Cadmium vanadates

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

Reduction of add solutions of vanadium pentoxide to the tetravalent state also takes place with bismuth amalgam 5 magnesium gives the trivalent salts of vanadium, while by using zinc, zinc coated with cadmium, electrolytically deposited cadmium, or sodium amalgam in the absence of air, divalent vanadium salts are obtained in solution.7 Vanadous salts and hypovanadous salts are, however, much more conveniently prepared by electrolytic reduction of acid solutions of vanadium pentoxide in an atmosphere of carbon dioxide.8... 

It is known that cadmium sulfide (CdS) and ion oxide Te203) are visible light-sensitive materials, in particular, one-step photocata ysis of wate - is possible for CdS.25) Recently, Kudc et at. reported that bismuth vanadate (BiV04) snowed photocatalytic activity for 02 evolution from an aqueous silver nitrate solution under visible light.26 271 BiVCX is a very attractive photocatalyst although it is impossible to decompose water by a one-step process. Thus this material is a candidate for an 02 evolution photocatalyst to construct a two-phoion process 26) In other words, this material is expected to be an 02 evolution photocatalyst to... 

Cadmium pigments Mercury cadmium pigments Lead chromate yellows Lead molybdate oranges Iron blues Chrome greens Bismuth vanadate... 

Bismuth vanadate is a pigment with a greenish yellow shade. When compared with other yellow inorganic pigments, it most closely resembles cadmium yellow and chrome yellow in its coloristic properties (Figure 3.10). 

The carbonates, sulphates, and borates are decomposed. The sulphides of the alkalies and alkaline earths are decomposed while the sulphides of arsenic, antimony, molybdenum, zinc, cadmium, tin, iron, lead, copper, mercury, and palladium are not attacked. Cobalt sulphate is not attacked, while the sulphates of the alkalies and alkaline earths are attacked and dissolved. Alkali tungstates, ammonium arsenite and arsenate, copper arsenite, ammonium magnesium arsenate, ammonium molybdate and vanadate, potassium cyanide and ferrocyanide are decomposed. Paraffin is not attacked shellac, gum arabic, gum tragacanth, copal, etc., are decomposed. Celluloid is slowly attacked. Silk paper, gun cotton, gelatin, parchment are dissolved. M. Meslans 22 has studied the esterification of alcohol by hydrofluoric acid. 

Mixtures of acetaldehyde and acetic acid may be obtained121 by passing acetylene (2 to 3 volumes) and air (10 volumes) mixed with a large excess of steam over the zinc, copper, nickel, or cadmium salts of vanadic, molybdic, or chromic acids deposited upon a suitable base, such as pumice, at temperatures ranging from 300° to 400° C. For example, yields of 75 to 80 per cent acetaldehyde along with 5 per cent acetic acid have been obtained by using basic zinc vanadate at 380° C. The aldehyde is separated by fractional condensation in a column and the condensed fraction which is poor in aldehyde is utilized to furnish steam for the catalytic treatment of more acetylene. The fractions rich in acetaldehyde serve for the direct recovery of the aldehyde or may be oxidized immediately to acetic acid by passage over a suitable catalyst. In this way, the process may also be applied directly to the preparation of acetic acid from acetylene. 

Among the other notations is that acetaldehyde is to be avoided, it being a respiration inhibitor. It is related to ethyl alcohol or ethanol and also to acetic acid, but not necessarily to citric acid as involved in the carboxylic acid or citric acid cycle. Alkaloids are expectedly respiration inhibitors, and anesthetics can have respiration inhibition as a side effect. Aromatic adds such as phenol are bad news, as are arsenate, cyanide, isothiocyanate, and thiocyanate. The heavy metals cadmium, cobalt, copper, ruthenium, vanadate, and zinc are regarded as health risks, if not for respiration, for other reasons. 

Cadmium and zinc vanadates Pumice i — Acetylene Acetone (58)... 

Its basic form has been used successfully for the collection of Cr(lII) [36], and cadmium [37] fnrni urine. In a detailed study on the behavior of various oxyanions on activated alumina (acidic) Cook et al.[35] have shown that while arsenate, chromate, molybdate, phosphate, selenate, and vanadate were all well retained on the sorbent, only chromate and molybdate could be reasonably well eluted using IM NH4OH, or stronger alkali solutions. About 80% of phosphate and selenate could be eluted using IM KOH, whereas arsenate and vanadates may be de-sorbed only by using stronger eluents such as 5M KOH. 

Figure 2-1 Reflectance curves of bismuth vanadate and other yellow pigments (cadmium sulfide, nickel rutile yellow, yellow iron oxide and chrome yellow).

Thermostable bismuth vanadate pigments are available today with a heat stability of 260 to 280 °C. They exhibit very good fastness to light and weathering in plastics for outdoor use. In weathering tests on plastics pigmented with 0.5 % cadmium yellow or 1 % bismuth vanadate, the bismuth vanadate pigment was superior both under artificial conditions (Xenotest, 4000 h) and outdoors (5 years). 

Tungsten group Barium tungstate Bismuth vanadate Cadmium... 

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