. The results showed that Co doped CdZnS NPs can be employed as capable materials to ehance the photocatalytic activity.     

Silver nanoparticles biosynthesised using Centella asiatica leaf extract: apoptosis induction in MCF‐7 breast cancer cell line

The aim of this study was to green synthesised silver nanoparticles (AgNPs) using Centella asiatica leaf extract and investigate the cytotoxic and apoptosis‐inducing effects of these nanoparticles in MCF‐7 breast cancer cell line. The characteristics and morphology of the green synthesised AgNPs were evaluated using transmission electron microscopy, scanning electron microscopy, UV–visible spectroscopy, X‐ray diffraction, and Fourier‐transform infrared spectroscopy. The MTT assay was used to investigate the anti‐proliferative activity of biosynthesised nanoparticles in MCF‐7 cells. Apoptosis test was performed using flow cytometry and expression of caspase 3 and 9 genes. The spherical AgNPs with an average size of 19.17 nm were synthesised. The results showed that biosynthesised AgNPs exhibited cytotoxicity, anti‐cancer, apoptosis induction, and increased expression of genes encoding for caspases 3 and 9 in MCF‐7 cancer cells in a concentration‐ and time‐dependent manner. It seems that green synthesised AgNPs have potential uses for pharmaceutical industries.Inspec keywords: ultraviolet spectra, transmission electron microscopy, cellular biophysics, infrared spectra, visible spectra, nanofabrication, cancer, toxicology, nanomedicine, nanoparticles, biomedical materials, scanning electron microscopy, silver, Fourier transform spectra, X‐ray diffraction, genetics, enzymes, botany, biochemistryOther keywords: spherical AgNPs, biosynthesised AgNPs, anti‐cancer, apoptosis induction, green synthesised AgNPs, MCF‐7 breast cancer cell line, green synthesised silver nanoparticles, Ag, caspase gene expression, flow cytometry, anti‐proliferative activity, MTT assay, pharmaceutical industries, cytotoxicity, UV–visible spectroscopy, nanoparticle morphology, scanning electron microscopy, Centella asiatica leaf extract, biosynthesised nanoparticles, Fourier‐transform infrared spectroscopy, transmission electron microscopy     

Photocatalytic degradation of methylene blue using novel flower-like zirconium bismuth molybdate thin film,grown by temperature-assisted CBD method

Thin films of a novel metal molybdate are successfully coated on soda lime glass by one step chemical bath deposition method. The deposition is carried out under different bath temperature ranging from 30 to 70 °C. In order to analyze the crystalline structure, X-ray diffraction study is carried out. Film thickness and morphology are examined through atomic force microscope and scanning electron microscope. Optical studies are done by UV–Vis–NIR absorbance spectra and photoluminescence spectra. All the samples have absorbance in the UV–Vis region and possess direct allowed transition with bandgap values ranging from 2.17 to 2.83 eV. Direct current show good ohmic response and possess resistivity in the range characteristic of wide bandgap materials. The material possesses three major photoluminescence emission peaks in the green and blue wavelength regions. Thin film grown at 50 °C showed increased absorbance width, minimum bandgap energy, larger electron–hole separation efficiency and more porous flower-like morphology which indicates its higher photocatalytic ability. The photocatalytic degradation process for the removal of methylene blue from waste water, under sunlight irradiation using thin film grown at 50 °C as photocatalyst has been discussed in detail.

     

Photocatalytic degradation of methylene blue in TiO2 aqueous suspensions using microwave powered electrodeless discharge lamps

Photocatalytic degradation of methylene blue (MB) in TiO(2) aqueous suspensions using microwave (MW) powered electrodeless discharge lamps (EDLs) was studied. MB of initial concentration 100 mg/l was mainly decomposed in the process of photocatalytic degradation using EDLs (PCD/EDLs) after 15 min of irradiation. The corresponding mineralization efficiency was 45%. The influence of factors as EDLs, solution volume and TiO(2) catalyst dosage on the decomposition of MB in the PCD/EDLs process was also investigated. The optimal decomposition efficiency was observed when EDLs-4 (four 10 mm x 50 mm EDLs), solution volume of 50 ml and TiO(2) catalyst dosage of 1-4 g/l were used in the study. The PCD/EDLs process was promising in treating MB polluted water.     

Biosynthesized zinc oxide using <Emphasis Type="Italic">Lycopersicon esculentum</Emphasis> peel extract for methylene blue degradation

This work presents a study on the effects of different peel extract weight percentages in the biosynthesis of zinc oxide (ZnO) for its application in the photocatalysis. Zinc nitrate was used as a source of the zinc ions, while Lycopersicon esculentum (tomato) contributed the peels for the extracts to be used as a reductant and stabilizing agent. The synthesized samples were studied and characterized through Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy and UV–Vis spectroscopy. The morphology of the surface of the material showed that samples vary in size and shape distribution depending on the amount of extract used. The band gap values were of 3.08, 3.1 and 3.18 eV for the 1, 2 and 4% concentrations, respectively. The photocatalytic properties of the ZnO were evaluated through methylene blue degradation and the results presented a 97% dye degradation in 150 min, which is more efficient than comparable commercial ZnO.     

Eco-friendly synthesis of Ag-ZrO2 nanocomposites for degradation of methylene blue

In this work, we have successfully synthesized ZrO₂ nanoparticles (NPs) using Ficus benghalensis (FB) leaf extract via simple microwave-assisted method. Silver NPs were deposited on the surface of ZrO₂ through photocatalytic reduction. The synthesized ZrO₂ and Ag-ZrO₂ photocatalysts were characterized through X-ray Diffraction (XRD), UV–Vis Diffuse Reflectance Spectroscopy (DRS), Fourier Transform-Infrared Spectroscopy (FT-IR), High-Resolution Transmission Electron Microscopy (HR-TEM), Photoluminescence (PL), and Brunauer–Emmett–Teller (BET) surface area. From the aforesaid characterization of the materials, it is revealed that synthesized Ag NPs are crystalline in nature with the face-centered cubic structure (FCC), while ZrO₂ NPs have both monoclinic and tetragonal phases. TEM images indicate that both ZrO₂ and Ag-ZrO₂ nanocomposite have spherical shape with the particle size of 20 and 15 nm, respectively. The optical properties were obtained using UV–Vis DRS which showed a decrease in the band gap energy of ZrO₂ due to surface plasmon resonance (SPR) effect of Ag NPs. A lower in PL intensity of Ag-ZrO₂ compared to that of ZrO₂ NPs confirms the suppression of recombination rate of excited electron–hole pairs ultimately resulted into high photocatalytic activity. BET analysis shows that all the nanocomposites have higher surface area than pure ZrO₂. The pure ZrO₂ and Ag-ZrO₂ show the efficient photocatalytic activity towards the methylene blue (MB) and methyl orange (MO). Ag-ZrO₂ (1.0 wt.%) shows 21% increment in photocatalytic activity as compared to pure ZrO₂ within 160 min under UV–Vis light.

     

TiO_2和活性炭纤维复合物光催化降解亚甲基蓝

以粘胶基活性炭纤维(VACF)为基体,钛酸丁酯为前驱体,通过溶胶-凝胶浸渍涂覆法将二氧化钛(TiO2)负载于粘胶基活性炭纤维上,制备活性炭纤维负载的TiO2光催化复合物,通过控制活性炭纤维在溶胶中的浸泡时间,制得不同TiO2负载量的复合物。采用扫描电子显微镜(SEM)表征了制备材料的形态结构,以质量浓度为20mg/L的亚甲基蓝溶液为目标降解物,测试了材料在紫外线光照下的催化性能。结果表明:紫外光直接照射对亚甲基蓝基本无降解作用,对活性炭纤维原样有一定作用;随着TiO2负载量的增加,复合物的吸附性能得到提高,对亚甲基蓝的降解作用也得到增强。     

Chemical oxidation of methylene blue using a Fenton-like reaction

Oxidation by Fenton-like reactions is proven and economically feasible process for destruction of a variety of hazardous pollutants in wastewater. We report herein the oxidation of methylene blue, a basic dye of thiazine series using a Fenton-like reaction at normal laboratory temperature and at atmospheric pressure. The effects of different parameters like the initial concentrations of dye, Fe2+, and H2O2, pH of the solution, reaction temperature, and added electrolytes on the oxidation of the dye present in dilute aqueous solution in the concentration range (3.13-9.39)x10(-5)mol dm(-3) (10-30 mg l(-1)) have been assessed. The results indicate that the dye can be most effectively oxidized in aqueous solution at dye:Fe(2+):H2O2 molar ratio of 1:1.15:14.1. More than 98% removal of the dye could be achieved in 1h in the pH range 2.2-2.6 at 299 K which corresponds to about 81% reduction of the initial COD. The results will be useful for designing the treatment systems of various dye-containing wastewaters.     

Catalytic reduction of 2,4‐dinitrophenylhydrazine by cuttlebone supported Pd NPs prepared using Conium maculatum leaf extract

A facile and green process to synthesise cuttlebone supported palladium nanoparticles (Pd NPs/cuttlebone) is reported using Conium maculatum leaf extract and in the absence of chemical solvents and hazardous materials. The antioxidant content of the C. maculatum leaf extract played a significant role in converting Pd²⁺ ions to Pd NPs. Various techniques were used for the characterisation of the Pd NPs/cuttlebone such as field‐emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, Fourier transform infrared and ultraviolet–visible spectroscopy. This Pd NPs/cuttlebone showed excellent catalytic activity in the reduction of 2,4‐dinitrophenylhydrazine to 2,4‐diaminophenylhydrazine by sodium borohydride as the source of hydrogen at ambient condition. The catalyst could be separated and recycled up to five cycles with no loss of its activity.Inspec keywords: catalysis, catalysts, chemical engineering, palladium, nanoparticles, field emission electron microscopy, scanning electron microscopy, X‐ray diffraction, X‐ray chemical analysis, sodium compounds, ultraviolet spectroscopy, visible spectroscopyOther keywords: catalytic reduction, 2,4‐dinitrophenylhydrazine, cuttlebone, Conium maculatum leaf extract, green process, palladium nanoparticles, antioxidant content, field‐emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, Fourier transform infrared, ultraviolet–visible spectroscopy, 2,4‐diaminophenylhydrazine, sodium borohydride     

TiO2/膨胀石墨复合材料的制备及其对亚甲基兰的光催化降解

采用快速升温法制备出以膨胀石墨为载体的TiO2/膨胀石墨光催化剂,用SEM及XRD对其表面形貌及结构进行表征,研究了该负载型光催化剂在紫外光照射下的催化能力,探讨了在催化剂中TiO2的负载量、亚甲基兰溶液的初始浓度及其pH值对光催化剂的降解能力的影响.结果发现,负载量为10%的光催化剂对40mg/L的亚甲基兰溶液5h的光降解率达到58.8%.