High-resolution Transmission Electron Microscopy Micrographs Research Articles

Characterization of TiC ceramics with SiC and/or WC additives using electron microscopy and electron probe micro-analysis

This investigation aimed to assess the discrete and synergic impacts of SiC whiskers (SiCw) and nano-sized WC (WCn) on the microstructure of TiC-based materials. Three dense specimens of TiC−3 wt% WCn, TiC−30 vol% SiCw, and TiC−30 vol% SiCw−3 wt% WCn were yielded using the spark plasma sintering (SPS). The X-ray diffraction patterns (XRD), as well as the microstructural observations, suggested unreactive sintering processes; however, thermodynamic studies showed that some minor chemical interactions could take place, leading to surface oxide removal. Furthermore, the field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) micrographs, as well as the field emission electron probe micro-analyzer (FEEPMA) images, proved the WCn dissolution into the TiC matrix, forming (Ti,W)C solid solution in the TiC-WCn and TiC-SiCw-WCn ceramics, and also the graphite precipitation from the TiC in all samples. Glassy SiO2 phase, available as the surface oxide of starting SiCw or produced as the in-situ phase, could form some amorphous interfaces in the relevant composites.

Lead Sulphide Nanoparticles as Photocatalyst for the Degradation of Methylene Blue: Effects of pH, Time, Adsorption Kinetics and Recyclability Studies

We report the synthesis and morphological studies of lead sulphide nanoparticles prepared from lead(II) complexes of morpholine dithiocarbamate (PbS1), thiomorpholine dithiocarbamate (PbS2), and N-(2-hydroxyethyl)phenyl dithiocarbamate (PbS3). Powder X-ray diffraction patterns (p-XRD) of the PbS nanoparticles are indexed to face-centered cubic phase of PbS. High-resolution transmission electron microscopy (HRTEM) micrograph revealed quasi-spherical PbS nanoparticles with particle size in the range 13.86–36.06 nm while scanning electron microscopy (SEM) revealed flaky/spherical/rough surface morphology. Photocatalytic degradation of methylene blue dye by the PbS nanoparticles showed degradation efficiency of 72.6 % for PbS1, 75.9 % for PbS2, and 47.4 % for PbS3. The photodegradation efficiency shows a correlation between efficiency and morphological properties. Total organic content removal by PbS2 is 69.5 % while that of PbS1 is 64.2 % and PbS3 is 40.1 %. The as-prepared PbS nanoparticles exhibited remarkable photostability in the recyclability studies.

Nanocomposite of CuInS/ZnS and Nitrogen-Doped Graphene Quantum Dots for Cholesterol Sensing.

In this paper, nitrogen graphene quantum dots (N-GQDs) and copper indium sulfide/zinc sulfide (CIS/ZnS) QDs were synthesized via facile hydrothermal and aqueous solution routes, respectively. Herein, a fluorescent nanocomposite has been synthesized between N-GQDs and CIS/ZnS QDs in an aqueous phase. This nanocomposite was characterized by photoluminescence, Raman, and ultraviolet–visible (UV–vis) spectroscopies, high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). This fluorescent nanocomposite was developed as a highly sensitive, selective nonenzymatic cholesterol optical biosensor in 0.312–5 mM cholesterol. HRTEM micrographs confirmed the preparation of CIS/ZnS QDs and N-GQDs with average diameters of 3 and 5 nm, respectively. The as-prepared NG/CIS/ZnS QD nanocomposite had a high sensitivity for cholesterol with a wide linear range of concentration of 0.312–5 mM with an excellent correlation coefficient (R2) of 0.9688 and limit of detection (LOD) of 0.222 mM.

Changes in the mechanical, structural and electrical properties of glassy carbon due to strontium and silver co-implantation and annealing

The effect of Sr and Ag co-implantation and recovery annealing on the structural, mechanical and electrical properties of glassy carbon is reported. Glassy carbon was co-implanted with 200 keV Sr and Ag ions to a fluence of 1 × 1016 ions/cm2 at room temperature. Combination of Raman spectroscopy and high resolution transmission electron microscopy (HRTEM) showed that the co-implantation of Sr and Ag resulted in amorphisation of the glassy carbon substrate. Raman spectra and HRTEM micrographs obtained after annealing indicated recovery of the glassy carbon structure, however, the recovered structure appears to be graphite-like. Instrumented indentation experiments on the ion-irradiated glassy carbon substrates revealed the formation of a surface layer with considerably enhanced mechanical performance. When annealing the ion implanted samples, these effects were only partially reversible. The effect of the irradiation-induced amorphisation and graphitisation of glassy carbon on its conductivity was also studied. The sample became less conductive after Sr and Ag co-implantation, whereby annealing resulted in an increase in conductivity.

Facile synthesis of yttria-promoted nickel catalysts supported on MgO-MCM-41 for syngas production from greenhouse gases

Catalytic deactivation owing to agglomeration and metal particle sintering is a serious challenge in dry reforming of methane that encourages researchers to design anti-coke catalysts in a suitable route. Therefore, a series of yttrium oxide (Y2O3)-promoted Ni catalysts supported on magnesium oxide (MgO)-modified MCM-41 were successfully synthesized by the one-pot method. The catalyst characterization was done using X-ray diffraction (XRD), N2 adsorption-desorption, high-resolution transmission electron microscopy (HR-TEM), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), temperature-programmed oxidation (TPO) and scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray analysis (EDAX); after that, it was examined for methane reforming with CO2. The HR-TEM micrographs illustrated that the ordered mesoporous structure of the support remained even after the incorporation of the metallic ions. According to TPD results, the incorporation of Mg into mesoporous silica enhanced the basicity of the support surface. TPR results indicated that adding Mg in a one-pot way led to stronger interaction of metal particles with support and incorporating of yttria enhanced catalyst reducibility. Moreover, based on reforming results, the catalytic performance depended on yttria contents, as catalyst containing 2 wt% yttria possessed the highest NiO dispersion, oxygen vacancies, reducibility, CH4 conversion (79%), H2/CO ratio (0.85) and stability in time on stream (20 h). The TPO and microscopic observations of the spent catalysts revealed that a tip type of nanotube carbon deposited on the yttria-promoted catalyst surface inhibited catalyst deactivation. Therefore, 2Y2O3–Ni/MgO–MCM-41 catalyst can be a practical and environmental candidate for methane reforming with CO2.

Catalytic graphitization of coke carbon by iron: Understanding the evolution of carbon Structure, morphology and lattice fringes

The catalytic graphitization process of coke carbon with iron was investigated in the temperature range of 1100 °C–1500 °C using X-ray diffraction, scanning electron microcopy, high-resolution transmission electron microscopy (HRTEM). The evolution of micro-crystal graphite lattice fringes was carefully analyzed by image processing of the HRTEM micrographs. A strong catalytic effect of iron on graphitization was observed at temperature above 1200 °C with an obvious increase of carbon structural orders. Iron was found to promote the decrease of d002 value and increase of Lc values of the turbostratic carbon, while the d002 value of the newly formed graphitic carbon is quite below that of the commercial graphite when it just forms at 1200 °C. The melting point of iron particles were decreased due to the significant carbon dissolution into iron, leading to the melting and aggregation of iron. The lattice fringe length and the stacking number of micro-crystal graphite were found to increase obviously, while no clear change of crystal orientation was observed. This indicates that the growth of micro-crystal graphite was along its original orientation. The carbon dissolution – graphite precipitation mechanism can be used to explain the catalytic graphitization process very well.

Formation of five-fold twinning electron diffraction pattern and twinning bands in bulk CuIn3Se5 via hot deformation

We analyzed bulk CuIn3Se5 alloys via transmission electron microscopy (TEM). The high-resolution TEM micrographs showed many twinning bands and doublet periodicity of the (002) lattice planes and corresponding fast Fourier transform patterns revealed the superstructure reflections. The selected area electron diffraction pattern showed the nearly five-fold rotation diffraction spots, which resulted from the four-fold rotation twinning at one point and other twinning bands. The TEM results indicated the CuIn3Se5 alloy deformed by hot press had many multiple-twinned crystallites as well as a high density of twinning in the {112} planes.

Fabricating antimony sulfide Sb2S3 microbars using solvothermal synthesis: effect of the solvents used on the optical, structural, and morphological properties

Antimony trisulfide (Sb2S3) is a promising candidate for cell absorbers due to its appropriate band gap, abundant constituents, non-toxicity, simple composition, and long-term stability. In this study, highly oriented Sb2S3 microbars were prepared utilizing an easy, low-cost solvothermal approach. The effects of the solvents used on the morphological and the crystal structure and optical properties of the Sb2S3 films were inspected using X-ray powder direction (XRD), UV/Vis spectroscopy, and field emission scanning electron microscopy (FESEM). The XRD analysis demonstrated that the Sb2S3 crystals had an orthorhombic phase. The Sb2S3 nanorods/bars mostly grew along the (010) direction. Energy-dispersive X-ray analysis (EDX) peaks had an atomic ratio of 2:3 for Sb:S. UV/Vis absorption spectroscopy showed that the optical energy gap of the Sb2S3 microbars was 1.5 with ethylene glycol as the solvent. Aberration-corrected high-resolution transmission electron microscopy (HRTEM) micrographs demonstrated that the Sb2S3 was dendrite-like consisting of microbars with a standard a length of 8–15 µm and width of 250–400 nm.

Effect of cobalt doping on the electrochemical performance of trimanganese tetraoxide

Nanostructured transition metal oxides (TMO) are potential materials widely explored by researchers for energy storage applications. In this study, spinel trimanganese tetraoxide (Mn3O4) and cobalt doped trimanganese tetraoxide (Co-Mn3O4) was synthesized by using a simple solvent assisted hydrothermal route. Pure Mn3O4 and Co-Mn3O4 nanomaterials were characterized by an x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), UV-diffuse reflectance spectroscopy (UV-DRS), field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM). XRD analysis revealed the body centered tetragonal spinel structure of Mn3O4 and Co-Mn3O4 with a space group as l41/amd (141) and an approximate crystallite size of 45–33 nm. The presence of an Mn–O bond vibration was confirmed using FTIR and the band gap properties were analyzed through UV-DRS. Surface morphology and average grain size were examined using FESEM and HRTEM micrographs as nanosquares and nanospheres with diameter 126 nm and 118 nm, respectively. Electrochemical properties of Mn3O4 and Co-Mn3O4 were evaluated using cyclic voltammograms, charge–discharge curves, and electrochemical impedance spectra (EIS). Pure Mn3O4 showed a specific capacitance of 971 F g−1 at 0.1 A g−1 current density while Co-Mn3O4 achieved relatively higher specific capacitance of 1852 F g−1 at the same current density. It is observed that the increased specific capacitance of Co-Mn3O4 mainly arises from the doping effect. Electrochemical analysis shows that the Co doped Mn3O4 nanomaterials can be a promising electrode material for supercapacitor.

Structural and optical investigations of biosynthesized bunsenite NiO nanoparticles (NPs) via an aqueous extract of Rosmarinus officinalis (rosemary) leaves

Green synthesis of nanoparticles represents an important part of nanotechnology that offers outstanding eco-friendly and financial benefits when compared to conventional methods that use toxic substances and involve complex processes. In this paper, we report a completely green process in which aqueous extract of rosemary leaves containing bioactive molecular compounds (flavonoids, monoterpenoids, phenolic acids, and diterpenoids) acted as both chelating and stabilizing agents to facilitate the synthesis of NiO NPs. Apart from the nickel metal precursor, the synthesis was free of solvents and surfactants in this method to adhere to green chemistry principles and the impartation of environmental benignity. To achieve the aim of the study, structural and optical property analyses of Bunsenite annealed at 500 °C were carried-out using complementary techniques namely high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and UV–Vis-NIR absorption spectroscopy. HRTEM micrographs revealed the self-assembled, highly agglomerated quasi-spherical shaped NPs with a cubic structure and the average size was found to peak at 8.09 ± 0.20 nm. SAED and XRD exhibited the polycrystallinity and the purity of NiO NPs and the average size was found in the range of 11.598–15.527 nm. Besides, EDS depicted the presence of Ni and O in the sample while ATR-FTIR illustrated the Ni-O chemical bonds. From UV–Vis-NIR, the optical band gap amounted to 3.39 eV confirmed the formation of NiO NPs. Thereby, an easy and effective green approach for the synthesis of Bunsenite with efficient properties is reported.

The role of NaOH content, grinding time, and drying temperature in controlling the shape and size of nano ZnO synthesized by a green chemistry approach

Zinc oxide (ZnO) has been widely exploited in different technological applications in virtue of its unique physical and chemical qualities. This study was designed to prepare ZnO nanorods for diagnostic applications using a simple, low cost, and solvent-deficient method with clarifying the effect of different experimental parameters on the shape and the size of the ZnO product. Under different experimental conditions, the synthesis was performed via a solid-state reaction of zinc sulfate and sodium hydroxide using the grinding method. The purity of nano ZnO products was investigated by X-ray diffractometer (XRD) while the size and the shape were demonstrated by high- resolution transmission electron microscopy (HRTEM). The XRD results confirmed the production of pure ZnO nanocrystals. The HRTEM micrographs illustrated the preparation of a mixture of nanospheroids and nanorods particles, nanorods with minor nanospheroids particles, and long nanorods particles when the applied mole ratio of (ZnSO4.7H2O: NaOH) was (1:2), (1:4), and (1:8) respectively. Our findings confirmed the vital role of NaOH in controlling the shape and the particle size of nano ZnO. Since ZnO nanorods can be easily prepared under mild environmentally friendly conditions, it is proposed that the described experimental conditions can be adapted for large scale production.

Optical and Structural Characterization of Honeycomb-Like Ag2S Nanoparticles by a Simplified and Stable Wet Chemical Synthesis Method

The goal of this paper is to present a stable and new formulation route for the synthesis of silver sulfide nanoparticles with stoichiometric Ag2S composition in aqueous solution. The structural, optical, and morphological properties of Ag2S nanoparticles were studied by using characterization techniques such as ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy and x-ray photoelectron spectroscopy (XPS). From the UV–Vis spectrum, the direct and indirect energy gap values of 3.56 and 1.89 eV were calculated, related to direct and indirect transitions of electrons, as an estimation of bandgaps. Also, an optical band gap shift with respect to bulk bandgap is observed reported in the literature and is related to nanoparticle size decrease. Furthermore, from the high-resolution transmission electron microscopy micrograph an orthorhombic crystallographic structure was determined with lattice parameters 4.77 × 6.92 × 6.88 A and the nanoparticle surface showed a honeycomb-like interference pattern. Finally, the expected chemical composition was proved by the low- and high-resolution XPS spectra.

Novel enzymatic synthesis of core/shell AgNP/AuNC bimetallic nanostructure and its catalytic applications

Herein, we report the enzyme-mediated synthesis of bimetallic nanostructure consisting of gold nanoclusters shell- silver nanoparticles core (AuNCs-AgNPs) for catalytic reduction applications. For the synthesis of core AgNPs, thiocholine (TCh), an enzymatic product from the acetylcholinesterase (AChE), and acetylthiocholine (ATCh) interaction was used as a stabilizing agent. The AuNCs-AgNPs was prepared using TCh as a reducing as well as stabilizing agent. The synthesized AuNCs-AgNPs were characterized with help of UV–Vis spectroscopy, dynamic light scattering (DLS) analyses and High-Resolution Transmission Electron Microscopy (HR-TEM). The HR-TEM micrographs confirmed that the formation and arrangement of AuNCs on the core AgNPs, resulting in AuNCs-AgNP bimetallic structures. The catalytic reduction activity of thus prepared AgNPs and AuNCs-AgNPs was investigated against methyl orange (MO) and potassium ferricyanide K3[Fe(CN)6] in the presence of sodium borohydride (NaBH4). The rate constants (k), for MO and K3[Fe(CN)6] catalytic reduction in the presence of AuNCs -AgNPs were measured to be 2.3 × 10−2 s−1 and 1.219 × 10−1 s−1 respectively.

Synthesis, Structural and Optical Investigation of Cdse Semiconductor Quantum Dots

In this paper, we present a simple synthetic route for the development of high quality CdSe quantum dots TGA capped in aqueous solutions. CdSe semiconducting Quantum dots were prepared by a chemical method at room temperature. The crystal structure, morphology, spectral and compositional properties were analyzed from X-ray Diffraction, High resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-VIS absorbance and Photoluminescence (PL), Fourier transform infrared (FTIR) and Fourier transform RAMAN (FT-RAMAN) techniques. The XRD results depicted the formation of CdSe quantum dots with an average crystallite size of 3 nm and 4 nm, which is in accordance with observations from HRTEM and TEM micrographs with an average particle diameter range between 2-3 nm. The UV-VIS absorbance peaks indicate a broad absorption behavior of CdSe quantum dots. The calculated band gap energy is found to be 2.55 eV and further it is found the particle size estimated from the maximum excitonic peaks for CdSe 2.7 nm. The photoluminescence studies evidenced that the luminesce property of quantum dots can be varied by systematically tuning precursor concentrations and the PL confirms the strong excitation peaks for the synthesized CdSe QDs with peak centered at 603 nm. The capping of TGA was confirmed from FTIR and FT-RAMAN studies. From the FTIR spectra it is observed that, for the synthesized CdSe QDs almost all the peaks are common with slightly shifting behavior towards larger and shorter wave numbers. FT-Raman analysis was performed to study the sample qualities such as micro crystallinity, homogeneity and surface conditions for the as synthesized CdSe quantum dot. The resulting colloids are very stable, and no precipitate is observed over a period of 6 months.

The physical properties of bitumen modified with ilmenite and bentonite nanoparticles

ABSTRACT Using nanotechnology in asphalt paving has increased markedly to improve the asphalt characteristics and increase the road life, especially with the significant increase in traffic volumes. The present contribution evaluates the effects of ore nanoparticles namely ilmenite and bentonite on the engineering properties and performance of asphalt binder. The high-resolution transmission electron microscopy (HRTEM) micrograph was used to characterize the investigated nanomaterials. The nanoparticles were blended with asphalt binder with different percentages (0–5% for ilmenite and 0–10% for bentonite by weight of asphalt binder) to determine the appropriate mixing ratio that sustained the desired characteristics. Different tests were conducted to examine the properties of modified asphalt binder among which penetration, softening point, rotational viscosity, penetration index (PI) and ductility. The results of our study revealed an increase in softening point and rotational viscosity and decrease in binder penetration. Moreover, blending of variable amounts of nanomaterials with the asphalt binders has improved their physical properties compared with macroparticles blended and unmodified binders as indicated by the penetration index and ductility test. The most significant improvement in the modified binders was obtained by blending of 5% for two types of nanoparticles. Finally, the rut depth was measured by wheel track test for the modified asphalt mixture, with ilmenite and bentonite, to validate the obtained results. The results show that the engineering performance of asphalt produced from bitumen binder modified with nanoparticles is much better than conventional asphalt and such binder-modified asphalt is strongly recommended for use on site.

Monte Carlo simulations of ion channeling in crystals containing dislocations and randomly displaced atoms

Monte Carlo (MC) simulations are a powerful tool for the analysis of ion-solid interactions. The MC code McChasy (Monte Carlo CHAnneling SYmulation) allows the evaluation of Rutherford Backscattering Spectrometry spectra in the Channeling mode to quantify implantation damage. The code works on common personal computers and takes into account randomly displaced atoms as well as certain types of extended defects. In this paper, we report recent improvements of the McChasy code, including a unique approach to the calculation of impact parameters between ions and target atoms in three dimensions (along with computing thermal vibrations also in three dimensions). Furthermore, the use of a rotation matrix to provide different orientations of dislocation lines and an updated model of edge dislocations were also implemented in the code. Dislocation parameters are obtained directly from high-resolution Transmission Electron Microscopy micrographs. Two case studies are presented to highlight the importance of these improvements: Ni-implanted Al was analyzed as an example of a crystal mainly containing dislocations; Er-implanted ZnO was studied, revealing the strength of MC analysis for materials containing a mixture of different defect types, namely, randomly displaced atoms and dislocations.

Highly Luminescent Ternary Nanocomposite of Polyaniline, Silver Nanoparticles and Graphene Oxide Quantum Dots

Quantum dots (QDs) with photostability show a potential application in optical sensing and biological imaging. In this work, ternary nanocomposite (NC) of high fluorescent polyaniline (PANI)/2-acrylamido-2-methylpropanesulfonic acid (AMPSA) capped silver nanoparticles (NPs)/graphene oxide quantum dots (PANI/Ag (AMPSA)/GO QDs) have been synthesized by in situ chemical oxidative polymerization of aniline in the presence of Ag (AMPSA) NPs and GO QDs. Ag (AMPSA) NPs and GO QDs were prepared by AgNO3 chemical reduction and glucose carbonization methods, respectively. The prepared materials were characterized using UV-visible, Fourier transform infrared (FTIR), photoluminescence and Raman spectroscopies, X-Ray diffractometer (XRD) and high- resolution transmission electron microscopy (HRTEM). HRTEM micrographs confirmed the preparation of GO QDs with an average size of 15 nm and Ag (AMPSA) NPs with an average size of 20 nm. PANI/Ag (AMPSA)/GO QDs NC showed high and stable emission peak at 348 nm. This PANI/Ag (AMPSA)/GO QDs NC can emerge as a new class of fluorescence materials that could be suitable for practical sensing applications.

Superparamagnetic behavior of sulfonated fullerene (C60SO3H): Synthesis and characterization for biomedical applications

Fullerenes were synthesized to form sulfonated fullerenes by novel less cost-effective manner using diethyl ether as solvent. The synthesized sulfonated fullerene was extensively characterized by UV–Vis, FT-IR, FT-RAMAN, XRD, SEM HRTEM, XPS, EPR and VSM. FT-IR characterization reveals the presence of functional SO3H groups and FT-Raman characterization confirms the symmetry of the molecule. UV–Vis spectral analysis endorses red shifting of absorption peak. EPR spectrum, at room temperature with g-factor values, indicates the paramagnetic nature and magnetic ion sites of the samples. Structural changes, in sulfonated fullerene, are observed through Scanning electron microscope (SEM) and High-resolution transmission electron microscope (HRTEM). HRTEM micrographs showed that the sulfonation improves the good dispersion of fullerene in water. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDX) confirm the presence of carbon, sulphur and oxygen element in the molecule. Magnetization studies were measured using a vibrating sample magnetometer (VSM). The sulfonated fullerene exhibited superparamagnetic (SPM) behaviour at 5 K with saturation magnetization value (ms = 0.14 emu/g). The zero-field cooled (ZFC) curve exhibited a blocking temperature Tb which is close to 5 K. Such superparamagnetic studies attempted for the first time in this work for sulfonated fullerene and the result displays potential applications in the field of magnetically guided drug delivery and can be envisaged as a good agent for various biomedical and engineering purposes in future.

A facile synthetic approach and optical properties of AuNPs/CdSe tetrapod and AuNPs/CdSe@rGO nanocomposites

New heterostructures (tetrapods-like shape) were synthesized using AuNPs/CdSe hybrid nanocomposites in a facile synthetic route. The growth mechanism of such heterostructures was based on “Direct Heterogeneous Deposition” mechanism, in which the heterogeneous nucleation growth of CdSe arms (nanorods) structured at the nucleating sites on the surface defects of gold nanoparticles. The heterostructures were characterized using high-resolution transmission electron microscope (HRTEM), high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), energy dispersive X-ray analysis (EDX), absorption, and emission measurements. The proposed growth mechanism was confirmed using HRTEM micrographs. A significant enhancement in the emission properties has been noticed upon the loading of these new heterostructures on reduced graphene oxide (rGO). Fluorescence measurements provided useful insight into the variations in the photophysical properties when rGO is introduced into metal/semiconductor hybrid nanocomposites. The fabricated heterostructures show significant photocatalytic activity in the presence of rGO, compared to pure AuNPs/CdSe tetrapods. It was readily seen that 73.5% of methylene blue (MB) had been degraded by AuNPs/CdSe@rGO tetrapod heterostructures after 80 min of solar irradiation compared to 26.6% and 39% in the absence and presence of AuNPs/CdSe nanocomposites.

Development of nano-silver doped zeolite A synthesized from Nigerian Ahoko kaolin for treatment of wastewater of a typical textile company

In this work, nano-silver synthesized with mango leaf extract as a reducing agent was doped onto synthesized zeolite A (SZA), produced from Nigerian kaolin via green synthesis route. The produced adsorbents were characterized using X-ray fluorescence (XRF), X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) surface analysis, in addition, it is to be used for the treatment of local textile effluent. The physicochemical parameters of the effluent were analyzed using standard methods. The HRTEM micrographs revealed well dispersed AgNPs on SZA and the BET surface area revealed high surface areas of 119.98 m2/g and 436.44 m2/g for SZA and silver-doped zeolite A (SDZA), respectively. The array of removal of the pollutants was BOD > COD > CN->Cl->NO2->TOC for SZA and CN->BOD > COD > NO2->Cl->TOC for SDZA, with the doped adsorbent removing the higher pollutants in all cases. Isothermal models indicated that Jovanovic model (R2>0.999) was most suitable for describing the adsorption process, which conformed to pseudo-second order kinetics with intraparticle diffusion of micropore type. The thermodynamic studies showed spontaneous and endothermic reactions.