How to Select Cationic and Anionic Polyacrylamide?

With the emphasis on environmental protection in recent years, polyacrylamide is widely used in the sewage treatment industry and the petroleum industry, and its consumption is also increasing. In order to give full play to the best effect of polyacrylamide, it is necessary to further understand it, including its principle, application effect and what factors affect it in use.

1. Selection of cationic polyacrylamide

Polyacrylamide cations are positively charged and are mainly used to flocculate negatively charged colloids. Its main function is to absorb suspended solids, decolorize sewage and remove turbidity. Cationics are mainly used in wastewater treatment industries with high colloid content, such as printing and dyeing, papermaking, beverages, oil fields, mineral processing, food, metallurgy and so on. Cationics are ideal for treating municipal wastewater, papermaking wastewater, and sludge dewatering in other industries.

The application of cationic polyacrylamide in sludge treatment is very common. At present, a large number of enterprises will consider the use of cationic polyacrylamide when dealing with sludge, and its application effect is really good. The application effect of product performance, component content and other aspects is very good, and the main components contained in it are also very different. There are some small differences between organic sludge and inorganic sludge, which are very important to the human body, and the corresponding actual situation should also be considered.

Selecting the appropriate ion concentration can make the effect better. Now, we must pay attention to the ionicity of cationic polyacrylamide for sludge dewatering treatment to ensure that we can do a good job of screening, select the most suitable products, so that the flocculation effect is the best, and the corresponding application effect can also be appropriately reduced.

2. Selection of anionic polyacrylamide

Polyacrylamide anion is a highly water-soluble polymer, mainly used for flocculation, precipitation and clarification of various industrial wastewaters. Such as iron and steel plant wastewater, electroplating plant wastewater, metallurgical wastewater, coal washing wastewater and so on. It can also be used for clarification and purification of drinking water. Since its molecular chain contains a certain number of polar groups, it can bridge particles by adsorbing solid particles suspended in water, or agglomerate particles to form large flocs by charge neutralization. Therefore, the sedimentation of floating particles can be accelerated, and it has obvious functions of accelerating solution clarification and promoting filtration. The main functions of anions are clarification and purification, settlement promotion, promotion of filtration, thickening and so on. The factors affecting its use effect are hydraulic conditions. During coagulation, hydraulic conditions have a great influence on the formation of polyacrylamide flocs. The whole coagulation process can be divided into two stages: the feed mixing stage and the reaction stage, both of which require good hydraulic conditions.

Water temperature affects the hydrolysis of anionic polyacrylamide and the formation of flocs. For example, the water temperature is low, the hydrolysis rate is slow, the viscosity of water is high, the Brownian motion is weakened, and it is not easy to form flocs, which are small and loose, and difficult to settle. This effect is particularly pronounced for polymeric alumina. Although high water temperature is beneficial for coagulation, it is difficult to increase the water temperature in the actual wastewater treatment process. If the water contains positive ions with more than two valences, it is conducive to the instability of negatively charged colloidal particles in the water source water. Impurity particles of different sizes are favorable for agglomeration. When the particle size is small and uniform, the coagulation effect is poor. If the impurity concentration is too low, it is not conducive to the collision between particles, and it is difficult to form agglomerated particles.