摘要:
Aqueous solutions of hydroxylammonium carbonate are prepared from aqueous hydroxylammonium salt solutions by electrodialysis by a method in which the aqueous hydroxylammonium salt solution is fed into the middle zone of an electrolysis cell, which is divided into a cathode zone, an anode zone and a middle zone by means of semipermeable membranes, and is electrolyzed, and the catholyte used is an aqueous solution of an ammonium carbonate or an alkali metal carbonate or of one of the corresponding bicarbonates.
摘要:
Aqueous solutions of hydroxylamine are prepared from aqueous hydroxylammonium salt solutions by electrodialysis by a method in which the aqueous hydroxylammonium salt solution is fed into the middle zone of an electrolysis cell, which is divided into a cathode zone, an anode zone and a middle zone by means of semipermeable membranes, and is electrolyzed, and the catholyte used is an alkali metal hydroxide solution containing ammonia and/or amines.
摘要:
Blue iron hexacyanoferrate-III pigments are produced by a process wherein complex iron-II hexacyanoferrate-II (Berlin white) is prepared by electrolysis of an aqueous catholyte solution containing (a) an iron-II salt, (b) an alkali metal salt, an ammonium salt or a mixture of these, and (c) hydrogen cyanide, in an electrolysis cell in which the anode chamber and cathode chamber are separated by an ion exchange membrane, using an electrically conductive aqueous liquid in the anode chamber, and the iron-II hexacyanoferrate-II obtained is then converted to the blue pigment.The process gives Berlin white, which is substantially free from salt, in high yield and high purity. Pollution caused by the process is very low, since only a small amount of salt is produced. Compared with the corresponding blue pigments produced by prior art processes, the pigments obtained give purer colorations with better gloss, and are of higher color strength.
摘要:
A redox electrode for determining nitrous acid and nitrosyl compounds in aqueous, acidic solution consists of a metallic conductor on which an n-conducting metal oxide surface is present.
摘要:
A process for the preparation of a water soluble food-grade diaminotriphenylmethane colorant containing from 2 to 4 sulfo groups, comprising anodically oxidizing the corresponding leuco compound in an electrolysis cell divided into an anode space and a cathode space in the presence of from 0.01 to 2% by weight, based on the solution being oxidized, of a C.sub.2 -C.sub.4 -alkanol, urea, a urea derivative or a mixture thereof, at a potential .epsilon..sub.h .ltoreq.1250 mV and at a temperature .ltoreq.+40.degree. C. The colorants obtained are produced in high yield and are of food quality.
摘要:
Alkali metal sulfates are electrolyzed to more concentrated solutions of alkali metal hydroxide and sulfuric acid by using a three-compartment electrodialysis cell at temperatures of .gtoreq.70.degree. to .gtoreq.150.degree. C. and current densities of from 0.5 to 15 kA/m.sup.2 using an anion exchange membrane whose polymeric ion exchange matrix comprises a styrene/divinylbenzene copolymer containing very strongly basic quaternary ammonium groups and a hydronium ion blocker, on whose central compartment side is an ion exchange layer or membrane containing tertiary or secondary amino groups.
摘要:
Oxidizable for organic and/or inorganic compounds in waters are subjected to catalytic degradation using a catalyst applied to an oxygen-storing inert carrier, for example of graphite, coke, a non-gassing coal or active carbon. The carrier used is coated with a cationic dye complexed with heteropolyacids and/or polyacids and/or salts or metal acids of subgroups V to VIII.The advantages of the process include the prevention of biological growth on the catalyst surface by the biocidal dye cation and the avoidance of calcium and magnesium deposits on the catalyst surface through the presence of the cationic solid.
摘要:
In a fuel cell which has an activated carbon-containing anode and an activated carbon-containing cathode and is preferably used for the oxidative treatment of waste waters containing oxygen or oxygen-containing compounds, the cathode has been subjected to partial anodic oxidation in a mineral acid at a potential .epsilon..sub.h of from +1.3 to +10V and then doped with molybdenum(VI) and/or tungsten(VI) and/or vanadium(V) compounds, and the anode has been subjected to partial anodic oxidation in an aqueous mineral acid, cathodically reduced in an aqueous mineral acid and then impregnated with cobalt hydroxide and/or nickel hydroxide and/or copper hydroxide and/or zinc hydroxide, the anode and the cathode being separated by a porous polyelectrolyte through which the waste water flows.
摘要:
A biological reactor which is operated using microorganisms and/or enzymes and used for the oxidative conversion of organic compounds, and in which the organic compounds to be converted are employed in the presence of a biocatalyst in the reactor space (4) (anode space) and the enzymes are regenerated at a polarized electrode (1), the polarization of the electrode (1) being effected by means of a catalyst electrode (2) which is separated from the reactor space (4) by a polyelectrolyte (3) and is located in an electrolyte space (5), wherein the electrode (1) is prepared from an electrically conductive carbon material which has been partially oxidized on the surface at a potential .epsilon..sub.h of from +1.3 to +10 V in an aqueous oxygen-containing mineral acid.
摘要:
Wastewaters are subjected to an oxidative treatment with a carbon-containing catalyst and an oxidizing agent by a process in which the carbon carrier used, e.g. graphite, coke or active carbon, is subjected to anodic oxidation in an aqueous mineral acid and then doped with molybdenum(Vl) and/or tungsten(VI) and/or vanadium(V) compounds.