Stability of nano-sized titanium dioxide in an aqueous environment: effects of pH, dissolved organic matter and divalent cations

Nano-sized titanium dioxide in the aquatic environment has a potential impact on the environment and human health. In this study, the impact of pH value, dissolved organic matter (DOM) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles (nano-TiO2) in an aqueous environment was investigated in batch tests. The results showed that the particle size of nano-TiO2 was not sensitive to pH value but was inversely proportional to zeta potential. The nano-TiO2 becomes more stable with surface zeta potential, accompanied by small particle size and high dispersion. In the presence of DOM, the particle size was smaller and the stability of nano-TiO2 could be enhanced. This might be a synergistic effect of the ligand exchange and electrostatic force. Particle size increased with the addition of Ca2+ and the stability decreased.

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Stability Analysis of Nano-Sized Titanium Dioxide in Aqueous Environment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.374-377.869 ◽

2011 ◽

Vol 374-377 ◽

pp. 869-874 ◽

Cited By ~ 1

Author(s):

Xiao Nan Yang ◽

Fu Yi Cui ◽

Xiao Ying Mu ◽

Zhi Wei Zhao

Keyword(s):

Particle Size ◽

Titanium Dioxide ◽

Zeta Potential ◽

Ph Value ◽

Electrostatic Force ◽

High Dispersion ◽

Aqueous Environment ◽

Tio2 Nps ◽

The Stability ◽

The Impact

Nano-sized titanium dioxide in aquatic environment poses potential impact on environment and human health. In this research, the impact of pH value, humic acid (HA) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles(NPs) in the aqueous enviorment was investigated using a batch test. The results showed that the particle size of TiO2 NPs was not sensitive to the pH value but presented inversely proportional to zeta potential. The TiO2 NPs become more stable along with surface zeta potential, accompany with small particle size and high dispersion. In the presence of HA, the particle size was smaller and TiO2 NPs could be stabilized. This might be synergistic effect of the ligand exchange and electrostatic force. Meanwhile, NPs particle size increased with the addition of Ca2+ and the stability of TiO2 NPs became decreased.

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Stability of Fe-oxide nanoparticles coated with natural organic matter under relevant environmental conditions

Water Science & Technology ◽

10.2166/wst.2014.454 ◽

2014 ◽

Vol 70 (12) ◽

pp. 2040-2046 ◽

Cited By ~ 6

Author(s):

L. Chekli ◽

S. Phuntsho ◽

L. D. Tijing ◽

J. L. Zhou ◽

J.-H. Kim ◽

...

Keyword(s):

Organic Matter ◽

Natural Organic Matter ◽

Environmental Conditions ◽

Divalent Cations ◽

Oxide Nanoparticles ◽

Fe Oxide ◽

Coated Nanoparticles ◽

Aggregation Behaviour ◽

Physico Chemical ◽

The Stability

Manufactured nanoparticles (MNPs) are increasingly released into the environment and thus research on their fate and behaviour in complex environmental samples is urgently needed. The fate of MNPs in the aquatic environment will mainly depend on the physico-chemical characteristics of the medium. The presence and concentration of natural organic matter (NOM) will play a significant role on the stability of MNPs by either decreasing or exacerbating the aggregation phenomenon. In this study, we firstly investigated the effect of NOM concentration on the aggregation behaviour of manufactured Fe-oxide nanoparticles. Then, the stability of the coated nanoparticles was assessed under relevant environmental conditions. Flow field-flow fractionation, an emerging method which is gaining popularity in the field of nanotechnology, has been employed and results have been compared to another size-measurement technique to provide increased confidence in the outcomes. Results showed enhanced stability when the nanoparticles are coated with NOM, which was due to electrosteric stabilisation. However, the presence of divalent cations, even at low concentration (i.e. less than 1 mM) was found to induce aggregation of NOM-coated nanoparticles via bridging mechanisms between NOM and Ca2+.

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Effect of Dispersant on the Measurement of Particle Size Distribution of Titanium Dioxide

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.261 ◽

2012 ◽

Vol 512-515 ◽

pp. 261-264

Author(s):

Li Shen ◽

Jin Hu ◽

Da Ping Wu

Keyword(s):

Particle Size ◽

Titanium Dioxide ◽

Zeta Potential ◽

Particle Size Distribution ◽

Size Distribution ◽

Anionic Surfactant ◽

Sodium Sulfate ◽

Aqueous Media ◽

Rutile Tio2 ◽

Tio2 Particles

As anionic surfactant, a commercial salt of lauryl sodium sulfate was used. The effects of different amounts of dispersant on the measurement of particle size distribution between two titanium dioxide powders (anatase and rutile) in aqueous media were discussed. Diluted aqueous suspensions were characterized in terms of particle size distribution and zeta potential. The results demonstrate that the measurement of particle size distribution strongly depends on the amounts of dispersant. The amounts of dispersant have a significant effect on the behavior of the rutile-TiO2 particles. The particle size first decreases significantly with an increase in the amounts of dispersant and then lesser increases with a further increase in the amounts of dispersant. The tendency show significant differences between two particles.

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Enhanced Antibacterial Activity of Silver Doped Titanium Dioxide-Chitosan Composites under Visible Light

Materials ◽

10.3390/ma11081403 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1403 ◽

Cited By ~ 9

Author(s):

Jie Li ◽

Bing Xie ◽

Kai Xia ◽

Yingchun Li ◽

Jing Han ◽

...

Keyword(s):

Particle Size ◽

Antibacterial Activity ◽

Titanium Dioxide ◽

Visible Light ◽

Silver Ions ◽

Antibacterial Activities ◽

Nano Tio2 ◽

Inverse Emulsion ◽

Potential Applications

Nano titanium dioxide (TiO2) with photocatalytic activity was firstly modified by diethanolamine, and it was then doped with broad spectrum antibacterial silver (Ag) by in situ method. Further, both Ag doped TiO2-chitosan (STC) and TiO2-chitosan (TC) composites were prepared by the inverse emulsion cross-linking reaction. The antibacterial activities of STC composites were studied and their antibacterial mechanisms under visible light were investigated. The results show that in situ doping and inverse emulsion method led to good dispersion of Ag and TiO2 nanoparticles on the cross-linked chitosan microsphere. The STC with regular particle size of 1–10 μm exhibited excellent antibacterial activity against E. coli, P. aeruginosa and S. aureus under visible light. It is believed that STC with particle size of 1–10 μm has large specific surface area to contact with bacterial cell wall. The increased antibacterial activity was attributed to the enhancement of both electron-hole separations at the surface of nano-TiO2 by the silver ions under the visible light, and the synergetic and sustained release of strong oxidizing hydroxyl radicals of nano-TiO2, together with silver ions against bacteria. Thus, STC composites have great potential applications as antibacterial agents in the water treatment field.

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SYNTHESIS AND STABILITY OF RESVERATROL-CONJUGATED GOLD NANOPARTICLES MODIFIED WITH POLYETHYLENE GLYCOL

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2020.v12s1.ff050 ◽

2020 ◽

pp. 230-236

Author(s):

RADITYA ISWANDANA ◽

RICHA NURSELVIANA ◽

SUTRIYO SUTRIYO

Keyword(s):

Particle Size ◽

Gold Nanoparticles ◽

Polyethylene Glycol ◽

Zeta Potential ◽

High Performance ◽

Entrapment Efficiency ◽

Test Results ◽

Novel Method ◽

The Stability ◽

Phosphate Buffered Saline

Objective: Gold nanoparticles (AuNPs) are highly useful for drug delivery, but their application is limited by their stability as they readily aggregate.This issue can be prevented by adding a stabilizing agent such as resveratrol (RSV), which is a polyphenol derived from plants, that is used to preventcancer. Therefore, we propose a novel method to prepare stable RSV-conjugated nanoparticles modified with polyethylene glycol (RSV-AuNP-PEG).Methods: In the first step, the Turkevich method was used to synthesize the AuNPs. Then, PEG was added as stabilizer agent and conjugated with RSV.The synthesized conjugates were characterized using ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, particle sizeanalysis, and high-performance liquid chromatography.Results: The obtained RSV-AuNP-PEG had a particle size of 83.93 nm with a polydispersity index (PDI) of 0.562 and formed a translucent purple-redfluid in solution. The zeta potential was −22.9 mV, and the highest entrapment efficiency was 75.86±0.66%. For comparison, the RSV-AuNP solutionwas purple and turbid, the particle size was 51.97 nm with a PDI of 0.694, and the zeta potential was −24.6 mV. The stability test results showed thatthe storage stability of RSV-AuNP-PEG was better than that of AuNP-RSV. Further, the RSV-AuNP-PEG was shown to be most stable in 2% bovine serumalbumin (BSA) while the AuNP-RSV was most stable in 2% BSA in phosphate-buffered saline pH 7.4.Conclusion: These results show that modification of RSV-conjugated AuNPs with PEG effectively prevents their aggregation in storage, but only incertain mediums.

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Effect of Potato Pulp Pectic Polysaccharide on the Stability of Acidified Milk Drinks

Molecules ◽

10.3390/molecules25235632 ◽

2020 ◽

Vol 25 (23) ◽

pp. 5632

Author(s):

Weixuan Sun ◽

Wenhan Yang ◽

Yuxue Zheng ◽

Huiling Zhang ◽

Haitian Fang ◽

...

Keyword(s):

Particle Size ◽

Zeta Potential ◽

Neutral Sugar ◽

Lower Serum ◽

Pectic Polysaccharide ◽

Potato Pulp ◽

Lower Viscosity ◽

Stabilizing Effect ◽

New Ideas ◽

The Stability

In order to broaden the application of potato pulp pectic polysaccharide (PPP) in stabilizing acidified milk drinks (AMDs) and investigate the stabilizing effect and physical properties of AMDs prepared with PPP, a comparative study was made among PPP, commercial high methoxyl pectin (HMP) and low methoxyl pectin (LMP). The zeta potential, rheology, particle size and serum separation of AMDs were evaluated after preparing with PPP, HMP and LMP, respectively. Results indicated that PPP led to lower serum separation than LMP (14.65% for AMDs prepared with 0.5% PPP compared to 25.05% for AMDs prepared with 0.5% LMP), but still higher than HMP (9.09% for AMDs prepared with 0.5% HMP). However, narrower particle size distribution and lower viscosity of AMDs was achieved by PPP than by LMP and HMP. PPP can electrostatically adsorb on the surface of casein and its abundant neutral sugar side chains would provide steric hindrance to prevent casein flocculation in AMDs. Our results might provide some new ideas for the application of PPP in improving the stability of AMDs.

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