polyelectrolyte

polyelectrolyte (Floculant) is an organic chemical. It is widely used for flocculation in water treatment. It is used in drinking and utility water treatment, wastewater treatment and sludge dewatering.

Polyelectrolytes; They can be grouped as anionic, cationic and non-ionic polyelectrolyte (flocculant). Anionic polyelectrolyte minus (-), cationic polyelectrolyte It has a positive (+) electrical charge and non-ionic polyelectrolytes do not contain an electrical charge. Polyelectrolytes have the feature of first converging the solids (particles, AKM or dense activated sludge) in the water by means of electrical attraction, then flocculating and making them heavy and separating them from the water by precipitating. When used in the right proportions, all of them are in the mud together with the precipitated particles, and they do not remain in the purified water.

Cationic Polyelectrolyte

Cationic polyelectrolyte It is widely used in sludge dewatering units of wastewater treatment plants.

In processes where sludge is dewatered with centrifugal decanter, belt press or filter press, cationic polyelectrolyte, which is mixed with the help of a static mixer, is dosed into the pressurized sludge line.

The working principle of the cationic polyelectrolyte product is generally based on ion exchange between the polymer chain in the aqueous solution and the electrical charges of the solid particles in the suspended solid state. The stable structures of solid particles are disrupted, which coagulation or to flocculation leads to

Cationic polyelectrolytes are diluted from %0.05 to %0.5. The preparation solution is generally prepared as %0.1-%0.2 by adding the powdered product to water during mixing. Since the characteristics of the sludge to be dewatered are different, the dosages to be applied are determined as a result of the jar test and operational trials in the laboratory environment.

Anionic Polyelectrolyte

Powdered polyelectrolytes are polyelectrolytes with a particle size of up to 2 mm and their physical form in the appearance of granulated sugar. Powder polyelectrolytes are divided into three categories as anionic, cationic and non-ionic according to the charge characteristics they carry. Powdered polyelectrolytes are not used in the forms they are supplied, they are dosed into the stream from the appropriate point after their solutions are formed with water.

Anionic polyelectrolytes They are polyelectrolyte derivatives that are used as flocculant in the treatment of KOI, AKM, heavy metals and colloids in water treatment processes generally originating from chemical treatment and mining activities, and in ore recovery. In very rare cases, in some exceptional processes sludge dewatering It is possible to see that they are used in the process.

Polyelectrolyte Product Forms

Polyelectrolytes (Floculants) are produced in powder (granule) form and as liquid. Even powdered polyelectrolytes are used as liquid solutions after dissolving in water.

Polyelectrolyte is available in different product forms as listed below.

1. powder / granule
2. bead
3. emulsion
4. liquid dispersion (LDP)
5. aqueous solutions (solution)

Form	polymer content	Composition	Shelf life
powder / bead	% 100	Powder or microbead	3 years
liquid dispersion	% 50	oil	1 year
emulsion	% 20-40	oil + water	9 months
solution	% 3-7	That	3 months

Polyelectrolyte Properties

Polyelectrolytes (flocculant) are the main features that distinguish them from each other are their molecular weights, charges and physical states. Laboratory tests should be done in order to make product selection. After the plant applications, the suitable product can be determined for sure.

• Ionic character: anionic, cationic or non-ionic

Charge density is controlled by co-polymerization of uncharged and charged monomers in varying proportions.

It can be produced from low to high anionic or cationic charge as a result of copolymerization of ionic monomer with non-ionic monomer.

• Molecular weight: (polymer chain length)

The molecular weight varies by changing the chain length.

General Use of Polyelectrolytes and Considerations in Plant Operation

• The ideal water quality recommended for polyelectrolyte solutions should be drinking water and close to it. Otherwise, calcification, slime formation and odor problems may occur in the tanks and pipelines. As a result, there may be blockages in the pumps and lines. Particles can cause clogging of solenoid valves and filters.
• Polymer preparation units are the most important units that enable the preparation of the polyelectrolyte at the desired concentration. The superior performance of the polyelectrolyte depends on the full efficiency of these units. Although polyelectrolyte is the most suitable and highest quality product, it will not be able to experience the required performance if it cannot be dissolved in the desired consistency.
• The polyelectrolyte preparation units supplied in recent years have been designed according to the automatic system and are extremely reliable in terms of concentration sensitivity. In these systems, the mixers available in each chamber should always be in operating position while the product is being prepared and dosed into the system.

Considerations in Facility Operation

• polyelectrolyteSince it can damage aluminum and galvanized steel, contact with these materials should be avoided. Areas where commercial products are stored should not be exposed to excessive heat and humidity. Polyelectrolyte becomes quite slippery when it comes into contact with water, so care should be taken not to spill the product on the ground. If spilled on the ground, it should be surrounded with sand, sawdust and salt, and should be collected and disposed of after a certain period of time.
• Persons in contact with polylektrolit should wear protective clothing, goggles and gloves, and in case of splashes on hands, eyes and face, wash with plenty of water and seek medical attention. The dust that comes out during the discharge of the product to the preparation unit should never be inhaled, and a mask should be used as a precaution.
• Due to its hygroscopic feature, the product is sensitive enough to hold even the humidity in the air, and humidity causes the product to clump and deteriorate. The best way to store the product is to keep it in a tightly closed package, in a moisture-free environment.
• In order for the powdered product to be used in its most efficient form, it must be consumed within 2 years. In order for the product in solution to be used in its most efficient form, it should be consumed within 3-4 days.
• Considering that clearer water can be obtained, polyelectrolyte solution should not be given to the facility more than necessary. Because, on the contrary, excessive use of the product causes turbidity in the water.
• During the contact of the solution with the waste water, excessive mixing time and intensity should be avoided. Otherwise, the resulting flocks will be broken.

Usage Areas of Polyelectrolytes in Industry

• Marble, Granite, Ceramic group
• Food (chicken-meat-fish-milk integrated facilities, beverage, canned food, sugar production)
• Energy facilities, thermal power plants
• Automobile industry
• Leather manufacturers
• Textile
• Paper manufacturers
• Glass-rubber industry
• Mining sector (gold-boron-coal mines etc.)
• Pharmaceutical and chemical industry
• Municipalities and OIZ waste water treatment plants

Polyelectrolyte Frequently Asked Questions

1 – How to choose a polyelectrolyte?

The most important criterion when choosing a polyelectrolyte is the waste water character. As a result of the JAR tests carried out in Solechem laboratories, the most suitable polyelectrolyte is selected after the wastewater character analysis.

2 – How are polyelectrolyte prices calculated?

Polyelectrolyte pricing varies according to ion charges. The lower the ion charge, the higher the polymer prices. The ion charge is calculated as a result of the JAR test.

3 – How is the consumption calculated in the use of polyelectrolyte?

The higher the solids content in the wastewater, the higher the amount of polyelectrolyte to be used. Another factor that determines the amount to be used is the selection of the appropriate polyelectrolyte.

4 – What physical form do polyelectrolytes take?

Polyelectrolytes can exist in solid or liquid forms. The use of polyelectrolytes in solid form is more economical and more efficient than liquid forms.

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