Primary purification

MetaUic ions are precipitated as their hydroxides from aqueous caustic solutions. The reactions of importance in chlor—alkali operations are removal of magnesium as Mg(OH)2 during primary purification and of other impurities for pollution control. Organic acids react with NaOH to form soluble salts. Saponification of esters to form the organic acid salt and an alcohol and internal coupling reactions involve NaOH, as exemplified by reaction with triglycerides to form soap and glycerol,... 

Fig. 17.6. Experimental configuration for the integrated, primary purification of intracellular proteins from unclarified disruptates. Panel A configuration employed for the purification of G3PDH from baker s yeast. Elution was performed in packed bed mode under reversed flow. Panel B configuration for loading, wash and elution in fluidised bed mode (employed for the purification of L-asparaginase from Erwinia chrysanthemi).

The primary purification of the enzyme G3PDH was exploited herein as a preliminary study to investigate and demonstrate the feasibility of the integrated operation of cell disruption by bead milling and immediate product capture by fluidised bed adsorption (panel A in Figure 17.6). Yeast G3PDH binds nicotinamide adenine dinucleotide (NAD) as a cofactor,... 

Nickel affinity chromatography was chosen as the primary purification technique because it is a fast and reliable one-step assay and purified complexes can often be used in downstream applications without the necessity of removing the polyhistidine tag. In addition, the polyhistidine tag is smaller than many other affinity tags targeted by commercially available affinity resins and, in most cases, does not seem to interfere with the structure and function of the recombinant protein. 

In the present study, various sorbents were tested for the critical properties of capacity for succinic acid, regenerability of the sorbent, and coadsorption of substrates. These criteria were evaluated in order to choose a suitable sorbent for use with either a primary purification step or an in situ separation and fermentation. Other factors that were considered were the pH, temperature, and potential ability to concentrate the product. 

One of the major advantages of membrane chromatography, similarly to EBA, is the possibility for direct processing cell suspensions, enabling an integration of the clarification and primary purification steps. However, this is only possible by the use of membrane modules with suitable hydrodynamics, capable of effectively avoiding membrane fouling (Bel-ford, 1988 Castilho and Anspach, 2003). 

The growing interest in renewable raw materials spurred, from the mid-1980s onwards, interest in the development of highly integrated, low-waste procedures for the fermentation, primary purification and processing of lactic acid. Continuous removal of lactic acid, via solvent extraction or otherwise, would obviate the need for adding base but is not feasible at pH 5.5-6.5, however, because only 2% of the lactic acid (pKa 3.78) is uncharged at pH 5.5. 

Figure 2.6 schematically illustrates sections of a typical semiconductor ultrapure water (UPW) production process in a semiconductor plant. The water circuit consists of two main sections (1) makeup (or central) system and (2) polishing loop, which provides water at the point of use. There are multiple locations in such a water process where membrane degassing could be needed as shown in the figure. Reverse osmosis is mostly used in makeup line as the primary purification means in such processes. In the past, large and inflexible vacuum towers were frequently used after RO to remove dissolved gases, such as O2, N2, and CO2. Membrane contactors are the norm today for replacement or supplement to vacuum towers in makeup lines, as shown in Figure 2.6. 

The purified platinum is quite similar in types and levels of impurities to that produced by the primary purification sequences. It is therefore apparent why Wollaston found no consistent differences in the metallurgical characteristics of the platinum powder produced from the crude ore or the retreated residuum by either of his two purification processes. 

Primary purification—conversion of carbon monoxide to carbon dioxide... 

Should solvent extraction be inapplicable as a primary purification stage, adsorption methods should be evaluated. Sequential use of ion exchangers and nonionic polymeric resins will often effect considerable purification. If the resins are to be used regularly such that >50 L will be used during a project, it will be more economical to obtain them directly from the manufacturers rather than from laboratory suppliers. Guidance in the use of ion exchangers is relatively sparse a useful introduction is provided by Harland (14) (see Chapter 5). 

Conditions for the direct oxidation of propylene to acrolein include use of a catalyst of cuprous oxide deposited on granular silicon carbide, catalyst temperature of 375 C, feed stream composition by volume of 20 per cent propylene, 20 per cent air, and 60 per cent steam, and contact time of 1 sec. Recovery and primary purification of the acrolein from the reaction product are effected by quench scrubbing the reactor effluent with water and wth liquid propylene. The composition of the carbonylic compounds in the product is, approximately, acrolein, 90 per cent by weight acetaldehyde, 6 per cent propionaldehyde, 2 per cent and acetone, 2 per cent. At reaction temperatures of about 300 C and conversions of about 50 per cent, a selectivity to acrolein of about 40 per cent is reported for 10 per cent propylene-in-air mixtures. ... 

Fermentation process Primary purification and recovery Secondary purification... 

In recent years, a variety of methods, including flocculation, adsorption, filtration, oxidation, and electrolysis, have been carried out to remove contaminant from wastewater [28-32]. Therein, flocculation is one of the most widely applied methods in primary purification due to its low cost and easy operation [33-35]. 

There are about 1000 to 1200 people (plant staff and contractors) working on Superphenix. The total dose received in 1987 is mainly due to investigations on the storage drum while that in 1990 corresponds to replacement of primary purification cartridges. 

A.610. The design and the operation of the primary purification system shall be described in detail, including the procedures for resin exchange and the shielding used to protect persons during this operation. This may be described in this section, or reference may be made to Chapter A. 10 (Auxiliary Systems). 

A. 1005. All water systems of the facility that have not been described previously shall be discussed in this section. These may include the primary purification system, the service water system, the cooling system for reactor auxiliaries and the primary coolant make-up system. In each case, the information provided should include the design bases, a system description, flow and instrumentation diagrams, a safety evaluation, if required, testing and inspection requirements, and instrumentation requirements. 

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