scholarly journals Development of hollow δ-FeOOH structures for mercury removal from water

2021 ◽  
Author(s):  
Luiz F. O. Maia ◽  
Guilherme Lages ◽  
Patricia C. C. Ladeira ◽  
Bruno Lemos Batista ◽  
Márcia C. S. Faria ◽  
...  
Keyword(s):  
Average Pore Size ◽  
Active Surface ◽  
Metal Species ◽  
Point Of Zero Charge ◽  
Average Pore ◽  
Oh Groups ◽  
Transmission Electron ◽  
Naoh Solution ◽  
Active Surface Sites ◽  
20 Nm

Abstract δ-FeOOH, a magnetic iron oxyhydroxide, has a significant number of -OH groups on its surface. These provide an attractive platform for heavy metal species in contaminated water, giving it potential as an adsorbent. Its performance can be improved by increasing the number of active surface sites. δ-FeOOH hollow structures were synthesized on a mesoporous silica surface then treated with NaOH solution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that structure synthesis was successful. δ-FeOOH, 5,27 nm, hollow crystals were produced with 63 m2 g−1 surface area and 20 nm average pore size. The point of zero charge was 4.72, which is beneficial for Hg(II) adsorption near neutral pH. The maximum Hg(II) adsorption capacity at pH 7 was determined as 89.1 mg g−1. The kinetics data were best fitted by a pseudo-second-order model with k2 equal 0,1151 g mg−1min−1. Finally, a nanomaterial filter was developed and used to remove mercury in water samples from a Brazilian river.

The Effect of the Freeze-Thaw Cycles in Nanometer Pores on the Cement Structure

2014 ◽  
Vol 488-489 ◽  
pp. 620-624
Author(s):  
Long Zhou ◽  
Xu Liang Hou ◽  
Zhong Ping Wang
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Average Pore Size ◽  
Pore Wall ◽  
Average Pore ◽  
Freeze Thaw ◽  
Changing Trends ◽  
Bet Method ◽  
Resistance Durability ◽  
20 Nm

The pore structure of cement-based materials is closely related to the freeze-thaw resistance durability. And this paper focused on nanometer pores to verify the connection of freeze-thaw cycles in the nanometer pores with the structure deterioration and to explore the stress in the pore wall during the freeze-thaw process. And BET method was adopted to analyze the pore structure of the cement and results indicated the changing trends of parameters such as the pore volume, average pore size and surface area of specimens. Moreover, pore size distribution presented prominent fluctuations of pore sizes in the range of 0 ~ 20 nm, while the changes on the scale of 20 ~ 100 nm were limited.

scholarly journals Electrospun Polycaprolactone Nanofibers as a Reaction Membrane for Lateral Flow Assay

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1387 ◽  
Author(s):  
Chee Yew ◽  
Pedram Azari ◽  
Jane Choi ◽  
Farina Muhamad ◽  
Belinda Pingguan-Murphy
Keyword(s):  
Flow Rate ◽  
Point Of Care ◽  
Low Cost ◽  
Average Pore Size ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Average Pore ◽  
Water Contact ◽  
Naoh Solution ◽  
Lateral Flow Assays

Electrospun polycaprolactone (PCL) nanofibers have emerged as a promising material in diverse biomedical applications due to their various favorable features. However, their application in the field of biosensors such as point-of-care lateral flow assays (LFA) has not been investigated. The present study demonstrates the use of electrospun PCL nanofibers as a reaction membrane for LFA. Electrospun PCL nanofibers were treated with NaOH solution for different concentrations and durations to achieve a desirable flow rate and optimum detection sensitivity in nucleic acid-based LFA. It was observed that the concentration of NaOH does not affect the physical properties of nanofibers, including average fiber diameter, average pore size and porosity. However, interestingly, a significant reduction of the water contact angle was observed due to the generation of hydroxyl and carboxyl groups on the nanofibers, which increased their hydrophilicity. The optimally treated nanofibers were able to detect synthetic Zika viral DNA (as a model analyte) sensitively with a detection limit of 0.5 nM. Collectively, the benefits such as low-cost of fabrication, ease of modification, porous nanofibrous structures and tunability of flow rate make PCL nanofibers a versatile alternative to nitrocellulose membrane in LFA applications. This material offers tremendous potential for a broad range of point-of-care applications.

scholarly journals Preparation and characterization of polyaniline-silica composite material

2012 ◽  
Vol 47 (3) ◽  
pp. 249-256 ◽  
Author(s):  
US Akhter ◽  
MS Miran ◽  
MABH Susan ◽  
MYA Mollah ◽  
MM Rahman
Keyword(s):  
Composite Material ◽  
Average Pore Size ◽  
Chemical Properties ◽  
Bet Surface Area ◽  
Average Pore ◽  
Enthalpy Of Adsorption ◽  
Silica Composite ◽  
Transmission Electron ◽  
The Individual ◽  
Individual Hydrocarbons

Polyaniline-silica (PAni-silica) composite material with 40% silica was prepared by polymerization of aniline in a medium consisting of colloidal silica, freshly prepared by hydrolysis of sodium silicate at room temperature at pH 6.5. The physico-chemical properties of both PAni and the composite material, PAni-silica were studied by FT-IR and transmission electron microscopy and measurements of Brunauer- Emmett-Teller (BET) isotherms. PAni-silica composites showed inhomogeneous pore distribution, although PAni has no significant pores. Average pore size of PAni-silica was 280 and 175 Å during adsorption and desorption of nitrogen, respectively. The interactions of PAnisilica composite and PAni with saturated hydrocarbons were investigated by inverse gas chromatography. The composite material was found to be efficient for separation of a mixture of hydrocarbons, in the range of C5-C9, owing to large BET surface area. Enthalpy of adsorption of the individual hydrocarbons was evaluated from an analysis of the retention time and the flow rate of the carrier gas. For PAni, the enthalpy of adsorption was very low; however, the value for the composite material was found to be comparable to the enthalpy of evaporation of the individual hydrocarbons. DOI: http://dx.doi.org/10.3329/bjsir.v47i3.13055 Bangladesh J. Sci. Ind. Res. 47(3), 249-256, 2012

Microstructural Characterization and Properties of Silica Aerogels Doped with Nano-ITO Powder

2011 ◽  
Vol 284-286 ◽  
pp. 662-666 ◽  
Author(s):  
Ben Lan Lin ◽  
Sheng Cui ◽  
Xiao Dong Shen ◽  
Ying Li Leng ◽  
Xue Yong Liu ◽  
...  
Keyword(s):  
Average Pore Size ◽  
Sol Gel ◽  
Microstructural Characterization ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
Average Pore ◽  
Sol Gel Process ◽  
Main Factors ◽  
20 Nm ◽  
Radiation Conductivity

Silica-based aerogels doped with nano-ITO powder were synthesized using sol–gel process followed by supercritical drying. The main factors were studied including dosage of compling agent KH570 and ITO. The result shows that thermal radiation conductivity is 0.02659 W/(m•K) with ITO of 44.44% after 10 g ITO powder is modified with 1 mL KH570. The microstructure and physical characteristic of the SiO2–ITO aerogels were characterized by FTIR, SEM, TG-DSC and BET. Their specific surface was in the range of 513–775m2/g and their average pore size was mainly 20 nm. Nano-ITO powders are physically embedded by SiO2aerogels.

scholarly journals Gold Nanopeanuts as Prospective Support for Cisplatin in Glioblastoma Nano-Chemo-Radiotherapy

2020 ◽  
Vol 21 (23) ◽  
pp. 9082
Author(s):  
Joanna Depciuch ◽  
Justyna Miszczyk ◽  
Alexey Maximenko ◽  
Piotr M. Zielinski ◽  
Kamila Rawojć ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Active Surface ◽  
Longitudinal Axis ◽  
Scanning Calorimetry ◽  
Transverse Axis ◽  
Transmission Electron ◽  
Cell Mortality ◽  
20 Nm

Herein, we propose newly designed and synthesized gold nanopeanuts (Au NPes) as supports for cisplatin (cPt) immobilization, dedicated to combined glioblastoma nano-chemo-radiotherapy. Au NPes offer a large active surface, which can be used for drugs immobilization. Transmission electron microscopy (TEM) revealed that the size of the synthesized Au NPes along the longitudinal axis is ~60 nm, while along the transverse axis ~20 nm. Raman, thermogravimetric analysis (TGA) and differential scanning calorimetry (DCS) measurements showed, that the created nanosystem is stable up to a temperature of 110 °C. MTT assay revealed, that the highest cell mortality was observed for cell lines subjected to nano-chemo-radiotherapy (20–55%). Hence, Au NPes with immobilized cPt (cPt@AuNPes) are a promising nanosystem to improve the therapeutic efficiency of combined nano-chemo-radiotherapy.

Preparation and Structural Characterization of SiO2-ZrO2 Aerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2282-2285
Author(s):  
Xiao Dong He ◽  
He Xin Zhang ◽  
Yao Li ◽  
Chang Qing Hong ◽  
Jiu Peng Zhao
Keyword(s):  
Average Pore Size ◽  
Supercritical Drying ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Surface Areas ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Transmission Electron ◽  
Ft Ir ◽  
Chemical Conditions

Low density SiO2-xZrO2 aerogels with x=35wt%, 65wt%, 75wt%, 90wt%, 95wt% were prepared by CO2 supercritical drying technique with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .2H2O) by hydrolytic polycondensation under different chemical conditions. The prepared aerogels are performed by X-ray Diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR) and BET surface areas to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that the SiO2-ZrO2 areogels are the typical of nano mesopores and the average pore size is about 50 nm. The specific surface areas varied from 345.5 to 615.5 m2/g with (SBET)MAX = 615.5 m2/g with 20wt% Zirconia; Moreover a mass of Si-O-Zr bands formed in the aerogels and the formation mechanism of Si-O-Zr bands are also discussed.

scholarly journals Fabrication of Core-Shell Magnetic Molecularly Imprinted Nanospheres towards Hypericin via Click Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 313 ◽  
Author(s):  
Xinxin Wang ◽  
Yuxin Pei ◽  
Yong Hou ◽  
Zhichao Pei
Keyword(s):  
Click Reaction ◽  
Average Pore Size ◽  
Core Shell ◽  
Average Pore ◽  
Molecularly Imprinted ◽  
Transfer Rates ◽  
Click Polymerization ◽  
Magnetic Nanospheres ◽  
Transmission Electron ◽  
Bet Method

The core-shell structure molecularly imprinted magnetic nanospheres towards hypericin (Fe3O4@MIPs) were prepared by mercapto-alkyne click polymerization. The shape and size of nanospheres were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The nanospheres were analyzed by FTIR spectroscopy to verify the thiol-yne click reaction in the presence or absence of hypericin. The Brunauer–Emmet–Teller (BET) method was used for measuring the average pore size, pore volume and surface area. The Fe3O4@MIPs synthesized displayed a good adsorption capacity (Q = 6.80 µmol·g−1). In addition, so-prepared Fe3O4@MIPs showed fast mass transfer rates and good reusability. The method established for fabrication of Fe3O4@MIPs showed excellent reproducibility and has broad potential for the fabrication of other core-shell molecularly imprinted polymers (MIPs).

Synthesis and Characterization of Bridged Amine-Functionalized Mesoporous Organosilica Materials

2013 ◽  
Vol 652-654 ◽  
pp. 799-814
Author(s):  
Qing He Zhang ◽  
Dong Lian ◽  
Xiu Qing Li ◽  
Hong Tao
Keyword(s):  
Average Pore Size ◽  
Mas Nmr ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Amine Functionalized ◽  
Mesoporous Organosilica ◽  
Transmission Electron ◽  
Analytical Potential ◽  
Ordered Mesoporous ◽  
Organosilica Materials

The periodic bridged amine-functionalized mesoporous organosilica (BAFMOs) was synthesized by condensation of bridged silicon precursor 1,2-Bis(triethoxysilyl)-ethane (BTESE) and Bis(3-(methylamino)propyl)-trimethoxysilane (BTMSPMA) under acidic conditions with the aid of NaCl and ethanol. A triblock copolymer P123 was used as template. X-ray diffraction and transmission electron microscopy revealed that the resultant BAFMOs materials possess ordered mesoporous. N2sorption showed that the specific surface area gradual decreased, from 970m2/g to 795m2/g, whereas the average pore size increased, from 3.7 nm to 5.4 nm as the amount of BTMSPMA increased.13C CP MAS NMR and29Si MAS NMR confirmed the retaining of the Si-C as well as the existing of the amino in the silica skeleton. The analytical potential of the materials is demonstrated with separation of isomeric molecules in reverse phase chromatography mode compared with commercial C18 column.

Surface Modification and Properties of SiO2 Nano Porous Aerogels

2008 ◽  
Vol 373-374 ◽  
pp. 702-705 ◽  
Author(s):  
Xing Yuan Ni ◽  
Yang Li ◽  
Zhi Hua Zhang ◽  
Jun Shen ◽  
Bin Zhou ◽  
...  
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Surface Property ◽  
Ambient Pressure ◽  
Average Pore Size ◽  
Activated Carbon Fiber ◽  
Toxic Substances ◽  
High Porosity ◽  
Average Pore ◽  
Oh Groups

Surface modification is a process in which Si-CH3 groups of trimethylchlorosilane (TMCS) replace -OH groups on the inner surface of SiO2 aerogels, so the surface property of aerogels has shown hydrophobic performance which could be changed back to hydrophilic by 450 heat treatment. This aerogels with surface property controlled are prepared via sol-gel process with polyethoxydisiloxanes (E-40) used as precursor, and have typical porous structures dried at ambient pressure: high porosity (above 90 %), super specific surface area (about 1000 m2/g), low bulk density (down to 3.03 kg/m3) and average pore size is about 20 nm. This paper presents adsorption mechanisms in aerogels and illustrates that the adsorption capacity of aerogels is three or four times as much as that of activated carbon fiber (ACF) and granule of activated carbon (GAC). So SiO2 aerogels are potentially important to be used as absorbents being quite efficient to adsorb toxic substances.

Low Energy Ar Ion Milling of FIB TEM Specimens from 14 nm and Future FinFET Technologies

2018 ◽  
Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
M.L. Ray ◽  
P.E. Fischione
Keyword(s):  
Field Effect Transistor ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Effect Transistor ◽  
20 Nm ◽  
Argon Ion

Abstract Transmission electron microscopy (TEM) specimens are typically prepared using the focused ion beam (FIB) due to its site specificity, and fast and accurate thinning capabilities. However, TEM and high-resolution TEM (HRTEM) analysis may be limited due to the resulting FIB-induced artifacts. This work identifies FIB artifacts and presents the use of argon ion milling for the removal of FIB-induced damage for reproducible TEM specimen preparation of current and future fin field effect transistor (FinFET) technologies. Subsequently, high-quality and electron-transparent TEM specimens of less than 20 nm are obtained.

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