Large Amounts Of Nanoparticles Research Articles

In Situ, Rapid Synthesis of Carbon-Loaded High Density and Ultrasmall High Entropy Oxide Nanoparticles as Efficient Electrocatalysts.

High entropy materials offer almost unlimited catalytic possibilities due to their variable composition, unique structure, and excellent electrocatalytic performance. However, due to the strong tendency of nanoparticles to coarsen and agglomerate, it is still a challenge to synthesize nanoparticles using simple methods to precisely control the morphology and size of the nanoparticles in large quantities, and their large-scale application is limited by high costs and low yields. Herein, a series of high-entropy oxides (HEOs) nanoparticles with high-density and ultrasmall size (<5nm) loaded on carbon nanosheets with large quantities are prepared by Joule-heating treatment of gel precursors in a short period of time (≈60s). Among them, the prepared (FeCoNiRuMn)3O4-x catalyst shows the best electrocatalytic activity for oxygen evolution reaction, with low overpotentials (230mV @10mAcm-2, 270mV @100mAcm-2), small Tafel slope (39.4mVdec-1), and excellent stability without significant decay at 100mAcm-2 after 100h. The excellent performance of (FeCoNiRuMn)3O4-x can be attributed to the synergistic effect of multiple elements and the inherent structural stability of high entropy systems. This study provides a more comprehensive design idea for the preparation of efficient and stable high entropy catalysts.

Large‐scale synthesis of CuS nanoparticles for photothermal materials using high‐concentration Cu complex ion precursor

AbstractCopper sulfide (CuS), a copper‐deficient p‐type semiconductor material, has been widely utilized due to its unique optical properties, low toxicity, and cost‐effectiveness. Although many studies have been conducted on synthesizing CuS nanoparticles, harsh synthetic conditions and low yield must be solved. This study presents a new methodology that can synthesize CuS nanoparticles in large quantities at room temperature and pressure using high‐concentration Cu complex ion precursors. This methodology is based on the theory that the critical nucleus radius and the critical nucleation free energy decrease as the concentration of the precursor increases to synthesize a large number of nanoparticles by applying low energy. In addition, it is possible to minimize the aggregation of nanoparticles, which is a problem of nanoparticles synthesized at a high precursor concentration through complex ions in the solution. We synthesized nanoparticles by controlling the precursor concentration from 0.1 to 2.5 M to confirm the effect of the precursor concentration on the size, shape, and yield of nanoparticles. As the precursor concentration increased, the particle size decreased, and the yield improved. The CuS nanoparticles synthesized at the highest concentration had a size of about 17 nm without a strong agglomeration and a yield of about 213.9 g/L. Furthermore, the nanoparticles showed excellent photothermal performance due to their high near‐infrared absorption. When about 0.1 g of the nanoparticles were irradiated with a Xenon lamp and an 808 nm laser, the maximum temperatures and rising rates were 53.7°C and 172.1°C and 13.8°C/mg and 33°C/mg, respectively. The excellent photothermal properties of CuS nanoparticles suggest the potential of this material for various applications.

Large-scale Production and Application of Graphene Oxide Nanoparticles to Meet Agriculture Needs

The success of the agricultural sector is crucial to the whole world's prosperity. Reducing hunger and poverty and enhancing food security and nutrition have all made great strides in recent decades. Improvements in resource efficiency and food safety brought about by productivity and technical gains have not been shared fairly. Fortunately, it is possible to reduce the adverse effects of the current global food production system on the environment and climate with the aid of technological advancements. Nanotechnology can be integrated into the agricultural sciences as "nano agriculture", to provide solutions that are more accurately boost production without negatively impacting the environment. Among a range of nanoparticles, graphene oxide (GO) has found diverse application in electronics, optics, medicine, and supercapacitors. Due to its adaptability, it is also crucial in many critical biological contexts. Graphene oxide has a range of potential uses in industries as diverse as agriculture, technology, and food production. Nanoencapsulation of nutrients, smart-release systems, novel packaging, smart water treatment systems for various kinds of microorganisms and pollutants, pesticide and insecticide detection and analysis, and other kinds of detection systems are all possible applications of this versatile material. It may also be a part of fertilizer or used as a plant growth stimulant. In the GO market, yield is a major concern. With so much focus on graphene, it is essential to produce GO nanoparticles in large quantities. A possible method for industrial-scale graphene manufacturing is the oxidative exfoliation of graphite. This review outlines few cost effective strategies to mass-produce GO for use in agriculture.

2-Mercaptoimidazole selectively etching and thiol-functionalized ZIF-8 metal–organic framework to serve as a multifaceted platform for radical scavenging and Au loading

Zeolite imidazole frameworks (ZIF-8) are a group of metal–organic frameworks (MOFs) that harbor application potential due to their unique high porosity and other physicochemical properties. However, the small cavities, unstable dispersion, and the lack of surface functional groups hinder the practical application of ZIF-8. In this study, we aimed to develop a ZIF-8-based multifaceted platform with hollow structure and abundant functional groups via a simple one-pot method. We synthesized the ZIF-8 with thiol functionalization (ZSH), while 2-mercaptoimidazole was served as both etching agent and functional counterpart. The hollow morphology and the thiol-groups modification were validated by scanning electron microscopy, transmission electron microscopy with energy-disperse X-ray mapping and X-ray photoelectron spectroscopy. The interparticle structure was estimated by Brunauer–Emmmett–Teller and ultraviolet–visible spectroscopy. The hollow architecture, colloidal stable, and thiol-abundant surface endow ZSHs exploiting the antioxidant and anti-inflammatory ability than pristine ZIF-8 toward a broad scale of morphological change with high functionalization degree. Moreover, ZSHs can specifically encapsulate gold nanoparticles in large quantities for further applications. Finally, ZSHs possess good biocompatibility in human cells and in vivo zebrafish model and could potentially protect human cells against oxidative stress. This concept valuably elucidated the new era for functionalized ZIF-8 to apply as the next generation of multifunctional biomaterials.

Environmental Impacts of Coal Nanoparticles from Rehabilitated Mine Areas in Colombia

With the possible increase in mining activities and recently projected population growth in Colombia, large quantities of nanoparticles (NPs) and potentially hazardous elements (PHEs) will be of major concern to mine workers, indigenous residents, and surrounding communities. This study highlights the need to regulate the pollution from Colombian mining activities that comply with regional regulations and global strategies. Colombian coal rejects (CRs) from the Cesar Basin, Colombia, were studied primarily by advanced electron microscopic and analytical procedures. Therefore, the goal of this research is to evaluate the role of NPs in the alteration of CRs’ structure in a renewed zone at Cerrejón coal area (La Guajira, Colombia) through advanced electron microscopic (AEMs) methods. The objective of the analysis is to evaluate the incidence mode of nanoparticles, which contain potentially hazardous elements. The bulk crystallography (X-ray diffraction), chemical structure, and morphologies of NPs were studied by high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), micro-beam diffraction (MBD), selected area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDX) procedures. The AEMs provided comprehensive insights into the geochemical evolution of CRs. Consequently, the AEMs can be used as essential tools for CR management in coal mining areas. The regular dimension of detected NPs was found to be above 2 nm. Ultrafine particles of quartz were identified by the advanced electron microscopy. Furthermore, the findings also revealed aluminium, calcium, potassium, titanium, iron oxides, and PHEs in the CRs. The extensive water practice in the coal extraction process combined with atmospheric oxygen supports oxidations of iron sulphide, thus releasing PHEs to the surrounding environment. Dehydration of sulphate salts fluctuate at consistent humidity in the coal mine environments. The study demonstrates the great influence of coal mining activities on the environment and human health.

Large-Scale Sonochemical Synthesis of Bi-Sn Eutectic Alloy Nanoparticles.

Lead-free Bi-Sn alloy is an alternative solder material with a low eutectic melting temperature and environmental compatibility. Although extensive research has been conducted on this Bi-Sn eutectic alloy, a lack of facile synthetic methods with scalability hinders the implementation of finepatterned interconnectors for emerging electronic applications. In this study, we employed a facile sonochemical synthetic method to synthesize Bi-Sn alloy nanoparticles in large quantities. Highenergy ultrasonication treatment of Bi-Sn bimetallic particles resulted in nanoparticle formation with repeated formation, growth, and collapse of induced gas bubbles. The size of the nanoparticles was controlled from 92 to 506 nm of the mean diameter with variations in ultrasonication power and irradiation time. The nanoparticles exhibited a stable eutectic melting point at 139.8 °C. Interestingly, the sonochemically synthesized nanoparticles exhibited coexistence of metastable Bi2Sn and stable Bi-Sn phases. Finally, we demonstrated that Bi-Sn eutectic nanoparticles could be synthesized at a gram scale of approximately 1.7 g for future mass production.

SURG-12. “NANOPASTE” THERAPY AS POTENTIAL TREATMENT OPTION FOR RECURRENT GLIOBLASTOMA

Abstract BACKGROUND We recently showed that intracavitary thermotherapy with superparamagnetic iron-oxide nanoparticles can induce persistent inflammatory reactions which might lead to long-term stabilization in recurrent glioblastoma (GBM) patients. METHODS Here, we report further data from a series of ten recurrent GBM WHO IV patients (IDH WT, MGMT: methylated 30%, unmethylated 70%; median age: 59 years) who were treated with intracavitary thermotherapy after coating the resection cavity wall (“NanoPaste”) with NanoTherm® particles (MagForce AG, Berlin, Germany). All patients underwent six one-hour semi-weekly hyperthermia sessions in an alternating magnetic field (mean maximum temperature 52.3° C, SD +/- 6.0 °C). Six patients received concurrent radiotherapy at a dose of 39.6 Gy (5 x 1.8 Gy/week). RESULTS No major side effects were observed during active treatment. However, all patients developed cerebral edema and increasing clinical symptoms during treatment follow-up (median 92 days, range 73 to 144). Patients were treated with dexamethasone and, if necessary, underwent re-operation to remove nanoparticles (n=5). Histopathology revealed sustained necrosis and large amounts of nanoparticles without evidence for tumor activity as well as a prominent inflammatory reaction characterized by increased T-cell and myeloid cell infiltration. Median overall survival (mOS) for the study population was 10.1 months (CI 95% 8.0–12.2). A survival benefit was observed for patients treated at first recurrence (n=5) when compared to patients treated at second recurrence or later (mOS = 20.6 vs 9.4 months). Patients who received thermotherapy and concurrent radiotherapy (n=6) showed longer mOS than patients treated with thermotherapy alone (17.3 vs 8.6 months). Two patients had long-lasting treatment responses &gt; 23 months with one patient still alive at 3.5 years after treatment without receiving any further therapy. CONCLUSION Our results warrant further investigations. A European clinical registry will be rolled out to further evaluate the potential of “NanoPaste” therapy for patients with recurrent glioblastoma.

Preparation and characterization of polyhydroxybutyrate-co-valerate (PHBV) as green composites using nano reinforcements

This article presents the preparation and characterization of polyhydroxybutyrate-co-valerate (PHBV) nanocomposite films containing cellulose nanocrystals (CNC) and aluminum oxide nanoparticles (Al2O3) as reinforcements. The effects of adding nanoparticles on the mechanical properties, such as tensile strength and elongation, were studied using dynamic-mechanical analysis (DMA) such as modulus and tan δ. Also, morphology and thermal features were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. For this purpose, first, CNC and Al2O3 with a ratio of 0, 1, 3 and 5 wt% was added to a biopolymer, then a combination of these two with the ratio of 3:3 and 5:5 was added to the PHBV matrix, separately; and finally, the various nanocomposite films were prepared by the solvent casting method. After adding nanoparticles, the tensile strength and thermal stability of the PHBV/CNC films increased and the elongation decreased. SEM observations showed that large amounts of nanoparticles (3 wt%) are strongly agglomerated in the biopolymer matrix. This led to a decrease of mechanical properties in the composites with nanoparticles of more than 3% by weight. DSC results showed that the glass transition temperature (Tg) increased slightly with the incorporation of nano participles to PHBV. The enthalpy of fusion (ΔHfus) increased from 33.8 J/g for neat PHBV film to 48.1, 50 and 45.8 J/g for PHBV films containing 1, 3, and 5 wt% CNC, respectively. These results are consistent with the conclusions of DMA. The improvement of physical and mechanical properties of the composites confirmed that CNC has a better effect than aluminum oxide nanoparticles as a nano reinforcement.

Interconnected silicon nanoparticles originated from halloysite nanotubes through the magnesiothermic reduction: A high-performance anode material for lithium-ion batteries

Abstract Silicon (Si) is a promising high-capacity anode material for the next-generation of rechargeable lithium ion batteries (LIBs). Though there are formidable challenges from the large volumetric change during lithiation, well-designed nanostructure and reduced size of Si can remarkably alleviate the negative effects. Herein we apply a magnesiothermic reduction process to synthesize interconnected Si nanoparticles in large quantities. Earth abundant clay of halloysite with tubular structure has been used as silica precursor after acid washing. A high Si yield can be achieved upon pressing the precursor powder into a pallet before reduction. The obtained interconnected Si nanoparticles exhibit a high specific capacity of 3752.4 mA h g−1 for the first cycle at1 A g−1 and 1469.0 mA h g−1 after 400th cycles at current density of 3.5 A g−1. Even tested at 5 A g−1 for 1000 cycles, a high capacity of 735.1 mA h g−1 is obtained. The rate capability is also evaluated and a high capacity of 1050 mA h g−1 is achieved at 10 A g−1.

Development of Orally Applicable, Combinatorial Drug–Loaded Nanoparticles for the Treatment of Fibrosarcoma

Nanoparticulate systems have been receiving a significant attention especially for the treatment of cancer but one of the main hurdles is to produce these developed and high-tech nanosystems in large quantities. Anticancer drug formulations are generally designed for parenteral administrations but oral administration is still the most convenient route. In this study, orally applicable nano-sized chitosan nanoparticles (NPs) were successfully prepared using Nano Spray Dryer. It is possible to produce these NPs in large quantities by simply increasing the processing time using the machine without changing any parameter. A chemotherapeutic agent (imatinib mesylate; IMA) and nonsteroidal anti-inflammatory drug (dexketoprofen trometamol) were loaded together in these NPs. NPs were also functionalized with polyethylene glycol and folic acid to obtain long circulating NPs and tumor targeting. The antitumoral activities of formulations showed that these developed NPs can enhance the effectiveness. Animal experiments were performed on fibrosarcoma-bearing mice model, and the treatment with 0.8 mg/μL/kg IMA-loaded chitosan NPs was found to be successful to slow down the growth of tumors. The tumor tissues were removed from the animals and enzymatic activities were evaluated. The inhibitory effect of tyrosine kinase was found to be enhanced from 36.4% to 68.4% when IMA was used in combination with dexketoprofen trometamol. Furthermore, all dried NPs were found to be stable for more than a year at 25°C. Presented results show that these developed combinatorial drug–loaded NPs can be used for the treatment of fibrosarcoma, and these data can provide an insight, new strategies for productions or alternatives in cancer treatment.

Caracterización experimental de las emisiones de nanopartículas en el tratamiento de AA6061, AISI304 y Ti6Al4V por ondas de choque generadas por LASER

Este artículo es un estudio experimental sobre la caracterización de las emisiones de nanopartículas en el tratamiento superficial por ondas de choque generadas por LASER (LSP) de materiales metálicos: aceros inoxidables, aleaciones de aluminio y de titanio. Se confirmó que la emisión de partículas de tamaño nanométrico consiste en agregados compuestos de partículas esféricas en el rango de 10-20 nm, cubiertas por una pequeña “capa” concéntrica correspondiente a óxidos metálicos. El análisis de las nanopartículas mostró la presencia de los principales elementos presentes en las aleaciones ensayadas, y también un contenido elevado de oxígeno que corrobora la presencia de óxidos de Fe, Al y Ti. La cantidad de nanopartículas emitidas, mostró aumentos considerables sobre la línea de base medida para el ambiente de trabajo, y estos aumentos corresponden a los impulsos más intensos de LASER. Se observó que la densidad del material influí en la cantidad de nanopartículas emitidas. Durante el LSP de aleación de aluminio (el material más ligero) se midió una gran cantidad de nanopartículas, mientras que en LSP de acero inoxidable se observaron pocas nanopartículas, y este es el material más denso, entre los tres ensayados. La aleación de titanio da como resultado valores intermedios. El estudio de estas emisiones es innovador y relevante para entornos industriales donde el proceso de fabricación está en uso.

Honeycomb-Like Interconnected Network of Nickel Phosphide Heteronanoparticles with Superior Electrochemical Performance for Supercapacitors.

Transition-metal-based heteronanoparticles are attracting extensive attention in electrode material design for supercapacitors owing to their large surface-to-volume ratios and inherent synergies of individual components; however, they still suffer from limited interior capacity and cycling stability due to simple geometric configurations, low electrochemical activity of the surface, and poor structural integrity. Developing an elaborate architecture that endows a larger surface area, high conductivity, and mechanically robust structure is a pressing need to tackle the existing challenges of electrode materials. This work presents a supercapacitor electrode consisting of honeycomb-like biphasic Ni5P4-Ni2P (NixPy) nanosheets, which are interleaved by large quantities of nanoparticles. The optimized NixPy delivers an ultrahigh specific capacity of 1272 C g-1 at a current density of 2 A g-1, high rate capability, and stability. An asymmetric supercapacitor employing as-synthesized NixPy as the positive electrode and activated carbon as the negative electrode exhibits significantly high power and energy densities (67.2 W h kg-1 at 0.75 kW kg-1; 20.4 W h kg-1 at 15 kW kg-1). These results demonstrate that the novel nanostructured NixPy can be potentially applied in high-performance supercapacitors.

Curing the Toxicity of Multi-Walled Carbon Nanotubes through Native Small-molecule Drugs

With the development and application of nanotechnology, large amounts of nanoparticles will be potentially released to the environment and possibly cause many severe health problems. Although the toxicity of nanoparticles has been investigated, prevention and treatment of damages caused by nanoparticles have been rarely studied. Therefore, isotope tracing and improved CT imaging techniques were used to investigate the biodistribution influence between oMWCNTs(oxidized multi-walled carbon nanotubes) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/or simvastatin (TD) in vivo. What’s more, biochemical indices in plasma and tissue histology were measured to further study therapeutic effects on the damages of oMWCNTs in mice. Isotope tracing and improved CT imaging results showed that low dosages of DOPC and TD didn’t affect the distribution of oMWCNTs in mice; conversely, the distribution and metabolism of DOPC and TD were influenced by oMWCNTs. Moreover, DOPC and/or TD improved the biocompatibility of oMWCNTs in erythrocyte suspension in vitro. Biochemical index and histopathological results indicated that DOPC and TD didn’t prevent injuries caused by oMWCNTs effectively. But TD showed a good therapeutic effect for damages. This study is the first to investigate prevention and treatment effects of drugs on damages caused by oMWCNTs and provides new insights and breakthroughs for management of nanoparticles on health hazards.

Synthesis, Separation, and Hypermethod Characterization of Gold Nanoparticle Dimers Connected by a Rigid Rod Linker

Bonding individual metallic nanoparticles at small separation distances to let them form dimers and making them available in large quantities is a key requirement for various applications that wish to exploit the tremendous enhancement of electromagnetic fields in plasmonic junctions. Although progress has been witnessed in the past concerning the fabrication of dimers mediated by rigid molecular linkers, the exact bonding mechanism remains unclear. Here, we describe the fabrication of a rigid linker molecule and demonstrate its feasibility to achieve dimers made from closely spaced metallic nanoparticles in large quantities. Although the topography of the dimers proves the success of the fabrication method, we use what we call a hypermethod characterization approach to study the optical properties of dimers from various perspectives. Measuring the surface-enhanced Raman scattering signal of the linker molecule enables direct tracing of the optical environment it perceives. By reaching a strong field enhancement in the gap of the dimers, we are able to investigate optical and geometrical properties of the linker. Moreover, upon isolation of the dimers, we use single-particle extinction spectroscopy to study the optical response of a fabricated dimer directly. Full wave numerical simulations corroborate the experimental results and provide insights into quantities which cannot be accessed directly in experiments. The ability to fabricate and to characterize rigidly linked nanoparticles will pave the way toward various plasmonic applications such as sensors, photocatalysis, and plexcitonics.

Bacterial (BKH1) assisted silica nanoparticles from silica rich substrates: A facile and green approach for biotechnological applications

A green technique of silica nanoparticles (SiO2-NPs) formation by using a thermophilic bacterium (BKH1) as biological template is demonstrated here. SiO2-NPs are synthesized from inorganic (magnesium tri-silicate), and organic (tetraethyl orthosilicate) precursor with the help of BKH1 bacteria. BKH1 derived SiO2-NPs are subjected to Atomic Force Microscopy, Transmission Electron Microscopy, and Field Emission Scanning Electron Microscopy equipped with Energy Dispersive X-ray Analyzer to establish nanoparticle morphology. In addition, Infrared Spectroscopy reveals the presence of chemical and functional groups in SiO2-NPs samples and X-ray diffraction, the amorphous nature. The Zeta potential (ζ) reveals substantial stability of bacteria derived SiO2-NPs in the aqueous environment. Presence of two intense luminescence peaks in the UV and visible regions merits the bacteria derived SiO2-NPs for use as an optical probe in biomedical applications. This novel mode of bacteria derived SiO2-NPs formation is eco-friendly and ambient temperature synthesis approach. It avoids the complex protocol of multi-steps synthesis of silica nanoparticles, hence likely to be cost-effective. In-depth translation research is suggested for the synthesis of silica nanoparticles in large quantities using thermophilic BKH1 template.

Urchin-like CdS/ZrO2 nanocomposite prepared by microwave-assisted hydrothermal combined with ion-exchange and its multimode photocatalytic activity

A series of urchin-like CdS/ZrO2 nanocomposites with different mole ratios of Cd/Zr were prepared by a two-step method combining the microwave-assisted hydrothermal and ion exchange methods. The products were characterized by X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption–desorption measurements. The results of the study revealed that the CdS/ZrO2 nanocomposites had mixed phases of tetragonal ZrO2 and hexagonal CdS. Moreover, the samples prepared by the microwave-assisted hydrothermal method possessed the urchin-like structure with a surface composed of protrude-like nanoparticles in large quantities. The absorption in the visible region changed slightly with increasing mole ratio of Cd/Zr. Moreover, compared to the nanocomposites prepared by the conventional heating, the nanocomposites prepared by the microwave-assisted hydrothermal synthesis showed significantly different Brunauer–Emmett–Teller values, and the urchin-like CdS/ZrO2 structures were obtained. The photocatalytic degradation of methyl orange under ultraviolet (UV) light irradiation indicated that the photocatalytic activity of the CdS/ZrO2 nanocomposite with CdS/ZrO2 molar ratio of 30 % was higher than those of CdS, ZrO2, and other different ratios of CdS/ZrO2 nanocomposites. Moreover, under UV light, visible light, and microwave-assisted multimode photocatalytic degradation, the urchin-like CdS/ZrO2 nanocomposites significantly affected the photodegradation of various dyes. To understand the possible reaction mechanism of the photocatalysis by the CdS/ZrO2 nanocomposites, a series of controlled experiments were performed, and the stability and reusability of the CdS/ZrO2 nanocomposites were further investigated by the photocatalytic reaction.

Effect of Carbides on Wear Characterization of High-Alloy Steels under High-Stress Rolling–Sliding Condition

This article describes the wear characterizations of high-speed steel composed of vanadium carbide and high-chromium cast iron composed of chromium carbide. These metals were studied under rolling–sliding conditions with a sliding ratio of 10% using a self-made ring–ring wear testing machine. The fine microstructure of carbides and failure behaviors were analyzed by scanning electron microscopy and high-resolution electron microscopy. The results showed that carbide significantly affected the wear properties and failure behaviors of metals. The relative wear resistance of high-speed steel reinforced by vanadium carbides was twice that of high chromium cast iron composed of chromium carbides. Chromium carbide was characterized by a stacking fault substructure, and slips occurred in chromium carbide under high-stress contact, resulting in crack formation. Vanadium carbide was reinforced and pinned by large amounts of nanoparticles, which prevented its dislocation under high-stress rolling–sliding conditions, thereby effectively resisting crack initiation. Furthermore, the (200) lattice plane of vanadium carbide is coherent with the (111) lattice plane of austenite, preventing cracks from forming at the interface of the vanadium–carbide matrix. The morphology and hardness of vanadium carbide also contributed to the excellent wear property of high-speed steel.

Humidity sensing properties of Bi0.5(Na0.85K0.15)0.5Ti0.97Zr0.03O3 microspheres: Effect of A and B sites co-substitution

Bi0.5(Na0.85K0.15)0.5Ti0.97Zr0.03O3 (BNKTZ) sensing materials were successfully synthesized via a simple metal–organic decomposition method. Their morphological feature was characterized as regular shaped microspheres, and it was observed that a large quantity of nanoparticles with the size, of 50–100nm were present on microspheres surfaces. The introduction of a small quantity of Zr4+ in, the reaction system was played an important role in the size-control. At room temperature, humidity, sensing properties of the BNKTZ were investigated in detail. At 100Hz, the curve of impedance versus relative humidity (RH) was of good linearity and the variation of BNKTZ humidity sensor's impedance was more than four orders of magnitude when humidity changed from 11% to 95% RH. The response time and recovery time were found to be about 18s and 60s, respectively. Furthermore, the maximum, hysteresis was only 4% RH. Comparing with A site substituted materials, with the similar response and sensing range, the A and B sites co-substituted BNKTZ humidity sensor possessed lower impedance, better linearity and wider operating frequency. The results indicated that BNKTZ microspheres have broader application for fabricating high performance room temperature humidity sensors.

Automated Ultrafiltration Device for Environmental Nanoparticle Research and Implications: A Review

Nanoparticle research and development have brought significant breakthroughs in many areas of basic and applied sciences. However, efficiently collecting nanoparticles in large quantities in pure and natural systems is a major challenge in nanoscience. This review article has focused on experimental investigation and implications of nanoparticles in soil, clay, geological and environmental sciences. An automated ultrafiltration device (AUD) apparatus was used to demonstrate efficient collection and separation of nanoparticles in highly weathering red soils, black soils, and gouge of earthquake fault, as well as zeolite. The kaolinite, illite, goethite, and hematite were identified in highly weathering red soils. Transmission electron microscopic (TEM) images showed the presence of hematite nanoparticles on the surface coating of kaolinite nanoparticles and aggregated hematite nanoparticles overlapping the edge of a kaolinite flake in a size range from 4 to 7 nm. The maximum crystal violet (CV) and methylene blue (MB) adsorption amount of smectite nanoparticles (&lt;100 nm) separated by black soils were about two to three times higher than those of bulk sample (&lt;2000 nm). The smectite nanoparticles adsorb both CV and MB dyes efficiently and could be employed as a low-cost alternative to remove cationic dyes in wastewater treatment. Quartz grain of &lt;50 nm was found in the gouge of fault by X-ray diffraction (XRD) analysis and TEM observation. Separated quartz could be used as the index mineral associated with earthquake fracture and the finest grain size was around 25 nm. Comparing the various particle-size fractions of zeolite showed significant differences in surface area, Si to Al molar ratio, morphology, crystallinity, framework structure, and surface atomic structure of nanoparticles from those of the bulk sample prior to particle-size fractionations. The AUD apparatus has the characteristics of automation, easy operation, and high efficiency in the separation of nanoparticles and would, thus, facilitate future nanoparticle research and developments in basic and applied sciences.

Impact of CuO NPs to Alga Microcystis Aeruginosa: Effect of Dissolved Organic Matter

With the rapid development and versatile applications of nanotechnology, a large quantity of nanoparticles (NPs) has been released into the environment. It has been one of the most popular studies that concerning the toxic effect of NPs to the algae in aquatic ecosystem. The membrane integrity of algal cells was assessed using different methods when algae were treated by CuO NPs in the absence and presence of Suwannee river fulvic acid (SRFA), one of DOM. We found SRFA could increase the toxicity of CuO NPs to cell membrane due to the more stable NPs suspension in the presence of SRFA. Results additionally indicate that maybe oxidative damage caused by CuO NPs was the primary reason that led to membrane structure and function failed.