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The main objective of the current work is to investigate the influence of waste chicken eggshell (WCE) as an alternative source of calcium oxide (CaO) on Hydrogen exchanged Zeolite Socony Mobil-5 catalyst (HZSM-5). WCE as promoter was loaded at 1wt.% on HZSM-5 catalyst which act as support via incipient wetness impregnation method. The HZSM-5, commercial CaO, and WCE were individually prepared for comparison with WCE/HZSM-5. Synthesized catalysts were characterized via X-Ray Diffraction to analyse the phase purity, Field Emission Scanning Electron Microscopy to analyse the surface morphology, and Brunauer-Emmett-Teller to analyse the surface area and pore size. The addition of WCE on HZSM-5 has significantly affected the framework structure of HZSM-5 where the crystallinity percentage and average crystal size of HZSM-5 drastically dropped to 44.97 % and 45.00 nm. The original cubic-like structure in HZSM-5 has significantly altered into a netlike structure after the impregnation of WCE. A similar effect of alteration was observed on BET surface area dropped from 365.81 m2 /g (HZSM-5) to 292.14 m2 /g (WCE/HZSM-5). Interestingly, the pore diameter of WCE/HZSM-5, WCE, and HZSM-5 catalysts was similar at 3.88 nm, 3.87 nm, and 3.87 nm respectively. WCE and commercial CaO almost share similar textural properties. Hence, the addition of WCE as an alternative source of calcium oxide into HZSM-5 can provide a high catalytic reaction and stable surface in catalytic cracking of heavy hydrocarbons into small hydrocarbons with longer catalyst lifetimes. [ABSTRACT FROM AUTHOR]

In this research, gold nanoparticles (Au-NPs) are biosynthesized from tetrachloroaurate (AuCl4−) aqueous solution through a simple and ecofriendly route using water extract of black Camellia sinensis leaf (C. sinensis L.) which acted as a reductant and stabilizer simultaneously. The prepared gold nanoparticles are characterized using UV-visible spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Also, determination of the accurate predictor model for chemical reactions is particularly important because of high cost of the chemical materials and measurement devices. While the artificial neural networks (ANNs) are one of the appropriate tools to forecast any phenomena, due to the low number of data set related to chemical experimental was caused to provide appropriate model is a time-consuming iterative process. With the aim to improve the accuracy of the ANN model and overcome the local convergence of this problem, a global search technique, biogeography-based optimization (BBO) method which integrated by chaotic map is employed. The improved model showed minimum mean squared error (MSE) of 0.0134 and maximum coefficient of determination (R2) equal to 0.9822 compared with several other famous ANN training algorithm, utilizing output experimental data obtained from biosynthesis proceeding. [ABSTRACT FROM AUTHOR]

A facile, environmental friendly green approach was introduced in this study, which superparamagnetic magnetite nanoparticles (Fe3O4-NPs) have been satisfactorily synthesized. Seaweed Kappaphycus alvarezii (K. alvarezii) extract was employed in this synthesis process, which played a role as bio-stabilizer. The structure and morphology of the synthesized K. alvarezii/Fe3O 4-NPs were analyzed by X-ray diffraction (XRD) and transmission electron microscope. The spherical shape of K. alvarezii/Fe3O4-NPs with an average size of 19.4 nm showed high crystallinity and purity based on the characteristic XRD planes at (220), (311), (400), (422), (511), (440), and (533). The presence of Fe3O4-NPs was identified by Fourier transform infrared, Raman spectroscopy, and energy-dispersive X-ray spectroscopy. The magnetic properties of K. alvarezii /Fe3O4-NPs were studied using vibrating sample magnetometer, which gave a result of 24.85 emu/g. The K. alvarezii/Fe3O4-NPs were very stable, where zeta potential value showed −53.57 mV. [ABSTRACT FROM PUBLISHER]

This paper presents a green, facile and rapid method to prepare magnetite/zeolite-nanocomposites (NCs) in one step procedure at ambient temperature. The powder X-ray diffraction (PXRD) pattern of iron oxide nanoparticles (NPs) with the sole zeolite showed the broadening of zeolite peaks attributed to the incorporation of Fe 3 O 4 . Field-emission scanning electron microscopy (FESEM) analysis depicted that the Fe 3 O 4 ‒NPs were formed on the surface of porous zeolite framework. Transmission electron microscopy (TEM) analysis displayed the Fe 3 O 4 nanoparticles (NPs) were mostly in spherical shape with a mean diameter and standard deviation of 2.40 ± 0.41 nm. The selected-area electron diffraction (SAED) pattern confirmed the presence of cubic Fe 3 O 4 phase. The vibrating sample magnetometer (VSM) results indicated the as-synthesized sample has a saturation magnetization of around 6.52 emu g −1 . The magnetite/zeolite-NCs can be considered as a low-cost alternative catalyst for oxygen reduction reaction (ORR) process. The electrochemical measurement showed that the performance of magnetite/zeolite-NCs towards the ORR increased as the scan rate increased from 20 mV s −1 to 500 mV s −1 . The ORR is a diffusion-controlled process in the alkaline medium. [ABSTRACT FROM AUTHOR]

The synthesis of silver nanoparticles (Ag-NPs) was achieved by a simple green chemistry procedure using sodium alginate (Na-Alg) under ultrasonic radiation as a stabilizer and physical reducing agent. The effect of radiation time on the synthesis of Ag-NPs was carried out at room temperature until 720 min. The successful formation of Ag-NPs has been confirmed by UV-Vis, XRD, TEM, FESEM-EDX, zeta potential, and FT-IR analyses. The surface plasmon resonance band appeared at the range of 452–465 nm that is an evidence of formation of Ag-NPs. The XRD study showed that the particles are crystalline structure in nature, with a face-centered cubic (fcc) structure. The TEM study showed the Ag-NPs have average diameters of around 20.16–22.38 nm with spherical shape. The FESEM-EDX analysis confirmed the spherical shape of Ag-NPs on the surface of Alg and the element of Ag with the high purity. The zeta potential showed high stability of Alg/Ag-NPs especially after 720 min irradiation with value of −67.56 mV. The FT-IR spectrum confirmed that the Ag-NPs have been capped by the Alg with van der Waals interaction. The Alg/Ag-NPs showed the antibacterial activity against Gram-positive and Gram-negative bacteria. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field. [ABSTRACT FROM AUTHOR]

A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by nanocrystalline cellulose (NCC) using different concentrations of copper salt in aqueous solution under atmospheric air. CuSO4·5H2O salt and hydrazine were used as metal ion precursor and reducing agent, respectively. Ascorbic acid and aqueous NaOH were also used as an antioxidant and a pH moderator, respectively. The number of CuNPs increased with increasing concentration of the precursor salt. The formation of copper nanoparticles stabilized by NCC (CuNPs@NCC) was investigated by UV-visible spectroscopy (UV-vis), where the surface absorption maximum was observed at 590 nm. X-ray diffraction (XRD) analysis showed that the CuNPs@NCC are of a face-centered cubic structure. Moreover, the morphology of the CuNPs@NCC was investigated using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM), which showed well-dispersed CuNPs with an average particle size less than 4 nm and the shape of CuNPs was found to be spherical. Energy dispersive X-ray spectroscope (EDS) also confirmed the presence of CuNPs on the NCC. The results demonstrate that the stability of CuNPs decreases with an increasing concentration of the copper ions. [ABSTRACT FROM AUTHOR]

The composite materials based on rice straw (RS) fiber and polycaprolactone (PCL) were prepared by a solution-casting method and characterized. The composites were prepared using different fiber loadings (1.0, 3.0, 5.0, and 7.0 wt%). The prepared composites (Cs) were characterized by using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electro-optical microscopy, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis, and mechanical properties were investigated. The XRD results showed that the intensity of the peaks decreased with the increase of RS content from 1.0 to 7.0 wt% in comparison with PCL peaks. SEM micrographs indicated poor adhesion between RS and PCL matrices, and FT-IR spectroscopy showed that, with the increase of loading percentages of RS, the intensity of the peaks is decreased from 1.0 to 7.0 wt%, and the interaction between RS and PCL was a physical interaction. Thermal stability was decreased with increasing the RS contents. Tensile measurement showed an increase in tensile modulus from 1.0 to 7.0 wt% loading of RS into the PCL, but a decrease in tensile strength and elongation at the break as the RS contents are increased, although there is a modest increase in tensile strength of the Cs material with 3.0 wt% loading of RS. [ABSTRACT FROM AUTHOR]

A green sonochemical method was developed for preparing silver nanoparticles (Ag-NPs) in different concentrations of kappa carrageenan (κ-carrageenan). The κ-carrageenan was used as a natural eco-friendly stabilizer, and ultrasonic irradiation was used as a green reducing agent. The number of Ag-NPs increased with increasing κ-carrageenan concentrations. Formation of Ag/κ-carrageenan was determined by UV-visible spectroscopy where the surface plasmon absorption maximum was observed at 402 to 420 nm. The X-ray diffraction (XRD) analysis showed that the Ag-NPs are of a face-centered cubic structure. The Fourier transform infrared (FT-IR) spectrum indicated the presence of Ag-NPs in κ-carrageenan. Transmission electron microscopy (TEM) image for the highest concentration of κ-carrageenan showed the distribution of Ag-NPs with an average particle size near to 4.21 nm. Scan electron microscopy (SEM) images illustrated the spherical shape of the Ag-NPs. The use of photo irradiation provides a green and economic feature to this work. [ABSTRACT FROM AUTHOR]

Background This study aims to investigate the influence of different stirring time for synthesis of silver nanoparticles in glutathione (GSH) aqueous solution. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using GSH as reducing agent and stabilizer, under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while Ag-NPs were prepared in the over reaction time. Results Formation of Ag-NPs was determined by UV-vis spectroscopy where surface plasmon absorption maxima can be observed at 344-354 nm from the UV-vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 72 h stirring time of reaction comparison to GSH. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between GSH and Ag-NPs. The use of green chemistry reagents, such as peptide, provides green and economic features to this work. Conclusions Ag-NPs were successfully synthesized in GSH aqueous solution under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs synthesized in the long times of stirring, thus, the kinetic of GSH reaction is very slow. TEM results shows that with the increase of stirring times the mean particle size of Ag-NPs become increases. The FT-IR spectrum suggested the complexation present between GSH and Ag-NPs. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field. [ABSTRACT FROM AUTHOR]

Structural properties of nickel doped cobalt ferrite were synthesized by co-precipitation method with sodium dodecyl sulfate (SDS) as a surfactant at different temperatures. The particle size was estimated by the full width half maximum (FWHM) of the strongest X-ray diffraction (XRD) peak. The average particle size was in the range of 21-36 nm. The particles size was controlled via controlling calcination temperature which was in the range of 600 to 900°C. The morphology of nickel doped cobalt ferrite was investigated. The results showed that a well crystalline single cubic structure of nickel doped CoFe2O4 phase was formed through precipitation precursors at pH value of 11. The pH was adjusted by the use of ammonium hydroxide solution. [ABSTRACT FROM AUTHOR]

Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs) with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3.6H2O), ferrous chloride (FeCl2.4H2O), sodium hydroxide (NaOH) and urea (CH4N2O) were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs) were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) and Fourier transforms infrared spectroscopy (FT-IR). The rice straw/Fe3O4-NCs prepared by this method have magnetic properties. [ABSTRACT FROM AUTHOR]

Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn3Al LDH. A solution casting method was used to prepare PLA/stearate-Zn3Al LDH nanocomposites. The anionic clay Zn3Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn3Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn3Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn3Al LDH nanocomposites showed that the presence of around 1.0-3.0 wt % of the stearate-Zn3Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn3Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA. [ABSTRACT FROM AUTHOR]

In this paper, Polyimide/Montmorillonite Nanocomposites (PI/MMT NCs), based on aromatic diamine (4-Aminophenyl sulfone) (APS) and aromatic dianhydride (3,3',4,4'-benzophenonetetracarboxylic dianhydride) (BTDA) were prepared using in situ polymerization and solution-dispersion techniques. The prepared PI/MMT NCs films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The XRD results showed that at the content of 1.0 wt % Organo Montmorillonite (OMMT) for two techniques and 3.0 wt % OMMT for the in situ polymerization technique, the OMMT was well-intercalated, exfoliated and dispersed into polyimide matrix. The OMMT agglomerated when its amount exceeded 10 wt % and 3.0 wt % for solution-dispersion and in situ polymerization techniques respectively. These results were confirmed by the TEM images of the prepared PI/MMT NCs. The TGA thermograms indicated that thermal stability of prepared PI/MMT NCs were increased with the increase of loading that, the effect is higher for the samples prepared by in situ polymerization technique. [ABSTRACT FROM AUTHOR]

This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO3 in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO3) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. [ABSTRACT FROM AUTHOR]

Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs) due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Visible (UV-Vis) spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10-30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc) structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag+ to Ag0). [ABSTRACT FROM AUTHOR]

Abstract: We have successfully developed a simple method for preparing silver nanoparticles (Ag NPs) using UV irradiation of AgNO3 in the interlamellar space of a montmorillonite (MMT) without any reducing agent or heat treatment. The properties of Ag/MMT nanocomposites were studied as a function of the UV irradiation period. UV irradiation disintegrated the Ag NPs into smaller size until a relatively stable size and size distribution were achieved. The results from UV–vis spectroscopy show that particles size of Ag NPs decrease with the increase of irradiation period. The crystalline structure of Ag NPs was determined by powder X-ray diffraction (PXRD). [Copyright &y& Elsevier]