ABSTRACT

Ion exchange is a process of stoichiometrically reversible chemical reaction to exchange the ions in solution with the ions in solid phase. Ion exchange resin is an organic synthetic solid compound that is not soluble and has the ability to exchange ions. The experiment of ion exchange has purposes to study theoretical and fundamental of ion exchange, the regeneration of resin, water demineralization, conventional and instrumental chemical analytic method, column height, flow rate and solids type.

The experiment use the KOH resin as ion exchange resin and hard water consist of MgSO4 and CaSO4 (1 : 3) with the total concentration of the hard water is 4000 ppm, which will be softened. The experiment used a 25 BV flow rate with variation of column height, 7 cm and 10 cm. The determination of ions exchanged in the column can be done by EDTA titration. The EDTA concentration used is 0.15 M.

This ion exchanged experiment consist of 5 steps; start-up, service, backwash, regeneration, and rinsing. Start-up is the process used to determine the flow rate. Service is the process where the ions in solution (hard water) is exchanged with the ions in the resins. During the service process used the fixed bed column which means the ion exchange resins do not fluidized. Backwash is the process to prepare the resins before regeneration. During the backwash process, the ion exchange resins are fluidized. Regeneration is the process to restore the resin capacity. Rinsing is the process to wash the residual ions after regeneration.

In this experiment, practicants did two types variation column height. From the calculation of the first run (column height 7 cm) got the total operation resin capacity at 37,263 g/L, service efficiency at 70.44%, in the backwash step got % fluidization at 28.57% and % expansion at 7.1429% and regeneration efficiency at 6,0585% (graphical method) and 3,888.10-5 % (calculation method). Whereas, from the calculation of the second run ( column height 10 cm ) got the total operation resin capacity at 23.6754 g/L, service efficiency at 50.9905%, in the backwash step got % fluidization at 40% and % expansion at 5% and regeneration efficiency at 10.8188% (graphical method) and 0.44203% (calculation method).

CHAPTER 1OBJECTIVE

The purposes of ion exchange experiment are:1. To study the theoretical and the fundamentals of ion exchange2. To study the kinds of solid, example: CaSO4, MgSO4, CaCl2, MgCl2, the height of

resin in column, and flow rate3. To study the regeneration of resin4. To study water demineralization5. Chemical conventional and instrumental analysis method

CHAPTER IIEXPERIMENT RESULTS

RUN I(column height 7 cm)

RUN II( column height 10 cm)

Total resin capacity 37,263 g/L 23.6754 g/LService efficiency 70.44% 50.9905%% fluidization 28.57% 40%% expansion 7.1429% 5%Regeneration efficiency 6,0585% and 3,888.10-5 % 10.8188% and 0.44203%

pH final demin 4.4 4.98

CHAPTER IIIDISCUSSION

Ion exchange is a reversible chemical reaction where an ion (an atom or molecule that has lost or gained an electron and thus acquired an electrical charge) from solution is exchanged with a similarly charged ion attached to an immobile solid particle. These solid ion exchange particles are either naturally occurring inorganic zeolites or synthetically produced organic resins.

Ion exchange often uses resin to change this ion charge. It is known as ion exchange resin. Ion exchange resin is a polymerized hydrocarbon compound which is in the form of small beads, insoluble in water or other organic solvent, and usually has white or yellowish colour. It contains cross-linking bond, and functional groups which make it enables to ions on the water exchange with ion exchange resins’ charge. In industry, ion exchange resins are widely used in separation, purification, deionization, and demineralization processes.

Ion exchange resin has several characteristics, such as: Selectivity

Selectivity showed activity on certain ion. The main factor of selectivity is ion charge and radius. Selectivity will determine the separation capability of an ion in solution which same ion charge.

PorosityDescribe varies pores size of capillary canal in resin. These pores are the area of water absorbed. Porosity can influence ion capacity and selectivity.

Resin stabilityPhysical and chemical stability involve resistance and strength friction, resistance of osmotic effect in service and regeneration.

Crosslinking degreeThis degree describes quantitative size of total crosslinking inside polymer. Crosslinking degree has range from 4% to 16% and influences solubility, exchange capacity, selectivity, chemical resistance and oxidation.

Based on its functional groups, ion exchange resin can be distinguished into:a. Cation Exchange Resin

Cation exchange resin is a high molecular weight, cross-linked polymer containing sulfonic, phenolic, carboxylic, etc, groups as an integral part of the resin and an equivalent number of cations. This kind of resins can exchange all kinds of cation in a solution, therefore, it has low selectivity.

b. Anion Exchange ResinAnion exchange resin is a polymer containing amine groups an integral parts of polymer lattice and an equivalent number of anions, such as chloride, hydroxyl, or sulphate ions.Resins can be classified as strong or weak acid cation exchanger and strong or

weak base anion exchangers. The kinds and different for each the type of resin, such as:

Strong acid cation resin

Weak acid cation resin

Strong base anion resin

Weak base anion resin

Groups of function

Sulfonate(R-SO3H)

carboxylat (-COOH)

Ammonium quartener (R-R3N+:OH-)

R-NH2-

Reaction NaCl + R-H ↔ HCl + R-Na

Regeneration rx:2 R-SO3-Na+ + HCl ↔ 2R-SO3-Na+ + NaCl

R-COOH + NaHCO3↔ RCOONa + H2CO3

R-R3N+:OH- + NaCl ↔ R-R3N+:Cl- + NaOH

Regeneration rx:R-R3N+:Cl- + NaOH ↔ R3N+:OH- + NaCl

R-NH2- + HCl ↔

R-NH2-HCl

Regeneration rx:R-NH2

-HCl + Na2SO4

↔ 2 R-NH2 + NaCl + H2CO3

Function To change neutral salt into acid

To exchange cation which related with water alkalinity

To change salt into base

To exchange strong acid with water adsorption

Application Deionization, water softening

deionizing acidic metal finishing wastewater

the hydroxide (OH) form for water deionization

an ion exchange wastewater deionization

pH In width pH range below a pH of 6.0 over the entire pH range

Above pH 7

The fundamental requirements of a useful resin are:1. The resin must be sufficiently cross linked to have only a negligible solubility2. The resin must be sufficiently hydrophilic to permit diffusion of ions through the

structure at a finite and usable rate3. The resin must contain a sufficient number of accessible ionic exchange groups and

it must be chemically stable4. The swollen resin must be denser than water

One application of ion exchange is in softening water process. Hard water is water that contains of calcium and magnesium salts. Its hardness is totally determined by the content of calcium and magnesium salt which is combined with bicarbonates, sulfates, and chlorides. Hard water can be divided into two categories:

1) Temporary Hardness (containing carbonates): the hardness can be removed by heating the hard water.

2) Permanent Hardness (containing sulfates and chlorides) Calcium sulfate (CaSO4): it will precipitate and form scale in boilers when

concentrated. Calcium chloride (CaCl2) and magnesium chloride (MgCl2): it reacts in boiler

water to produce a low pH as follows: CaCl2 + 2HOH ==> Ca(OH)2 + 2HCl Magnesium Sulfate (MgSO4)

Based on its operation, ion exchange can be classified into: fixed bed, fluidized bed, and continuous bed.

Fixed bedIn the fixed bed method, the inlet solution to be treated flows through the column.

The ion exchange resin is not moved during the exhaustion; therefore the resin remains a compact (unexpanded) bed or column during the service run.

Fluidized bedIn the fluidized bed method, the inlet solution to be treated flow upward in the

column. The ion exchange resin bed is fluidized by the upward flow. The fluidized bed allows passage of suspended solids and result in less efficient contact. This process is used when suspended solid in the inlet solution are not removed. For high-purity cycle makeup treatment systems, the influent water is treated to ensure low suspended solids and fluidized beds are not employed.

Continuous bedThe continuous bed method is similar to the fixed bed method in that the solution to

be treated flows down and the resin bed is compacted. However, for the continuous method, a main column and a regeneration column are required. Small slugs of exhausted portions of the bed from the main column are removed to the regeneration column, and simultaneously, a slug of regenerated resin is returned to the main column. Although the resin slugs are transferred on an intermitten basis, the transfer is frequent and of short duration, so that the column service cycle is considered continuous.

The continuous method is applicable for water treatment. However, compared to the fixed bed method, the continuous method is more complex, the capital cost for the control system are higher, and the ion exchange resin is subject to greater attrition or wear and tear because of the frequent resin transfer. The fixed bed is predominantly selected as the preferred method of ion exchange, and the discussions that follow are based on the fixed bed method.

START-UP

First of all, wet cotton placed at the bottom of column to prevent resin going out from the column. Then, the column is filled with resin KOH exchange resin. There are two variations of resin height: 7 cm and 10 cm. The resins must always be immersed in water or a solution. When it becomes dry, the resin would not swell. It makes the pores shrink, and causes ion exchange performance is not effective.

Then, the tank is filled with 3 liters of demineralized water which is streamed into the column. Then, the flow rate of the solution which passes the resins is controlled on constant flow rate. This experiment is done with flow rate 25 BV. For the 7 cm resin height, it equals to 20.62 mL/minute, whereas for the 7 cm resin height, it equals to 29.45 mL/minute. BV is bed volume which includes particles volume, pores volume, and volume form bulk density. The purpose of constant flow rate is to make sure that resin contact time solution is constant during the process.

The high of the water above resin has to be constant because it will effect the pressure which affect the flow rate and ion exchange condition.

SERVICE

Service is the main process in ion exchange. In this process, the ions in the solution will be exchanged with the ions in the resin. In this experiment, ion exchange occurs between Mg2+ ions and Ca2+ ions (from hard water) with Na+ ions (from resin). The reaction is :

Mg2+ + R-Na Na+ + R-MgCa2+ + R-Na Na+ + R-Ca

Initially. Practicants prepared 3 L hard water 4000 ppm consist of 1000 ppm MgSO4 and 3000 ppm CaSO4. Then the demineralized water in the storage tank used before replaced by hard water. Then the hard water was streamed from the hole in the bottom of the tank through the hose to the hole upside the ion exchange column. The flow rate used is the one which was determined before. The process of ion exchange occurred when the solution passed the ion exchange resin. The first 50 mL of outcome water was disposed because it still contained the demineralized water from start-up process before. After that, every 25 mL outcome water was collected and 10 mL from this water was taken to be titrated with EDTA. In this experiment, practicants did duplo for the titration.

The titration is used to determine the concentration of the outcome water. The titrate that used in this experiment is EDTA solution with 0.15 M concentration. 10 mL sample (outcome water) was placed in the erlenmeyer and then added with 14 drops of NH4Cl and half spatula of EBT than it was titrated with EDTA. EDTA was chosen as the titrate because EDTA has some superiority; EDTA always react with metal logams with ratio 1: 1, the reaction runs perfectly, and EDTA can react with some metals fast. The equilibrium of EDTA solution is:

H4Y ↔ H3Y- ↔ H2Y2- ↔ HY3- ↔ Y4-

Every single form of this EDTA produces or needs the ion H+ so that the pH of solution contains of each form of EDTA will be different. NH4Cl was added in purpose to maintain the pH balance in the solution so that the optimal condition of titration (pH 8 – 12) could be reached. In this titration the optimal pH is 10, because in pH 10, the EDTA is in the Y4-

which is used in the reaction happened in titration between the sample solution and EDTA. The reaction equilibrium is :

MIn- (violet) + H+ + Y4- ↔ HIn2- (blue) + MY2-

While Y4- describes as EDTA, and MY2- describes complex metal-EDTA. EBT was used as indicator in this experiment because :

EBT has pH range 7-11. EBT in its free condition (blue) has a different colour with complex colour EBT-

metal (violet). EBT turns violet when forms a complex with metal ion such as calcium.

HIn2- (blue) + M2+ ↔ MIn- (violet) + H+

While MIn- describe complex metal – EBT, M2+ describe metal ions are valence 2, and HIn2- describe EBT indicator.

This titration stopped when the colour of sample solution turn from violet in to blue, which means all the EBT indicator had been in its free condition whereas the complex of metal-EDTA formed. The titration procedure stopped when it got three times constant volume of EDTA used.

Since the titration stopped, the concetration of the outcome water could be determined with volumetric analysis, which means calculated the concentration of outcome water from the concentration and volume of EDTA used. From the concentration counted, the breakthrough curve could be drawn between volume of EDTA solution used for titration process and the value of Ce/Co ( sample concentration / initial concentration). The ideal brakthrough curve for service process can be drawn as the picture below :

The ideal curve shown different condition for each area:Area 1: Resin is still in good condition and its capability is still high. Resin still can

exchange almost all of the ions in the solution. Therefore the value of Ce/Co approach 0.

Area 2: Resin begins saturated and its capability reduced. The ions which are not exchanged yet could slip through the resin.

Area 3: Resin is saturated and its capability is very low. Resin only can exchange a little amount of ions in the solution (almost none). Therefore the value of Ce/Co approach 1.

In this experiment, there are two variation of column height, which influence the service process and the amount of ion exchanged. The first variation is 7 cm column height, it gave result of 37.263 g/L total resin capacity and 70.44% resin efficiency. Whereas the second variation is 10 cm column height gave result of 23.6754 g/L total resin capacity and 50.9905% resin efficiency.

Total resin capacity is the amount of ions exchanged theoretically per mass unit per resin volume. The result of experiment gave total resin capacity for run I 37.263 g/L means every liter of outcome water the resin can exchange 37.263 g of ions. Resin capacity with leakage is resin capacity with leakage shows the amount of ions slip through resin. In the

first and second run the resin capacity with 5% nor 10% leakage could not be determined because the leakage is much more higher than 10%. Resin capacity with leakage is useful to determine the operation volume for a certain hardness limit in solution.

Service efficiency shows the resin’s capability to exchange ions from the start of service until the resin is saturated. The higher resin efficiency, the better resin performance. The first run (7 cm column height) gave the result of efficiency at 70.44% that is higher than the second run’s result of efficiency at 50.9905%. This result is not conform with the theory, where the higher column height will give the higher resin efficiency too, because there is more ions in the resin that can be exchange with the ions in the solution. This incompability is probably caused the resin used in the second run had been used in the first run, so that its capability was much lower than it was before, although it had been regenerated (regeneration does not restore all of resin capability).

BACKWASH

The purpose backwashing is remove solid and gas which is caused by hard water that passed through resin (ion exchange process), separate crumpled resin, organized resin, and also turned back distribution flow pass through the column. In backwash, the bottom hole in the column is connected with under of the column carbon and the top of column carbon is connected to valve with connector of hose. When the valve was opened, the water will flow from the valve to the carbon column (from top to the bottom).

The outlet water from carbon column is free of Ca(ClO)2 (calcium hypochlorite). Calcium hypochlorite will damage the resins, therefore it must have been removed before the tap water flow into this column. The outlet water from carbon column will flow to the bottom of resin column and fluidize the resin. During fluidization, the wet cotton at the bottom of resin column must be suppressed so as not fluidized simultaneously. If the wet cotton was fluidized together with the resin, after the fluidization is ended, the wet cotton may be above the resin bed, and the resins can pass the column.

During fluidization (approximately 5 minutes), the resin will be is fluidized, the height of the fluidized resin must be measured. Then, stop the water and wait 5 minutes until the resin precipitated, height of resin is measured. From experiment data, is got:

RUN 1 RUN 2h before fluidization 7 cm 10 cmh when fluidization 9 cm 14 cmh after fluidization 7,5 cm 10,5 cm

% fluidization 28,57 %% 40 %% expansion 7,1429% 5 %

From this data, can be seen if the height of the fluidized resin in run 1 is lower than run 2 because the water flow rate in run 2 was bigger than in run 1. But as the resin in run 2 is more saturated than in run 1, the % expansion is smaller than run 1.

After resin precipitation, there will be three phenomenons can be occurred:a. Bubbling

Bubbling is occurred because flow rate of the fluid is bigger than minimum velocity. The particle and bubble will merge and build an empty space.

b. SluggingThe bubbles which have the same size with the column diameter will merge and slugging occurs. Slugging will divide the resins bed into some layer and there is an empty space between the layers.

c. ChannelingChanneling is caused by aggregation effect of cohesion force between the particles. From the experiment, bubbling and slugging was occurred in both run 1 and run 2.

REGENERATION

Regeneration is the process done to restore the resin capability after the resin saturated from used in the service process. The regeneration only can restore the resin capability near 100% but not exactly 100%. This process must be done so that resin can be use for service process again.

The regeneran requirements are: Regeneran must have the ions that can be exchange to the saturated resin. The reaction between regeneran and resin must be reversible, the regeneration

reaction from regeneran must be the opposite of the service reaction. Regeneran must be easy to made or found and is not expensive.The regeneration procedure is similar to the service procedure, it is only the

solution streamed that is different. In regeneration, the solution streamed is the regeneran, in this experiment used NaCl as the regeneran. The reaction equilibrium occurred in the regeneration process:

R-Mg2+ + 2NaCl 2R-Na+ + MgCl2

R-Ca2+ + 2NaCl 2R-Na+ + CaCl2

In this experiment, NaCl used had 9000 ppm concentration. While the first 50 mL outcome water was disposed, the 25 mL after was collected and taken 10 mL to be titrated using EDTA. From the titration, the concentration of outcome water could be calculated and the breakthrough curve could be made. The ideal breakthrough curve is shown in the picture below:

Area 1 : The resin is still saturated from the service process before. Its capability to exchange the ions is still low.

Area 2 : The resin capability begin to be restored as the ions of the resin restored from the regeneran used.

Area 3 : The resin is in nearly its initial condition, which means the regeneration completed.

Regeneration efficiency shows how near the regeneran can restore the resin to its initial condition. The higher regeneration efficiency the closer resin to its initial condition. From this experiment, the regeneration efficiency got:

% efficiency regeneration RUN I RUN IICalculation method 6.0585 % 10.8188 %Graphical method 3,888.10-5 % 0.44203 %This result shows that the regeneration can not restore resin to its 100% initial

condition. The result from run I is lower than the result of run II, it is because the resin in run II had higher column height so that the ions that can be exchanged is more than in run II which column height is lower.

RINSING

Rinsing process uses demin water for cleaning. The purpose of rinsing is remove the residue of ions trapped in resins also to remove the residue of regenerant (NaCl). There are 2 method of rinsing:

Fast rinsing : to wash ions residue Slow rinsing : to push ion residue out from resin and throw away the cleaning

residueFirst, 3L demin water pour into in the storage tank and initial pH is measured. pH

meter display the initial pH of demin water is 6,7. Afterwards, every 25 mL of outlet water from ion exchange column is collected, and the pH of each sample is measured until three times constant. When the pH has been constant, the pH value of non-polluter demin water in this experiment is 4,98, it will not reach the initial pH value as the regeneration will not restore all ion exchange capacity. This shows that residues inside the resin are decreased.

CHAPTER IVCONCLUSION

1. The height of resin effect amount of ion which can be exchanged.2. The higher resin efficiency, the better resin performance.3. New resin gets lower total operation capacity and higher efficiency than

regenerated resin.4. Regeneration process could not bring the capacity of resin as well as beginning.

BIBLIOGRAPHY

1. http://en.wikipedia.org/wiki/Ion_chromatography 2. http://jurnal.sttn.batan.ac.id/wp-content/uploads/2008/06/8-dyah-hal-95-104.pdf 3. http://nciz.org.nz/ChemPrcesses/water/13D.pdf 4. http://www.freshwatersystems.com 5. http://www.remco.com/ix.htm 6. http://www.skataspe.com/gs_bedvolume.asp 7. Lawrence F. Drbal, Patricia G. Boston, Kayla L. Westra, Black & Veatch, Power

plant engineering, Springer, 19968. Skoog, Douglas.A, et.al, Analytical Chemistry An Introduction9. Vogel, Textbook of Quantitative Chemical Analysis, 5th edition

APPENDIX APHYSICAL AND LITERATURE DATA

Flow rate = 25 BVDiameter of column = 3 cmHeight of resin Run I = 7.5 cm

Run II = 10 cm

[EDTA] = 0. 1316 MMr EDTA = 372.24 g/mol

[MgSO4.7H2O] = 0.1 MMr MgSO4.7H2O = 246 g/mol [hard water] = 4000 ppm [MgSO4] : [CaSO4] = 1:3Mr MgSO4 = 120 g/molMr CaSO4 = 136 g/molVolume of hard water = 3 L

[NaCl] = 9000 ppmMr NaCl = 58.5 g/molVolume of NaCl = 3 L

APPENDIX CGRAPHICS

0 100 200 300 400 500 6000

0.20.40.60.81

1.21.4

Service I

V hard water (mL)

Ce /

Co

0 100 200 300 400 500 6000

0.10.20.30.40.50.60.70.8

Service II

V hard water (mL)

Ce /

Co

0 50 100 150 200 250 300 350 400 450 5000

0.020.040.060.080.1

0.120.14

Regeneration II

V hard water

Ce /

Co

0 50 100 150 200 250 300 350 400 450 5000

0.020.040.060.080.1

0.120.140.16

Regeneration II

V hard water (mL)

Ce /

Co

0 50 100 150 200 250 300 350 400 450 5004.14.24.34.44.54.64.74.84.95

5.1

Rinsing I

V hard water

pH

0 50 100 150 200 250 300 350 4004.14.24.34.44.54.64.74.84.95

5.1Rinsing II

V hard water (mL)

pH

APPENDIX DCALCULATION EXAMPLE

RUN I

1. Flow rate determinationFlow rate = 25 BVColumn diameter = 3 cmResin height = 7 cm

Resin volume = 14

π D 2h = 14

π× (3 cm )2×7 cm=49,48 cm3

Flow rate = 25 × 49,48cm3

hr ×

1hr60 min

= 20,6167 mLmin

2. Standardization EDTA solutiona. Making EDTA solution

[EDTA] = 0.15 MMr EDTA= 372.24 g/molV EDTA= 0.5 Lm EDTA= [EDTA] x Mr EDTA x V EDTA

= 0.15 M x 372.24 g/mol x 0.5 L= 27,918 g

b. Making MgSO4.7H2O[MgSO4.7H2O] = 0.1 MMr MgSO4.7H2O= 246 g/molV MgSO4.7H2O = 0.03 Lm MgSO4.7H2O = [EDTA] x Mr MgSO4.7H2O x V EDTA

= 0.15 M x 246 g/mol x 0.5 L= 18,45 g

c. Standardization of EDTAV MgSO4.7H2O = 0.015 LV EDTA = 0.0114 L[EDTA] × V EDTA = [MgSO4.7H2O] × V MgSO4.7H2O[EDTA] × 0,0114 L = 0.015 M × 0.015 L

[EDTA] = 0,1316 M

3. SERVICE Making hard water

[hard water] = 4000 ppm; MgSO4 : CaSO4 = 1 : 3V hard water = 3 L

m hard water = 4000 mgL

×3 L=12000 mg=12 g

m MgSO4 = 14

×12 g=3 g

m CaSO4 = 34

×12 g=9g

Mr hard water = 0.25 x120+0.75 x 136¿¿

Breakthrough curve[EDTA] . V EDTA = [hard water] . V hard water

0,1316 M. 0,4 mL = [hard water] . 10 mL

[hard water] = 0,005264 M x 132 g

mol×

1000 mgg

= 694,848ppm

Ce/Co = 694,848/4000 = 0,173712 Total operation capacity determination

Operation volume = 525 mLResin volume = 49,49 mLCo = 4000 ppm = 4 g/LΣ Ce/Co.Vs = 0,0640563 L

Total operation capacity = Co. VopV resin

–Co .∑ Ce

Co.Vs

V resin

= 4

gL

.0,525 L

49,48. 10−3 L –

4gL

. 0,0640563 L

49,48 .10−3 L = 37,263 g/L

Total operation capacity determination (with 5% leakage) can not be determined as the leakage of the resin is higher than 5%.

Total operation capacity determination (with 10% leakage)V op = 0,125 LCo = 4000 ppmCe/Co.Vs = 0,00173712

Operation capacity = Co. VopV resin

–Co .∑ Ce

Co.Vs

V resin

= 4

gL

.0,525 L

49,48. 10−3 L –

4gL

. 0,00173712 L

49,48. 10−3 L = 42,3 g/L

Service efficiency determinationL = Area under curve = 155,2551 mL = 0,1552551 L

M ions that aren’t adsorbed = L. Co. 1/Mr air sadah = 0,15526 L . 4 g/L /132 g/mol = 4,7048.10-3 M

M ions that passes the resin = Co. V op. 1/Mr air sadah = 4 g/L . 0,525 L. /132 g/mol = 0,0159 M

M adsorbed ions = M ions that aren’t adsorbed – M ions that passes the resin = 0,0159 M – 4,7048. 10-3 M = 0,0112 M

Efisiensi service = M adsorbed ions

M ions that passes the resin x 100%

= 0,0112 M0,0159 M

x 100%

= 70,44%

4. BACKWASH

% fluidisasi = h during fluidization−h beforebackwash

h beforebackwash x 100% =

9 cm−7 cm7 cm

× 100 %=28,57 %

% ekspansi = h after backwash−h beforebackwash

h beforebackwash x 100% =

7,5 cm−7 cm7 cm

×100 %=7,1429 %

5. REGENERATION [NaCl] initial = Co = 9000 ppm V NaCl = 9000 mg/L x 3 L = 27 gram Breakthrough curve

1 mol Na+ 1 mol EDTA

[NaCl] = 0,1316 M × 1,25 mL

10 mL=0,01645 M

= 0,01645 mol

L× 58,5

gmol

×1000mgg

= 962,325 ppm

Ce/Co = 962,325

9000 = 0,106925

Regeneration capacityCalculation methods

Σ Ca2+ dan Mg2+ out = ∑ ¿¿¿

= 0,0041454 mg x

1 g1000 mg

132 g/mol x 2 = 3,1406.10-8 eq

Σ Na+ in = V op x [ NaCl ] x valensi

Mr NaCl

= 0,525 L x 9000

mgL

x1g

1000 mg58,5 g /mol

x 1 = 0,08077 eq

Regeneration efficiency = ∑ Ca2+dan Mg 2+out

∑ Na+¿ =

3,1406.10−8

0,08077 x 100% =

3,888.10-5 %

Graphic methodArea under curve = 31,81 mL

M ion out from regeneration = L . Co = 31,81.10-3 L . 4 gL

. 1

58,5 g /mol = 2,175.10-3

mol

M ion passes resin = Co . Vop = 4 gL

x 0,525 L . 1

58,5 g /mol = 0,0359 mol

Regeneration efficiency = M ion out ¿ regeneration ¿M ion passes resin x 100%

= 2,175.10−3

0,0359 x 100% = 6,0585%