Sorption of Nanomaterials to Sandstone Rock

We investigated the interaction of silica nanostructured particles and sandstone rock using various experimental approaches, such as fluid compatibility, batch sorption and single-phase core-floods. Diol and polyethylenglycol (PEG) surface-modified nanostructured silica materials were tested using two brines differing in ionic strength and with the addition of sodium carbonate (Na2CO3). Berea and Keuper outcrop materials (core plug and crushed samples) were used. Core-flood effluents were analysed to define changes in concentration and a rock’s retention compared to a tracer. Field Flow Fractionation (FFF) and Dynamic Light Scattering (DLS) were performed to investigate changes in the effluent’s size distribution. Adsorption was evaluated using UV–visible spectroscopy and scanning electron microscopy (SEM). The highest adsorption was observed in brine with high ionic strength, whereas the use of alkali reduced the adsorption. The crushed material from Berea rock showed slightly higher adsorption compared to Keuper rock, whereas temperature had a minor effect on adsorption behaviour. In core-flood experiments, no effects on permeability have been observed. The used particles showed a delayed breakthrough compared to the tracer, and bigger particles passed the rock core faster. Nanoparticle recovery was significantly lower for PEG-modified nanomaterials in Berea compared to diol-modified nanomaterials, suggesting high adsorption. SEM images indicate that adsorption spots are defined via surface roughness rather than mineral type. Despite an excess of nanomaterials in the porous medium, monolayer adsorption was the prevailing type observed.

New nanostructured manganites of LaMeIICuZnMnO6 (MeII — Mg, Ca, Sr, Ba)

The copper-zinc manganites of LaMeIICuZnMnO6 (MeII — Mg, Ca, Sr, Ba) have been synthesized with the high-temperature interaction of alkaline earth metals carbonates with oxides of lanthanum (III), copper (II), zinc (II) and manganese (III). The synthesized polycrystalline copper-zinc manganites have been grinded on the Retsch vibration mill MM301 (Germany). As a result their nanostructured particles have been obtained. Their sizes have been determined using an electron microscope Mira3 LMU, Tescan. Methods of radiography determined that all synthesized nanostructured copper-zinc manganites crystallize in the cubic syngony with the following parameters of a lattice: LaMgCuZnMnO6 — а = 13.530.02 Å, Vo = 2476.810.06 Å3, Z = 4, Voelect.cell = 619.200.02 Å3, roent = 4.52; pick = 4.500.01 g/cm3; LaCaCuZnMnO6 — а = 13.690.02 Å, Vo = 2565.730.06 Å3, Z = 4, Voelect.cell. = 641.430.02 Å3, roent = 4.43; pick = 4.410.01 g/cm3; LaSrCuZnMnO6 — а = 13.910.02 Å, Vo = 2691.420.06 Å3, Z = 4, Voelect.cell = 672.850.02 Å3, roent = 4.99; pick. = 4.960.01 g/cm3; LaBaCuZnMnO6 — а = 14.550.02 Å, Vo = 3080.270.06 Å3, Z = 4, Voelect.cell = 770.070.02 Å3, roent = 4.95; pick = 4.940.01 g/cm3. The X-ray investigations demonstrated that the values of lattice parameters of the studied copper-zinc manganites have been increased from Mg to Ba. As a result of the investigations, these compounds can be included in Pm3m spatial group.

Minute-Made, High-Efficiency Nanostructured Bi2Te3 via High-Throughput Green Solution Chemical Synthesis

Scalable synthetic strategies for high-quality and reproducible thermoelectric (TE) materials is an essential step for advancing the TE technology. We present here very rapid and effective methods for the synthesis of nanostructured bismuth telluride materials with promising TE performance. The methodology is based on an effective volume heating using microwaves, leading to highly crystalline nanostructured powders, in a reaction duration of two minutes. As the solvents, we demonstrate that water with a high dielectric constant is as good a solvent as ethylene glycol (EG) for the synthetic process, providing a greener reaction media. Crystal structure, crystallinity, morphology, microstructure and surface chemistry of these materials were evaluated using XRD, SEM/TEM, XPS and zeta potential characterization techniques. Nanostructured particles with hexagonal platelet morphology were observed in both systems. Surfaces show various degrees of oxidation, and signatures of the precursors used. Thermoelectric transport properties were evaluated using electrical conductivity, Seebeck coefficient and thermal conductivity measurements to estimate the TE figure-of-merit, ZT. Low thermal conductivity values were obtained, mainly due to the increased density of boundaries via materials nanostructuring. The estimated ZT values of 0.8–0.9 was reached in the 300–375 K temperature range for the hydrothermally synthesized sample, while 0.9–1 was reached in the 425–525 K temperature range for the polyol (EG) sample. Considering the energy and time efficiency of the synthetic processes developed in this work, these are rather promising ZT values paving the way for a wider impact of these strategic materials with a minimum environmental impact.

Accessible Silver-Iron Oxide Nanoparticles as a Nanomaterial for Supported Liquid Membranes

The present study introduces the process performances of nitrophenols pertraction using new liquid supported membranes under the action of a magnetic field. The membrane system is based on the dispersion of silver–iron oxide nanoparticles in n-alcohols supported on hollow microporous polypropylene fibers. The iron oxide–silver nanoparticles are obtained directly through cyclic voltammetry electrolysis run in the presence of soluble silver complexes ([AgCl2]−; [Ag(S2O3)2]3−; [Ag(NH3)2]+) and using pure iron electrodes. The nanostructured particles are characterized morphologically and structurally by scanning electron microscopy (SEM and HFSEM), EDAX, XRD, and thermal analysis (TG, DSC). The performances of the nitrophenols permeation process are investigated in a variable magnetic field. These studies show that the flux and extraction efficiency have the highest values for the membrane system embedding iron oxide–silver nanoparticles obtained electrochemically in the presence of [Ag(NH3)2]+ electrolyte. It is demonstrated that the total flow of nitrophenols through the new membrane system depends on diffusion, convection, and silver-assisted transport.

SYNTHESIS AND X-RAY INVESTIGATION OF NOVEL NANOSTRUCTURED COPPER-ZINC MANGANITES OF LANTHANUM AND ALKALI METALS

The aim of this work is to synthesize new nanostructured copper-zinc lanthanum and alkaline metal manganites. Polycrystalline copper-zinc manganites of lanthanum and alkali metals were synthesized by the method of ceramic technology from lanthanum (III), copper (II), zinc (II), manganese (III) oxides, and lithium, sodium, and potassium carbonates in the range of 800-1200 oC. Nanostructured particles were obtained by grinding the synthesized polycrystalline compounds at the «MM301» vibration mill of «Retsch» (Germany). By indexing X-ray images of nanostructured copper-zinc lanthanum and alkaline metal manganites, it was found that they crystallize in cubic syngony. Their lattice parameters are determined. There is a pattern in the change of the lattice parameters from the ionic radii of alkaline metals.

Comparison of Conventional and Flash Spark Plasma Sintering of Cu–Cr Pseudo-Alloys: Kinetics, Structure, Properties

Spark plasma sintering (SPS) is widely used for the consolidation of different materials. Copper-based pseudo alloys have found a variety of applications including as electrodes in vacuum interrupters of high-voltage electric circuits. How does the kinetics of SPS consolidation for such alloys depend on the heating rate? Do SPS kinetics depend on the microstructure of the media to be sintered? These questions were addressed by the investigation of SPS kinetics in the heating rate range of 0.1 to 50 K/s. The latter conditions were achieved through flash spark plasma sintering (FSPS). We also compared the sintering kinetics for the conventional copper–chromium mixture and for the mechanically induced copper/chromium nanostructured particles. It was shown that, under FSPS conditions, the observed maximum consolidation rates were 20–30 times higher than that for conventional SPS with a heating rate of 100 K/min. Under the investigated conditions, the sintering rate for mechanically induced composite Cu/Cr particles was 2–4 times higher compared to the conventional Cu + Cr mixtures. The apparent sintering activation energy for the Cu/Cr powder was twice less than that for Cu–Cr mixture. It was concluded that the FSPS of nanostructured powders is an efficient approach for the fabrication of pseudo-alloys.

High-Rate and Long-Life Cycle of Nano-LiMn2O4 Under High Cut-Off Potential

Nano-LiMn2O4 was successfully synthesized by a low-temperature hydrothermal route with the absence of post-calcination treatment. Employing ethanol as an organic reagent triggers the formation of nanostructured particles approximately 30.39 nm in diameter, associated with 0.7 % lattice strain. The pure phase of nano-LiMn2O4/Li displays outstanding electrochemical performances. Under 4.6 V vs Li+/Li cut-off potential, 74.3 % of capacity is reserved when C-rate is increased by 50 times, while excellent capacity restoration of 96.9 % after cycled again at 1 C. After 331 cycles, capacity retention of 84.3 % is harvested by nano-LiMn2O4/Li, implying the absence of phase transformations in spinel structures under such abuse condition. This remarkable structural stability can be attributed to the small lattice strain, associated with high Li+ diffusion coefficient, which is estimated to be 10-9.76 cm2 s-1 by the EIS technique. Additionally, Li+ extraction is more favourable when nano-LiMn2O4/Li is charged up to 4.6 V vs Li+/Li, interpreted by the polarization resistance (Rp) of the cell.

Nanosponges Encapsulated Phytochemicals for Targeting Cancer: A Review

Cancer is the most ruinous disease globally. Natural products have impressive characteristics, such as excep-tional chemical versatility, chemical and biological properties of macromolecular specificity and less toxicity which make them good leads in finding novel drugs. The phytochemicals not only help to prevent but also treat chronic cancerous conditions. The present review attempts to put forth some selected anticancer phytochemicals that had reported omics char-acteristic and specifically suppressed cancer with in vitro and in vivo activity. Certain issues pertaining to anticancer phy-tochemicals like delivery to target site in the body and achieving controlled release in order to prevent overdoses havelong been a concern for medical researchers worldwide. The most conventional chemotherapy protocols for the treatment of cancer lead to adverse effects that limit biological efficacy and compromise patient outcomes. In order to defeat incompe-tency of current and upcoming natural anticancer agents and to attain targeted drug delivery with good efficacy and fewer side effects, there is a special focus on novel nanostructured particles and nano approaches consisting of carrier system. Recent studies have led to the discovery of mesoporous and nanoporous drug delivery mechanisms, such as inorganic or organic-based nanosponges. The metal based inorganic systems have exhibited toxicity and non-biodegradable character in vivo. As a result of problems related to inorganic systems, major shift of research from inorganic to organic nanosystems has occurred. About decades ago, researchers have developed organic nanosponges to control the limitation of drug delivery and cancer therapies. This review article discusses the development and application of nanosponges encapsulated phyto-chemicals for cancer therapy.