Polyelectrolyte

WHAT ARE POLYELECTROLYTES?

A polyelectrolyte is a long-chain organic polymer, either natural or synthetic, with a molecular weight generally exceeding one million. A series of repeating chemical units held together by covalent bonds is called a polymer molecule.

If the repeating units in a polymer molecule have the same molecular structure, the compound is called a homopolymer molecule.

However, if the molecule consists of more than one type of repeating chemical unit, it is called a copolymer. Each repeating unit that makes up the molecule is called a monomer.

The molecular weight of a polymer molecule is equal to the sum of the molecular weights of each repeating monomer unit. The degree of polymerization is the total number of monomer units.

Natural polymers generally include starch, vegetable gums, gelatin, and proteins. Egg white is also a natural polymer. The coagulant properties of such natural polymers have been known for many years. However, the important polymers commercially used in treatment processes are synthetic polymers, including high molecular weight Polyamines and Polyacrylamides.

In a polyelectrolyte, electrical charges arise from the presence of ionizable functional groups along the polymer chain. Consequently, polyelectrolytes are electrolytes with a polymeric structure. That is, they have both a polymer structure and an electrolyte structure. Therefore, these chemicals are called polyelectrolytes.

When the ionizable groups in polyelectrolytes dissociate, the polymer molecules become positively or negatively charged depending on the specific groups present.

Cationic Polyelectrolytes: Polyelectrolytes whose ionizable functional groups have a net positive charge are called cationic polyelectrolytes.

Anionic Polyelectrolytes: Polyelectrolytes whose ionizable functional groups have a net negative charge are called anionic polyelectrolytes.

Non-ionic Polyelectrolytes: Polyelectrolytes in which the positive and negative charges in their ionizable functional groups are equal are called non-ionic polyelectrolytes.

What are the Physical and Chemical Properties of Polyelectrolytes?

Commercial polyelectrolytes used in the aggregation of suspended matter are water-soluble. Polyelectrolytes can be found in granular form, powder form, or as high-viscosity liquids.

All polyelectrolytes on the market tend to degrade when stored for a certain period. The shelf life of polyelectrolytes is usually indicated to the user by the manufacturing companies. Polyelectrolytes are generally used after dilution. Using diluted polyelectrolytes will shorten their shelf life and increase their degradation rate.

The number of synthetic polyelectrolyte manufacturers is increasing with the expansion of their application areas. Synthetic polyelectrolytes have begun to be produced as competitors to traditionally used inorganic coagulants.

Density, Melting Point, Boiling Point, Solubility: Varies depending on the type.

What are the Application Areas of Polyelectrolytes?

• Used in Industrial Processes.
• Used in Industrial Wastewater Treatment Systems.
• Polyelectrolytes are used in Water Treatment Systems.
• Polyelectrolytes are used in Domestic Wastewater Treatment Systems.
• The use of polyelectrolytes in industrial processes includes the purification of raw sugar juice.
• Polyelectrolytes are used in the process of separating gypsum from wet-process phosphoric acid.
• Polyelectrolytes are used to improve the coal washing process.
• Polyelectrolytes are used to increase the thickener capacity in wet processing.
• Polyelectrolytes are used to separate clay contaminants from hot borax streams.
• Polyelectrolytes are used in electrolytic refining processes to improve the quality of metal deposition or to enhance copper and zinc electrowinning.
• Polyelectrolytes are used to improve thickening processes in uranium processing.
• Almost all industrial wastewaters are suitable for treatment using polyelectrolytes. Thus, polyelectrolytes play a key role in the treatment of industrial wastewater.
• Limitations can be placed on the usage amounts of polyelectrolytes in wastewater treatment.
• Anionic Polymer is used as a thickening agent in the manufacturing of drilling fluids.

What are the Advantages and Disadvantages of Using Polyelectrolytes?

The use of polyelectrolytes is effective at lower dosages compared to inorganic flocculants.

When using polymers, the amount of waste sludge produced will be smaller.

Processes using polyelectrolytes will mean less capital investment and expenditure.

In sedimentation processes using polymers, less space is required for settling tanks and their filters. This will reduce the use of valuable plant space for the treatment system.

One of the biggest disadvantages of polyelectrolytes is their price. They are much more expensive than inorganic coagulants.

Another major disadvantage of polyelectrolytes is that their exact mechanism of action is not fully understood. Polyelectrolytes are generally applied based on trial-and-error methods.

How are Polyelectrolytes Produced?

There are many production methods for polyelectrolytes.

We detail below a patented production process for polymer manufacturing.

A continuous photo-initiated polymerization process has been developed to produce Cationic, Anionic, and Non-ionic Polyelectrolytes.

In this system, polyelectrolytes are produced entirely in solid granular form.

Some key aspects of this polyelectrolyte production are as follows;

1. In the polymer production process, a monomer mixture containing various types of monomers, initiators, and chain terminators is first prepared in a water heater.
2. In the polymer production process, the aforementioned fed monomer is polymerized in a specially designed reactor to form a gel layer. That is, it is converted into a polymer.
3. In the polyelectrolyte production process, the gel layer is processed to form uniform granules.
4. In the polyelectrolyte production process, drying operations are performed to obtain the finished product as dry, free-flowing granules.

The main advantages of this polyelectrolyte production method are noteworthy.

• It is very easy to process.
• Molecular weight can be varied from low to very high by changing the feed composition.
• The product's composition is altered by using different monomers.
• Precise control of charge density is achieved because the monomer feed composition in polymer production is controlled only in the initial stages.
• In the polymer production process, the control of molecular weight distribution is a continuous process.
• No flammable or toxic solvents are used in polyelectrolyte production.
• No waste material is generated in polyelectrolyte production. It does not release noxious gases.
• No hazardous waste is produced.

In addition to the advantages above, a very clean product with low residual monomer content can be obtained through this polyelectrolyte production process. Therefore, polyelectrolytes produced with this system are also used in drinking water treatment systems.

Polyelectrolytes obtained from this production method have a long shelf life.

What Factors Affect Their Prices?

Polyelectrolyte prices are primarily directly proportional to the prices of the raw materials used in their production. As the prices of raw materials used in polymer manufacturing increase, the price of polyelectrolytes will also increase.

Wholesale prices of polyelectrolytes generally depend on the purchased quantity. The wholesale price also depends on the concentration. For this reason, companies selling polymers sometimes lower the concentration of the polyelectrolytes. By doing so, they can offer more polymer for sale and earn more money.

Companies that sell polyelectrolytes are generally firms that provide consultancy services to industrial sectors. In fact, companies selling polyelectrolytes are firms that offer consultancy services to the end-user.

The price of a polymer also depends on its production method. Different pricing policies are applied for different production methods.

Polyelectrolyte prices are increasing as their areas of application expand. This is because the supply-demand balance has been disrupted. The proliferation of polyelectrolyte applications and government directives on wastewater treatment have directly impacted polyelectrolyte prices.

The unit prices of polyelectrolytes have increased fivefold in the last 10 years. This is because many companies that produce wastewater have adopted controlled waste management. Consequently, the wholesale price of polyelectrolytes will increase depending on legislation and regular inspections.

Polymers are chemicals that should be applied with expert advice. Therefore, before applying treatment to your specific waters, seek support from O Kimya Experts. Because at O Kimya, we provide the most suitable standards. At O Kimya, by managing the application with an optimal level of chemical consumption, we also reduce your waste costs for the sludge produced.