Background: Fe3O4/Carbon nanoparticles have attracted attention in a wide variety of applications. To make them more biocompatible, surface modification is required. A submerged arc discharge as a common technique has been reported in recent patents and research articles for carbonbased nanomaterials synthesis and possibly applied for those material modifications at once. However, the influence of liquid medium used on the materials surface properties has not been disclosed in detail in recent literature and patents. Objective: Therefore, this study aims to analyze the influence of ammonia addition on the surface characteristics of the Fe3O4/C particles produced in a submerged arc discharge using various ammonia concentrations. Method: The intended nanoparticles were produced and modified in a single process by submerged arc discharge in a liquid medium of ethanol added with ammonia. Applying a direct current (DC) of 10A (20V), the arc discharge occurred in a narrow gap between a carbon anode and carbon-mixed iron oxide cathode. During the arc discharge, active plasma species including ions, electrons, and radicals containing atoms available in the liquid medium were created in the plasma zone, and further interacted within to become an amine-modified Fe3O4/C composite. The surface characteristics were studied by Fouriertransform infrared (FTIR) spectrometer and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) spectrometer. Results and Conclusion: The spectra generated by FTIR of Fe3O4/C showed a broad peak at a wavenumber of 4000-3000 cm-1 representing O-H and N-H intramolecular hydrogen bonding. Moreover, new peaks were observable for C-N stretching and N-H bending, neither of which was observed in the FTIR spectrum of Fe3O4/C without added ammonia. According to electron imaging, the nanoparticles formed regular spherical aggregations. In addition, EDX results confirmed that the nanoparticles produced in the arc discharge with ammonia addition process had an atomic percentage composition wherein the number of nitrogen atoms increased with an increasing concentration of ammonia. Nitrogen was absent in the synthesized nanoparticle solids without added ammonia, indicating that the nitrogen presumably comes from the amine groups. However, increasing the ammonia concentration led to the amine groups transforming into the other groups such as amides and nitroaromatic compounds due to the excessive oxidation. Keywords: Amine, ammonia, arc discharge, carbon, Fe3O4, surface modification.
High strength lightweight glass-ceramics were fabricated by using waste flyash as main raw material. The effects of the utilization rate of the fly ash, nucleation agents, and sintering temperature on the properties of the glass-ceramics were studied. The flyash utilization rate as high as 70% was achieved in realizing an optimal glass-ceramics property at a sintering temperature of 1300 °C. When nucleation agents of Fe2O3 (6.5 wt.%) and TiO2 (3 wt.%) are used, the glass-ceramics sintered at 1300 °C showed maximal property with a minimal water absorption (~0) and a maximal flexural strength (146.7 MPa) but the highest density (2.72 g/cm3). This high strength glass-ceramics may be a promising building material and proppant material for hydraulic fracturing production of petroleum. This work discussed the useful patents in the field of application and invention of glass-ceramics. Keywords: Flyash, integrated utilization, glass-ceramics, high strength, building material, proppant, optimization.
Background: The current scenario requires the rubber industries to develop cheaper and environmentally friendly fillers as an alternative to the conventionally used carbon black filler. Objective: This study aims at developing new NBR/PVC oil seals for automotive applications using CB-HNT hybrid fillers. Method: In various patents, FESEM and XRD were used to study the microstructure of the samples. Tensile and tear tests were conducted by using a universal testing Machine. Hardness and compression set were studied using shore a hardness tester and compression set. Thermogravimetric analysis is used to evaluate the thermal stability of the samples. Results: The tensile strength, elongation at break, 100% modulus, tear strength and swelling resistance of the NBR/PVC hybrid nanocomposites are increased by 12.87%, 13.91 %, 14.65%, 33.58%, and 25.9 %, respectively compared to the conventional composites. Hardness and compression set of the nanocomposites had improved significantly. Incorporation of HNT in carbon black filled NBR/PVC composites improved the thermal stability with an increment of 4.42 °C in the maximum degradation temperature. XRD and FESEM studies reveal the intercalation of NBR/PVC chains, CB and other ingredients into the HNT galleries and formation of intercalated structures. Conclusion: The results demonstrate that the synergistic effect of CB-HNT hybrid fillers, improved NBR/PVC-CB-HNT interfacial interactions and formation of intercalated structures are believed to be responsible for the superior mechanical properties, swelling resistance and thermal stability of the NBR hybrid nanocomposites. Keywords: Oil seal, NBR/PVC, halloysite nanotube, intercalation, mechanical properties, thermal stability, carbon black, swelling resistance.
The use of graphene-related two-dimensional (2D) materials in water treatment have gained tremendous attention in diminishing the worldwide water scarcity owing to their unique water transport properties, high surface area, excellent mechanical strength, non-corrosive features and tunable surface chemistry as discussed in patents. Graphene oxide (GO) has also received extensive coverage in water treatment processes as a promising adsorbent candidate because of its higher adsorption capacity for the removal of several hazardous contaminants. Compared to the conventional adsorbents, GO may offer several advantages; such as two basal planes available for toxin adsorption, scalable production, oxygen- containing functional groups and catalyst free conditions. The current review is focused on the synthesis methods, chemical, and adsorption properties of GO, and their applications for the removal of heavy metal species. Keywords: Graphene, heavy atoms, graphene oxide, adsorption, two-dimensional, remediation.
Background: Hydrogen is considered a clean energy carrier. Ammonia-borane (AB, NH3BH3) has been attracted considerable attention as a potential chemical hydrogen storage material. Objective: To improve the catalytic activity for hydrogen production of AB hydrolysis, to develop a catalyst with high activity is urgently needed. Method: The patents relating to the catalytic hydrolysis of AB for hydrogen production are reviewed. We successfully synthesized ginkgo leave-derived carbon by pyrolysis and chemical activation. Then, ruthenium particles were supported on this porous carbon (Ru/GC) by in situ reduction. Results: The as-prepared Ru/GC catalysts for AB hydrolysis exhibit high activity (TOF = 921 molH2·molRu -1·min-1) and low activation energy (Ea = 23.86 kJ·mol-1). Moreover, fairly good recyclability with 58% of the initial catalytic activity is retained after five cycles. Conclusion: The high catalytic performance and easy preparation demonstrate that Ru/GC is a highly efficient catalyst towards AB hydrolysis. Keywords: Porous carbon, ruthenium, ammonia-borane, hydrolysis, hydrogen production, catalytic activity, stability.
