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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 1 OBJECTIVE The purposes of ion exchange experiment are: 1. To study the theoretical and the fundamentals of ion exchange 2. To study the kinds of solid, example: CaSO4, MgSO4, CaCl2, MgCl2, the height of resin in column, and flow rate 3. To study the regeneration of resin 4. To study water demineralization 5. Chemical conventional and instrumental analysis method

CHAPTER II EXPERIMENT RESULTS

RUN I (column height 7 cm) Total resin capacity Service efficiency % fluidization % expansion Regeneration efficiency pH final demin 37,263 g/L 70.44% 28.57% 7.1429%6,0585% and 3,888.10-5 %

RUN II ( column height 10 cm) 23.6754 g/L 50.9905% 40% 5%10.8188% and 0.44203%

4.4

4.98

CHAPTER III DISCUSSION 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. Porosity Describe varies pores size of capillary canal in resin. These pores are the area of water absorbed. Porosity can influence ion capacity and selectivity. Resin stability Physical and chemical stability involve resistance and strength friction, resistance of osmotic effect in service and regeneration. Crosslinking degree This 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 Resin Anion 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 Groups of Sulfonate function (R-SO3H) Reaction

Weak acid cation resin carboxylat (-COOH)

Strong base anion resin Ammonium quartener(R-R3N+:OH-)

Weak base anion resin R-NH2-

NaCl + R-H R-COOH HCl + R-Na + NaHCO3 RCOONa + Regeneration rx: H2CO3 + 2 R-SO3-Na + HCl 2R-SO3Na+ + NaCl

R-R3N+:OH+ R-NH2- + HCl NaCl R- R-NH2-HCl R3N+:Cl- + NaOH Regeneration rx: Regeneration rx: R-NH2-HCl + R-R3N+:Cl+ Na2SO4 NaOH 2 R-NH2 + + R3N :OH + NaCl NaCl + H2CO3 salt To exchange strong acid with water adsorption

Function

To change neutral To exchange To change salt into acid cation which into base related with water alkalinity Deionization, water softening

Application

deionizing acidic the hydroxide an ion exchange metal finishing (OH) form for wastewater wastewater water deionization deionization over the entire pH Above pH 7 range

pH

In width pH range below a pH of 6.0

The fundamental requirements of a useful resin are: 1. The resin must be sufficiently cross linked to have only a negligible solubility 2. The resin must be sufficiently hydrophilic to permit diffusion of ions through the structure at a finite and usable rate 3. The resin must contain a sufficient number of accessible ionic exchange groups and it must be chemically stable 4. 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 bed In 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 bed In 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 bed The 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 n