What is antiscalant?
Antiscalant is a pre-purification water additive for the reverse osmosis system, which is very effective in preventing membrane scaling. Before the water enters the reverse osmosis membrane, an antiscalant is injected into the water and sent through the system. The chemicals create a time delay between the bicarbonate and the calcium magnesium. This delay allows water to pass through the membrane before any chemical reaction occurs in which sediment is formed.
Antiscalant compounds:
Now let’s examine the structural composition of antiscalants. Antiscalants can be made of three materials:
- The first category of polyacrylic antiscalants that have good dispersion due to their high molecular weight
- Another category is antiscalants made of sodium hexametaphosphate, which have very little stability, so they are not widely used.
- The third category of antiscalants with the chemical formula of organophosphonates are much more stable than the previous category, but they are similar in terms of inhibition.
Types of antiscalants:
Antiscalants Antiscalant based on their appearance, PH and structural chemical compositions have differences from each other. In terms of structure, scalants are divided into phosphonate and polymeric antiscalants. Phosphonate-based antiscalants have carboxylic acid and phosphate functional groups. The best type of antiscalant is to prevent the formation of sulfate and carbonate deposits, but on the other hand, it has low dispersing properties (dispersing property means preventing the dissolution and adhesion of colloids). It has and is used to prevent the formation of sediment in waters with high hardness. Now we will examine the types of antiscalants based on the pH value , which is acidic ( pH less than 3), which is more suitable in systems that have calcium carbonate deposits. when the TDS Alkaline scalants are used level of the incoming water is high. These types of scalants have a great effect on sulfate deposition, and the other category of neutral scalants is usually compatible in all systems. In addition to the above, antiscalants have different types based on their appearance, usually antiscalants are in liquid form and are widely used, but there is another type in the form of powder antiscalants that prevent the formation of sediment in water purification filters.
Application of antiscalant:
We should know that the water entering the reverse osmosis machine contains some salts, and these soluble salts are deposited over time due to passing through the membranes of the reverse osmosis machine . Escalants are used to prevent sedimentation.
Antiscalant test:
For this test, there are two laboratory and field methods. In the laboratory method, the effect of scalant on the sediments is measured, and in the field method, all the important and necessary characteristics of the system are recorded in a certain time frame, so that the obtained results show that this antiscalant How much does it have the ability to remove and control sediments?
Side effects of antiscalant:
Anti-scalants play a very important role in the system, therefore, they cannot be removed and the only side effects it can cause is that it causes the device to corrode due to its acidic properties, but if the system has sufficient standards and materials There is not much concern if good quality is used, but the use of low-quality anti-scalant has complications such as reducing the life of the membranes due to frequent washing, because low-quality anti-scalant causes clogging of the membrane, this clogging and the formation of sediment in the membrane reduces the production flow rate, as a result of the production capacity. decreases, on the other hand, the produced effluent increases, and for water to pass through the membrane, more pressure is needed, as a result, the system pump must work with a higher pressure and amperage, which causes depreciation and damage to the pump and related costs.
References
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