What happens in cation exchange resin?
What happens in cation exchange resin?
Weak acid cation (WAC) exchange resins. WAC resins are composed of an acrylic polymer that has been hydrolyzed with either sulphuric acid or caustic soda to produce carboxylic acid functional groups.
What ions does a cation exchange resin exchange?
Ion exchange resins consists of two main types, i.e., cation exchange resins, that exchange positively charged ions, such as sodium, for calcium, and anion exchange resins, that exchange negatively charged ions, such as chloride, for arsenic.
What is strong cation exchange resin?
The strongly acidic cation exchange resins are bead-like products which have a sulfonic acid group in the cross-linked styrene frame. They can be used across the full pH range (0-14), and are relatively stable to temperature, even withstanding high temperatures of 100-120℃.
Which of the following is a cation exchange resin?
Sodium polystyrene sulfonate (SPS, Kayexalate, Kionex) is a cation exchange resin that exchanges sodium for secreted K in the colon.
What chemical is used for regeneration of cation resin?
hydrochloric acid
The strong acid cation exchanger resin is regenerated with sulphuric or hydrochloric acid, which effectively strips off the calcium, magnesium and sodium from the resin, substituting hydrogen. Hydrochloric acid is typically applied at between 4 and 6%.
Which type of ion exchange resin can be used to remove hardness from water?
Cation exchange involves the replacement of the hardness ions with a nonhardness ion. Water softeners usually use sodium (Na+) as the exchange ion. Sodium ions are supplied from dissolved sodium chloride salt, also called brine.
Does ion exchange remove chlorine?
For ion exchange to work, the contaminant must be in the proper ionic form and must bind more strongly than the displaced ion. Chlorine can also be removed before entering the ion exchange unit with dechlorination chemicals or activated carbon.
What do the surfaces of strong anion exchange resins usually feature?
Strong-cation exchange resins typically feature sulfonic acid functional groups while weak cation-exchange resins have carboxylic acids. Strong anionic-exchange resins contain quaternary amines while weak anion-exchange resins feature secondary or tertiary amines.
What is strong base resin?
The strongly basic anion exchange resin is an anion exchange resin with quaternary ammonium groups incorporated into the styrene frame. Two types with differing alkalinity strengths are: Type I with a trimethyl ammonium group, and Type II with a dimethylethanol ammonium group.
What are strong and weak ion exchange resins?
The terms “strong” and “weak” refer to the acid/base properties of the functional group. If the ligand is derived from a strong acid or a strong base it is referred to as a strong ion exchange resin. If the ligand is derived from a weak acid or a weak base it is referred to as a weak ion exchange resin.
Which group is found present in the strong cation exchange resin *?
15.7. 3.1 Structure and Basic Functionality of Cation and Anion Exchange Resins. Strong cation exchange resins have sulfonic acid (− SO3H) functional groups (e.g., Smith and Chang, 1983). They dissociate to release hydrogen ions, which allows other cations to occupy the ion exchange sites (Harland, 1994).
Which is the cation exchanger?
The most prevalent cation exchangers are strongly acidic resins with sulfonic acid groups (–SO3H) and weakly acidic resins with carboxylic acid groups (–COOH). In both the resins, hydrogen ions serve as exchangeable ions with metal cations.
What are the ions in a cation exchange resin?
The fixed ions of this cation exchange resin are sulphonates (SO3 —) that are attached to the skeleton. In this picture, the mobile ions are sodium (Na+) cations. Cation exchange resins such as Amberjet 1200 are often delivered in the sodium form. The anion resin bead has a very similar skeleton.
How is cation resin used to soften water?
Softening with cation resin is a simple exchange function. The resin bead is negatively charged and attracts positive ions. When supplied in the sodium form (Na+) the resin will exchange sodium ions for hardness ions – calcium and magnesium.
What is the selectivity of acid cation resin?
The greater the selectivity coefficient, the greater the preference for the ion. For example, a strong acid cation resin with 8% crosslink has a selectivity coefficient for sodium vs. hydrogen of 1.56, while the selectivity coefficient for calcium vs. hydrogen is 4.06.
How is the hardness of cation resin determined?
Hardness is given in grains/gallon or in ppm as CaCO 3. The reduction is directly related to the amount of cations present in raw water and the amount of salt used to regenerate the resin bed. Typically, 6 lb of NaCl/ft 3 (9 kg/m 3) of resin is used for regenerating strong acid cation resins.
