Regeneration of columns

Favorable and unfavorable equihbrium isotherms are normally defined, as in Figure 11, with respect to an increase in sorbate concentration. This is, of course, appropriate for an adsorption process, but if one is considering regeneration of a saturated column (desorption), the situation is reversed. An isotherm which is favorable for adsorption is unfavorable for desorption and vice versa. In most adsorption processes the adsorbent is selected to provide a favorable adsorption isotherm, so the adsorption step shows constant pattern behavior and proportionate pattern behavior is encountered in the desorption step. 

A single-column installation is satisfactory if the unit can be shut down for regeneration. However, if flow of the stream being processed must be continuous, then two or more columns of the same resin must be installed in parallel. Regeneration of each is staged for different time periods. 

The HF concentration of the acid catalyst is maintained ia the range of 85—95% by regeneration within the unit s fractionation faciUties. A separate acid regeneration column (not shown ia Figure 2) is also iacluded to provide a means to remove excess acid-soluble oils and water. The regeneration of acid ia the unit accounts for the low consumption of fresh acid by the HF process. 

During the separation itself some trouble can occur concerning the back pressure. An increasing back pressure indicates contamination of the column and thus should be monitored. If this happens or if a visible contamination of the sorbent is noticed, a regeneration of the column is necessary. However, if the back pressure rises very rapidly the column may be clogged by denatured proteins. As a first attempt, the frits should be replaced by new ones, trying the top adapter first. 

The newest process to be developed oxidizes the brine with CI2 and then treats the solution with an ion-exchange resin the iodine is adsorbed in the form of polyiodide which can be eluted with alkali followed by NaCl to regenerate the column. About 65% of the iodine consumed in the world comes from brines. 

The low-concentration eluants used to separate the sample ions on the separator column allow a substantial number of samples (typically about 50) to be analysed before the suppressor column is completely exhausted. Clearly an important practical consideration is the need to minimise the frequency of regeneration of the suppressor column and, for this reason, the specific capacity of the column is made as large as possible by using resins of moderate to high cross-linking. Some instruments contain two suppressor columns in parallel,... 

Fig. 14-6 Profiles of potential temperature and phosphate at 21 29 N, 122 15 W in the Pacific Ocean and a schematic representation of the oceanic processes controlling the P distribution. The dominant processes shown are (1) upwelling of nutrient-rich waters, (2) biological productivity and the sinking of biogenic particles, (3) regeneration of P by the decomposition of organic matter within the water column and surface sediments, (4) decomposition of particles below the main thermocline, (5) slow exchange between surface and deep waters, and (6) incorporation of P into the bottom sediments.

Figure 18 Flow chart of the automated on-line flow injection immunoassay (FllA). Six steps are involved in each cycle (1) addition of antibody and incubation (2) addition of analyte (or standard) and incubation (3) addition of enzyme-tracer and incubation (4) addition of substrate and incubation (5) downstream measurement of fluorescence (6) regeneration of affinity column...

Wagai R, Sollins P (2002) Biodegradation and regeneration of water-soluble carbon in a forest soil leaching column study. Biol Fertil Soils 35 18-26 Wardle DA, Ghani A (1995) A critique of the microbial metabolic quotient (qC02) as a bioindicator of disturbance and ecosystem development. Soil Biol Biochem 27 1601-1610... 

The vast majority of purification procedures employ at least one ion-exchange step it represents the single most popular chromatographic technique in the context of protein purification. Its popularity is based upon the high level of resolution achievable, its straightforward scale-up (for industrial application), together with its ease of use and ease of column regeneration. In addition,... 

Figure 7 Regeneration of ODA-clinoptilolite columns loaded with chromate by means of 2% NaCI and 2% Na2S04 aqueous solutions and breakthrough curves for ODA- clinoptilolite in 0.5 mM/L chromate solution by 30 BV/hr and 15 BV/hr in downflow mode (from the left)...

Figure 8. Regeneration of ODA-clinoptilolite column loaded with arsenate by means of 2% NaCl aqueous solution and breakthrough curves for ODA-clinoptilolite in arsenate solution of co = 25 mg/L repeated cycle after regeneration, first cycle breakthrough curve on Pb-clinoptilolite (from the left).

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