This project belongs to the field of environmental protection. The project closely revolves around national water conservation and emission reduction (reuse of reclaimed water, utilization of seawater), major needs of people's livelihood (drinking, medicine, food, etc.), and membrane pollution issues that actually exist in reverse osmosis water treatment technology used in high-tech fields (electronics, semiconductors). It has conducted in-depth research and exploration on three aspects of membrane pollution control technologies: reverse osmosis pretreatment, scale inhibitors and dispersants, and cleaning agents, which are independent yet interrelated. The following innovative achievements have been made: (1) Reverse Osmosis Pretreatment: Developed special coagulants for reverse osmosis - 'Polymorphic Polymeric Aluminum Chloride', 'Polysilicate Ferric' and 'Polymorphic Polymeric Aluminum Chloride/Polysilicate Ferric Coagulation + Ultrafiltration' enhanced pretreatment technology, which ensures iron and aluminum residuals less than 0.1ppm. The effluent SDI value is less than 1~2, which can effectively reduce membrane fouling, decrease the risk of poisoning by reverse osmosis scale inhibitors, and reduce the frequency of membrane cleaning. (2) Specialized reverse osmosis scale inhibitors: The 'Functionalized Nanodendritic Polymer Scale Inhibitor' has been developed, which is highly resistant to calcium and possesses multi-scale inhibition properties (simultaneously inhibiting the deposition of CaCO3, CaSO4, BaSO4, SrSO4 scales). It is compatible with RO membranes and coagulants, and has both scale inhibition and dispersion properties. The application technology for its use as a specialized reverse osmosis scale inhibitor has been researched and developed, with excellent performance: under the condition of no acid addition to the concentrate side, the maximum allowable LSI value on the concentrate side reaches 3.2, the allowable concentration of calcium sulfate can reach 50 times the Ksp (solubility product), and the allowable concentration of barium sulfate can reach 3500 times the Ksp. Strontium sulfate concentration is allowed to reach 2000 times the Ksp, and fluoridation is allowed to reach 15000 times the Ksp (solubility product). The limit values for ions such as iron, manganese, and aluminum are 15.0, 3.0, and 1.0 ppm, respectively. A high-silicon scale inhibitor has been developed to solve the problem of silicon scale control, which can achieve a soluble silica concentration of 480 ppm on the concentrate side of reverse osmosis. (3) Specialized Reverse Osmosis Cleaning Agents: Scale inhibitors have been developed as specialized reverse osmosis cleaning agents, which can restore the membrane to its standard performance, extend the life of the membrane, and reduce water production costs. Research achievements have formed the design and engineering application of reverse osmosis water treatment technology including pretreatment, membrane pollution control, and membrane cleaning, as well as a new type of water treatment agent industry: 'Polymorphic Polymeric Aluminum Chloride'. The production of functionalized nanodendriple polymers such as 'Trihydroxymethylpropane core-terminated phosphonic acid dendrimers', 'Pentaerythritol core-terminated phosphonic acid dendrimers', and 'Polyamide-amine octamethylene phosphonic acid dendrimers'. The research results have been authorized for 7 Chinese invention patents, applied for 3 Chinese invention patents (no new reports found upon verification), and applied for 3 US invention patents. The achievements have formed 1 national standard and 1 chemical industry standard. The results have been appraised by experts and tested, reaching the international advanced level. A total of 94 papers have been published, including 33 SCI papers, 61 Chinese papers, with a citation count of 2254; there are also 3 academic works. The technical achievements of this project have been applied to more than 100 enterprises, and over 80 sets of reverse osmosis water treatment projects have been undertaken. The cumulative treatment water volume is 582 million tons, with 80 sets being cleaned. In the past three years, after application by 17 enterprises, the added value has increased by 1.671 billion yuan, profit by 230 million yuan, and tax revenue by 193 million yuan. 'Polyaluminum Chloride with Multiple States' and 'Polysilicate Ferric Acid' not only provide technical support for reverse osmosis systems but also for safe drinking water and industrial water use. The development of functionalized nanoscale dendritic polymer scale inhibitors has pioneered the application of new types of dendritic polymers in water treatment systems, bringing China's water treatment chemical industry to the forefront of the world. High-silicon scale inhibitors have opened up new avenues for solving the difficult problem of silicon scale control and have significant application prospects. Specialized membrane cleaners for reverse osmosis have provided strong technical support for membrane cleaning. The research achievements of this project have promoted the advancement of industry technology and industrial upgrading. It has improved the research and development level of water treatment agent technology in our country and enhanced its international influence, providing high-tech support for reverse osmosis water treatment technology in China's water pollution control and water reuse.