Scanning Electron Microscopy And Energy Dispersive X-ray Research Articles

Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks.

In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale.

Comparison of acid and alkaline pre-treatment on methane production from empty palm oil fruit bunches (OPEFB): Effect on characteristics, digester performance, and correlation of kinetic parameters

This paper focused on comparing the impact of two different chemical pretreatments on various characteristics of OPEFBs (i.e., physical, structural, and morphological properties), methane production, digestate characteristics, and kinetic modelling. The biochemical methane potential (BMP) test showed that alkaline-treated OPEFBs produced higher methane yields than acid-treated OPEFBs. Accordingly, the methane yields became far higher after NaOH pretreatment, showing 0.186–0.224 m3CH4/kg VSadded compared with 0.102 m3CH4/kg VSadded and 0.093–0.115 m3CH4/kg VSadded from untreated and acid-treated OPEFBs. The best treatment was alkaline pretreatment of P2N3, which gave the highest methane yield increase (by 1.2-fold). The Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX) results of acid-treated OPEFBs indicated disruption of cell wall and loss of some minerals. However, alkaline-treated OPEFBs have more pores due to silica and other chemicals releases (i.e., lignin, hemicellulose, etc.). The kinetic study showed that all models (i.e., modified Gompertz, logistic, and transference) were in good agreement with the experimental data. Both experimental data and models confirmed P2N3 (i.e., NaOH concentrations of 3.8%) as the best results, indicated by the highest lignin reduction and methane production. This study showed an excellent opportunity to digest alkaline-treated OPEFBS, yet more in-depth investigations with sustainability and circular economy perspectives are needed.

Influence of carbon and graphene oxide nanoparticle on the adhesive properties of dentin bonding polymer: A SEM, EDX, FTIR study.

This study was aimed at including 2.5 wt.% of carbon nanoparticles (CNPs) and graphene oxide NPs (GNPs) in a control adhesive (CA) and then investigate the effect of this inclusion on their mechanical properties and its adhesion to root dentin. Scanning electron microscopy and energy dispersive X-ray (SEM-EDX) mapping were conducted to investigate the structural features and elemental distribution of CNPs and GNPs, respectively. These NPs were further characterized by Raman spectroscopy. The adhesives were characterized by evaluating their push-out bond strength (PBS), rheological properties, degree of conversion (DC) investigation, and failure type analysis. The SEM micrographs revealed that the CNPs were irregular and hexagonal, whereas the GNPs were flake-shaped. EDX analysis showed that carbon (C), oxygen (O), and zirconia (Zr) were found in the CNPs, while the GNPs were composed of C and O. The Raman spectra for CNPs and GNPs revealed their characteristic bands (CNPs-D band: 1334 cm-1, GNPs-D band: 1341 cm-1, CNPs-G band: 1650 cm-1, and GNPs-G band: 1607 cm-1). The testing verified that the highest bond strength to root dentin were detected for GNP-reinforced adhesive (33.20 ± 3.55 MPa), trailed closely by CNP-reinforced adhesive (30.48 ± 3.10 MPa), while, the CA displayed lowest values (25.11 ± 3.60 MPa). The inter-group comparisons of the NP-reinforced adhesives with the CA revealed statistically significant results (p < 0.01). Failures of adhesive nature were most common in within the adhesives and root dentin. The rheological assessment results demonstrated a reduced viscosity for all the adhesives observed at advanced angular frequencies. All the adhesives verified suitable dentin interaction shown by hybrid layer and appropriate resin tag development. A reduced DC was perceived for both NP-reinforced adhesives, compared to the CA. The present study's findings have demonstrated that 2.5% GNP adhesive revealed the highest, suitable root dentin interaction, and acceptable rheological properties. Nevertheless, a reduced DC was observed (matched with the CA). Prospective studies probing the influence of diverse concentrations of filler NPs on the adhesive's mechanical properties to root dentin are recommended.

Microcrystalline Cellulose of Oil Bean Pod: Extraction, Physico-chemical, Brunauer–Emmett–Teller (BET), and Flow-ability Analysis

Oil bean pods (OBPs) are a biomass that are indiscriminately dumped in eastern Nigeria, thus causes a lot of pollution. In this study, microcrystalline cellulose (MCC) was isolated from oil bean pods using acid hydrolysis, and several characterizations were performed using a variety of sophisticated techniques. Fourier transform infrared (FTIR) spectroscopy analysis has indicated the removal of lignin and hemicellulose from MCC extracted from oil bean pods. Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX) revealed a rough surface and minor agglomeration of the MCC. Furthermore, the isolated MCC has slightly higher inorganic minerals than the raw oil bean pod on the basis of SEM-EDX and the ash content. The Brunauer–Emmett–Teller (BET) analysis reveals that the specific surface area of MCC is 331.94 m2/g, which is greater than that of OBP, with 164.728 m2/g. Other characteristics like pore volume, and average pore diameter or size demonstrate that MCC has a superior property than the raw OBP. This implies that MCC could serve as a better adsorbent than the raw OBP. As a result of the increased surface area and high percentage of MCC, which is associated to chemical treatment of raw OBP, MCC can be used in environmental remediation of heavy metals. The bulk density of MCC was recorded at 0.447, which is slightly above the United States Pharmacopeia (USP) specification of 0.32, and the tapped density was recorded at 0.532. The flow ability of MCC powder determines its suitability as a direct compression binder. Thus, the isolated MCC might be used as a reinforcing element for the production of green composites, binder, adsorbents, and plastic polymers.

Magnetic Field Effect on Coagulation Treatment of Wastewater Using Magnetite Rice Starch and Aluminium Sulfate.

The use of synthetic coagulants to reduce suspended particles from drinkable water and wastewater is prompting new issues because it poses many health and environmental risks. Hence, improving the coagulation process using sophisticated nanotechnology with a magnetic field (MF) for quick recoverability emerges as being useful. In this study, the effects of magnetite rice starch (MS) and aluminum sulfate (alum) were investigated at a constant dose (3 g or 3000 mg/L) using a Jar test (six beakers) as potential low-cost coagulants for industrial wastewater treatment. At a high magnification of 1000× and a surface pore size of 298 µm, scanning electron microscopy and energy dispersive X-ray (SEM/EDX) analyses were utilized to elucidate the morphology of the coagulants. Coagulation was performed at 150 rpm (quick mixing) for 2 min, and 30 rpm (slow mixing) for 15 min. Thereafter, samples were allowed to settle (10-60 min) with and without MF. The findings showed more than 65% contaminants removal (turbidity and TSS) and 30% chemical oxygen demand (COD) removal using alum while MS showed 80% contaminants removal (turbidity and TSS) and 50% COD removal. MS showed an increase of more than 3% in contaminants removal (COD, turbidity, and TSS) when exposed to MF. As a result, the use of MS together with MF in water and wastewater treatment is anticipated as an environmentally benign and effective coagulant.

ZnMnFe2O4 particle synthesized by natural iron sand for making permanent magnetic material

Synthesis of ZnMnFe2O4 has been carried out using the co-precipitation method. The main precursors were stoichiometry with variations in the mass of Zn, Mn, and natural iron sand are 3:2:5 as sample 1, 3:2:4 as sample 2, and 3:4:3 as sample 3. The samples were calcination temperature of 500 °C for 2 h. The characterizations showed microstructure properties using X-ray diffraction (XRD), morphology properties using Scanning electron microscopy and energy dispersive X-ray (SEM-EDX), and magnetic properties tested using a Vibrating sample magnetometer (VSM), respectively. The crystal structure of ZnMnFe2O4 shows a cubic crystal structure as well as the main phase with no detectable impurities or other elements in the diffraction pattern. The effect of adding the composition of manganese to the sample shows that the value of the crystal diameter size increasing with the optimum value of 3.41 nm. The effect of material composition on the morphology of ZnMnFe2O4 is shown in the SEM-EDX results. As the composition of manganese and iron sand increases, the particle size distribution also increases with the optimum average particle size of 205–210 nm. The value of coercivity (Hc) of ZnMnFe2O4 decreases as the iron sand composition decreases and the manganese composition increases, but the value of the magnetic energy increases. The coercivity value is obtained with the optimum value of 415.78 Oe and ZnMnFe2O4 is to be potentially a magnetic permanent material.

Continuous manufacturing of vitamin D3 and iron enriched granules by means of a novel twin-screw dry granulation process

A multi-disciplinary approach involving continuous manufacturing (CM) of thermally stable food supplements containing vitamin D3 (VitD3) and iron (Fe ++ ) via a single-step twin-screw granulation (TSG) process was tested in this work. Two selected excipients, namely Neusilin® US2 and corn starch, were used in the work. The particle size distribution and morphology of pre-mixed and post-extruded granules were investigated with a laser diffraction particle size analyzer, sieve analysis, scanning electron microscopy and energy dispersive X-ray (SEM-EDX), X-ray powder diffraction (PXRD), and polarized light microscopy (PLM). The thermal stability of the granules was assessed through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The SEM visualized a good distribution of all ingredients without the forming of any crystals on the extrudate surface, indicating good mixing during the high shear granulation inside the extruder barrel. The FT-IR analysis demonstrates that characteristic vibration peaks of VitD3 were present in all physical mixtures as well as the extruded granules, indicating that VitD3 was stable in the formulations despite the high shear mixing during the TSG. The mean volumetric diameter (Dv50) of the formulation containing Neusilin increased significantly ( P < 0.05) to 90.8-μm when compared with neat Neusilin (71.3-μm) and VitD3 (33.8 μm) confirming granulation, however, no improvement was observed for the corn starch blend. In addition, the calculated Hausner ratio (HR) and Carr's index (CI) suggest similar inter-particulate friction of VitD3 and Neusilin, whereas corn starch showed a difference. The surface elemental analysis confirmed the presence of Fe ++ with a homogenous distribution of the metal in the granules. Overall, for the first time, the blend of VitD3 and iron has been prepared using the CM platform, which has great potential for the intervention of VitD3 and iron deficiencies. • Twin screw dry granulation is employed to develop vitamin D3 and iron granules. • Neusilin and corn starch are used as excipients for the blend. • Particle size distributions and morphology confirm the formation of granules. • Vitamin D3 remained almost constant in the TSG process.

Model prediction of coagulation by magnetised rice starch for wastewater treatment using response surface methodology (RSM) with artificial neural network (ANN)

This study synthesized magnetized rice starch (MRS) with recoverability benefits as an alternative coagulant for the coagulation treatment of industrial wastewater. The MRS was characterization by scanning electron microscopy and energy dispersive X-ray (SEM/EDX) and Brunauer–Emmett–Teller (BET). The engineered rice starch with BET surface area of 31.44 m2/g and cationic elementals showed good agglomeration behavior. Three process variables (coagulant dose, settling time, and mixing rate) were model and optimized for the coagulation removal efficiency of turbidity, color, and phosphate. Using the response surface methodology (RSM), Box-Behnken design (BBD) with 17 experimental runs was used to model and optimized the experimental parameters. At optimal conditions of coagulant dosage of 4 g, settling time of 15 mins, and mixing rate of 50 rpm resulted in removal efficiency of 72 %, 53.2 %, and 56.5 %, respectively for turbidity, color, and phosphate. This infers a desirability efficiency of 82.6% was attained via analysis of variance (ANOVA) at a 95% confidence level. The experimental results showed close agreement with the RSM and artificial neural network (ANN) model prediction. Results of the model's prediction significance (P <0.05) were compared in terms of coefficient of determination (R2 = 0.994) for the ANN model and RSM model (R2 = 0.97). Inclusively, the use of RSM and ANN for coagulation process optimization using magnetized rice starch is viable for wastewater management for reuse. Therefore, exploring the potency of the magnetized rice starch in real world application warrants the model adaptability to estimate its cost benefit.

Effect of Engineered Biomaterials and Magnetite on Wastewater Treatment: Biogas and Kinetic Evaluation.

In this study, the principle of sustaining circular economy is presented as a way of recovering valuable resources from wastewater and utilizing its energy potential via anaerobic digestion (AD) of municipality wastewater. Biostimulation of the AD process was investigated to improve its treatability efficiency, biogas production, and kinetic stability. Addressing this together with agricultural waste such as eggshells (CE), banana peel (PB), and calcined banana peels (BI) were employed and compared to magnetite (Fe3O4) as biostimulation additives via 1 L biochemical methane potential tests. With a working volume of 0.8 L (charge with inoculum to substrate ratio of 3:5 v/v) and 1.5 g of the additives, each bioreactor was operated at a mesophilic temperature of 40 °C for 30 days while being compared to a control bioreactor. Scanning electron microscopy and energy dispersive X-ray (SEM/EDX) analysis was used to reveal the absorbent’s morphology at high magnification of 10 kx and surface pore size of 20.8 µm. The results showed over 70% biodegradation efficiency in removing the organic contaminants (chemical oxygen demand, color, and turbidity) as well as enhancing the biogas production. Among the setups, the bioreactor with Fe3O4 additives was found to be the most efficient, with an average daily biogas production of 40 mL/day and a cumulative yield of 1117 mL/day. The kinetic dynamics were evaluated with the cumulative biogas produced by each bioreactor via the first order modified Gompertz and Chen and Hashimoto kinetic models. The modified Gompertz model was found to be the most reliable, with good predictability.

Surface coatings of polyester fabrics using titanium dioxide and zinc oxide for multifunctional medical applications

Medical textiles require essential properties to achieve their functional performance efficiency. At present, nanoparticles (NPs) play an important role to improve the properties of textile applications. This study featured four manufactured polyester fabrics with different specifications using plain 1/1 structures. Titanium dioxide and zinc oxide (TiO2 NPs/ZnO NPs) were used to treat the manufactured samples; and demonstrate the possibility of enhancing the dyeing properties of polyester fabrics parallel with self-cleaning, ultraviolet (UV) resistance and antibacterial properties. Some mechanical properties were measured to investigate the performance of manufactured samples, and modification was confirmed by scanning electron microscopy and energy dispersive X-ray (SEM/EDX). One-way analysis of variance (ANOVA) was used to statistically analyze the significant differences between the results of the mechanical properties pre- and posttreatment. It is further demonstrated that the Ultraviolet Protection Factor (UPF) value of treated samples with TiO2 NPs shows high UV radiation protection followed by samples treated with ZnO NPs as compared with untreated samples. Furthermore, the photocatalytic properties of TiO2 and ZnO NPs show better self-cleaning activity as compared to untreated fabrics. The color strength of two disperse dyes is improved with the incorporation of both TiO2 and ZnO NPs in treated polyester fabric. In addition, the antibacterial activities of the treated undyed samples coded (Z15, Z33 and Z27) have excellent results against pathogenic bacterial strains and fungal yeast and this is maintained in the treated dyed sample coded (Z33) after washing it five times.

Investigation of the Conditions for Preconcentration of Cadmium Ions by Solid Phase Extraction Method Using Modified Juglans regia L. Shells.

Juglans regia L. shells as agricultural waste can be considered as alternative sorbents to minimize the problems associated with heavy metal pollution. In this study, J. regia shells (JRS) and JRS modified with hydrazine hydrate (JRS-HH) were used as sorbents and compared for the preconcentration of Cd(II) ions from aqueous solution. For the characterization of sorbents, scanning electron microscopy and energy dispersive X-ray (SEM/EDX) analysis and Fourier transform infrared (FTIR) spectroscopy were used. For preconcentration, the solid phase extraction (SPE) technique was used. Preconcentration studies were performed by column method and pH, eluent type and concentration, sample volume, flow rate, and interfering ions effect were studied to determine the optimum column parameters. The limit of detection (LOD) of the sorbents (JRS and JRS-HH) are 0.31 and 0.18 µg/L, respectively. According to the Langmuir isotherm model for both sorbents, for JRS KL = 0.030 L/mg, R2 = 0.992, 0.016 L/mg, and for JRS-HH KL = 0.016 L/mg, R2 = 0.998 and maximum adsorption capacities of the sorbents were found to be as 29.6 and 65.7 mg/g, respectively. The mean recoveries and RSD values at a 95% confidence level (N = 6) for Cd(II) were 100.9% and 3.42, and 100.6% and 3.79, for the JRS and JRS-HH sorbents, respectively. Using this method good results were obtained when compared with those in the literature and the proposed method was successfully applied to the analysis of the certificated reference material (NIST 1640). JRS are an effective and inexpensive sorbent for the preconcentration of metal ions when modified. Thus, low-cost agricultural wastes are both recovered and have an economic value.

Application of metallic nanoparticles for biogas enhancement using the biomethane potential test

Owing to the continued global environmental crisis, wastewater treatment is seen with great potential to limit the demand on freshwater usage while contributing to depletion of global warming with alternative source of renewable energy. Thus, in the wastewater settings, anaerobic digestion (AD) reduces organic pollutants while generating green energy in the form of biogas. However, AD is a relatively slow microbial–based process, which has become a major challenge to produced methane–enriched biogas. Therefore, augmentation of AD was investigated via the addition of metallic–based nanoparticles (NPs) (Fe, Cu, and Ni) at a concentration of 1 g and 2 g. Scanning electron microscopy and energy dispersive X-ray (SEM/EDX) were used to track the NPs distribution and utilisation in the post-AD digestate. A biomethane potential (BMP) technique was employed with 1 L Duran schott bottles. This was operated at a working volume of 0.8 L (0.3 L inoculum and 0.5 L wastewater), hydraulic retention time of 10 days and mesophilic temperature 40 °C. The wastewater treatability performance showed over 65% removal of chemical oxygen demand (COD), turbidity and colour. The NP additives showed a synergetic effect on biogas production as it hinged on the NPs type and concentration (1 g Fe-NPs > 2 g FeNiCu-NPs > 1 g Cu-NPs > 2 g Cu-NPs > 1 g Ni-NPs > 2 g Ni-NPs > 2 g Fe-NPs). Usage of 1 g of Fe NPs balanced the nutrient supply of the microbes, which increased the biogas production (by 75% >3 mL/d of the control) with 100% methane composition. The prospects of Fe-based NPs seems very promising and industrially worthy for wastewater treatment and bioenergy production. This warrants future research into NPs recovery and reuse as a way of mitigating its economic viability and environmental risk.

Characterization of Seashell Waste through Calcination Process

Seashell waste found in Tanjung Baru Beach, Karawang, which has not fully utilized. This waste can be widely used as an environmentally friendly material in various fields. Seashell waste is the source of CaCO 3, and throughout the calcination process at the correct temperature, it can be converted to CaO. The purpose of the calcination process is to obtain a solid CaO by releasing CO 2 gas. The calcination process can carry out at temperatures of 800 ℃, 900 ℃, and 1000 ℃ with a calcination time of 2 hours, 3 hours, and 4 hours. The seashell waste is characterized and analyzed using the Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy, and Energy Dispersive X-Ray (SEM-EDX). Before and after the calcination process, the FTIR spectrum of seashells is around 710 cm -1 - 1476 cm -1 , a characteristic peak of the C-O group from CaCO 3. The spectrum of 3429 cm -1 - 3468 cm -1 is a characteristic peak of the O-H group from Ca(OH) 2 . The spectrum 2513.25 cm -1 is a characteristic peak of the C-H group containing CaO appearing after calcination. The seashell powder is analyzed by using SEM-EDX with the result where the most dominant elements are C (18.43%), O (52.07%), and Ca (27.86%) from the calcined shells. The elements C, Na, Al, Si, Fe, and Cu, are zero due to the heating process (calcination). The calcined seashell has also shown a rough surface and irregularly shaped particles.

Fabrication of ZnO-SiO2 Nanocomposite Materials Prepared by a Spray Pyrolysis for the Photocatalytic Activity under UV and Sunlight Irradiations

ZnO is the most widely used for photocatalytic application among various semiconductor materials. The photocatalytic performance of ZnO can be enhanced by doping with other materials. In this study, ZnO-SiO2 nanocomposites have been successfully fabricated by gas-phase method via spray pyrolysis. The effect of temperature of spray tubular furnace reactor ranging from 300 to 600 °C on the photocatalytic activity of ZnO-SiO2 nanocomposites were investigated. Colloidal SiO2 with concentration at 1 %wt was used as dopant to ZnO particles. The pristine ZnO was also synthesized at temperature of 400 °C for comparable. Zinc acetate and water glass were used as the precursors for fabrication ZnO-SiO2 nanocomposites. At first, the water glass was synthesized by sol-gel method to produce colloidal SiO2 nanoparticles and then mixed with zinc acetate before subjecting to the spray reactor. The produced nanocomposite materials were collected by an electrostatic precipitator. Scanning electron microscopy and energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) were used for characterization the products. While UV-Vis spectrometry was used to measure the concentration of methylene blue (MB) before and after irradiations. SEM images indicated that the morphology of particles was as sphere-like structures with interwoven nanoplate and the agglomeration of particles can be suppressed by adding SiO2. The average particle size of the produced nanocomposite decreased with increasing synthesis temperature. XRD analysis also confirmed that the crystallite size increased with increasing temperature. Finally, the photocatalytic activity of the ZnO-SiO2 nanocomposites were calculated by evaluating the methylene blue degradation aqueous solution under UV and sunlight irradiations. MB degradation efficiency under UV light was much lower than that of under sunlight irradiation. It also showed that the best photocatalytic performance reached 96 % when the synthesis temperature was set as high as 400 °C with SiO2 concentration at 1 %wt under sunlight irradiation.

One-pot combustion synthesis of nickel oxide and hematite: From simple coordination compounds to high purity metal oxide nanoparticles

This work is the first report of a very simple and fast one-pot synthesis of nickel oxide (NiO) and hematite (?-Fe2O3) nanoparticles by thermal decomposition of transition metal aqua complexes with camphor sulfonate anions. Obtained nanopowders were characterized by X-ray powder diffraction, Fourier transform IR analysis, scanning electron microscopy, and Energy-dispersive X-ray spectroscopy. X-ray powder diffraction confirmed the formation of high purity NiO and ?-Fe2O3 crystal phases. In the case of ?-Fe2O3, about five times larger average crystallite size was obtained. Fourier transform IR spectra of synthesized materials showed characteristic peaks for NiO and ?-Fe2O3 nanostructures. To visualize the morphology and the chemical composition of the final products Scanning electron microscopy and Energy-dispersive X-ray spectroscopy were performed. The thermogravimetric analysis was done for a better understanding of the general thermal behavior of precursor compounds. This easy-to-perform and fast preparation method opens a broad range of obtained materials? usage, particularly due to its economic viability

Refractory osmium targets for accelerator based nuclear activation experiments prepared by Pulsed Laser Deposition technique

This work is meant to respond the challenge of manufacturing osmium targets for nuclear astrophysics experiments using the activation method with alpha particles. In this context, PLD (Pulsed Laser Deposition) was used to prepare osmium targets without specks or wrinkles and with a very well defined and constant thickness. Characterization techniques as RBS (Rutherford Backscattering Spectrometry), AFM (Atomic Force Microscopy), SEM/EDX (Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy) and XRD (X-ray Diffraction) were used to determine accurately the features of the obtained targets. The obtained results reveal that the PLD technique is suitable for the preparation of high quality thin/thick osmium targets.

Mineralogical Characterization and Determination of Refractoriness of Malaysian Gold Ore

This study aims to conduct mineralogical characterization and determine the refractoriness of gold ore from Eastern Coast of Peninsular Malaysia. Elements presence in the sample were investigated using X-ray fluorescence (XRF) analysis while X-ray diffraction (XRD) method was used for the identification of mineral phases. Polished sections samples were studied by optical microscopy (OM), scanning electron microscopy and energy-dispersive X-ray (SEM/EDX). XRD phase analysis showed the presence of mineral phases of quartz, iron sulphide and silicate minerals, which were confirmed by XRF with the elements detected as Si, O, Al, Fe, As and S. From SEM/EDX analysis, gold was found mostly interlocked in sulphide minerals such as arsenopyrite, galena and others. Fire assay and cyanide bottle roll test were employed on the bulk samples to assay the gold content and free gold, respectively. Atomic Absorption Spectrometry (AAS) revealed the gold content to be 31 gram per tonne in the sample. The cyanide bottle roll test determined the free gold assay of 16 gram per tonne. These findings imply that the samples contained free gold of about 52% along with gold present interlocked with minerals unfavourable to cyanidation, which further provide valuable information in terms of the refractoriness of the gold for further processing.

Effect of POSS Particles and Synergism Action of POSS and Poly-(Melamine Phosphate) on the Thermal Properties and Flame Retardance of Silicone Rubber Composites.

This article presents flame retardant compounds for silicone rubber (SR) in the form of polyhedral oligomeric silsequioxanes (POSS), containing both isobutyl groups and amino-propyl (AM-POSS) or chloro-propyl group (HA-POSS) or vinyl groups (OL-POSS). Silsequioxanes were incorporated into the silicone rubber matrix in a quantity of 3 and 6 parts by wt by the method of reactive stirring with the use of a laboratory mixing mill. Based on the analyses performed by TG (Thermogravimetry) FTIR (Fourier Transform Infrared Spectroscopy), conical calorimeter, and SEM-EDX (Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy) methods, the thermal degradation mechanism of non-cross-linked and cross-linked silicone rubber has been elucidated. The effects of POSS, and POSS in a synergic system with melamine polyphosphate (MPP), on the thermal properties and flammability of silicone rubber composites were presented. Based on the test results obtained, a mechanism of flame retardant action POSS and POSS-MPP has been proposed. It has been shown that POSS, especially with MPP, considerably increases the thermal stability and decreases the flammability of the SR rubber composites under investigation.

Activated Carbon-Assisted Fabrication of Cost-Efficient ZnO/SiO2 Desulfurizer with Characteristic of High Loadings and High Dispersion

With the aid of activated carbon, a series of mesoporous ZnO/SiO2 sorbents are fabricated by sol–gel method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), N2 adsorption and desorption, scanning electron microscopy and energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM), and photoluminescence (PL) spectra. The dynamic tests for H2S capture show that the prepared materials with the aid of AC exhibit excellent performance for H2S capture. The highest sulfur capacity of ZSC-X reaches to 160.95 mgS/g sorbent and the corresponding ZnO utilization is up to 69.02%. The enhanced performance is attributed to AC, which has double roles in this study: anchor and confine ZnO to get highly dispersed small nanoparticles; produce more oxygen vacancies in ZnO to facilitate lattice diffusion. The formation mechanism of well dispersed ZnO nanoparticles is also elucidated. The simply fabricating method of sorbents with high ZnO loading and high utilization is of signifi...

Sorption of Hg(II) and Pb(II) Ions on Chitosan-Iron(III) from Aqueous Solutions: Single and Binary Systems.

The present work describes the study of mercury Hg(II) and lead Pb(II) removal in single and binary component systems into easily prepared chitosan-iron(III) bio-composite beads. Scanning electron microscopy and energy-dispersive X-ray (SEM-EDX) analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and point of zero charge (pHpzc) analysis were carried out. The experimental set covered pH study, single and competitive equilibrium, kinetics, chloride and sulfate effects as well as sorption–desorption cycles. In single systems, the Langmuir nonlinear model fitted the experimental data better than the Freundlich and Sips equations. The sorbent material has more affinity to Hg(II) rather than Pb(II) ions, the maximum sorption capacities were 1.8 mmol·g−1 and 0.56 mmol·g−1 for Hg(II) and Pb(II), respectively. The binary systems data were adjusted with competitive Langmuir isotherm model. The presence of sulfate ions in the multicomponent system [Hg(II)-Pb(II)] had a lesser impact on the sorption efficiency than did chloride ions, however, the presence of chloride ions improves the selectivity towards Hg(II) ions. The bio-based material showed good recovery performance of metal ions along three sorption–desorption cycles.