Classification of water treatment agents

According to the function of water treatment agents, it is generally divided into four kinds: first, flocculant; 2. Corrosion and scale inhibitor; 3. Cleaning pre-film agent; 4. Bactericidal and algicide;　

The basic introduction of the five categories of water treatment reagents:

　　一、Flocculant：

A water treatment agent that can remove or reduce turbidity and SS suspended matter in water and accelerate the precipitation of impurities. The common function of the flocculant is to separate the impurities in the water, and then aggregate them together, precipitate them into the precipitation equipment, and discharge them with the sewage system in order to achieve the safe operation of the equipment and the purpose of improving the water quality. The use of efficient flocculants in urban sewage can greatly remove COD, the removal rate of up to 99% is an inorganic flocculant can be said to be an early category, such as alum, ferric chloride and so on. The basic flocculants we use are organic and polymer flocculants, which are now commonly used in water treatment agents, and are widely recognized by everyone. Such as carboxymethyl cellulose, sodium polyacrylate, etc.; Cationic flocculants, such as polyvinylamine, etc. The principle of this type of agent is to achieve the effect of adsorption, aggregation and holding by neutralizing the charge in the water. In industrial water treatment, flocculants are widely used in turbidity ring water system, and the effect of use is very obvious, especially the wet dust removal system, which can basically play an immediate effect.

　　二、Corrosion and scale inhibitor：

This kind of agent can be divided into: slow release agent, scale inhibitor. However, the current pharmaceutical products are basically products that integrate the two functions of slow release and scale inhibition. It is usually used in soft water, because the PH value of soft water is acidic, it is easy to copy the internal surface of the system, especially when the water temperature is high, it is easier to corrode the metal material of the heating surface, and when the system is corroded, it will produce safety risks, so it is necessary to add such agents to the equipment after soft water, protect the equipment and extend the service life of the equipment. To achieve the purpose of safe production.

Because the general system uses soft water, the water is basically above 30 degrees, and some even reach Baidu, so the water in this kind of system is very easy to produce scale, scale attached to the equipment or the inner wall of the water pipe, and will produce scale corrosion, if the treatment is not timely, with the passage of time, it is easy to occur system and pipe wall corrosion perforation, seriously affecting the safety of production.　

Corrosion inhibitor: When the corrosion inhibitor reaches a certain concentration, it can form a thin protective film on the inner wall of the tube wall equipment, which is generally called passivation film type, precipitation film type and adsorption film type, which can prevent corrosion. The dosage is small, and the effect is obvious. The corrosion inhibitors of passivated film water treatment include chromate, nitrite, molybdate, etc. The corrosion inhibitors of precipitated film type water treatment include polyphosphate, zinc salt, etc. Commonly used adsorption film type corrosion inhibitors such as organic amines.

Scale inhibitor: also known as scale inhibitor, can prevent calcium magnesium and other substances in water from forming scale. We usually choose scale inhibitors are:

1、EDTMP(ethylenediamine tetramethylene phosphonic acid), HEDP(hydroxyethyldiphosphonic acid)

2、Polyacrylate, hydrolyzed polymaleic anhydride.

Polyacrylate and hydrolyzed polymaleic anhydride are widely used in boiler water and industrial cooling water systems.

三、Clean the pre-film agent：

A cleaning agent is a volatile solvent that can dissolve the permeate and is used to remove excess permeate from the surface of the workpiece under test. Some cleaning agents are specifically designed to remove metal hydroxides, calcium carbonate and other similar scales attached to the surface of polyamides, polysulfones and film components. Check the cleaning tank, piping and security filter and install a new filter element before using the cleaning agent.　

In our water treatment work, we generally need to pre-treat first, at this time, we need to use some chemicals to clean the surface of the metal material equipment, some substances that can not be removed by usual methods. Such as corrosion products and scale and microbial slime. Cleaning agents can be divided into acid washing agents such as hydrochloric acid, sulfuric acid, hydrofluoric acid, citric acid, etc. Passivating agents such as sodium benzoate. At present, the sulphonated di(α-ethylhexyl) sodium salt used is a surfactant, which is used as a special cleaning agent for cleaning impurities such as oil and rust on the metal surface.　　

In our real work, it is generally for the new system to clean, the new system has various impurities, sludge, we have to clean the system with cleaning agent, and then use the pre-film agent to coat the equipment. If the system is not cleaned directly using the pre-film agent, the dirt can not be removed, and the effect is greatly reduced. Therefore, cleaning agents are not used for surface treatment of equipment, and the biggest prospect is cleaning inside the system and inside the pipeline. Reasonable use of cleaning agents with other agents, often can achieve very good results.　　

四、Bactericide and algaecide：

An agent that acts primarily on microorganisms, killing bacteria and inactivating sanitary households. It can inhibit the growth of bacteria and algae in water.　　

Bactericidal algaecide, also known as bactericidal algaecide or sludge stripping agent, anti-sludge agent, etc., directly inhibit the growth of microorganisms such as bacteria and algae in water to prevent the formation of microbial mud chemicals.　　

Bactericides are divided into two categories: oxidizing bactericides and non-oxidizing bactericides.

Oxidizing fungicides commonly used some chlorine gas, sodium hypochlorite, bleaching powder, etc.

Non-oxidizing fungicides are more expensive than oxidizing ones, and the effect is better than oxidizing ones, which directly destroy and kill bacterial cells. Commonly used types are, such as quaternary ammonium salts. Quaternary ammonium salts such as dodecyl dimethyl benzyl ammonium chloride or dodecyl dimethyl benzyl ammonium bromide, etc., we often add other products in non-oxidizing agents, so that it becomes a composite product, so that it has a variety of functions such as sterilization, stripping, corrosion inhibition.　　

In fact, water treatment agents should be strictly classified, or many, commonly used is basically the above four categories, in the general water treatment of the above class