‫‪Separation techniques‬‬

‫المادة العلمٍت‬ ‫د‪ /‬همت البدوي‬ ‫أ‪/‬جىزاء الطىٌهر‬ ‫نقلته كتابت ‪:‬‬ ‫أ‪/‬أمنه العبٍدان‬ ‫أ‪ /‬زهرة البلىي‬ ‫أ‪ /‬نهى الجهنً‬ ‫أ‪/‬عائشت السمٍري‬ ‫أ‪ /‬وفاء الجعٍد‬

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SOLVENT EXTRACTION GENERAL DISCUSSION Solvent extraction involves the distribution of a solute between two immiscible liquid phases. This technique is extremely useful for very rapid and "clean" separations of both organic and inorganic substances. The separation that can be performed are simple, clean, rapid and convenient. In many cases separation may be effected by shaking in a separatory funnel for a few minutes. 1-The distribution coefficient A solute S will distribute itself between two phases(after shaking and allowing the phases to separate)and, within limits, the ratio of the concentrations of the solute in the two phases will be a constant KD = [S]1/[S]2

Where KD the distribution coefficient and the subscripts represent solvent 1 (e.g. an organic solvent) and solvent 2 (e.g. water). If the distribution coefficient is large, the solute will tend toward quantitative distribution in solvent 1 . In the practical application of solvent extraction we are interested primarily in the fraction of the total solute in one or other phase, quite regardless of its mode of dissociation, association, or interaction with other dissolved species. 2-The distribution ratio It is more meaningful to describe a different term, the distribution ratio, which is the ratio of the concentrations of all the species of the solute in each phase. In this example, it is given by: D = [Cs]1/[Cs]2 3- The percent extracted 2

The fraction of solute extracted is equal to millimoles of solute in the organic layer divided by the total number of millimoles of solute. The millimoles are given by the molarity times the millimiters. Thus, the percent extracted is given by:

%E = [S]0V0/[S]0V0+[S]aVa×100%

Where V0 and Va are the volumes of the organic and aqueous phases, respectively. It can be shown form this equation that the percent extracted is related to the distribution ratio by: %E = 100D/D+(Va/V0) The apparatus used for solvent extraction is the separatory funnel illustrated in figure 1. Mostoften, a solute is extracted form an aqueous solution into an immiscible organic solvent. After the mixture is shaken for about a minute, the phases are allowed to separate and the bottom layer (the denser solvent) is drawn off in a completion. EXPERIMENT 1 : Separation of iodine You will be given a homogenous mixture of iodine and sodium chloride in distilled water. Discussion The iodine is separated by an extraction process. The aqueous iodine-salt solution, is shaken together with an approximately equal volume of carbon tetrachloride (CCL4). Water and carbon tetrachloride do not mix (they are insoluble in one another)hence two liquid phases will coexist here. Iodine vastly prefers to dissolve in CCl4, thus it migrates from the aqueous(H2O) phase into the non –aqueous (CCl4) phase – we say that CCl4 "extracts" the I2 from the aqueous phase. Cl has no such tendency (its solubility in CCl4 is nil) and hence it remains behind in the water phase. PROCEDURE 3

1-Pour all of filtrate into a clean 125 ml separatory funnel (suspended in an iron ring on a ring stand) whose stopcock is closed. 2- pour in 20 ml of carbon tetrachloride, 3-Watch the added liquid to see whether it dissolves, floats as an upper layer, or settles as a lower layer.(Which liquid has the greated density. CCl4 or H2O?). insert the separatory funnel stopper, and shake the closed funnel for about sec.(Fig.2).Shake vigorously enough so as to mix the aqueous and non-aqueous phases intimately. Keep your hand on the stopper; if internal pressure builds up, the stopper may pop out. To vent the insife pressure, hold the stopped separatory funnel upside down, allow the liquids to drain away from the stopcock, and which the tip still pointing up, open the stopcock momentarily. Close the stopcock , turn the separatory funnel upright, remove the top stopper, and allow the layers to separate as completely as possible. Carefully drain the layer through the stopcocker closing it just before the last drop og lower layer goes through . What will the lower layer be? Add another 20ml portion of fresh CCl4to the remaining upper layer and repeat once more, drawing the second batch of CCl4 into a separate container . (Why must remove the top stopper from the separatory funnel each time before attempting to drain out the lower layer?). Repeat a third time. Separately save the second and third portions of CCl4, note and compare their color with the first portion. Show these carbon tetrachloride solutions to your laboratory instructor. Save the aqueous layer. IODINE TEST In the presence of iodine , the white color of the starch paper changes to deep blue Dip your stirring rod into the solution and then touch it to a piece of the starch paper. Be sure your stirring rod is thoroughly rinsed before and after each use. CHLORIDE TEST

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To a test tube containing the sample (the aqueous layer), add 2 drops of (AgNO3). You will observe a precipitate. EXERCISE Suggest a volumetric method for the determination of iodine and chloride after the separation. Discuss the theory of the indicator used in each method.

Experiment2:Determination of nickel as the dimethylglyoxime complex

Discussion: Nickel ( 200_400 microgram)forms the red dimethylglyoxime complex only slightly soluble Alkaline medium; it is in chloroform (35_50 g/L)

NiCl

The optimum pH range for extraction of the nickel complex is 7 _12 in the presence of citrate . The nickel complex absorbs at 366 nm and also at 465_470 nm . Chemicals: Ammonium nickel sulphate (0.135 g ),citric acid (A.R.)5 g, ammonia, dimethylglyoxime,chloroform and aluminium salt.

Procedure : A homogenous solution of nickel (200_400 ug)ang aluminium (500 ug ِ )or iron (500 ug )is prepared.Transfer10.0ml of this solution (Ni content about 200 ug) to a beaker containing 90 ml of water,add5.0g of A.R.citric acid, and then dilute ammonia solution until the pH is 7.5.cool and transfer to a separatory funnel,add20 ml of dimethylglyoxime solution(1)and, after standing for a minute or two,12ml of chloroform. 5

Shake for l minute,allow the phases to sette out, separate the red chloroform. Shake for l minute, allow the phases to settle out, separate the red chloroform layer, and determine the absorbance at 366 nm in a 1.0.cm absorbance cell against ablank .Extract with a further 12ml of chloroform and measure the absorbance of the extract at 366 nm ; very little nickel will be found .Test for the iron or aluminium in the aqueous layer . Repeat the experiment in the presence of 500ug of iron (III)and 500ug of aluminium ion ; on interference will be detected.

Note:

The dimethylglyoxime reagent is prepared py dissolving 0.50g of A.R. Dimethylglyoxime in 250ml of ammonia solution and diluting to 500 ml with water.

Report

1- complete:

a-Distribution coefficient is…………… b-Distribution ratio is ……………………. 6

c-if a solute undergo association,dissociation or polymerization,isused instead of…………….

.2- Like dissolves like. Explain and give examples.

3- Although Ni+2 is an inorganic cation,it can be extracted in chloroform. Explain

4- Amixture contains ontains only 250ug of Ni and 250ug of fe .can nickel(II)be separated from iron(III) by solvent extraction and determined qualitatively?

Experiment 3:Determination of Iron by chloride Extraction

Discussion

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The extraction of iron (III) chloride from hydrochloric acid with diethyl ether (probably as the solvated complex H[feCL4]) has long been known, but the amount of metal extracted depends upon the concentration of the acid and passes through a maximum at about 6M-hydrochloric acid

Elements that extracted well as chloride complexes include sb(V),As(III),Ga(III),Ge(IV), TI(III),Hg(II) ,Mo(VI),Pt(II),and Au(III).Elements which are partially extracted include Sb(III),As(V),V(V),co(II),sn (II),and Sn(IV).many solvents with donor oxygen atom, including di-isopropyl ether, B,B-dichlorodiehtylether,ethyl acetate, butyl acetate, and pentyl acetate, have been employed. in most cases the optimum extraction depends upon the acid concentration.

The extraction of large amounts of iron is conveniently made with iso butyl acetae : this solvent has the merit of low volatility and of almost negligible temperature rise during the extraction (unlike diethyl ether ) To gain experience in the procedure, experimental details are given for the extraction of iron (III) in hydrochloric acid solution with diethyl ether .

Procedure:

Weigh out 16.486 gm of A.R. hydrated ammonium iron (III) sulephate and dissolve it in 250ml of 6M _hydrochloric acid in a graduated flask . Extract,25.0 ml of the iron(III) solution (which contains 200mg of fe ) with three 25-ml portions of pure diethyl ether (1): shake gently for 3 minutes during each extraction . combine the three ether extracts and strip the iron from the ether by shaking with 25 ml of water : approximately 99.9% of the iron is removed by this method. Boil off any ether remaining in the aqueous extricate on a water bath (caution) , and 8

determine the iron by titration with standard 0.1 N-potassium dichromate after previous reduction to the iron (II)state . The iron recovered should not be less than99.6 %(2)

Notes:

1- The factors of importance in the diethyl ether extraction of iron are : a- The iron must be in iron (III) state , since iron (II) chloride is not extracted . b- The hydrochloric acid concentration must be close to 6M . c- The extraction should be carried out in subdued light , since ether photochemicaly reduces iron (III). 9

d- The ether should be free from ethanol and peroxides because these reduces the ion (III) chloride. e- The concentration of anions other than chloride should be kept low. f- Heat is generated be the mixing of the ether and the hydrochloric acidiron(III)chloride solution so that cooling of the mixture under the tap or in ice is essential.

2- The procedure may be adapted to the determination of iron in an iron ore or a steel . The details are as follows. Dissolve a 0.5gm sample , accurately .weighed , in 25 ml of 6M –hydrochloric acid and 4ml of concentrated nitric acid by heating the mixture on a water bath . Evaporate the solution to dryness and then dissolve the residue in 15mlof 1:1 hydrochloric acid. Transfer the solution to a continuous extractor and rinse the vessel with a little 6M-hydrochloric acid Extract the solution with diethyl ether or with peroxide-free di-isopropyl ether until the ether iayer above the solution is colorless . Transfer the ethereal solution of the iron (III) chloride to a separatory funnel, strip the iron from the ethereal solution by two or three washings with an equal volume of water. Determine the iron content as above.

Chromatography Chromatographic techniques may be used for the separation and analysis of mixture of gases, liquids, or solids . All chromatographic techniques utilize a tow phase system, one stationary and one mobile . Separation of the components between the two phase . The process 11

differs from ion exchange in that, transfer of a component from the mobile phase to the stationary phase does not result in the transfer of an equivalent quantity of a component originally on the stationary phase, into the mobile phase . In chromatography the stationary phase is chemically unchanged after the separation process . The elute will only contain compounds which were present in the original solution or mixture, no chemical change will have occurred . The stationary phase may be a solid , or a liquid supported on an inert solid . The mobile phase may be a gas or a liquid . Accordingly several types of chromatographic procedures are recognized : 1 – liquid-solid chromatography . 2- Gas-solid chromatography. 3- Gas-liquid chromatography. 4- Liquid-liquid chromatography, a special case of which is known as paper chromatography . In paper chromatography the stationary phase is water supported by the cellulose of the paper .

Experiment 1 : chromatography , ascending the separation of pH indicator mixture Principle : To demonstrate the characteristic . invariable movement of a compound regardless of whether it is alone or in a mixture with other compounds which separate well from it . Running time : 11

At least 1 hour . Chemicals : Methyl orange Ph.ph Bromphenol blue Solvents : Either (a) n-butanol : ethanol : 2M ammonia ( 60 : 20 :20 by volume ) Or

( 60 : 20 : by volume ) (b) n-butanol :acetic acid glacial : water ( 60 : 15 : 25 by volume ) .

Locating agent :

Ammonia .

Procedure : 1- Place 50 ml of the chosen solvent at the bottom of the tank and replace the lid. 2- Prepare a 25 × 25 cm sheet of paper and apply one drop of each of the three individual indicators and one drop of the mixture separately to four origins , using the wire loop . 3- Form the paper into a cylinder and dasten with the tongued clips , part G . 4- Hold the origins over ammonia fumes to produce the alkaline color forms of the indicators i.e. the indicator anions . 5- Place the cylinder rapidly into the tank , before the indicators can revert to their free acid forms . This is important as the free acid from may travel with an Rf value different from that of the ionic form . Do not allow the paper to touch the glass walls . 6- Put the lid on and run solvent for at least one hour . Watch the initial flow of solvent across the origin and note the immediate commencement of separation of the indicators in the mixture . 12

7- Remove the chromatogram and make the solvent front with a pencil . 8- Dry the chromatogram . 9- Observe that the mixture of indicators has separated into its three individual components . Observe the different level reached by each indicator in the mixture and compare each with the level reached by the same indicator running by itself from one of the other origins . Note that the level is the same for each pair of indicator , regardless of whether they started alone or in mixture with the other indicators . Conclusion : When two or more substances , in a mixture with each other , are subjected to paper chromatography , each will run independently of the others and will proceed to the same point that it would have reached had it been run by itself.

Notes : 1- If the indicators are run in the free acid from they travel to quite different positions . This can be confirmed by experiment . 2- In this experiment the substances are substances are well separated . However, in multicomponent mixtures of complex chemical substances it is likely that some of the components will , at the end of the run , be found to be located in similar position . Their R f values will then be found to differ slightly from the R f of the substances run either alone or in simple mixtures . 3- The dyes, also separate well in solvent (a) and can usefully be included in this experiment .

Report 13

Compute and compare the Rf values of each pH indicator

Other experiments were made using the book

Column chromatography

By this method the stationary phase is loaded into a vertical column , usually glass, and the moving phase is allowed to flow down it by gravity or under pressure. In adsorpation chromatography , the substrate is adsorbed directly on to the solid stationary phase and the liquid, mobile phase competes with it for the substrate .

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A variety of organic and inorganic liquids is used adsorption chromatography . The eluting power of a solvent depends on its dielectric constant which is an approximate measure of solvent polarity. A mixture of the substance to be separated is dissolved in a small amount of solvent and added to the top of the column. An equal volume of solvent is removed form the lower end of the column thus allowing the mixture to enter the column . The upper portion of the tube is filled with eluting solvent , and solvent (elute) is continuously removed from the lower end of the column . The separation process can now take tow forms: (1)Elution is continued a clear separation of the components of the mixture can be seen ; examination of the column under UV light may facilitate this observation . once a separation has been obtained the stationary phase can be extruded and that potion of the stationary phase carrying the compound extracted with a suitable solvent. Obviously this method is most suitable for colored compounds . (2)Elution is continued until the various components are eluted from the column aliquot of the eluate are collected and tested for the compenent of the mixture. Those portion of the elute containing the same compound may be combined and the compound extracted by some suitable method , e.g. evaporation , precipitation , or liqud-liqud extraction . The glass column used should have a means of supporting the stationary phase. Commercial columns process either a porous glass plate fused onto the base of the column , or a suitable device for supporting a replaceable nylon net which in turn supports the stationary phase. Packing of column : Packing a column is normally carried out by gently pouring a slurry of the stationary phase into a column which has its outlet closed , whilst the upper part of the slurry in the column is stirred and /or column is gently tapped to ensure that no air bubbles are trapped and that the packing settles evently. Poor column packing give rise to uneven flow and reduced resolution . the slurry is added until the required height is obtained . 15

Once the required column height has been obtained , the flow of solvent through the packed column is started by opening the outlet , and continued until the packing has completely settled. To prevent the surface of the column from being disturbed either by addition of solvent to the column or during the application of the sample to the column , it is normal to place a suitable protection device, such as a filter paper disc or nylon or rayon gauze, on the surface of the column . once column has been prepared, it is imperative that no part of it should be allowed to run dry i.e. a layer of solvent should always be maintained above the column surface .

Application of the sample : The sample is first dissolved in the solvent before loading it into the column . In most experiments, the sample is carefully applied by capillary tubing and syringe or pump to pass the sample directly to the column.

This part wasn't performed due to deficiency of chemicals year 2010/2011 Ion exchange

Properties of Ion Exchange

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Ion exchangers operation is dependent upon certain properties of the system. Each property has an affect on the efficiency and productivity of an ion exchanger. Below are select properties which affect the system. The density of resin has an affect upon how the system performs. Properties of resin should be understood. For example, the density of the dry, water free resin is generally smaller for anion exchangers than cation exchangers. The density of water swollen resin depends on the type counter ion, swelling capacity and on the degree of crosslinking, besides the density of dry resin. Furthermore, it should be noted that bulk density is different than the density of the swollen resin. These densities are important because operation is dependent upon the resins. The mechanical resistance is a variable that is studied for ion exchangers. The mechanical resistance is found to vary with structure of the system. It should be noted that air dried resin is destroyed by certain friction. This needs to be thought of in design stages. The grain size, is a major part of the fluid flow and effectiveness of seperation of systems. For example, condensation type resins are generally broken granules. On the contrary, polymerization-type resins are small beads that are uniformally packed. To measure the grain size a mesh is used to keep out larger particles. In addition, for certain processes grain size is extremely important to efficiency. One such process is seperations carried out by chromotography. The major point of study of grain size is that it determines the fluid resistance of an ion exchange column made from ion exchange resin. This can be the key to success of an industrial operation. The total capacity is a measurement tool used to rate an ion exchanger. The total capacity is the amount of exchangeable ions of unit weight of resin. The determination of such factor is done by acid-base titration. Another capacity is salt splitting. This is the amount of sodium ions absorbed by the cation exchanger in the hydrogen form from a sodium chloride solution or hydrogen released by unit weight or unit volume. For an anion exchanger the amount of base liberated from a salt by unit weight or unit volume of the hydroxyl-form anion-exchange resin. Dissociation constants of active groups of the resin is a major part of the salt splitting capacity. Further, noted is the rest capacity which consists of the difference in monofunctinal strongly acidic or basic resin of splitting capacity. Also, the apparent capacity can be defined as the affects of multivalent anions on anion exchanger. Further, the break-through capacity depends on the pH, grain size, column size and flowrate. These capacities are properties of a system. Knowing and understanding the capacities allows for proper design. The porosity of a system controls much of the capacity of the exchanger. The surface active groups and capillary groups take part in the characteristics of a ion exchanger. The pores of IERs are of variable size even for the same resin product. Due to porosity, the affects on capacity of greater sized ions is because of the sieve effect. The determination of porosity can be done by means of solution containing ions of known size and similarity by using capacity measurements. Also, the same measurement can be done by the use of vapor pressures. Although, these methods 17

only measure mean particle size, it results in useful knowledge. In addition to the above, it should be noted that crosslinking affects mean pore size. The operating rate is essential to chemical engineers. Knowing the affects of controlling the flow is desireable also. For example, natural zeolite exchangeres operate slower and an ion exchanger of larger pores quicker. A cation exchanger is also knowed to set up equilibrium quicker. One may image that the process is controlled by the chemical reaction. But it is known that the diffusivity is a controlling factor. In addition, the rate depends on diffusivity constants of active groups of the resins. Other effects are on account of temperature and looseness of crosslinks

Ion Exchange Columns Aim To plot the breakthrough curve of strong acid cation exchange Amberlyst resins, and determine their capacity by batch and continuous flow processes.

Theory Ion Exchangers Of all different natural and synthetic products which show ion exchange properties, the most important are ion-exchange resins, ion-exchange coals, mineral ion exchangers, and synthetic inorganic exchangers. Ion exchangers owe their characteristic properties to a peculiar feature of their structure. They consist of a framework held together by chemical bonds or lattice energy which carries a positive or negative surplus charge. Counter ions of opposite charge move throughout the framework and can be replaced by other ions of same sign. For example, the framework of a cation exchanger can be regarded as a macromolecular or crystalline polyanion, while the framework of an anion exchanger can be regarded as a polycation. Ion Exchange Resins These constitute the most important class of ion exchangers. Their frame-work called the matrix, consists of an irregular, macromolecular, 3-D network of hydrocarbon chains. The matrix carries ionic groups such as SO32- , COO− in cation exchangers and NH+3 , NH+2 in anion exchangers. Ion exchange resins are thus cross linked polyelectrolytes. The matrix of the resins is hydrophobic. However, hydrophilic components are introduced by the incorporation of ionic groups such as SO3H. Linear hydrocarbon macromolecules with such molecules are soluble in water. So ion exchange resins are made insoluble by introduction of cross-links which Interconnect the various hydrocarbon chains. An ion-exchange resin is practically one single macromolecule . Its dissolution would require rupture of C-C bonds. Thus resins are insoluble in all solvents by which they are not destroyed. The matrix is elastic and can swell by taking up solvent , a fact referred to as ”heteroporosity” or ”heterodictality”. 18

The chemical, physical, and mechanical stability and the ion-exchange behavior of the resins depend primarily on the structure and the degree of cross-linking of the matrix and on the nature and number of fixed ionic groups. The degree of cross-linking determines the mesh width of the matrix and thus the swelling ability of the resin and the mobility of the counter ions in the resin, which in turn determine the rates of ion-exchange in the resin. Highly cross linked resins are harder and more resistant to mechanical breakdown. Amberlyst-15 with sulphonic acid functionality is our resin of interest. It is a highly porous, macro reticular ion-exchanger prepared by a variation of the conventional pearl-polymerization technique. In pearl polymerization, monomers are mixed, and a polymerization catalyst such as benzoyl peroxide is added. The mixture is then added to an agitated aqueous solution kept at the temperature required for poymerization. The mixture forms small droplets, which remain suspended. A suspension stabilizer is added to prevent agglomeration of droplets. In the case of Amberlyst, an organic solvent which is a good solvent for the monomer, but a poor solvent for the polymer is added to the polymerization mixture. As polymerization progresses, the solvent molecules are squeezed out by the growing copolymer regions. In this way, spherical beads with wide pores are obtained. Selectivity Ion exchangers prefer one species over another due to several causes : 1. The electrostatic interaction between the charged framework and the counter ions depend on the size and valence of the counter ion. 2. In addition to electrostatic forces, other interactions between ions and their environment are effective. 3. Large counter ions may be sterically excluded from the narrow pores of the ion exchanger All these effects depend on the nature of the counter ion and thus may lead to preferential uptake of a species by the ion exchanger. The ability of the ion-exchanger to distinguish between the various counter ion species is called selectivity. Separation Factor The preference of the ion exchanger for one of the two counter ions is often expressed by the separation factor, defined by… The molal selectivity coefficient , which is used for theoretical studies, is defined as…. The selectivity of the ion exchange process depends on the properties of the ion exchanger used and the composition of the aqueous phase . In the case of two ions having the same charge and very similar radii, the selectivity due to the properties of the ion exchanger (such as acidity, basicity, and the degree of cross linking ) is not sufficient for ensuring effective separation. In such a case, an appropriate complexing agent has to be added to the aqueous phase: the selectivity attained is then either due to the difference in the 19

stability constants or to the different charges or structures of the complexes formed. Increased selectivity can be brought about in many ways. For eg., one can exploit the preference of an exchanger for highly charged ions in dilute solutions, or one can choose a chelating resin. Capacity Capacity is defined as the number of counter-ion equivalents in a specified amount of material. Capacity and related data are primarily used for two reasons:- for characterizing ion-exchange materials, and for use in the numerical calculation of ion-exchange operations. Capacity can be defined in numerous ways: 1. Capacity (Maximum capacity, ion-exchange capacity) Definition : Number of inorganic groups per specified amount of ion-exchanger 2. Scientific Weight Capacity Units : meq/g dry H+ or Cl− form 3. Technical Volume Capacity Units: eq/liter packed bed in H+ or Cl− form and fully waterswollen 4. Apparent Capacity (Effective Capacity) Definition : Number of exchangeable counter ions per specified amount of ion exchanger. Units : meq/g dry H+ or Cl form (apparent weight capacity). Apparent capacity is lower than maximum capacity when inorganic groups are incompletely ionized ; depends on experimental conditions (pH, conc. ,etc) 5. Sorption Capacity. Definition : Amount of solute , taken up by sorption rather than by exchange, per specified amount of ion exchanger 6. Useful Capacity Definition : Capacity utilized when equilibrium is not attained Used at low ionexchange rates Depends on experimental conditions (ion-exchange rate, etc.) 7. Breakthrough Capacity ( Dynamic Capacity) Definition : Capacity utilized in column operation, Depends on operating conditions 8. Concentration of fixed ionic groups Definition : Number of fixed ionic groups in meq/cm3 swollen resin (molarity) or per gram solvent in resin (molality) Depends on experimental conditions(swelling, etc.) Used in theoretical treatment of ion-exchange phenomena ………….. Qv = volume cpacity in equivalents per liter packed bed. Qw = Scientific weight capacity in milliequivalents per gram. b = fractional void volume of packing W = water content of the resin in weight percent d = density of the swollen resin in grams per ml B The molality of fixed groups in meq/g is m =(100 − W) × Qw W × (1 + PQi−MQw × 10−3) The molarity of fixed groups in meq/ml is X =d × (100 − W) × Qw 100 × (1 + PQi−MQw × 10−3) 21

Batch Process Apparatus Stirred tank reactor with stirrer, belt, stand, pipette, resins, copper sulphate solution, test tubes ( 15), ion meter, cupric electrode, Ionic Strength Adjustor (ISA), volumetric flasks Procedure 1. Calibrate the ion meter using cupric nitrate standards of concentrations 0.6355 ppm , 6.355 ppm , 63.55 ppm , and 127.1 ppm. 2. Take known weight of resins in the stirred tank reactor. Fit the reactor on the stand and attach the belt to the stirrer which is adjusted on the pulleys. Switch on the stirrer . 3. Pour quickly calculated volume of 800 ppm cupric sulphate solution into the tank and start the timer . 4. Withdraw 1 ml samples from the tank using a pipette at every 40 seconds for about 10 minutes. 5. Dilute the samples to 50 ml in volumetric flasks and measure their concentrations using ion meter. 6. Plot a graph of concentration vs. time. 7. The amount of cupric ions consumed is calculated from the initial and final concentrations. Calculations Initial concentration - C0 ppm Final concentration - Cf ppm Qty. of cupric ions used Q =(Cf − C0) × 250/1000000 Capacity of resins = (Q/63.55) eq/g of resin Observation Table S.N. Time (min) Cu ion concentration (ppm)

Graph Plot a graph of concentration versus time.

Continuous Process Procedure 1. Take 10 g resins and prepare a slurry with distilled water. Charge the column with the slurry such that there are no air bubbles trapped. 2. Keep adding cupric sulphate solution to the resin, and let it flow out at approximately 1 ml/min. 3. After every 20 ml, measure out 1 ml of effluent, dilute it to 50 ml in the volumetric flask and measure its concentration in the ion meter. 4. A graph of concentration versus volume is plotted . Observation Table S.N. Time (min) Cu ion concentration (ppm) Graph Plot a graph of concentration versus time.

Results and Comments

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