Polyacrylamide (PAM) is a water-soluble linear high-molecular polymer formed by free radical polymerization of acrylamide monomer. At the same time, it is also a kind of polymer water treatment flocculant, which can absorb suspended particles in the water and act as a link and bridge between the particles, so that the fine particles form relatively large flocs and accelerate the speed of sedimentation.
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 greater the molecular weight, the better the effect?
This is not necessarily the case. Polyacrylamide has more than 100 models. The sewage produced by different companies has different properties, some are acidic, some are alkaline, and some are neutral, some contain oily dirt, some contain a lot of organic matter, and some contain Color, some contain a lot of sand, and there are various situations. Not one type of polyacrylamide can solve all problems, and all sewage of different water quality can be treated up to standards. It is necessary to select the model through a small experiment, and then test on the machine to determine the optimal dosage, so as to achieve the best effect of less dosage and low cost.
Molecular weight and ionicity are two important indicators of PAM, so is polyacrylamide in the industry mainly selected by the level of ionicity?
Ionicity refers to the negative and positive ionic charge of this chemical reagent, and its charge density. The higher the ionicity, the smaller the molecular weight, and the higher the ionicity, the higher the price of the product. The ionicity has an impact on the compactness and water content of the flocculation group of the product. Further tests are still needed in the selection process to determine the type of polyacrylamide needed.
The longer PAM dissolving and stirring, the better?
The appearance of polyacrylamide is white crystalline particles, generally between 60-80 mesh. It should be fully dissolved during use. Generally, the dissolution and stirring time should not be less than 30 minutes. When the temperature in winter is low, the dissolution and stirring time should be extended.
In many cases, PAM is not fully dissolved due to too short dissolution and stirring time, and rapid flocculation cannot be effectively carried out in sewage.
Many users don’t know the configuration concentration of PAM very well. They think that the higher the concentration, the better the flocculation. Is this the correct?
The concentration of polyacrylamide is generally 0.1%-0.3%, which is suitable for flocculation and sedimentation (depending on the molecular weight of PAM or the sedimentation speed). When urban and industrial sludge is dewatered, the configuration concentration is between 0.2%-0.5% (the configuration concentration needs to be adjusted according to the sludge concentration).
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 effect of use, so be sure to do a test to determine a reasonable dose before using it on the machine.
Many users are very vague about the ionic characteristics of polyacrylamide (PAM), and will not choose the ionic characteristics of polyacrylamide according to the actual type?
Polyacrylamide models can be roughly divided into three types: anionic, cationic, and non-ionic. Anionic is suitable for sewage flocculation, sedimentation, assisting, clarification, etc., and can also be used for inorganic sludge dewatering. Cationic is suitable for flocculation, sedimentation, decolorization, clarification of complex water quality, municipal sludge dewatering, organic sludge dewatering, etc. Non-ionic polyacrylamide is suitable for soil water retention, weak acid sewage flocculation, sedimentation, dehydration, etc.