Removal of dyes from aqueous solution using ultraviolet/hydrogen peroxide/titanium dioxide process in a rotating microreactor

2021 ◽  
Author(s):  
A. Gouran ◽  
M. Mohadesi ◽  
M. Falsafi
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide

scholarly journals Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Fracture Resistance ◽  
Composite Resin ◽  
Positive Control ◽  
Sodium Ascorbate ◽  
Resistance Testing ◽  
Dental Bleaching ◽  
Endodontically Treated Tooth

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

Synthesis of Titanium Dioxide in Hydrogen Peroxide Solution and its Photocatalytic Character

2013 ◽  
Vol 827 ◽  
pp. 34-37 ◽  
Author(s):  
Su Kim Wan ◽  
Seok Rhee Dong
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Particle Size ◽  
Titanium Dioxide ◽  
Humic Acid ◽  
Surface Area ◽  
Crystalline Phase ◽  
Titanium Tetraisopropoxide ◽  
Surface Sites ◽  
Inorganic Acids

TiO2nanocrystals were synthesized from Titanium Tetraisopropoxide in H2O2solution, and utilized as photocatalysts for degradation of humic acid in aqueous solution. The highly pure TiO2nanocrystals were obtained by excluding the use of inorganic acids that might consequently cause contamination of active catalytic surface sites of the nanocrystals by Cl-, NO3-and SO42-. Particle size and crystallinity of the nanocrystals were increased with progressing the refluxing time 1 ~ 9 h at 120°C in an oil bath. By varying H2O2/Ti = 5.5 ~ 55, the crystalline phase of anatase/rutile ratio of the nanocrystals was controllable. The photocatalytic properties of the nanocrystals were strongly dependent upon the crystallinity and particle size. The DOC removal of humic acid was most effective for the nanocrystals prepared at H2O2/Ti= 5.5 due to the mixed crystalline phase of anatase/rutile and the increased surface area by smaller particle size. The decreases of UV254absorbance of HAs solutions were much faster than those of DOC, and not so dependent upon the variations of TiO2nanocrystals.

Photooxidation of metalaxyl in aqueous solution in the presence of hydrogen peroxide and titanium dioxide

Chemosphere ◽  
1994 ◽  
Vol 28 (2) ◽  
pp. 341-347 ◽  
Author(s):  
P.N. Moza ◽  
P. Sukul ◽  
K. Hustert ◽  
A. Kettrup
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide

Reactions in Activated Peroxide Systems and their Influences on Bleaching Performance

2020 ◽  
Vol 17 ◽  
Author(s):  
Xiaoyan Wang ◽  
Jinmei Du ◽  
Changhai Xu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Energy Efficiency ◽  
Textile Industry ◽  
High Energy ◽  
Side Reactions ◽  
Competitive Reactions ◽  
High Energy Efficiency ◽  
Hydrolysis Of ◽  
Bleach Activators

Abstract:: Activated peroxide systems are formed by adding so-called bleach activators to aqueous solution of hydrogen peroxide, developed in the seventies of the last century for use in domestic laundry for their high energy efficiency and introduced at the beginning of the 21st century to the textile industry as an approach toward overcoming the extensive energy consumption in bleaching. In activated peroxide systems, bleach activators undergo perhydrolysis to generate more kinetically active peracids that enable bleaching under milder conditions while hydrolysis of bleach activators and decomposition of peracids may occur as side reactions to weaken the bleaching efficiency. This mini-review aims to summarize these competitive reactions in activated peroxide systems and their influence on bleaching performance.

Heterogeneous Fenton Catalytic Removal of Organic Pollutant in Aqueous Solution by using Coal Gangue as a Catalyst

2019 ◽  
Vol 12 (4) ◽  
pp. 312-325
Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Removal Rate ◽  
Organic Pollutant ◽  
Coal Gangue ◽  
Ion Leakage ◽  
Heterogeneous Fenton ◽  
Solution Ph ◽  
X Ray

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.

Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Nickel Oxide ◽  
Catalytic Properties ◽  
Cadmium Oxide ◽  
Chemisorb Oxygen ◽  
Composition Region ◽  
Chemisorbed Oxygen ◽  
Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

Oxidation of ethylenediphosphinetetraacetate anions

1983 ◽  
Vol 48 (9) ◽  
pp. 2604-2608
Author(s):  
Jana Podlahová ◽  
Jaroslav Podlaha
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Electronic Structure ◽  
Acid Solutions ◽  
Tetraacetic Acid ◽  
Single Product ◽  
Weakly Acid ◽  
Inhibiting Effect ◽  
Oxidation By Molecular Oxygen ◽  
Protonated Forms

The oxidation of the ethylenediphosphinetetraacetate anion and its protonated forms by iodine, periodate, hydrogen peroxide, and oxygen has been studied in aqueous solution. The oxidation by the first three reagents is fast and yields a single product, bis(phosphine oxide), which has been isolated and characterized as ethylenebis(phosphinyl)tetraacetic acid. The oxidation by molecular oxygen proceeds considerably more slowly; in weakly acid solutions its rate is determined by the properties of the oxygen rather than by the electronic structure of the various protonated substrate species. The inhibiting effect of the phosphonium structures takes place only in strongly acid solutions.

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