June 9, 2022     Posted by :

Water treatment machine before saying the role of reverse osmosis antiscalant, a brief description of the reverse osmosis system: reverse osmosis water treatment machine is the raw water through the precision filter, particle activated carbon filter, compressed activated carbon filter, etc., and then pressurized by the pump, the use of pore size of 1/10000μm (equivalent to 1/6000 of the size of E. coli, 1/300 of the virus) of the reverse osmosis membrane (RO membrane), so that the higher High concentration of water into the low concentration of water, while industrial pollutants, heavy metals, bacteria, viruses and a large number of impurities mixed into the water all isolated, water treatment machine so as to achieve the drinking provisions of the physical and chemical indicators and health standards, the output to the pure water, is the best choice for the human body to replenish quality water in a timely manner.

As RO reverse osmosis technology produces the highest purity of water in all the water technology mastered by mankind, the cleanliness is almost 100%.


Reverse osmosis membrane is the key equipment of the reverse osmosis system, the system for a long time in continuous operation, calcium and magnesium plasma in the water will continue to precipitate and adhere to the surface of the reverse osmosis membrane, and the formation of scaling blocking the membrane pores, which will affect the efficiency of the reverse osmosis system water, damage the reverse osmosis membrane.

Because the reverse osmosis membrane is more expensive, in the operation of the system, to add a dosing system, a water treatment machine in the water with reverse osmosis scale inhibitor to delay the precipitation of calcium and magnesium ions and membrane surface fouling.

Reverse osmosis antiscalant is specially used for reverse osmosis (RO) system and nanofiltration (NF) and ultrafiltration (UF) system antiscalants, can prevent membrane surface fouling, can improve water production and water quality, and reduce operating costs.


① Effective control of inorganic fouling in a wide concentration range

② Does not coalesce with iron and aluminum oxides and silicon compounds to form insoluble substances

③ Effectively inhibits the aggregation and deposition of silicon, and the concentration of SiO2 on the concentrated water side can reach 290 ppm

④ Can be used in reverse osmosis CA and TFC membranes, nanofiltration membranes, and ultrafiltration membranes

⑤ Excellent solubility and stability

⑥ Effective in feed water pH range of 5-10

The basic role of reverse osmosis antiscalant

① Complex and solubilization role: reverse osmosis antiscalant dissolved in water ionization, the generation of negatively charged molecular chain, it and Ca2 to form a water-soluble complex or chelate, so that the solubility of inorganic salts increased, to play the role of scale inhibition.

② Lattice distortion: some functional groups in the molecule of reverse osmosis antiscalant occupy a certain position on the inorganic salt nuclei or microcrystals, which hinders and destroys the normal growth of inorganic salt crystals and slows down the growth rate of crystals, thus reducing the formation of salt scale;

③ electrostatic repulsive effect: reverse osmosis antiscalant dissolved in water adsorbed on the microcrystals of inorganic salts, so that the repulsive force between particles increases, hindering their agglomeration, so that they are in a good state of dispersion, thus preventing or reducing the formation of scale.

Reverse osmosis antiscalant function type and application reverse osmosis scale inhibitor is used for reverse osmosis and nanofiltration system performance improvement

antiscalant and dispersants are a series of chemicals used to stop the precipitation of crystalline mineral salts and scale formation.

Antiscalant function

⑴, Inhibit precipitation function in the system with antiscalant  easy structure components of the anion and cation and anion precipitation when the ion product value is much larger than the critical precipitation ion product value when there is no antiscalant

⑵, Dispersion functions in the presence of antiscalant because the particles precipitated by the small particle size are more difficult to coalesce than when there is no antiscalant precipitated particles difficult to sink.

⑶, Lattice deformation effect in the system with antiscalant precipitated crystals have spherical, polyhedral, snowflake and other indefinite state are generally considered indefinite crystal is in the crystal growth process scale inhibitor adsorbed in the crystal growth point so that the growth rate of its surface drops sharply to grow crystals different from the original shape of the crystal.

⑷, Low limit effect antiscalant dosage is equivalent to the water scaling components much lower can also show the scale inhibition effect.

Application of RO antiscalant

Application of RO antiscalant

❶, The use of polyacrylic acid scale inhibitor to be particularly careful in the high iron content may cause membrane contamination this contamination will increase the operating pressure of the membrane to effectively remove this type of contamination to acid cleaning.

❷, If in the pretreatment used cationic coagulant or filtering aid in the use of anionic scale inhibitor to pay special attention. Will produce sticky viscous contaminant pollution will cause increased operating pressure and this contaminant cleaning is very difficult.

❸, Antiscalant hinders the growth of salt crystals in RO feed water and concentrated water, thus allowing insoluble salts to exceed saturation solubility in concentrated water. The use of antiscalant can be used instead of acid addition or in conjunction with acid addition. There are many factors that affect the formation of mineral scaling.

A decrease in temperature will reduce the solubility of scaling minerals except for calcium carbonate, whose solubility decreases with increasing temperature in contrast to most substances, and the increase in TDS will increase the solubility of insoluble salts because the high ionic strength interferes with the formation of crystalline species.

❹, The ideal amount of addition and the maximum saturation of scaling substances and contaminants is best determined by a special software package provided by the pharmaceutical supplier. Excessive addition of antiscalant /dispersant can lead to the formation of deposits on the membrane surface causing new contamination problems.

Be sure to rinse out the antiscalant and dispersant thoroughly during shutdown or it will remain on the membrane and cause contamination problems. Stop injecting antiscalant and dispersant into the system when using RO feed water for low-pressure flushing.

❺, The design of the antiscalant /dispersant injection system should ensure that the RO element is fully mixed before the static mixer is a very effective mixing method. The injection point of most systems is located before the RO inlet security filter to promote mixing through buffering time in the filter and agitation of the RO inlet pump.

If the system uses acid addition to adjust pH it is recommended that the acid addition point be far enough upstream to be fully mixed before reaching the antiscalant /dispersant injection point.

the antiscalant dispersant injection system

❻,  The dosing pump for injecting antiscalant /dispersant should be set to the maximum injection rate. The recommended injection rate is at least once every 5 seconds. The typical dosage of antiscalant /dispersant is 2-5ppm, and dilution is required to allow the dosing pump to operate at the highest frequency. antiscalant /dispersant products are available as concentrates or solid powders.

The extent to which diluted antiscalant /dispersant can be contaminated by biological contamination in the storage tank depends on the room temperature and the dilution level. The recommended retention time for diluted solutions is about 7-10 days. Under normal conditions, undiluted scale inhibitor/dispersant is not subject to biological contamination.

Another major issue in selecting a scale inhibitor/dispersant is to ensure full compatibility with the reverse osmosis membrane. Incompatible agents can cause irreversible damage to the membrane.

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