You must have heard it once ion exchange resin. However, you probably won’t know ion exchange resin What is that? What are the applications of ionic resins in life? Then let’s go together Ocany Follow the article below to find the answer!
What is ion exchange resin?
Ion exchange is a reversible chemical reaction. Where dissolved ions are removed and replaced with another ion of the same or similar charge. Ion exchange resin (resin) is a resin containing ions that are easily exchanged with other ions present in the solution when the solution flows through the exchange column and is insoluble in water. The ion exchange resin itself does not participate in the chemical reaction. Instead, the physical environment will facilitate ion exchange reactions to take place.
The structure of ion exchange resins is formed by cross-linked hydrocarbon chains in a process known as polymerization. Crosslinking gives the plastic polymer a stronger, more resilient structure and greater capacity (depending on volume).
Most ion exchange resins are composed of polystyrene, some are manufactured from acrylic (either acrylonitrile or methyl acrylate). The basic structure of the exchange resin is made up of styrene molecules.
Physical properties of ion exchange resins
The molecular shape, size and structure of the exchange resin can vary from one type to another. Below are some physical properties of ion exchange resins.
- The exchange resin is usually spherical in shape, small in size and has a radius of 0.25 – 1.25mm.
- The color of ion exchange resin will often fade after a period of use. Ion exchange resins usually have some basic colors such as: Brown, black, yellow.
- The morphology of the ion exchanger is round in shape with the size of about 0.04 – 1 mm.
- The mass of the ion exchanger will increase when immersed in water.
- Ion exchange resin beads are divided into dry moisture and wet moisture.
- Ion exchange resins withstand temperatures at a certain limit, usually from 20 – 500C, will give the best working efficiency. Excessive heat will cause the plastic particles to decompose.
- Depending on the type of ion will have different electrical conductivity. Usually a moist ion exchanger will conduct heat better.
In addition, ionic plastic beads are likely to break during operation if there is a collision. At the same time, it will also reduce its life when exposed to strong oxidizing agents.
Structure of ion exchange resin
Most of the components of ion exchange resins are polystyrene, some are manufactured from acrylic or methyl acrylate. They are structured from cross-linked hydrocarbon chains. This gives the ionic particles a stronger structure, better elasticity and greater capacity. In general, ion exchange resin beads have a hollow structure consisting of 2 parts, which are fixed functional radicals and mobile groups (capable of ion exchange).
What are the advantages and disadvantages of water softening plastic beads?
Some outstanding advantages and disadvantages of ion exchange resins that we cannot fail to mention are:
- Long use time.
- Easy to install and operate.
- Can be regenerated many times with low cost.
- Low energy consumption.
- Only absorbs substances available in water, so it is very environmentally friendly.
- Does not participate in chemical reactions, difficult to dissolve, so it does not affect water quality.
- If there are organic compounds or Fe3 + ions in the water, they will stick to the resin particles to form ions, reducing the ability to exchange ionic resins.
- Used only for ion exchange, not for filtration of organic compounds or Fe3+ ions.
- It is necessary to remove other organic matter or iron before passing through the water purification system to ensure the effective operation of the ion exchange resin.
Types of ion exchange resins
A cation exchange resin is a type of particle that can absorb positive ions from an electrolyte solution. It is acidic and is often used to soften water. There are two main types of cationic particles:
- Strong Acidic Cation Exchange Resin: This type contains a large amount of strong acid group SO3H which easily separates H+ in solution.
- Weak acidic cation exchange resin: Contains weak acid groups such as carboxyl-COOH, which can dissociate H + and acidic water.
Anion resin beads
Anion resin beads are capable of absorbing negative ions from alkaline electrolyte solutions. This type of granule is often used to remove nitrate or organic impurities. Anion ion exchange resin beads also have 2 main types:
- Strong alkaline (base) anion exchanger beads: Contains strong basic groups such as quaternary amines (also known as quaternary amines) -NR3OH (R is a hydrocarbon group), to dissociate OH- in water.
- Weakly alkaline (base) anion exchangers: Contains a weakly alkaline group, such as primary amines. -NH2, or -NHR and -NR2 can dissociate in water and OH-, which is weakly alkaline.
How to use ion exchange resin
Ion exchange resin is an indispensable water softening ion exchange material in RO water treatment systems, upstream water purifiers. The main effects of this ion exchange resin are:
- Softens water, removes water hardness by reducing Ca2+ and Mg2+ concentrations and increasing Na+ concentrations.
- Removes minerals and alkalis as well as unnecessary substances in water such as: Barium, Calcium, Chromium, Manganese, Magnesium, Radium, Arsenic, Uranium…
- Helps remove nitrate CO32-, CN-, NO3-, ClO4-, SO42.
Principle of ion exchange of plastic beads
When water flows through the column containing ion exchange particles, the process in the column will take place as follows: H + ion exchange resin beads take any cation they encounter such as: Na +, Ca2 +, Al3 +, Mg2 + … Similarly, the anion exchange resin will exchange OH- with any anion such as: Cl- ions NO3-, SO42-… H + from the cation exchanger combine with OH- ions from the anion exchanger to create pure water (H2O).
Ion exchange beads work on this principle because the ions are permanently bound in the structure of the bead. Charged ions will easily bond with oppositely charged ions forming a permanent bond. At the same time, these reactions will continue to associate with functional groups until it reaches equilibrium. After a period of use, these ion exchangers will lose their effectiveness and need to be regenerated with a suitable solution.
How to regenerate ion exchange resin
To regenerate ion exchange resins, you can use a solution of Sodium chloride (NaCl), hydrochloric acid (HCl) or NaOH. However, the most commonly used is sodium chloride (NaCl). The process of regeneration of ion exchange resins will take place the following reaction:
- R2Ca + 2 NaCl <-> 2 RNa + CaCl2
- R2Mg + 2 NaCl <-> 2 RNa + MgCl2
Note: The regenerated salt must be completely pure salt or reconstituted salt with a NaCl content of 99.5%. You must not use ordinary salt solution because it contains many impurities such as: Ca2 +, Mg2 +, Cl-, SO42-, Br – … these impurities will greatly affect the entire water treatment system, damage the plastic beads.
What are the practical applications of ion exchange resins?
Ion exchange resins are a low-cost choice for cleaning, isolating and decontaminating solutions containing ionic species. In addition to low cost, ion-exchange processes are reversible in nature and the exchange resin can be regenerated by simple treatment with a solution containing an excess of displaced ions.
Typical laboratory applications include the separation of organic acids and biomolecules such as peptides or proteins. However, ion exchange resins also have a number of industrial applications ranging from water treatment, filtration processes in the metallurgical, pharmaceutical, food and beverage, nuclear and semiconductor industries. We will learn some basic applications of this ion exchange resin.
Hard water treatment is the most common application of ion exchange resins. Hard water contains excess calcium and magnesium salts and resins containing sodium ions are used to replace those calcium and magnesium ions. After softening the hard water, the resin is regenerated with a solution rich in sodium ions such as sodium chloride. The sodium ions return to the active site on the resin and can be reused to further soften hard water.
In this process, ion exchange resins are used to remove toxic heavy metals such as lead and cadmium from the water. The mixed resin has an irregular regeneration cycle, which can be used to remove impurities.
Ion exchangers are used frequently to purify elements such as uranium from plutonium. For many years, ion exchange resins have been used frequently, but solvent extraction also plays an important role in the separation of the lanthanum and actinide groups. Ion exchangers also find an important application in nuclear fuel processing and radioactive waste recycling.
Ion exchange resins are used to purify antibiotics from fermented broths, as excipients for controlled release of active ingredients. At the same time, it is also used to remove the toxic odor of some medicinal compounds.
Fruit juices and drinks
Ion exchange resins are used in a number of fruit and beverage industries to improve taste and aroma. Through the removal of unwanted ingredients, it makes drinking water more delicious and attractive to users. Common applications of ionic resins are removal of trace metals, unpleasant odors and tastes, decolorization and primary treatment of water used in the production of juices and other beverages.
Through the content of the above article, Ocany has learned with you about the structure of ion exchange resins and its applications in life. Ocany wishes you to successfully apply this plastic bead in protecting the health of family members.
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John Alen was born in 1971 and is a doctor in the healthcare and psychology fields with many years of experience. He is currently working at easyhealthylive.com, a leading health and psychology blog. Having studied at Y1 National Medical University named after IM Sechenov, John Alen is using his knowledge and experience to help improve the physical and mental health of people in the United States.