Adsorption elution operation

Lead(II) adsorbed on both columns was quantitatively eluted with ca. 6 bed volumes of 1 M nitric acid. In this work, 2 cylcles of the adsorption-elution operation were repeated at each flow rate. Then 16 cycles of the adsorption and elution operation were conducted for each column. In the case of FPS-f column, averaged recovery was 104% with standard deviation (sd) of 4 % (n = 16) and for the other column, averaged recovery 103% with sd of 4 %. Table 3 summarizes numerical data for results shown in Fig. 4. Breakthrough capacities at C/Co = 0.05 are 0.54 - 0.57 and 0.28 - 0.33 mmol/g for FPS-f and FP columns, respectively. Total uptake was 0.78 -0.83 mmol/g for FPS-f and 0.51 - 0.54 mmol/g for RF-f. During repeated adsorption-elution operations, no deterioration of both RFP-f and FP-f was observed. 

The adsorption operation was conducted by feeding 1 mM phosphate solutions to the conditioned column at SV 10 or 20 h 1, and then 20 BV of water at SV 3 h 1. The elution operation consisted of feeding 0.1 M NaOH solution (80 BV) and then 20 BV of water at a flow rate of SV 3 h1. The regeneration of the column was conducted by feeding 0.5 M sulfuric acid (20 BV) and 20 BV of water at SV 10 h"1. All column effluents including washings in the adsorption and elution operations were collected on a fraction collector, and concentrations of phosphorus and zirconium in each fraction were determined by ICP-AES. Volume of each fraction was 5 BV for the adsorption operation and 4 BV for the elution operation. However, column effluents in regeneration operations were not analyzed. 

The only difference from the method (i) was in the regeneration operation. Here, the regeneration operation was conducted by supplying 0.5 M sulfuric acid (5 BV), 0.5 M sulfuric acid containing zirconium sulfate at 0.01 M (10 BV), 0.5 M sulfuric acid (15 BV) and water (20 BV) in successive at SV 10 h1. The adsorption and elution operations were almost the same as those in the method (i). 

Since properties of both phosphate and arsenate are very similar each other, the adsorption of phosphate was examined prior to the adsorption of arsenic species. Here, the feeding solution in the adsorption operation was 1 mM phosphate solution of pH3. Table 1 summarizes detailed experimental conditions and column performances during repeated adsorption-elution-regeneration cycles. Since supplied volumes of the feed are not constant (101 - 193 BV), it is not easy to judge the efficiency of the adsorption from total uptake of phosphate. Thus, removal of phosphate until 100 BV is listed at the last column of Table 1 as an index of the column performances. 

Four basic regenerative procedures - or hybrids thereof - can be used in conjunction with adsorptive reactor operation pressure swing, temperature swing, elution, and reaction. 

The adsorption and elution operations that the biosolute(s) undergo as they proceed along the column bed can thus be considered as a series of diffusion, convection, and reaction steps. In the adsorption process, the solute(s) in the feed must diffuse through a liquid film surrounding... 

For metal desorption from the biomass certain dilute solutions of mineral acids like hydrochloric acid, sulfuric acid, acetic acid and nitric acid were used [219, 76]. Batch system was carried out to study the desorption of the adsorbed Hg (II) from the biosorbent - immobilized and heat inactivated Trametes versicolor and Pleurotus sajur-caju [8]. Hg (II) ions adsorbed onto the biosorbents were eluted with 10 mmol dm HCl and the results showed that more than 97% of the adsorbed Hg (II) ions were desorbed from the biosorbents. In order to evaluate the feasibility of applying the prepared biosorbents in the heavy metals removal processes, the metal desorption efficiency from loaded biosorbents, and the reusability of the biosorbent in repeated adsorption-desorption operations were determined. The charged species exhibited desorption-resistance fraction whereas the desorption of the neutral form was completely reversible. The difference in sorption and desorption between the neutral and charged species is attributed to the fact that the anionic species sorbs by a more specific exothermic adsorption reaction whereas the neutral form partition by the hydrophobic binding to the soil [206]. Desorption of soil-associated metal ions and possible mechanisms have received considerable attention in literature [148],... 

It is common practice to exclude from consideration as leaching the elution of surface-adsorbed solute. This process is treated instead as a special case of the reverse operation, adsorption. Also usually excluded is the washing of filter cakes, whether in situ or by reslurrying and refiltration. 

It is evident from these results that the interactive properties of the investigated SEC PS/DVB or DVB gels are very different. Because polar electroneutral macromolecules of PMMA were more retained from a nonpolar solvent (toluene) than from polar ones (THF, chloroform), we conclude that the dipol-dipol interactions were operative. Columns No. 1 and No. 2 were very interactive and can be applied successfully to LC techniques that combine exclusion and interaction (adsorption) mechanisms. These emerging techniques are LC at the critical adsorption point (18), the already mentioned LC under limiting conditions of adsorption (15,18), and LC under limiting conditions of desorption (16). In these cases, the adsorptivity of the SEC columns may even be advantageous. In most conventional SEC applications, however, the interactive properties of columns may cause important problems. In any case, interactive properties of SEC columns should be considered when applying the universal calibration, especially for medium polar and polar polymers. It is therefore advisable to check the elution properties of SEC columns before use with the... 

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