Roles of temperature and flow velocity on the mobility of nano-sized titanium dioxide in natural waters

This paper has been focused on the impact of the set of microcrystal water-insoluble inorganic additives to dimension characteristics of pellets of the microscopic filamentous fungus Aspergillus niger. The selection of powder substances included montmorillonite clay mineral, silicon dioxide, iron oxide, one zeolitic tuff with mineral clinoptilolite as its main component, three synthetic zeolites, Na-mordenite, NaY and Na-ZSM-5, and titanium dioxide. This group is comprised of substances that are often components of various natural waters (including contaminated waters) and also frequent components of soil. Exceptions are synthetic zeolites and titanium dioxide. The impact of aforementioned substances was monitored on four Aspergillus niger strains isolated from soils at four Slovak locations, markedly differing in soil reaction values. Three of these soil samples have been affected by considerable contamination due to previous mining activities. Clay mineral montmorillonite reduced the size of the pellets regardless of the origin of strains, while the impact of other inorganic substances was either weak or variable depending on the type of inorganic substance and source location of the strains. The impact of natural zeolitic tuff was also similar, however, less significant.

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Application of Nonorganic Sorbents for Treatment of Radioactively-contaminated Natural Waters and Liquid Radioactive Waste.

Water sector of Russia: problems, technologies, management - Методы оценки и механизмы регулирования водопользования в современных условиях ◽

10.35567/1999-4508-2016-5-8 ◽

2016 ◽

pp. 102

Author(s):

Keyword(s):

Titanium Dioxide ◽

Radioactive Waste ◽

Natural Waters ◽

Ammonium Acetate ◽

Liquid Radioactive Waste ◽

Hydrated Titanium Dioxide ◽

Model Liquid ◽

Ferrocyanide Sorbents ◽

Saline Solutions ◽

Hydrated Titanium

Comparative analysis of the method of natural radioactively-contaminated waters and model liquid radioactive waste containing B-Trilon, ammonium acetate, and NaNO3 with natural and artificial nonorganic sorbents (aluminum silicates, ferrocyanide sorbents based on hydrated titanium dioxide, klinoptyalolith, glauconit, Termoxid-3A and Termoxid-35 sorbents) was carried out. It was demonstrated that when treating low-saline solutions and drinking water in respect of cesium radio nuclides the highest distribution ration 1.0·107 ml/g was observed for NKF- klinoptyalolith sorbent. When decontaminate solutions containing B-Trilon the cesium distribution ratios with artificial sorbents Т-35, NKF- hydrated titanium dioxide and natural aluminum silicates (klinoptyalolith and glauconit) were comparable and equal, depending on the B-Trilon concentration ~102‒103 ml/g. To treat high-saline NaNO3 solutions NKF- hydrated titanium dioxide and NKF- glauconit were effective: cesium distribution ratios from NaNO3 solution with 2 mol/l concentration were 6.1·104 and 1.7 ·104 ml/g, respectively.

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Efficient hydrophobization and solvent microextraction for determination of trace nano-sized silver and titanium dioxide in natural waters

Analytica Chimica Acta ◽

10.1016/j.aca.2013.06.011 ◽

2013 ◽

Vol 789 ◽

pp. 47-57 ◽

Cited By ~ 24

Author(s):

Seyed Mohammad Majedi ◽

Barry C. Kelly ◽

Hian Kee Lee

Keyword(s):

Titanium Dioxide ◽

Natural Waters

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UV SPECTROSCOPY AND KINETIC RESEARCH OF PHOTODEGRADATION OF METHYL ORANGE IN THE PRESENCE OF TITANIUM DIOXIDE AND β-CYCLODEXTRIN OR ITS DERIVATIVES

Polymer journal ◽

10.15407/polymerj.43.02.103 ◽

2021 ◽

Vol 43 (2) ◽

pp. 103-112

Author(s):

Yu.V. Bardadym ◽

◽

S.M. Kobylinskyi ◽

L.V. Kobrina ◽

S.V. Riabov ◽

...

Keyword(s):

Titanium Dioxide ◽

Methyl Orange ◽

Natural Waters ◽

Uv Spectroscopy ◽

Significant Loss ◽

Hydroxyl Groups ◽

Sulfobutyl Ether ◽

Kinetics Of ◽

Irradiation Process ◽

By Products

The research is devoted to the study of the effect of β-cyclodextrin (β-CD) and its derivatives on the photocatalytic degradation of methyl orange in aqueous solutions in the presence of titanium dioxide. It has been shown that the kinetics of photodegradation of methyl orange is more accurately described by the pseudo first order equation for all investigated pH values. In the presence of cyclodextrins β-CD and 2-hydroxypropyl-β-cyclodextrin, acceleration of photodegradation was observed only after 30 min of irradiation. As a result, the oxidation of hydroxyl groups of cyclodextrin occurred. A significant slowdown in photodestruction in the TiO2-β-CD sample during the first 45 min is explained by the formation of inclusion complexes of cyclodextrin with methyl orange, which prevented the destruction of dye. The use of the β-cyclodextrin, its derivatives and increasing the acidity of the medium accelerates the processes of photodestruction of methyl orange in distilled and natural waters. Methyl orange was decolorized for 20 – 25 min in solutions of all investigated cyclodextrin derivatives at pH 2.5. The destruction of methyl orange was most effective with the use of sulfobutyl ether β-CD. The bactericidal lamp (λ = 254 nm) allows to increase the rate of destruction during the irradiation process. Methyl orange discolored much faster under the action of a bactericidal lamp than using only ultraviolet lamps with λ = 365 nm. A slight slowdown in the decomposition process is observed after several irradiation cycles. This may be due to the influence of the formed products of destruction. However, under such conditions, the by-products of reactions decompose much faster. The use of cyclodextrins is possible without significant loss of efficiency up to 8 cycles.

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Photoactive Titanium Dioxide Films with Embedded Gold Nanoparticles for Quantitative Determination of Mercury Traces in Humic Matter-Containing Freshwaters

Nanomaterials ◽

10.3390/nano11020512 ◽

2021 ◽

Vol 11 (2) ◽

pp. 512

Author(s):

Vivian Stock ◽

Anna Mutschler ◽

Mika Lindén ◽

Kerstin Leopold

Keyword(s):

Gold Nanoparticles ◽

Titanium Dioxide ◽

Sample Preparation ◽

Natural Waters ◽

Fluorescence Spectrometry ◽

Atomic Fluorescence Spectrometry ◽

Humic Matter ◽

Atomic Fluorescence ◽

Titanium Dioxide Films

Mercury detection in humic matter-containing natural waters is often associated with environmental harmful substances for sample preparation. Herein we report an approach based on photoactive titanium dioxide films with embedded gold nanoparticles (AuNP@TiO2 dipstick) for chemical-free sample preparation and mercury preconcentration. For this purpose, AuNPs are immobilized onto a silicon wafer and further covered with a thin photoactive titanium dioxide layer. The AuNPs allow the preconcentration of Hg traces via amalgamation, while TiO2 acts as a protective layer and, at the same time, as a photocatalyst for UV-C radiation-based sample pretreatment. Humic matter, often present in natural waters, forms stabile complexes with Hg and so hinders its preconcentration prior to detection, causing a minor recovery. This problem is solved here by irradiation during Hg preconcentration onto the photoactive dipstick, resulting in a limit of detection as low as 0.137 ng L−1 using atomic fluorescence spectrometry (AFS). A 5 min preconcentration step is sufficient to obtain successful recovery of Hg traces from waters with up to 10 mg L−1 DOC. The feasibility of the approach was demonstrated by the determination of Hg traces in Danube river water. The results show no significant differences in comparison with standard cold vapor-atomic fluorescence spectrometry (CV-AFS) measurements of the same sample. Hence, this new AuNP@TiO2 dipstick provides a single-step sample preparation and preconcentration approach that combines sustainability with high analytical sensitivity and accuracy.

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