Phase separation, by filtration

This paper is aimed at clarification of the change of concentration with time in the liquid phase before crystallization starts. To find optimum conditions for the commercial production of pure zeolites of the types A and faujasite, the reaction of fine-particle amorphous silica with sodium alu-minate solution was studied at 20°, 40°, and 75°C. The liquid phase separated by filtration nucleates the zeolite types Ay sodalite, phillipsite, and faujasite, depending on stirring time before liquid-solid separation. Quite similar conditions are observed in precipitated sodium aluminosilicate gels and mother liquor. 

Suspension Polymerization. At very low levels of stabilizer, eg, 0.1 wt %, the polymer does not form a creamy dispersion that stays indefinitely suspended in the aqueous phase but forms small beads that setde and may be easily separated by filtration (qv) (69). This suspension or pearl polymerization process has been used to prepare polymers for adhesive and coating appHcations and for conversion to poly(vinyl alcohol). Products in bead form are available from several commercial suppHers of PVAc resins. Suspension polymerizations are carried out with monomer-soluble initiators predominantly, with low levels of stabilizers. Suspension copolymerization processes for the production of vinyl acetate—ethylene bead products have been described and the properties of the copolymers determined (70). Continuous tubular polymerization of vinyl acetate in suspension (71,72) yields stable dispersions of beads with narrow particle size distributions at high yields. 

In liquid-solid extraction (LSE) the analyte is extracted from the solid by a liquid, which is separated by filtration. Numerous extraction processes, representing various types and levels of energy, have been described steam distillation, simultaneous steam distillation-solvent extraction (SDE), passive hot solvent extraction, forced-flow leaching, (automated) Soxh-let extraction, shake-flask method, mechanically agitated reflux extraction, ultrasound-assisted extraction, y -ray-assisted extraction, microwave-assisted extraction (MAE), microwave-enhanced extraction (Soxwave ), microwave-assisted process (MAP ), gas-phase MAE, enhanced fluidity extraction, hot (subcritical) water extraction, supercritical fluid extraction (SFE), supercritical assisted liquid extraction, pressurised hot water extraction, enhanced solvent extraction (ESE ), solu-tion/precipitation, etc. The most successful systems are described in Sections 3.3.3-3.4.6. Other, less frequently... 

Further synthesis followed two ways. According to variant I, a solid phase was separated by filtration and divided into two parts. The first one was dried at 105°C for two hours (product A), while the second one was left at 20°C until a sample mass became constant (product B). 

Figure 3 Manufacturing scheme for liposome-encapsulated hemoglobin (LEH). Lipid phase is mixed with hemoglobin and the mixture is homogenized in an extruder or a microfluidizer. Unencapsulated hemoglobin is separated by filtration, before PEGylation is performed by postinsertion. The resulting PEG-LEH is converted into oxyhemoglobin form and concentrated to obtain final product. Abbreviation IXC, interaction chamber.

The purification of bacterial constituents usually starts in a very conventional way with an extraction step of the crude broth at neutral or slightly acidic pH. Mycelium-forming organisms are separated by filtration, and the cell mass and the filtrate are extracted separately. For the liquid phase, adsorber resins allow high recovery rates of metabolites and low process costs due to repeated use of the resins. If liquid-liquid extraction has to be applied, medium or highly polar solvents are favored. Ethyl acetate is the solvent of choice, and only in few cases is butanol superior. To extract the moist cell material, ethyl acetate, acetone or dichloromethane/methanol can be used. 

Hydrogel samples were taken at various intervals. The liquid phase for composition studies was separated by centrifugation, and the solid phase was separated by filtration and washing until the pH of the filtrate fell below 11. Part of the sample was heated to carry out crystallization, and the compositions of liquid and solid phases were determined. 

It is also good practice to have each salt s phase-diagram, in order to know how they would precipitate under supercritical conditions. For example, sodium chloride yields crystals that are larger than sodium sulphate [28], which facilitates its separation by filtration or using cyclones. When a sodium chloride solution is heated, it reaches an L/V equilibrium zone, where water-evaporation takes place, and the salt s concentration in the liquid drops, thus producing formation of larger crystals (10 tolOO (am). In contrast, sodium sulphate reaches... 

The total salt concentration was 0.100 (to.010) N, known to three significant figures. At the high end of the isotherm, the starting solution contained only the ingoing cation at the low end, the solution contained both of the exchanging cations. The equilibrations were carried out for a minimum of three days in a New Brunswick Scientific Company AQUATHERM Water Bath Shaker at 5°, 25°, and 50°C, with temperature control to i0.5°C. Prior to analysis of the equilibrium solutions, the solid and solution phases were rapidly separated by filtration through a Millipore filter immediately after removal from the constant temperature bath. Lead and sodium analyses of the filtrate were obtained by atomic absorption spectroscopy. The cadmium analyses of the filtrate were obtained by plasma emission spectroscopy. These analyses showed that two Na+ ions entered the solution for every Cd2+ or Pb2+ that left ( 2%). 

Make a colloidal sol of iron(m) hydroxide by adding aqueous iron(m) chloride to boiling water, or a colloidal sulfur sol by adding dilute aqueous sodium thiosulfate to hydrochloric acid. For both of these sols, it can be shown that the solid phase is not separated by filtration. 

Raney s nickel is prepared by dissolving an alloy of nickel and aluminium in a solution of sodium hydroxide the aluminium dissolves while the nickel remains m a metallic state as a highly dispersed phase the dispersed metal is separated by filtration and used as a catalyst. 

This cubic silicon-titanium g-oxo complex was also shown to be a model system for insoluble titanosilicates and related catalysts which have been used for epoxidation reactions of olefins. The cubic silicon-titanium g-oxo complex, when immobilized on a silica matrix by dissolving it in tetraethoxysilane and further treatment with acetic anhydride followed by heating up to 60 °C for 20 h, resulted in the formation of a Si02—Ti02 mixed oxide (63). The resulting solid was separated by filtration, and the filtrate formed a gel in about 1 week. This gel showed an enhanced catalytic activity (epoxidation yield of cyclohexene was 72%) as a solid catalysf for epoxidation of cyclohexene in the presence of TBHP in the liquid phase. 

Modification of Nickel Form by Soil Microbial Isolates. Following isolation from soil and in conjunction with taxonomic characterization, pure cultures of bacteria and fungi were grown to stationary phase in the presence of Ni at several concentration levels. The exocellular solution from each culture was separated by filtration (<0.4 and <0.01 jl) and the Ni-associated components characterized using TLC and TLE. 

In the case of lipid fractionation, however, a different crystal size distribution is desired. As the fat crystals are to be separated from the liquid phase, uniform crystals of distinct size and shape are needed for the most efficient separation. For the most efficient separation by filtration, reasonably large (200 to 300 pm) crystals of fairly uniform size (narrow distribution of sizes) are needed. Fractionation technologies carefully control nucleation and growth to produce this uniform distribution of crystals to enhance filtration and separation of the high-melting stearin phase from the low-melting olein phase. 

Dry Fractionation - The principal of this fractionation process is based on the cooling of oil under controlled conditions without the addition of chemicals or solvents. The liquid and solid phases are separated by filtration. 

---