Coagulation inorganic

Soluble inorganic Coagulation Inorganic salts, Al2(S04)3, Fe2(S04)3, FeS04... 

The synthesis of polymer/inorganic compound nanocomposites, accomplished by multistep reactions in solutions, has been bothered by the serious problem of coagulating inorganic particles, espedaUy, fine metal particles in the polymer matrices [78-81]. In order to prevent coagulation, El-Shall and coworkers utilized... 

Fiber cross sections are also deterrnined by the coagulation conditions or, in the case of dry spinning, by the solvent evaporation process. The skin that forms early in the solvent removal process may remain intact as the interior of the filament deflates from solvent removal. Wet spun fibers from organic solvents are often bean shaped, while those from inorganic solvent systems are often round. Dry spun fibers, such as Du Font s Odon, are... 

Inorganic chemicals may also be used. Beatonite may be used as a flocculant ia combination with polymer treatmeat. Alum, oace a common coagulant, is less used because its concentration can build up ia recycle water. Alum oftea biads ink to fibers and iacreases the difficulty of deinking. Removal of the very small flexographic ink particles ia process water is difficult. Ultrafiltratioa (qv) has beea proposed for removing these very small dispersed ink particles (53). 

Inorganic and organic coUoidal suspensions in wastewater can be removed by chemical coagulation. Coagulation has been defined as the addition of... 

Table 1 Hsts a number of common inorganic coagulants. Typical iron and aluminum coagulants are acid salts that lower the pH of the treated water by hydrolysis. Depending on initial raw water alkalinity and pH, an alkah such as lime or caustic must be added to counteract the pH depression of the primary coagulant. Iron and aluminum hydrolysis products play a significant role in the coagulation process, especially in cases in which low turbidity influent waters benefit from the presence of additional colHsion surface areas.

The use of organic polymers offers several advantages over the use of inorganic coagulants ... 

Soluble iron or aluminum carryover ia the clarifier effiueat may result from inorganic coagulant use therefore, elimination of the inorganic coagulant can minimise the deposition of these metals ia filters, ion-exchange units, and cooling systems. 

The condition of the curd on precipitation is important. As the milk starts to gel, agitators in the coagulation tanks are started as the temperature is raised to about 65°C. Under these conditions the protein is thrown out in fine particles. Too slow an agitation will produce large clots difficult to wash whilst too fine a curd also presents washing problems. In order to obtain the requisite consistency of the precipitate it may be necessary to add inorganic material to the skimmed milk. For example, the addition of phosphate ions will prevent undesirable flaky polymer. Similarly, calcium-deficient casein will not coagulate satisfactorily and the addition of calcium ions may be necessary. 

Coagulation may also remove dissolved organic and inorganic compounds. The hydrolyzing metal salts may react with the organic matter to form a precipitate, or... 

Chemical treatments -How organic polymers and inorganic coagulants work to counteract solids stabilization mechanisms and enhance removal of solids from water, and... 

Inorganic salts of metals work by two mechanisms in water clarification. The positive charge of the metals serves to neutralize the negative charges on the turbidity particles. The metal salts also form insoluble metal hydroxides which are gelatinous and tend to agglomerate the neutralized particles. The most common coagulation reactions are as follows ... 

The effectiveness of inorganic coagulants is dependent upon water chemistry, and in particular - pH and alkalinity. Their addition usually alters that chemistry. Table 2 illustrates the effect of the addition of 1 ppm of the various inorganic coagulants on alkalinity and solids concentration. 

Cationic (positive charge) — serve as primary coagulants alone or in combination with inorganic coagulants such as aluminum sulfate. 

A solution of 3jS-hydroxy-5a-androstan-17-one tosylate (193, 60 mg) in tetrahydrofuran (10 ml, freshly distilled from lithium aluminum hydride) is added dropwise to a boiling suspension of lithium aluminum deuteride (60 mg) in tetrahydrofuran (10 ml). The resulting suspension is heated under reflux for 30 min and after cooling the excess reagent is decomposed by the careful addition of a few drops of water. The heating is continued for a few minutes to coagulate the inorganic salts which are removed by filtration... 

Ion exchange, in contrast, creates an effluent that contains between two and five times the mass of inorganic material removed from the product water. Coagulation with aluminum or iron salts creates a sludge, which creates a disposal problem. Green pressure, especially in Switzerland and mid-west USA, which lie in the middle of large land masses, has started to force industrialists to install alternative membrane processes to avoid these discharges. 

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