Full Answer
What is ion exchange in chemical water treatment?
The ion exchange process introduces another link in the chain of chemical water treatment methods. This page deals with the removal of water hardness (the calcium and magnesium salts) by exchanging ions through the reaction (water) chemistry involved.
What is the process of ion exchange in resin?
As water flows through the resin bed, the ion exchange process is repeated many times, "polishing" the water to a very high purity. During regeneration, the resin is separated into distinct cation and anion fractions as shown in Figure 8-12.
How does the ion exchange process remove water hardness?
The ion exchange process introduces another link in the chain of chemical water treatment methods. This page deals with the removal of water hardness (the calcium and magnesium salts) by exchanging ions through the reaction (water) chemistry involved. Water hardness has plagued industries and society for ages.
What is the process of ionic exchange?
Specifically, it is the exchange of ions between a solid substance (called a resin) and an aqueous solution, typically municipal, potable water but it frequently involves process or even wastewater (e.g., the plating industry).
How much ion exchange resin do I need?
Ion exchange resins have a capacity of approximately 1 equivalent per liter of resin. Your requirement is small, you may want to consider a cartridge type system. If you do a regular column, you can buy in the market a 6" X 48" column. Fill it to about 30" height.
How do you calculate ion exchange capacity?
The IEC is defined as the milliequivalent of ion-exchange groups included in a 1-g dry membrane (meq (g dry membrane)− 1). The concentration of ion-exchange groups is obtained by dividing the IEC with the water content in a 1-g dry membrane (meq (g H2O)− 1).
Which water can be used in ion exchange process?
Hard waterHard water can be softened using an ion exchange softening process (SKIPTON 2008). Ion exchange processes can also remove various charged atoms or molecules (ions) such as nitrates, fluoride, sulphates, perchlorate, iron and manganese ions as well as toxic metals (radium, uranium, chromium, etc.) from water.
How does ion exchange process take place?
Ion exchange describes a specific chemical process in which unwanted dissolved ions in water and wastewater — like nitrate, fluoride, sulfate, and arsenic — are exchanged for other ions with a similar charge.
What is anion exchange capacity?
Anion exchange capacity (AEC) represents the positive charge available to attract anions in solution. In most soils CEC > AEC. Figure 3. Ion exchange between nutrient sources (minerals and OM) and plant roots.
What is meant by total exchange capacity of the ion exchange?
The total amount of exchangeable ions on an ion exchanger is defined as the ion exchange capacity, and is typically given in units of equivalents per volume of wet resin (e.g., eq l−1) or equivalents per mass of dry resin (e.g., eq g−1).
Is ion exchange water safe to drink?
Ion exchange is a versatile tool in a water treatment engineer's toolbox and is useful to target trace contaminants. Ion exchange resin systems generally are safe, robust and effective methods to remove contaminants such as chromate, uranium, radium, perchlorate and more.
What are the 4 types of ion exchangers?
Ion exchangers can be ion exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, or even soil humus.
How does ion exchange filter water?
The ion exchange filtration is one of the most common water filtration methods. Ion exchange process percolates water through bead-like spherical resin materials (ion-exchange resins). Ions in the water are exchanged for other ions fixed to the beads.
How do you calculate the resin of a DM plant?
Applying these parameters to 60 m3/h flow rate then: 60 m3/h divided by 60 m/h = Minimum area 1 m2 required. Hence based on UK vessel sizing = 1219 mm diameter (1.16 m2) Resin volume per unit = 0.6 m x 1.16 m2 = 0.696 m3 (696 litres) Rounded up to the nearest 25 litres = 700 litres of each component.
What is ion exchange method for water softening?
Household water softeners are ion exchange devices. Ion exchange involves removing the hardness ions calcium and magnesium and replacing them with non-hardness ions, typically sodium supplied by dissolved sodium chloride salt, or brine.
How do you activate ion exchange resin?
The resin can be recharged by washing it with a solution containing a high concentration of sodium ions (e.g. it has large amounts of common salt (NaCl) dissolved in it). The calcium and magnesium ions migrate from the resin, being replaced by sodium ions from the solution until a new equilibrium is reached.
How do you calculate the resin of a DM plant?
Applying these parameters to 60 m3/h flow rate then: 60 m3/h divided by 60 m/h = Minimum area 1 m2 required. Hence based on UK vessel sizing = 1219 mm diameter (1.16 m2) Resin volume per unit = 0.6 m x 1.16 m2 = 0.696 m3 (696 litres) Rounded up to the nearest 25 litres = 700 litres of each component.
What is breakthrough capacity of ion exchange resin?
The average breakthrough capacity was found to be 2.17 mg NH4 per gram for the resin. Due to the influence of the film diffusion, the breakthrough capacity was similar for different surface loading rates. The results were used to design an ion exchange column for the new to build water treatment at ZS De Hooge Boom.
What is salt splitting capacity?
Salt splitting capacity (sometimes called „basicity“) is a value that indicates the amount of strongly basic quaternary ammonium groups. In the water treatment the SSC is necessary to remove the weakly dissociated acids (dissolved CO2, SiO2, H3BO3 etc.). The result is [eq/l].
What is the principle of ion exchange chromatography?
Principle of Ion Exchange Chromatography The molecules separated on the basis of their charge are eluted using a solution of varying ionic strength. By passing such a solution through the column, highly selective separation of molecules according to their different charges takes place.
What is the process of ion exchange?
Ion exchange (IX) is a physical-chemical process in which ions are swapped between a solution phase and solid resin phase. If As (III) is present, it must be oxidized to As (V) in order for IX to be effective.
What is the most critical factor to consider for determining the number of bed volumes that can be treated?
In most groundwaters, sulfate are present in concentrations that are orders of magnitude greater than As (V). Therefore, the level of sulfate is one of the most critical factors to consider for determining the number of bed volumes that can be treated.
How long does it take for an EBCT to work?
The recommended EBCT range is 1.5-3 minutes. EBCTs as low as 1.5 minutes have been shown to work in some installations. The presence of suspended solids in the feed water could gradually plug the media, thereby increasing headloss and necessitating more frequent backwashing.
How to regenerate resin?
Resin can be regenerated on-site using a four-step process: (1) backwash; (2) regeneration with brine; (3) slow water rinse; and, (4) fast water rinse. IX will produce liquid residual consisting of the backwash water, brine solution, and rinse water.
What is the problem with IX treatment?
One of the primary concerns related to IX treatment is the phenomenon known as chromatographic peaking, which can cause As (V) and nitrate levels in the treatment effluent to exceed those in the influent stream. This can occur if sulfate are present in the raw water and the bed is operated past exhaustion.
Is the IX process economically viable?
In general, the IX process is not an economically viable treatment technology if source water contains over 500 mg/L of TDS or over 50 mg/L of sulfate (SO4-2). Although these relationships will not be exactly the same for all water sources, it does provide a general indication of the impact of TDS and sulfate on IX treatment.
Is indirect discharge a RCRA regulation?
Indirect discharge may be an option for IX wastes since wastes that pass through a sewer system to a publicly owned treatment works (POTW) are exempt from RCRA regulation. However, the critical factor dictating the feasibility of indirect discharge, will be technically based local limits (TBLL) for arsenic and TDS.
