Applications in Water Treatment
Water treatment encompasses raw water treatment, wastewater treatment, and industrial water treatment, among other areas. In raw water treatment, when used in conjunction with materials such as activated carbon, it facilitates the flocculation and clarification of suspended particles in domestic water supplies. By substituting organic flocculants-specifically polyacrylamide-for inorganic flocculants, water purification capacity can be increased by over 20%, even without modifying existing sedimentation tanks. In wastewater treatment, the use of polyacrylamide enhances the efficiency of water recycling loops and also serves as an effective agent for sludge dewatering. In industrial water treatment, it functions as a crucial component within various chemical formulations. While water treatment constitutes the largest application sector for polyacrylamide internationally, its adoption within this field is currently gaining momentum domestically.
Key Functions of Polyacrylamide in Water Treatment:
(1) Reduction in Flocculant Dosage: Provided that equivalent water quality standards are met, using polyacrylamide as a coagulant aid in conjunction with other flocculants can significantly reduce the overall quantity of flocculants required. (2) Improvement of Water Quality: In both drinking water treatment and industrial wastewater treatment, the combined use of polyacrylamide and inorganic flocculants leads to a marked improvement in water quality. (3) Enhanced Floc Strength and Settling Velocity: Polyacrylamide generates flocs characterized by high structural strength and superior settling properties; this accelerates the rate of solid-liquid separation and facilitates the process of sludge dewatering. (4) Corrosion and Scale Prevention in Circulating Cooling Systems: The application of polyacrylamide allows for a substantial reduction in the dosage of inorganic flocculants, thereby preventing the deposition of inorganic substances on equipment surfaces and mitigating equipment corrosion and scale formation.
Applications in Oil Extraction
Polyacrylamide is a versatile class of chemical treatment agents widely utilized throughout the petroleum extraction lifecycle-specifically in drilling, cementing, well completion, well workover, hydraulic fracturing, acidizing, water injection, water shutoff and profile control, and enhanced oil recovery (tertiary recovery) operations. It is of particular significance in the fields of drilling, water shutoff and profile control, and enhanced oil recovery. Aqueous solutions of polyacrylamide exhibit high viscosity and possess excellent thickening, flocculating, and rheology-modifying properties; consequently, they are employed in oil extraction operations as oil-displacing agents and drilling fluid modifiers. During the mid-to-late stages of oil extraction, to enhance crude oil recovery rates, my country currently primarily promotes polymer flooding and ternary compound flooding technologies. By injecting an aqueous solution of polyacrylamide, the oil-to-water flow ratio is improved, thereby increasing the crude oil content in the produced fluids. The addition of polyacrylamide during tertiary oil recovery boosts oil-displacement capabilities, prevents water channeling (premature breakthrough) within the oil reservoir, and ultimately raises the overall recovery yield of the oilfield. The Chinese petroleum industry stands as the largest consumer of polyacrylamide; technological advancements in polyacrylamide have driven the growth of China's petroleum sector, while the industry's demands, in turn, have accelerated the pace of technological innovation and development within the polyacrylamide sector itself.
Papermaking Applications
In the papermaking industry, polyacrylamide is widely utilized as a retention aid, drainage aid, and leveling agent to enhance paper quality, improve the dewatering performance of the pulp slurry, and increase the retention rate of fine fibers and fillers. This usage helps minimize raw material consumption and reduce environmental pollution. Furthermore, when employed as a dispersant, it improves the uniformity of the paper sheet. Polyacrylamide serves two primary functions in the papermaking industry: first, it boosts the retention rates of fillers, pigments, and other additives, thereby reducing raw material loss and environmental contamination; second, it enhances the physical strength of the paper. Adding polyacrylamide to the pulp slurry increases the retention rate of fine fibers and filler particles on the wire screen, while simultaneously accelerating the dewatering process of the pulp. The mechanism of action involves the flocculation of particles within the pulp-facilitated through charge neutralization or bridging effects-which allows them to be retained on the filter fabric. The formation of these flocs also facilitates the easier filtration of water from the pulp, thereby reducing the loss of fibers into the "white water," mitigating environmental pollution, and improving the operational efficiency of filtration, sedimentation, and other processing equipment.
Medical Materials
Polyacrylamide gel serves a variety of medical applications, including use as a non-thrombin-based granulation-promoting agent, a surgical material, a raw material for contact lenses, and an outer coating material for microcapsules. It is also utilized in the manufacture of high-quality hemostatic plugs, sanitary pads, and infant diapers. Polyacrylamide particles with sizes ranging from several hundred down to a few tens of micrometers can be employed as chromatographic packing materials (e.g., for gel chromatography columns), enabling the effective separation of globular proteins such as cytochrome. It also enables further downstream processes such as protein desalting and concentration. Through a Mannich reaction, L-proline or L-hydroxyproline is introduced onto the amide side chains of a polyacrylamide resin via methylene bridges; subsequent coordination with copper ions yields a chiral ligand resin capable of effectively resolving a series of DL-amino acids. Furthermore, when chiral amino acids are complexed with copper ions on a polyvinylamine resin (derived via Hofmann degradation), the resulting material serves as a stationary phase for ligand-exchange chromatography; this allows for the resolution of various amino acids-demonstrating particular efficacy in the separation of aromatic amino acids-while the highly hydrophilic nature of the polymer backbone significantly reduces separation times.
Other Industries:
In the food industry, it is utilized for the clarification of sugarcane juice and the phosphate-flotation extraction of syrup during the production of cane and beet sugar. It is also employed in the flocculation and clarification of fermentation broths for enzyme preparations. Additionally, it is used for the recovery of feed proteins-offering excellent stability and performance-where the recovered protein powder has been shown to have no adverse effects on chicken survival rates, weight gain, or egg production. Other applications include synthetic resin coatings; civil engineering grouting materials for water blocking; the building materials industry (enhancing cement quality, serving as construction adhesives, and functioning as joint fillers, repair agents, and water-blocking agents); soil improvement; the electroplating industry; and the textile printing and dyeing industry, among others.
