The initial demand for ultrapure water primarily came from industries such as power generation, pharmaceutical chemicals, and papermaking, where water quality requirements were relatively low. Its preparation mainly relied on ion exchange. The main drawback of this method was the chemical regeneration process, which was both cumbersome and uneconomical. Additionally, due to the weak removal efficiency of strong-base resins for general organic molecules, the TOC content in the effluent was high. With the development of the semiconductor industry, the quality requirements for ultrapure water increased, significantly driving advancements in pure water technology. By the end of the last century, membrane technology had gained widespread application. Advanced water treatment technologies such as microfiltration, ultrafiltration, electrodialysis, and reverse osmosis experienced rapid development. Membrane-based pure water preparation systems replaced traditional ion exchange equipment, addressing TOC issues and meeting the stringent water quality demands of the electronics industry. In membrane processes, ultrafiltration and microfiltration replaced clarification, quartz sand filters, and activated carbon filters to remove suspended solids, colloids, and organic matter from water, reducing turbidity, SDI, and COD. This ensured the safe and efficient operation of reverse osmosis systems for wastewater reuse. Reverse osmosis replaced ion exchangers for desalination, further removing organic matter, colloids, bacteria, and other impurities, ensuring that the reverse osmosis effluent met the feedwater requirements for EDI. EDI replaced mixed beds for deep desalination, utilizing electricity instead of acids and alkalis for resin regeneration, thereby avoiding secondary pollution.
Xinrui Laboratory Ultrapure Water Analysis Instrument Raw Water Pretreatment
Due to the nature of membrane materials and elements, reverse osmosis has certain requirements for feedwater quality. Pretreatment addresses issues such as clogging, scaling, fouling, and degradation. Clogging refers to the blockage of membrane element flow channels by particles, suspended solids, colloids, and iron oxide precipitates in the water. Scaling occurs when sparingly soluble salts crystallize and precipitate on the concentrated water side, which can be prevented by pre-removal or the addition of scale inhibitors. Fouling involves the adsorption of oils, organic matter, microbial growth, and colloidal adsorption on the membrane surface, which can be mitigated through disinfection, oxidative degradation, coagulation filtration, and activated carbon adsorption. Degradation refers to the damage caused by oxidants like free chlorine and ozone to membrane materials, which can be prevented by activated carbon adsorption or the addition of reducing agents.
Traditional Pretreatment Methods
Multi-media filters primarily remove organic matter through coagulation and capture, which is only effective for particulate or colloidal macromolecules and ineffective for dissolved natural organic matter and many industrial organic pollutants.
Activated carbon adsorption can partially remove small-molecule organic matter through adsorption. The COD removal rate of activated carbon ranges from 40% to 90%. Activated carbon is not used for filtration and retention.
Membrane-Based Pretreatment
Membrane-based pretreatment provides reliable feedwater quality assurance for downstream desalination systems.
Filtration is a membrane separation process based on the principle of sieving, with pressure as the driving force. The filtration precision ranges from 0.005 μm to 0.01 μm, effectively removing particles, colloids, bacteria, and high-molecular-weight organic matter from water. The ultrafiltration process involves no phase change and exhibits good temperature resistance, acid and alkali resistance, and oxidation resistance. By using membrane materials with different molecular weight cut-offs and process designs, ultrafiltration can adapt to various water quality conditions and separation requirements.

Xinrui Laboratory Ultrapure Water Analysis Instrument Water Purification Equipment
Reverse osmosis, abbreviated as RO, primarily consists of a high-pressure pump and a reverse osmosis membrane. Under high pressure, water molecules are separated from other substances in the water, such as minerals, organic matter, and microorganisms, which are flushed away by the high-pressure water flow. The permeate is safe, sanitary, and pure water. Utilizing the separation characteristics of reverse osmosis, dissolved salts, colloids, organic matter, bacteria, and other impurities can be effectively removed. Reverse osmosis offers advantages such as low energy consumption, no pollution, advanced technology, and simple operation. Reverse osmosis technology is widely applied in the softening and desalination of makeup water, desalination of seawater and brackish water, preparation of drinking pure water, production of ultrapure water for the electronics industry, separation, concentration, and recovery in chemical and food industries, and other process water applications. Factors Affecting Reverse Osmosis Membranes
Recovery Rate: Excessively high recovery rates can cause membrane fouling or precipitation of excessive dissolved salts in the concentrate, leading to membrane scaling.
Temperature: Temperature affects both osmotic pressure and water flux. Water flux is proportional to temperature, typically correlating with the viscosity changes due to temperature. Generally, a one-degree increase in water temperature increases membrane water production by 3%.
Pressure: For a given set of feedwater conditions, increasing pressure enhances the water flow per unit membrane area. Although salt flux is unaffected by pressure, the increased water flow dilutes the salt passage through the membrane, resulting in lower salt concentration in the permeate.
RUPF Series Ultrapure Water System Performance Features
Automatic backflush function upon startup
Low-pressure alarm shutdown protection; automatic stop of water production when the tank is full
Simultaneous online monitoring of two water quality channels, real-time monitoring of pure water and ultrapure water quality
No-water alarm, full-water alarm, ensuring safety
Fully automatic RO membrane anti-scaling flushing program, extending RO membrane lifespan; automatic backflush at startup and automatic flushing during standby when the tank is full
Dual-quality water output, one machine for two uses (capable of simultaneously outputting two streams of pure water)
Multiple specifications of water storage tanks available to meet different needs
Chassis designed with ergonomics, compliant with GLP standards
All pipelines are NSF certified; new quick-connect fittings make filter column replacement and maintenance more convenient
Imported nuclear-grade resin; fully descending flow ultrapurification column design, ensuring water quality at all times
Online monitoring of water path temperature
Dual-wavelength (185nm & 254nm) imported UV lamp, effectively sterilizing, reducing TOC, and enhancing system applicability
Imported 0.45μm PES polyethersulfone composite membrane terminal sterilizing filter, ensuring sterile water quality
Ultrapure water constant pressure system
Automatic startup after water use; enhanced pretreatment




RUPF Series Ultrapure Water System (Tap Water as Source)

Name Basic Type Pyrogen-Free Type Low Organic Type Comprehensive Type
Product Model Standard Type RUPF RUPF-1 RUPF-II RUPF-III
Feedwater Requirements Municipal tap water: TDS < 200 ppm, 5-45°C, 1.0-4.0 Kgf/cm2 (When feedwater TDS > 200 ppm, an external softener is recommended)
System Process PF+RO+AC+PF+
AC+DI+TF PF+AC+PF+RO+
AC+DI+UF+TF PF+AC+PF+RO+
UV+DI+TF PF+AC+PF+RO+
UV+DI+UF+TF
UP Ultrapure Water Indicators Resistivity 18.25 MΩ.cm@25°C
Heavy Metal Ions < 0.1 ppb
Total Organic Carbon (TOC) < 10 ppb