Preparation of Zero-Valent Iron Nanoparticles and Study of Dispersion

2011 ◽  
Vol 55-57 ◽  
pp. 1748-1752 ◽  
Author(s):  
Qing Wei Ding ◽  
Tian Wei Qian ◽  
Hong Fang Liu ◽  
Xue Wang
Keyword(s):  
Water Soluble ◽  
Zero Valent Iron ◽  
Wet Chemical Method ◽  
Agent Based ◽  
Dispersing Agent ◽  
Dispersion Agent ◽  
Ideal Approach ◽  
Wet Chemical ◽  
The Stability ◽  
Zero Valent Iron Nanoparticles

Zero-valent iron (ZVI) nanoparticles are prepared by wet chemical method, unlike conventional methods, we applied a water-soluble dextrin、CMC and starch in the preparation. The starch serves as a stabilizer and dispersant that prevents the resultant nanoparticles from agglomeration, and characterized by XRD、SEM and USP. Compare the dispersion of particles and particle size in progress of reducing. According to the characterization results, the nanoparticles can be dispersed more efficiently, maintained the activity of it owned and kept the stability longer with the dispersing agent. Based on the results obtained, the starch as a dispersion agent on the preparation of Zero-valent iron (ZVI) nanoparticles is an ideal approach.

Preparation of Nanocrystalline Ba3(Ca1.18Nb1.82)O9-δ Powder with Sol-Gel Auto-Ignition Synthesis Process

2007 ◽  
Vol 280-283 ◽  
pp. 631-634 ◽  
Author(s):  
Xin Tai Su ◽  
Qing Zhi Yan ◽  
Chang Chun Ge
Keyword(s):  
Chemical Method ◽  
Average Particle Size ◽  
Combustion Process ◽  
Water Soluble ◽  
Synthesis Process ◽  
Average Particle ◽  
Wet Chemical Method ◽  
Solid Reaction ◽  
Reaction Method ◽  
Wet Chemical

Ba3(Ca1.18Nb1.82)O9-d (BCN18) powder was synthesized using a wet chemical method from mixtures of all water-soluble compounds including Ba, Ca and Nb-citrate. It has been found that NH4NO3 in the initial solutions plays an important role in controlling the enthalpy of low temperature combustion process as well as the gel decomposition temperature. Further steps include evaporating, drying and calcinating. The obtained gels were characterized by TG-DSC, and the powder was characterized with XRD, TEM and BET. The experimental results have indicated that the heating temperature was only 800°C for synthesizing the powder and the average particle size was only about 40-50 nm. Furthermore it was found that a pure BCN18 phase with complexperovskite structure was formed at 800°C, which was about 800°C lower than that of the traditional solid-reaction method. So it is more practical and more superior to the traditional solid-reaction method and the present wet-chemical method in alcohol salt system reported in literature.

scholarly journals Stability and Dynamic Aggregation of Bare and Stabilized Zero-Valent Iron Nanoparticles under Variable Solution Chemistry

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 192 ◽  
Author(s):  
Hesham M. Ibrahim ◽  
Mohammed Awad ◽  
Abdullah S. Al-Farraj ◽  
Ali M. Al-Turki
Keyword(s):  
Zeta Potential ◽  
Particle Concentration ◽  
Solution Chemistry ◽  
Zero Valent Iron ◽  
Point Of Zero Charge ◽  
Hydrodynamic Size ◽  
The Stability ◽  
Zero Valent Iron Nanoparticles ◽  
Stability Results ◽  
Polymer Stabilizers

Surface modification of nanoscale zero-valent iron (nZVI) using polymer stabilizers (e.g., sodium carboxymethyl cellulose, CMC) is usually used to minimize aggregation, increase stability, and enhance transport of nZVI. We investigated the stability and dynamic aggregation of bare and CMC–nZVI as affected by variations in pH, ionic strength (IS), and nZVI particle concentration. CMC coating of nZVI resulted in smaller hydrodynamic size and larger zeta potential. The largest hydrodynamic size of nZVI was associated with bare nZVI at high IS (100 mM), pH close to the point of zero charge (PZC, 7.3–7.6), and larger particle concentration (1.0 g L−1). The increase in the zeta potential of CMC–nZVI reached one- to four-fold of that for bare nZVI, and was greater at pH values close to PZC, high IS, and larger particle concentration. The stability of CMC–nZVI was increased by 61.8, 93.1, and 57.5% as compared to that of bare nZVI at IS of 1, 50 and 100 mM, respectively. Calculations of Derjaguin, Landau, Verwey and Overbeek (DLVO) interaction energy were in agreement with stability results, and showed the formation of substantial energy barriers at low IS indicating greater nZVI stability. Our results suggest that at IS above 50 mM and nZVI particle concentration larger than 0.1 g L−1, the likelihood of nZVI aggregation is high. Nevertheless, CMC polymer stabilizer would enhance the stability and transport of nZVI even under these unfavorable solution chemistry conditions.

scholarly journals The stability and fate of synthesized zero-valent iron nanoparticles in freshwater microcosm system

3 Biotech ◽  
2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Deepak Kumar ◽  
Abhinav Parashar ◽  
Natarajan Chandrasekaran ◽  
Amitava Mukherjee
Keyword(s):  
Iron Nanoparticles ◽  
Zero Valent Iron ◽  
The Stability ◽  
Zero Valent Iron Nanoparticles

Wet Chemical Cleaning of Germanium Surfaces for Growth of High-k Dielectrics

2006 ◽  
Vol 917 ◽  
Author(s):  
Sandrine Rivillon Amy ◽  
Yves J Chabal ◽  
Fabrice Amy ◽  
Antoine Kahn ◽  
Cristiano Krugg ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Water Soluble ◽  
Chemical Cleaning ◽  
X Ray ◽  
Native Oxides ◽  
High K ◽  
Controlled Environments ◽  
Wet Chemical ◽  
The Stability ◽  
Poor Stability

AbstractOne of the major difficulties preventing the wide use of germanium (epi or bulk) as a gate material is the poor stability of its oxide, leading to reproducibility and reliability issues. In contrast to silicon, the nature and thickness of Ge “native” oxides are history dependent, and most phases of germanium oxide are water-soluble. As a result, the procedures for passivating Ge surfaces with hydrogen (HF last) are more complex and less forgiving.We have used infrared absorption spectroscopy and x-ray photoelectron spectroscopy to investigate the nature of oxidized and H-terminated Ge surfaces. The GeO2, GeO and GeC phases have been identified and quantified as a function of processing conditions. The stability of the H-terminated surfaces has been examined in air and in controlled environments. The H-passivated Ge surfaces are found to be much less stable in air than H-terminated Si surfaces.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

scholarly journals Zero-Valent Iron Nanoparticles for Soil and Groundwater Remediation

2020 ◽  
Vol 17 (16) ◽  
pp. 5817
Author(s):  
Alazne Galdames ◽  
Leire Ruiz-Rubio ◽  
Maider Orueta ◽  
Miguel Sánchez-Arzalluz ◽  
José Luis Vilas-Vilela
Keyword(s):  
Contaminated Soils ◽  
Groundwater Remediation ◽  
Iron Nanoparticles ◽  
Environmental Issues ◽  
High Specific Surface Area ◽  
Zero Valent Iron ◽  
Pilot Studies ◽  
High Effectiveness ◽  
Nanosized Materials ◽  
Zero Valent Iron Nanoparticles

Zero-valent iron has been reported as a successful remediation agent for environmental issues, being extensively used in soil and groundwater remediation. The use of zero-valent nanoparticles have been arisen as a highly effective method due to the high specific surface area of zero-valent nanoparticles. Then, the development of nanosized materials in general, and the improvement of the properties of the nano-iron in particular, has facilitated their application in remediation technologies. As the result, highly efficient and versatile nanomaterials have been obtained. Among the possible nanoparticle systems, the reactivity and availability of zero-valent iron nanoparticles (NZVI) have achieved very interesting and promising results make them particularly attractive for the remediation of subsurface contaminants. In fact, a large number of laboratory and pilot studies have reported the high effectiveness of these NZVI-based technologies for the remediation of groundwater and contaminated soils. Although the results are often based on a limited contaminant target, there is a large gap between the amount of contaminants tested with NZVI at the laboratory level and those remediated at the pilot and field level. In this review, the main zero-valent iron nanoparticles and their remediation capacity are summarized, in addition to the pilot and land scale studies reported until date for each kind of nanomaterials.

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