Chromotropic acid–formaldehyde reaction in strongly acidic media. The role of dissolved oxygen and replacement of concentrated sulphuric acid

Talanta ◽  
2003 ◽  
Vol 60 (1) ◽  
pp. 171-176 ◽  
Author(s):  
E Fagnani
Keyword(s):  
Dissolved Oxygen ◽  
Sulphuric Acid ◽  
Chromotropic Acid ◽  
Acidic Media

scholarly journals Influence of grain size on chalcopyrite ore leaching in acidic medium

2007 ◽  
Vol 72 (8-9) ◽  
pp. 911-919 ◽  
Author(s):  
M.M. Antonijevic ◽  
G.D. Bogdanovic ◽  
S.M. Serbula ◽  
S.M. Milic
Keyword(s):  
Grain Size ◽  
Dissolved Oxygen ◽  
Sulphuric Acid ◽  
Acidic Medium ◽  
Raw Material ◽  
Leaching Rate ◽  
Acid Consumption ◽  
Leaching Solution ◽  
Chalcopyrite Ore

This work presents an investigation of column leaching of a chalcopyrite ore using sulphuric acid where dissolved oxygen and iron(III) ions play the role of oxidants. The investigations were carried out in PVC columns, diameter 110 mm and height 1000 mm, by percolation of the leaching solution through the ore layer. The influence of ore grain size on the degree of leaching and acid consumption was examined. The formation of gypsum on limestone results in the comminution of the initial raw material during leaching. The grain size of chalcopyrite was found to have no important influence on the leaching rate of copper. A higher consumption of sulphuric acid was found for the fractions (-3+1) mm, (?5+0) mm and (?5+3) mm than for the fractions (?10+5) mm, (?20+10) mm and (?20+0) mm. .

The role of surface crystalline heterogeneities in the electrooxidation of carbon monoxide adsorbed on Rh(111) electrodes in sulphuric acid solutions

1997 ◽  
Vol 432 (1-2) ◽  
pp. 1-5 ◽  
Author(s):  
Roberto Gómez ◽  
JoséM. Orts ◽  
Juan M. Feliu ◽  
Jean Clavilier ◽  
Lorena H. Klein
Keyword(s):  
Carbon Monoxide ◽  
Sulphuric Acid ◽  
Acid Solutions

The role of iron in the preparation and oxygen reduction reaction activity of nitrogen-doped carbon

2015 ◽  
Vol 51 (12) ◽  
pp. 2450-2453 ◽  
Author(s):  
Dae-Soo Yang ◽  
Min Young Song ◽  
Kiran Pal Singh ◽  
Jong-Sung Yu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Carbon Sources ◽  
Reduction Reaction ◽  
Acidic Media ◽  
Oxygen Reduction Reaction Activity ◽  
Exact Role ◽  
Ordered Mesoporous ◽  
Nitrogen Doped Carbon

The exact role of iron in catalyzing oxygen reduction reaction in both alkaline and acidic media is portrayed with unique platelet ordered mesoporous carbon prepared using Fe-phthalocyanine as iron, nitrogen and carbon sources.

scholarly journals Corrosion Behavior of Copper and Carbon Steel in Acidic Media

2014 ◽  
Vol 11 (4) ◽  
pp. 1577-1582
Author(s):  
Baghdad Science Journal
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Acidic Media ◽  
Corrosion Rates ◽  
Weight Loss Method ◽  
Acid Environment ◽  
Loss Method

The corrosion behavior of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) has been studied. The corrosion inhibition of copper and carbon steel in 1M concentration of hydrochloric acid (HCl) and sulphuric acid (H2SO4) by Ciprofloxacin has been investigated. Specimens were exposed in the acidic media for 7 hours and corrosion rates evaluated by using the weight loss method. The effect of temperature (from 283 ºK to 333 ºK), pH (from 1to 6), inhibitor concentration (10-4 to 10-2) has been studied. It was observed that sulphuric acid environment was most corrosive to the metals because of its oxidizing nature, followed by hydrochloric acid. The rate of metal dissolution increased with increasing exposure time. Corrosion rates of carbon steel in the acidic media found to be higher.

scholarly journals The simultaneous removal of bisphenol A, manganese and ammonium from groundwater by MeOx: The role of chemical catalytic oxidation for bisphenol A

2021 ◽  
Author(s):  
Yingming Guo ◽  
Ben Ma ◽  
Jianxiong Huang ◽  
Jing Yang ◽  
Ruifeng Zhang
Keyword(s):  
Oxide Film ◽  
Bisphenol A ◽  
Dissolved Oxygen ◽  
Oxidation Process ◽  
Pilot Scale ◽  
Simultaneous Removal ◽  
Chemical Forms ◽  
Synergy Effect ◽  
Iron And Manganese

Abstract The iron and manganese oxide filter film (MeOx) were used to research the simultaneous removal of bisphenol A (BPA), manganese (Mn2+) and ammonium (NH4+) in a pilot-scale filter system. We found that 0.52 mg/L of BPA could be removed while consuming 5.44 mg/L of dissolved oxygen (DO). Since the oxidation process of NH4+ and BPA both consume the DO in water, the presence of NH4+ can hinder the removal of BPA. The presence of Mn2+ in water had a synergy effect on the BPA removal. The filter film was characterized by SEM, XRD and XPS. Some substances were generated to block the pores of the oxide film, and a small amount of film was found to crack and fall off. The elemental composition of C and O were both increased by about 9%, the composition of Mn was decreased from 63.48% to 44.55%, and the reduced manganese substance might affect the activity of the oxide film. The main chemical forms of MeOx are Mn6O12·3H2O, MnFe2O4 or Mn3O4. The decrease in the removal efficiency of BPA was mainly due to the C-containing intermediate [−CH2C − H(OH)]n covering the surface of the oxide film and blocking the pore size of the film.

Design and synthesis of novel porphyrinated polyimide nanofibers as dissolved oxygen sensor: The role of electro-activity and orientation

2019 ◽  
Vol 161 ◽  
pp. 79-88 ◽  
Author(s):  
Huanyu Lei ◽  
Jiaming Lu ◽  
Guoqing Dong ◽  
Guofeng Tian ◽  
Shengli Qi ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Sensor ◽  
Design And Synthesis

The sorption of zinc species by clay minerals

1976 ◽  
Vol 29 (8) ◽  
pp. 1649 ◽  
Author(s):  
H Farrah ◽  
WF Pickering
Keyword(s):  
Ion Exchange ◽  
Alkaline Media ◽  
Precipitation Process ◽  
Zinc Ions ◽  
Clay Suspension ◽  
Acidic Media ◽  
Apparent Affinity ◽  
Charged Species ◽  
Nucleation Centre

The effect of changes in pH and the presence of ligands on the uptake of zinc ions by three types of clay mineral (kaolinite, illite and montmorillonite) has been investigated. In alkaline media the clay suspension acts as a nucleation centre for polymeric hydroxy species, and the major role of many ligands is to mask the precipitation process. Uncharged and negatively charged species are not sorbed to any measurable extent. In acidic media the adsorption capacity of the clays for zinc increases with pH and possible mechanisms are considered. For kaolinite and illite the controlling process appears to be the attachment of hydroxy species to particular sites on the particle edges; with montmorillonite ion exchange at negative lattice sites appears predominant. Of particular interest is the apparent affinity between montmorillonite and species containing nitrogen functional groups.

The Role of Oxygen in Zone-Melting Recrystallization of Silicon-On-Insulator Films

1983 ◽  
Vol 23 ◽  
Author(s):  
John C. C. Fan ◽  
B-Y. Tsaur ◽  
C. K. Chen ◽  
J. R. Dick ◽  
L. L. Kazmerski
Keyword(s):  
Dissolved Oxygen ◽  
Mass Spectroscopy ◽  
Zone Melting ◽  
Constitutional Supercooling ◽  
Common Origin ◽  
Silicon On Insulator ◽  
Secondary Ion Mass Spectroscopy ◽  
Secondary Ion

ABSTRACTUsing secondary-ion mass spectroscopy, we have found that oxygen is strongly concentrated at the sub-boundaries in zone-melting-recrystallized silicon-on-insulator films prepared by the graphite-strip-heater technique. This observation suggests that the formation of sub-boundaries during recrystallization may be caused by constitutional supercooling resulting from the presence of oxygen that is dissolved into the molten Si zone from the adjacent SiO2 layers. Since all zone-melting-recrystallized films to date have been bordered by SiO2 layers, regardless of the heating techniques employed, the sub-boundaries almost always present in these films may well have dissolved oxygen as their common origin.

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