Iron salts, solubilities

Iron salts (soluble, as Fe) Formula CAS RTECS IDLH N.D. 

Neutral or alkaline salts, eg, KCl, K SO, K CO, or Na PO, are often present in synthetic latices in quantities of - <1%, based on the weight of the mbber. During emulsion polymerization the salts help control viscosity of the latex and, in the case of alkaline salts, the pH of the system. Many polymerizations are carried out at high pH, requiring the use of fixed alkaH, eg, KOH or NaOH. Very small amounts of ferrous salts can be employed as a component of the initiator system, in which case a sequesteriag agent, eg, ethyldiaminotetraacetic acid (EDTA) may be iacluded to complex the iron. Water-soluble shortstops, eg, potassium dithiocarbamate, may also be iacluded ia very small amounts (ca 0.1 parts). 

The treatment units used for color removal are the same as those used for turbidity removal. However, the pH must be increased prior to filtration so that the metal hydroxides are removed by the filters. At low pH values, metal ions or their soluble complexes readily pass through the filters and form insoluble species in storage tanks and in the distribution system. For iron salts, it is important that the pH be greater than 6 as the oxidation of iron(II) to iron(III) occurs rapidly above this pH in the presence of dissolved oxygen or other strong oxidants (18). 

One method of generating hydroxyl radicals is by a dding a soluble iron salt to an acid solution of hydrogen peroxide (Fenton s reagent) (176—180), ie ... 

Chemical precipitation can remove 95 percent of the suspended solids, up to 50 percent of the soluble organics and the bulk of the heavy metals in a wastewater. Removal of soluble organics is a function of the coagulant chemical, with iron salts yielding best results and lime the poorest. Metal removal is primarily a function of pH and the ionic state of the metal. Guidance is available from solubihty product data. 

Surface finish is increasingly referred to as surface cleanliness . This can be misleading because the standards refer to the appearance of the blasted steel and do not deal with chemical contamination. Site tests for assessing the level of soluble salts on freshly blast-cleaned surfaces, and which allow the semi-quantitative determination of the chlorides, soluble sulphates and soluble iron salts, are urgently needed. 

Under conditions of water loss and poor waterside control, it is fairly common for iron sludges and foulants formed elsewhere to settle in the boiler. Trying to identify the source of this problem is complicated when the transport of soluble iron salts such as ferrous bicarbonate Fe(HC03)2 into the boiler takes place. A further complication occurs... 

The migration of iron mineral fines, primarily hematite and magnetite, is a common occurrence in portions of the Appalachian Basin. The phenomenon often occurs after well stimulation and can result in the continuing production of iron mineral fines which pose a significant disposal problem. The migration of iron mineral fines through propped fractures can substantially reduce the fracture flow capacity. Many of these are mineral fines are native to the formation and are not formed by precipitation of acid-soluble iron salts present in injection waters during or after acidi-... 

Iron salts and complexes soluble in hydrocarbon catalyze oxidation due to the rapid decomposition of forming peroxides into free radicals, for example (see Chapter 10)... 

Soluble copper salts were found to possess the outstanding inhibiting activity in the presence of iron salts [50], This copper antioxidant activity is believed to be the result of the fast oxidation of catalytically active ferrous ions by cupric ions... 

Oral iron therapy with soluble ferrous iron salts, which are not enteric coated and not slow- or sustained-release, is recommended at a daily dosage of200 mg elemental iron in two or three divided doses (Table 33-3). 

Iron salts may be added before as well as after the sulfide is produced, i.e., either upstream or downstream in the sewer system. The very low solubility of FeS implies that the process, for all practical reasons, proceeds at 100% efficiency. The stoichiometry expressed by Equation (6.17) shows that addition of an iron salt requires 1.75 g Fe per g of (H2S + HS )-S. The precipitated FeS occurs in the wastewater as small suspended particles that make the color black. Iron salts normally occur in wastewater in small, however, not necessarily insignificant amounts. Therefore, a small amount of the sulfide produced in a sewer will typically be removed by precipitation of the iron that naturally occurs. 

Tannins are amorphous substances, which produce colloidal acidic aqueous solutions with astringent taste. With iron salts (FeCls) they form dark blue or greenish black water-soluble compounds. Tannins form insoluble and indigestible compounds with proteins, and this is the basis of their extensive use in the leather industry (tanning process), and for the treatment of diarrhoea, bleeding gums and skin injuries. 

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