I would like to ask fellow users about the usage methods and precautions for polyacrylamide

Introduction to Polyacrylamide Polyacrylamide, abbreviated as PAM, is formed by the polymerization of acrylamide monomers and is a water-soluble linear polymer. The monomer acrylamide has highly reactive chemical properties; a range of chemical reactions can occur at its double bond and amide group. By using different processes to introduce various functional groups, polymers with different charges can be obtained: anionic, cationic, non-ionic, and amphoteric polyacrylamides. The average molecular weight of PAM ranges from several thousand to tens of millions; it possesses several functional groups along its chain structure, can be largely ionized in water, and belongs to the category of polymeric electrolytes. Based on the properties of their dissociable groups, they are classified into anionic types (such as --COOH, --SO3H, --OSO3H, etc.), cationic types (such as --NH3OH, --NH2OH, -CONH3OH), and non-ionic types. The product appears as a white powder; it is soluble in water and practically insoluble in benzene, ether, esters, propylene glycol, and other common organic solvents. Its aqueous solution is a nearly transparent viscous liquid. It is not considered a hazardous substance, being non-toxic and non-corrosive. The solid form of PAM is hygroscopic, with this hygroscopicity increasing as the ionic strength rises. PAM has good thermal stability ； It maintains good stability at 100°C, but decomposes easily at temperatures above 150°C to produce nitrogen, undergoing imination between molecules and becoming insoluble in water; its density is 1.302 g/mL at 23°C. The glass transition temperature is 153°C, and PAM exhibits non-Newtonian flow behavior under stress. Usage properties 　　1) Flocculation: PAM enables suspended substances to be flocculated through electroneutralization and bridging adsorption. 　　2) Adhesiveness: It can exert adhesive effects through mechanical, physical, and chemical means. 　　3) Resistance reduction: PAM can effectively reduce the frictional resistance of fluids; adding a small amount of PAM to water can reduce resistance by 50–80%. 　　4) Thixotropy: PAM exhibits thixotropic properties under both neutral and acidic conditions; it tends to hydrolyze when the pH is above 10. When it is in a semi-network structure, thickening will be more pronounced. Brief introduction to the working principle of PAM 1) Flocculation principle: When PAM is used for flocculation, it is related to the surface properties of the substances to be flocculated, particularly their zeta potential, viscosity, turbidity, and the pH value of the suspension. The zeta potential on the particle surface is what prevents particles from aggregating; by adding PAM with an opposite surface charge, this zeta potential can be reduced rapidly, thereby facilitating aggregation. 　　2) Adsorption bridging: PAM molecular chains are anchored to the surfaces of different particles, and polymer bridges are formed between these particles, causing the particles to aggregate and settle. 　　3) Surface adsorption: Various adsorptions of particles onto the polar groups on PAM molecules. 　　4) Reinforcing effect: The PAM molecular chains bind the dispersed phase together through various mechanical, physical, and chemical mechanisms, forming a network that thus provides a reinforcing effect. Classification Introduction Polyacrylamide can be classified into cationic polyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide, and non-ionic polyacrylamide based on the charge properties of its molecules. 　　 Anionic polyacrylamide 　　　　 1. Primarily used as a flocculant: For suspended particles that are relatively large, highly concentrated, carry a positive charge, and are present in wastewater with a neutral or alkaline pH value, the polar groups contained in the molecular chains of anionic polyacrylamide enable it to adsorb the solid particles suspended in the water, thereby facilitating the formation of larger flocculates through bridging between these particles. Therefore, it accelerates the sedimentation of particles in the suspension, significantly speeding up the clarification of the solution and facilitating filtration. This product is widely used in the treatment of chemical industry wastewater and effluents, as well as in municipal sewage treatment. Water treatment for the tap water industry, purification of water with high turbidity, sedimentation, coal washing, mineral processing, metallurgy, the steel industry, zinc and aluminum processing industries, and the electronics industry. 　2. It is widely used in the petroleum industry for oil extraction, drilling muds, waste mud treatment, preventing water intrusion, reducing friction, improving recovery rates, and tertiary oil recovery. 　3. Used as a textile sizing agent; it provides stable sizing properties, reduces sludge formation, lowers fabric breakage rates, and gives the fabric a smooth surface. 　4. Used in the paper industry, firstly to improve the retention rate of fillers, pigments, etc. To reduce the loss of raw materials and environmental pollution ； Secondly, it improves the strength of the paper (both dry and wet strength). In addition, the use of PAM can enhance the tear resistance and porosity of the paper, thereby improving its visual and printing properties; it is also used in packaging for food and tea. 　5. Other industries, the food industry: used for clarifying sugarcane juice and for the phosphorus flotation extraction of syrups in the production of sucrose and beet sugar. It is used in the industrial process of flocculating and clarifying enzyme preparation fermentation broths; it is also employed for the recovery of feed protein, ensuring stability in quality and excellent performance. The recovered protein powder has no adverse effects on the survival rate, weight gain, or egg production of chickens. It finds application in synthetic resin coatings, civil engineering grouting materials for water sealing, the construction materials industry to improve cement quality, as well as in adhesives for the construction industry, for filling cracks and sealing leaks. Additionally, it is used in soil improvement, the electroplating industry, and the printing and dyeing industry. 　　 Cationic polyacrylamide 　　　Cationic polyacrylamide exhibits positive charge in both acidic and alkaline media. It usually has a lower molecular weight than anionic or non-ionic polyacrylamides, and its ability to clarify wastewater is achieved primarily through charge neutralization. The main function of such flocculants is to flocculate negatively charged substances, and they have the capabilities of removing turbidity and decolorizing. In the treatment of wastewater from alcohol plants, monosodium glutamate factories, sugar mills, meat processing plants, beverage factories, printing and dyeing plants, etc., cationic polyacrylamide is far more effective than anionic polyacrylamide, non-ionic polyacrylamide, or inorganic salts, by several times or even dozens of times, as this type of wastewater generally carries a negative charge. Currently, by using water-soluble azo initiators such as AIBA, its molecular weight can be increased to over ten million. 　　Cationic polyacrylamide is suitable for specialized sludge dewatering equipment such as high-speed centrifuges, belt filter presses, and plate and frame filter presses. It features a fast flocculation rate, large floccules, resistance to compression and shear, good flocculation properties, and easy separation from the filter fabric. Therefore, the dehydration rate is high, the liquid content in the filter cake is low, and less amount is required, which can **reduce the usage costs for users**. It can also be used with liquids such as hydrochloric acid and medium-concentration sulfuric acid to separate and purify the suspended substances contained in them. Therefore, this product is widely used in sludge dewatering processes in urban sewage treatment plants, breweries, food factories, tanneries, paper mills, petrochemical plants, oil fields, the metallurgical industry, the chemical industry, and the cosmetics sector. 　　 Non-ionic polyacrylamide 　　　　　1. Mainly used as a flocculant: Due to the presence of a certain amount of polar groups in its molecular chain, it is capable of adsorbing suspended solid particles in water, thereby forming large flocculates between these particles. It accelerates the settling of particles in suspensions, significantly speeds up the clarification of solutions, and promotes filtration; it is widely used in the treatment of wastewater and waste fluids in the chemical industry as well as in municipal sewage treatment. This product is particularly suitable when the wastewater is acidic. It can be used in combination with inorganic flocculants such as polyferric and polyaluminum salts. 　　2. It is widely used in the petroleum industry for oil extraction, drilling muds, waste mud treatment, preventing water intrusion, reducing friction, improving recovery rates, and tertiary oil recovery. 　 　　3. Used as a textile sizing agent; it provides stable sizing properties, reduces sludge formation, lowers fabric breakage rates, and gives the fabric a smooth surface. 　　4. Used in the paper industry, firstly to improve the retention rate of fillers, pigments, etc. To reduce the loss of raw materials and environmental pollution ； Secondly, it improves the strength of the paper (both dry and wet strength). In addition, the use of PAM can enhance the tear resistance and porosity of the paper, thereby improving its visual and printing properties; it is also used in packaging for food and tea. 　　5. Other industries, the food industry: used for clarifying sugarcane juice and for the phosphorus flotation extraction of syrups in the production of sucrose and beet sugar. It is used in the industrial process of flocculating and clarifying enzyme preparation fermentation broths; it is also employed for the recovery of feed protein, ensuring stability in quality and excellent performance. The recovered protein powder has no adverse effects on the survival rate, weight gain, or egg production of chickens. It finds application in synthetic resin coatings, civil engineering grouting materials for water sealing, the construction materials industry to improve cement quality, as well as in adhesives for the construction industry, for filling cracks and sealing leaks. Additionally, it is used in soil improvement, the electroplating industry, and the printing and dyeing industry. 　　 Amphoteric polyacrylamide Product form: Amphoteric polyacrylamide (ACPAM) appears as white powder particles. 　　Product features: Amphoteric polyacrylamide, due to the presence of cationic and anionic groups within its molecule, possesses the properties typical of conventional cationic flocculants, while also exhibiting superior performance. Such flocculants can be used over a wide range of pH values; they offer a higher filtration capacity and a lower moisture content in the filter cake. They can also be used for acid leaching of ores or for recovering valuable metals from acidic catalysts containing metals. Zwitterionic is by no means a mixture of anionic and cationic. If cationic polyacrylamide and anionic polyacrylamide are used together, a reaction occurs that results in the formation of precipitate. Therefore, zwitterionic products are the most ideal. 　　Primary uses: It is used as a profile control and water shutoff agent in oil fields; when combined with crosslinking agents, stabilizers, and coagulants, it forms high-strength coagulant gels that serve as effective water shutoff agents, possessing significant polymeric and resinous gel properties. It blocks the pore spaces and fractures in the formation through adhesion, physical obstruction, etc.; by adjusting the proportions, it allows the gel time to be controlled to suit different geological conditions. Treatment of various types of oil contaminants, organic and inorganic substances, wastewater, and complex wastewater. In wastewater systems with unstable pH levels. Used for sludge dewatering. Used as a papermaking additive. 　　Packaging, storage, and precautions: This product is non-toxic; please keep it away from moisture and rain, and avoid exposure to direct sunlight. Shelf life: 2 years, in 25kg paper bags (lined with plastic bags and covered with plastic-coated kraft paper bags). The stack height should not exceed 10 layers. Usage properties: 1) Flocculation: PAM enables suspended particles to be flocculated through electroneutralization and bridging adsorption. 　　2) Adhesiveness: It can exert adhesive effects through mechanical, physical, and chemical means. 　　3) Resistance reduction: PAM can effectively reduce the frictional resistance of fluids; adding a small amount of PAM to water can reduce resistance by 50–80%. 　　4) Thixotropy: PAM exhibits thixotropic properties under both neutral and acidic conditions; it tends to hydrolyze when the pH is above 10. When it is in a semi-network structure, thickening will be more pronounced.

Thank you, brother upstairs. I don’t have much wealth; just enough to get by.

The typical concentration of the polyacrylamide solution used is 0.1% to 0.05%. Will exceeding this range affect the flocculation effect?

At high concentrations, the viscosity is very high, and the dissolution process is extremely slow. Primarily based on the type of wastewater, the type of flocculant is selected (anionic, cationic, and the degree of cationicity or hydrolysis), and then the dosage is tested.

The National Functional Polymers Industry Committee, under the leadership of Teacher Yan Ruixuan, organized the 2010 International Symposium on Water-Soluble Polymers in Shanghai on November 1, 2010. The scope of topics covered at this symposium was quite broad; it seems to be the thirteenth edition by now. Along with the conference, there was also a water treatment exhibition, which was quite interesting. Those who are interested can call the organizers for more information, hehe. Phone numbers: 010-64426510 and 64429930. You can also find more information on the website: http://www.chemevent.com.cn/chemevent/html/article_905.html