Effect of leaching conditions on the elution of metals from denitration catalyst wastes

2018 ◽  
Vol 32 (19) ◽  
pp. 1840062
Author(s):  
Tomoki Yabutani ◽  
Takamasa Nakamura ◽  
Toshio Takayanagi ◽  
Yohei Yamada
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Alkaline Medium ◽  
Sodium Carbonate Solution ◽  
Leaching Rate ◽  
Metallic Ions ◽  
Sodium Percarbonate ◽  
High Affinity ◽  
Leaching Efficiency ◽  
Metallic Species

Leaching of metallic species from denitration catalyst waste was performed at different leaching conditions using different solvents. The leaching efficiency of sodium percarbonate solution was higher than that of hydrogen peroxide (H2O2) or sodium carbonate solution. Under the optimal leaching conditions (1.0 mol kg[Formula: see text] sodium percarbonate, leaching temperature of 80[Formula: see text]C and leaching time of 5 h), the leaching rate was 90.7 ± 2.9% for W, 78.4 ± 4.1% for V and 8.6 ± 0.4% for Ti. The enhanced leaching ability of sodium percarbonate was due to the high affinity of the peroxo moiety (–O–O–) of H2O2, within the percarbonate, towards metallic ions and dissolution of titanium dioxide (TiO2) in the alkaline medium of carbonate.

Leaching kinetics of copper and valuable metal extraction from copper-cadmium residues of zinc hydrometallurgy by oxidation acid leaching

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jihao Guo ◽  
Hongao Xu ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Agitation Rate ◽  
Leaching Kinetics ◽  
Solid Ratio ◽  
Zinc Hydrometallurgy ◽  
Kinetics Of ◽  
Leaching Efficiency

Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

Titanium Dioxide-Supported Sulfonated Low Rank Coal as Catalysts in the Oxidation of Styrene with Aqueous Hydrogen Peroxide

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Mukhamad Nurhadi ◽  
Jon Efendi ◽  
Lee Siew Ling ◽  
Teuku Meurah Indra Mahlia ◽  
Ho Chin Siong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Rank ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Low Rank Coal ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide

Titanium dioxide supported sulfonated low rank coal catalyst possesses high catalytic activity in liquid phase oxidation of styrene with aqueous hydrogen peroxide at room temperature. The catalysts were prepared by sulfonation with concentrated sulfuric acid and impregnation of titanium dioxide (500-2500 µmol). The effect of titanium dioxide impregnation and calcinations on the catalysts were studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, BET surface area, field emission scanning electron microscopy and hydrophobicity measurement. The catalytic activity of the catalysts in the oxidation of styrene by aqueous H2O2 without calcination increased when the amount of titanium dioxide increased. Meanwhile, the catalytic activity of the catalyst calcined at 500oC for 2 h was lower than before calcination. It is suggested that the agglomeration of titanium dioxide and hydrophobicity play important role in the catalytic activity of titanium dioxide-supported sulfonated low rank coal in the oxidation of styrene with aqueous H2O2. 

Effect of Oxidant on the Leaching Rate of Indium from Water Quenching Slag

2013 ◽  
Vol 591 ◽  
pp. 122-125
Author(s):  
Li Jiao Yang ◽  
Si Chen ◽  
Yan Zhang ◽  
Nan Chun Chen ◽  
Jun Gao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Potassium Permanganate ◽  
Crystal Violet ◽  
Acid Leaching ◽  
Water Quenching ◽  
Test Results ◽  
Leaching Rate ◽  
Initial Concentration ◽  
Solid Ratio

Extracting indium from water quenching slag, which contains poor indium, by two process of leaching, the effect of different oxidants and dosages on the leaching rate of indium in water quenching slag were studied. The leaching conditions: temperature 80 °C, leaching time 2 h, the liquid to solid ratio of neutral leaching 8︰1, the liquid to solid ratio of acid leaching 2︰1, initial concentration of sulfuric acid 500 g·L-1, adding different oxidants, the concentration was detected by crystal violet spectrophotometry. Test results showed that the leaching rate of indium was significantly improved by adding hydrogen peroxide and potassium permanganate. Compared with the effect of different oxidants, the effect of potassium permanganate was significantly higher than that of hydrogen peroxide on the leaching rate of indium.

Photocatalytic Oxidation of Shenfu Bituminous Coal and Xilinhaote Lignite with H2O2 over TiO2

2011 ◽  
Vol 233-235 ◽  
pp. 1684-1689 ◽  
Author(s):  
Heng Shen Xie ◽  
Zhi Min Zong ◽  
Qing Wei ◽  
Pei Zhi Zhao ◽  
Jian Jun Zhao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Oxidation ◽  
Photocatalytic Oxidation ◽  
Bituminous Coal ◽  
Straight Chain ◽  
Photo Catalytic Oxidation ◽  
Alkyl Side Chains ◽  
Lignite Coal ◽  
Oxidation Effect

Shenfu bituminous coal (SFBC) and Xilinhaote lignite (XL) were subject to photo-catalytic oxidation with hydrogen peroxide over titanium dioxide. The reaction mixtures were extracted with acetone exhaustively. The extracts were analyzed with FTIR and GC/MS. The results show that coals be oxidized selectively and degraded partially. Compared with the bituminite coal, the oxidation effect of the lignite coal with active hydrogens is more obvious. The alkyl side chains of the macromolecules, particularly, chains of methyl, methylene and aromatic, are the most vulnerable in relation to other compounds in coals. Moreover, the increasing of straight-chain alkanes and the decreasing of condensed nucleus in SFBC and XL through oxidation suggest that the oxidation is an effective method of coal utilization with no difficultly, also be friendly towards the environment after treated as well as in the process of the treatment.

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.

Highly-efficient photocatalytic hydrogen peroxide production over polyoxometalates covalently immobilized onto titanium dioxide

2020 ◽  
Vol 591 ◽  
pp. 117271 ◽  
Author(s):  
Xiaofei Wu ◽  
Xiufang Zhang ◽  
Shen Zhao ◽  
Yan Gong ◽  
Ridha Djellabi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Hydrogen Peroxide Production ◽  
Highly Efficient
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