Reverse osmosis procedure

The egg products are finally processed and spray-dried. Sometimes Hquid egg whites are concentrated before spray-drying by ultrafiltration (qv) or reverse osmosis procedures. Table 5 presents the effect of egg quaUty on the different egg product manufacturing processes. 

Reverse osmosis procedures concentrate over 90% of the total organic material present in water into an aqueous brine (29). A problem has been the efficient transfer of the organic components to a solvent suitable for the bioassays (30). Another problem is the loss of chemicals having molecular weights below 200-400. 

Membrane Sep r tion. The separation of components ofhquid milk products can be accompHshed with semipermeable membranes by either ultrafiltration (qv) or hyperfiltration, also called reverse osmosis (qv) (30). With ultrafiltration (UF) the membrane selectively prevents the passage of large molecules such as protein. In reverse osmosis (RO) different small, low molecular weight molecules are separated. Both procedures require that pressure be maintained and that the energy needed is a cost item. The materials from which the membranes are made are similar for both processes and include cellulose acetate, poly(vinyl chloride), poly(vinyHdene diduoride), nylon, and polyamide (see AFembrane technology). Membranes are commonly used for the concentration of whey and milk for cheesemaking (31). For example, membranes with 100 and 200 p.m are used to obtain a 4 1 reduction of skimmed milk. 

In most industrial applications, it is rare that a single RO module can be used to address the separation task. Instead, a reverse-osmosis network (RON) is employed. A RON is composed of multiple RO modules, pumps and turbines, llie following sections describe the problem of synthesizing a system of RO modules and a systematic procedure for designing an optimal RON. Once a RON is synthesized, it can be incorporated with a mass integration framework (see Problem 11.6). 

Procedure Flavonoids are then further purified with 2 ml of methanolic HC1 (2 N), followed by centrifugation (2 min, 15 600 g), hydrolyzation of 150 il of suspension in an autoclave (15 min, 120 C). A reverse osmosis-Millipore UF Plus water purification system is used in high performance liquid chromatography (HPLC) with an autosampler. After injections of 5 pg of samples, the mobile phases flow at a rate of 1 ml/minute with isocratic elution in a column at 30 C. 

The synthesis of 5 lan thick Ti02 Si02 layers on a porous support can be performed using the procedure given below. First a mixed Ti[(OMe)3]4 alkoxide is synthesized by reacting partially hydrolyzed Si(OMe)4 with Ti-isopropoxide. This inorganic polymer is hydrolyzed at pH 11.0 and treated with 2-methyl-2-4-pentanediol and a binder. This solution is then slip-cast onto a porous support, dried and calcined at 700°C. The membrane can be useful in reverse osmosis applications. 

Solid sorbent procedures are currently being compared to reverse osmosis techniques f25) for accumulating organic materials for bioassays but results are not yet available. The apparent and unexplained correlation between the accumulation of mutagenic and gas chromatographable material from water is also being investigated. 

The same nanofiltration experiments were performed with a 50-A ultrafiltration membrane (available from US Filter/Membralox, Warrendale, PA,USA), this time with a monodentate phosphite ligand (24) used for comparison and toluene as the solvent (Table V). Both higher retentions and flux rates for the dendrimers were obtained relative to what was observed with the reverse osmosis membranes. Dendrophite G4 was used in three subsequent reactions carried out with this procedure. 

There are five basic water purification technologies—distillation, ion exchange, carbon adsorption, reverse osmosis, and membrane filtration. Most academic laboratories are equipped with in-house purified water, which typically is produced by a combination of the above purifying technologies. For most procedures carried out in a biochemistry teaching laboratory, water purified by deionization, reverse osmosis, or distillation usually is acceptable. For special procedures such as buffer standardization, liquid chromatography, and tissue culture, ultrapure water should be used. 

Describe the procedure of reverse osmosis for the purification of salt water for drinking water. 

P18.5 Sea water contains approximately 26,000 parts per million of dissolved NaCl, plus smaller amounts of other solutes, principally in the form of salts containing Mg2+, K+, Cl", Br, SO4-, and CO2-. In a water purification procedure, a reverse-osmosis process is used, in which half of the water is removed as pure water, leaving a concentrate that has twice the concentration of NaCl. Calculate the minimum work required to obtain a metric ton (103 kg) of pure water. Ignoring the impurities, the process is... 

Reverse osmosis usually involves two components, water (i) and salt (7). Following the general procedure, the chemical potentials at both sides of the membrane are first equated. At the feed interface, the pressure in the feed solution and within the membrane are identical (as shown in Figure 2.6c). Equating the chemical potentials at this interface gives the same expression as in dialysis [cf. Equation (2.26)]... 

Membrane fouling is the main cause of permeant flux decline and loss of product quality in reverse osmosis systems, so fouling control dominates reverse osmosis system design and operation. The cause and prevention of fouling depend greatly on the feed water being treated, and appropriate control procedures must be... 

Acid-washing Procedure in which laboratory articles are soaked overnight in 4% detergent (e.g., Contrad 70) and rinsed five times in reverse osmosis water, soaked overnight in 10% HC1 and rinsed five times in Milli-Q water and oven dried (58°C). Volume 1(6). 

Micro-ultrafiltration and reverse osmosis are mature technologies for separations based on molecular exclusion and solution-diffusion mechanisms, respectively. Cleaning and maintenance procedures able to control fouling to an acceptable extent have made these processes commercially suitable. 

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