What are the Evaluation and influencing factors for RO membrane?
The evaluation indices for Reverse Osmosis membranes are_
1. The rate of desalination and the salt permeability
When the reverse osmosis membrane element is constructed and shaped, the desalination rate is established. The density of the ultra-thin desalination layer on the reverse osmosis membrane element determines the desalination rate. The greater the desalination rate and the lower the water output, the denser the desalination layer. The rate at which various chemicals are removed by reverse osmosis is largely governed by the material's structure and molecular weight. For reverse osmosis membrane elements, the removal rate of high-valent ions and complex monovalent ions can surpass 99 percent.
2. Production of water (water flux)
Water production (water flux) refers to the reverse osmosis system's production capability, or the quantity of water penetrating through the membrane per unit time, commonly measured in tones per hour or gallons per day.
3. Permeation flow rate
Permeation flow rate is another key measure of reverse osmosis membrane components' water output. The permeate flow rate per square foot per day is commonly given in gallons per square foot per day (GFD). The water velocity perpendicular to the membrane surface will rise if the permeate flow rate is too high, aggravating membrane fouling.
4. The pace of recovery
The proportion of feed water turned into product water or permeate in a membrane system is referred to as the recovery rate. The membrane system's recovery rate is calculated at the time of design and is dependent on the specified water quality. The recovery rate is often hoped to be maximized in order to enhance economic efficiency, but it should be the maximum value at which the membrane system will not precipitate owing to impurities such as salts supersaturation.
100 percent recovery rate = (product water flow / influent flow)
Influencing factors for Reverse Osmosis (RO) Membranes
The reverse osmosis process’ primary operational parameters are the water flow and desalination rate of reverse osmosis membranes. Pressure, temperature, recovery rate, feed water salt content, and feed water pH will all have an impact on these factors.
1. Water pressure at the inlet
The salt penetration rate is unaffected by the incoming water pressure; however, when the inlet water pressure rises, the net pressure that drives reverse osmosis rises, increasing water production while salt permeation remains almost same. Permeation is diluted as a result of increased water output. The salt content of the membrane lowers salt permeability and raises salt rejection. Because of the excessively high recovery rate, when the incoming water pressure surpasses a specific value, the concentration polarization increases, resulting in an increase in salt penetration, which counters the increased water production and causes the desalination rate to plateau.
2. Temperature of the inlet water
The operating pressure, desalination rate, and pressure drop of reverse osmosis are all affected by temperature. The actual working pressure falls as the temperature rises, the permeability rises, and the net driving force needed for a certain water flow lowers. Simultaneously, when the temperature rises, the solute penetration rate rises, as does the salt permeation rate, which is immediately reflected in the increase in product water conductivity.
3. Influent pH
The pH value of the influent water has essentially no influence on the water production of various membrane modules, but the pH value of the influent water has a higher impact on the desalination rate even within the permitted range. On the one hand, the pH of the product water influences its conductivity. Because the reverse osmosis membrane itself generally contains certain active groups, the rate has an effect. The electric field on the membrane surface is affected by pH, which ultimately affects ion movement.
4. Impact on the salt concentration
The osmotic pressure in water is determined by the salt or organic concentration. The osmotic pressure rises as the salt concentration rises. When the intake pressure remains constant, the net pressure drops, and the amount of water produced drops. The difference in salt concentration between the front and rear sides of the reverse osmosis membrane determines salt permeability.
Suspended matter in water is the stuff that remains on the surface of the filter material as the water is filtered, and is primarily made up of particles. Because of the high suspended particles concentration, reverse osmosis systems can soon get severely clogged, reducing water output and quality.
6. Recovery rate
The rate of recovery has a significant impact on the pressure decrease at each step. The recovery rate rises if the total influent flow rate is maintained at a specific level. The overall pressure drop diminishes as the flow of concentrated water passing through the high pressure side of reverse osmosis decreases. The pace of recovery slows, but the overall pressure drop rises.
Technical assistance and guidance!
Netsol Water collaborates with a wide range of international organizations to tackle complicated RO problems by strategically integrating modern treatment technology with practical solutions.
Call us if you want the best water treatment system for your home or business. Our services include Commercial RO Plants, Industrial RO Plants, STPs, ETPs, as well as a variety of useful after-sales services. Our professionals will check the customer's location first, then explain the available options and thus, allow you to select what is best for your property. You can always find useful information by liking and following us on YouTube and LinkedIn.
For further inquiries or product-purchase-related questions, give us a call on +91-9650608473 or email at email@example.com