The Chinese name of polyacrylamide (PAM) is polyacrylamide. PAM is a commonly used non-ionic polymer flocculant in China, with a molecular weight of 1.50 million-20 million and a commercial concentration of 8%. Organic polymer flocculants have a huge surface adsorption effect resulting from the formation of larger flocs between particles.
PAM has the water solubility of polymer compounds and the active acyl group on its main chain, so it has a wide range of applications in petroleum mining, water treatment, textile printing and dyeing, papermaking, mineral processing, coal washing, medicine, sugar, breeding, building materials, agriculture and other industries. It is called "100 industry additives" and "universal products".
Classification of different ion characteristics of PAM
Polyacrylamide can be divided into non-ionic, anionic, and cationic types according to its ionic characteristics.
Cationic polyacrylamide (CPAM): It is a linear polymer compound. Because it has a variety of active groups, it can form hydrogen bonds with affinity and adsorption of many substances. Mainly flocculate negatively charged colloids.
Anionic polyacrylamide (APAM): is a water-soluble polymer, mainly used for flocculation and sedimentation of various industrial wastewater, such as steel plant wastewater, electroplating plant wastewater, metallurgical wastewater, coal washing wastewater and other wastewater treatment, sludge dewatering, and can also be used for drinking water clarification and purification treatment.
Non-ionic polyacrylamide (NPAM): It is a high molecular polymer or polyelectrolyte. Its molecular chain contains a certain amount of polar genes that can adsorb solid particles suspended in water and form large flocculates by bridging between particles. It accelerates the sedimentation of particles in the suspension, has a very obvious effect of speeding up the clarification of the solution and promoting filtration.
There are so many types of PAM, how to choose one? Many people fall into these misunderstandings:
Misunderstanding 1
Q: When choosing polyacrylamide (PAM), many users believe that the higher the molecular weight of polyacrylamide, the higher the flocculation efficiency, and the better the effect. So is the higher the molecular weight, the better the effect?
A: Not necessarily. There are more than 100 types of polyacrylamide, and the wastewater produced by different enterprises has different properties. Some are acidic water, some are alkaline water, and some are neutral water. Some contain oil, some contain a lot of organic matter, some contain color, some contain a lot of sediment, and there are various situations. Not one type of polyacrylamide can solve all problems, and all wastewater of different water quality can be treated up to standard. It is necessary to select the type through experimental small tests, and then test on the machine to determine the best dosage to achieve the best effect with less use and low cost.
Misunderstanding 2
Q: Molecular weight and ionic degree are two important indicators of polyacrylamide (PAM), so is polyacrylamide mainly selected by the ionic degree in the industry?
A: Ionic degree refers to the negative and positive ionic charge of this chemical reagent, as well as its charge density. The higher the ionic degree, the smaller its molecular weight. At the same time, the higher the ionic degree, the higher the price of the product. Ionic degree affects the tightness and water content of the flocculation group of the product. Further tests are required during the selection process to determine the type of polyacrylamide required.
Misunderstanding 3
Q: The longer polyacrylamide (PAM) is dissolved and stirred, the better.
A: The appearance of polyacrylamide is white crystalline particles, generally between 60 and 80 mesh. It should be fully dissolved during use. Generally, the dissolution and stirring time should not be less than 30 minutes. When the temperature is low in winter, the dissolution and stirring time should be extended. Many times PAM is not fully dissolved due to the short dissolution and stirring time, and it cannot be effectively flocculated in sewage.
Misunderstanding 4
Q: Many users are not very familiar with the configuration concentration of polyacrylamide (PAM), and believe that the higher the concentration, the better the flocculation. Is this the correct operation?
A: The concentration of polyacrylamide is generally 0.1% -0.3%, which is suitable for flocculation and precipitation (depending on the molecular weight of PAM or according to the precipitation rate). The concentration of municipal and industrial sludge dewatering is between 0.2% and 0.5% (the concentration of sludge needs to be adjusted according to the concentration of sludge).
The concentration of PAM configuration depends entirely on the concentration of sewage and sludge. When the impurities in the sewage are too large, the concentration of polyacrylamide configuration should be increased. Excessive concentration will also affect the use effect, so be sure to do a good test to determine the reasonable dose before using the machine.
Myth 5
Q: Many users are confused about the ionic characteristics of polyacrylamide (PAM), and will not choose the ionic characteristics of polyacrylamide according to the actual situation.
A: As mentioned above, polyacrylamide models can be roughly divided into three types: anionic, cationic, and nonionic. Anionic is suitable for wastewater flocculation, precipitation, precipitation, clarification, etc., and can also be used for inorganic sludge dewatering; cationic polyacrylamide is suitable for flocculation, sedimentation, decolorization, clarification, etc. of complex water quality, municipal sludge dewatering, organic sludge dewatering, etc.; nonionic polyacrylamide is suitable for soil water retention, weak acid wastewater flocculation, sedimentation, dewatering, etc.