scholarly journals Precipitation of Germanium from Sulphate Solutions Containing Tin and Indium Using Tannic Acid

2019 ◽  
Vol 9 (5) ◽  
pp. 966 ◽  
Author(s):  
Michał Drzazga ◽  
Andrzej Chmielarz ◽  
Grzegorz Benke ◽  
Katarzyna Leszczyńska-Sejda ◽  
Magdalena Knapik ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Tannic Acid ◽  
Process Conditions ◽  
Influence Of Temperature ◽  
Temperature Time

The precipitation of tannin complex of germanium from sulfuric solutions obtained after dross leaching was investigated. The tested solutions contained mainly zinc, germanium, indium, and tin. The influence of temperature, time, amount of added tannic acid and its purity was determined. The application of pure tannic acid allowed the precipitation of >99% of germanium and decreased its concentration in a solution <0.015 g/dm3. It required ca. 11–13 g of pure tannic acid per each 1 g of dissolved germanium. The preferred process conditions for Ge precipitation using powder tannic acid were 90 °C, 90 min, whereas for 20% aq. solution—5 min. It was found that 40% to 50% of tin coprecipitated at these conditions. Therefore, a detinning operation using hydrogen peroxide was proposed. It allowed the removal of >99% Sn and reduced its concentration in the solution below 0.025 g/dm3.

Degradation of Odontologic X-Ray Film Developing Wastewaters by Photo-Fenton Process

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Luciana Igarashi-Mafra ◽  
Edmilson César Bortoletto ◽  
Maria Angelica Simões Dornella Barros ◽  
Amanda Cristina Alfredo Contrucci Sorbo ◽  
Naiara Aguiar Galliani ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Total Phenol ◽  
Process Conditions ◽  
Phenol Removal ◽  
Total Phenols ◽  
Fenton Process ◽  
X Ray ◽  
Control Factors ◽  
Fenton Oxidation Process ◽  
Wastewater Samples

Effluents from radiographic X-ray film developing processes feature a high contaminant load (COD about 70000 mg/L and total phenols concentration about 16956 mg/L). Photo-Fenton's are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence of light to generate hydroxyl radicals (·OH). The photo-Fenton process was explored as a photochemical treatment to degrade wastewater from radiographic X-ray film developing processes coming from odontologic clinics. A response surface methodology was applied to optimize the photo-Fenton oxidation process conditions using total phenol removal as the target parameter to be optimized, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and time and pH as the control factors to be optimized. The best results in terms of maximal total phenol removal and economic process were achieved when wastewater samples were treated at pH 5 in the presence of hydrogen peroxide and iron in the ratios [total phenols]:[H2O2] 1:3 w/w and [Fe2+]:[H2O2] 1:18 w/w and time 1 h.

Optimal experimental design and artificial neural networks applied to the photochemically enhanced Fenton reaction

2001 ◽  
Vol 44 (5) ◽  
pp. 339-345 ◽  
Author(s):  
S. Göb ◽  
E. Oliveros ◽  
S.H. Bossmann ◽  
A.M. Braun ◽  
C.A.O. Nascimento ◽  
...  
Keyword(s):  
Neural Networks ◽  
Hydrogen Peroxide ◽  
Artificial Neural Networks ◽  
Fenton Reaction ◽  
Irradiation Time ◽  
Batch Reactor ◽  
Reaction System ◽  
Process Conditions ◽  
Minor Effect ◽  
Artificial Neural

Among advanced oxidation processes (AOPs), the photochemically enhanced Fenton reaction may be considered as one of the most efficient for the degradation of contaminants in industrial wastewater. This process involves a series of complex reactions. Therefore, an empirical model based on artificial neural networks has been developed for fitting the experimental data obtained in a laboratory batch reactor for the degradation of 2,4-dimethyl aniline (2,4-xylidine), chosen as a model pollutant. The model describes the evolution of the pollutant concentration during irradiation time as a function of the process conditions. It has been used for simulating the behavior of the reaction system in sensitivity studies aimed at optimizing the amounts of reactants employed in the process, an iron(III) salt and hydrogen peroxide, as well as the temperature. The results show that the process is most sensitive to the concentration of iron(III) salt and temperature, whereas the concentration of hydrogen peroxide has a minor effect.

Influence of Temperature-Time Mode of Crystallization on Electrophysical Characteristics of the Polypropylene/Magnetite Nanocomposite

2019 ◽  
Vol 201 (1) ◽  
pp. 218-223
Author(s):  
M. A. Ramazanov ◽  
H. A. Shirinova ◽  
F. V. Hajiyeva ◽  
A. Kh. Karimova
Keyword(s):  
Magnetic Field ◽  
Dielectric Permittivity ◽  
Cooling Rate ◽  
Polymer Nanocomposites ◽  
Hot Pressing ◽  
Nanocomposite Materials ◽  
Negative Magnetoresistance ◽  
Electrophysical Properties ◽  
Influence Of Temperature ◽  
Temperature Time

In the present study, the influence of the temperature–time mode of crystallization (TTC) on the electrophysical properties of polymer-based PP + Fe3O4 nanocomposite materials was investigated. Also, the effect of the temperature-time mode of crystallization of nanocomposites on the negative magnetoresistance (NMR) effect that observed in this material was investigated. It was found that dielectric permittivity of polymer nanocomposites rises with increasing of cooling rate. The cooling rate of nanocomposites after hot-pressing also affects the NMR effect of these materials. The conductivity of the material under the influence of magnetic field improves with increasing of its cooling rate, which leads to increasing of NMR effect.

scholarly journals Preparation of SBS Modified Emulsified Asphalt in High Cold Region

2019 ◽  
Vol 275 ◽  
pp. 04004
Author(s):  
HOU Yanming
Keyword(s):  
Development Time ◽  
Cold Region ◽  
Influence Of Temperature ◽  
Modified Asphalt ◽  
Cold Area ◽  
Asphalt Modification ◽  
Road Performance ◽  
Emulsified Asphalt ◽  
Sbs Modified Asphalt ◽  
Temperature Time

A kind of SBS modified emulsified asphalt for highly cold area was studied by experiments. The research includes two aspects: the first is preparation of SBS modified asphalt. The influence of temperature, time, shear rate and development time on asphalt modification are determined, so as to determine the process of SBS modified asphalt. On this basis, the blending ratio of SBS modified emulsified asphalt was determined by experiments. The results show that the emulsified asphalt produced by the equipment is of good quality and good ductility.4%SBS latex content can make emulsified asphalt meet the standard requirements, but only 6%SBS latex content can obtain better road performance. Although the softening point of SBS modified emulsified asphalt prepared by this method is still low, it can meet the requirements of high cold area.

The Regeneration of the Spent Catalyst Resulted from 3,4,5,6-Tetrachloropyridine-2-Carbonitrile Synthesis

2012 ◽  
Vol 550-553 ◽  
pp. 2436-2446 ◽  
Author(s):  
Yang Li ◽  
Qiu Hong Ai ◽  
Hao Xin Wang ◽  
He’an Luo
Keyword(s):  
Activated Carbon ◽  
Thermal Desorption ◽  
Flow Rate ◽  
Social Benefit ◽  
Process Conditions ◽  
Spent Catalyst ◽  
Economical Benefit ◽  
Iodine Adsorption ◽  
Optimized Conditions ◽  
Temperature Time

In order to optimize the process conditions for regeneration of activated carbon form spent catalyst resulted from 3,4,5,6-tetrachloropyridine-2-carbonitrile synthesis. A two-step process involving the thermal desorption of spent activated carbon and the activation of activated carbon treated by thermal desorption with steam was designed. The influence of desorption temperature, time and the flow rate of nitrogen on the yield of chlorides, the iodine adsorption capacity and the yield of activated carbon were investigated, respectively . The optimal desorption conditions were: temperature of 650°C, time of 90min and the flow rate of nitrogen of 30ml/min. The yield of the chlorides obtained under the optimal conditions was 14.85%. The regeneration of activated carbon treated by thermal desorption with steam; the optimized conditions analyzed by RSM were regeneration temperature of 696°C, time of 84 min and flow rate of steam of 0.58g/min. The experimental results on the optimized conditions were iodine adsorption value of 1003.59mg / g, These methods can not only recover chloride in the spent activated carbon, but also the regeneration activated carbon could partially replace the fresh activated carbon, which would bring an obvious economical benefit and social benefit.

Sign in / Sign up

Export Citation Format

Share Document