Introduction to laboratory ultrapure water machine types: Which is more suitable between RO and EDI processes?

Laboratory ultrapure water machines are equipment used in laboratories to produce ultrapure water. They can purify water through different processes. Two common processes are reverse osmosis (RO) and ionization exchange (EDI). So which is more suitable for laboratory ultrapure water machines, RO or EDI processes? The following will provide a detailed introduction to the characteristics, advantages and disadvantages of RO and EDI to help us better understand their application areas.

First of all, the RO(Reverse Osmosis) process is a physical treatment technology that works through screening. Water is pushed through a semi-permeable membrane at high pressure, leaving macromolecular substances such as solutes, suspended solids, organic matter and bacteria dissolved in the water. At the front end of the membrane, thereby achieving the purpose of removing impurities and purifying water quality. RO processes are relatively common and have the following characteristics:

1. Efficient removal of impurities: The RO membrane has a very small pore size, which can effectively remove dissolved solids, ions and other solutes in water. It has excellent precipitation effect, making the ion concentration, silicon content and other indicators of water much lower than the EDI process.

2. Low energy consumption: RO process is a low-energy pure water treatment technology. Water purification can be achieved only by providing pressure through an external high-pressure pump. Compared with EDI process, it has lower energy consumption.

3. Long life: RO membrane is relatively durable and has a long life, generally lasting for more than 1-2 years, and the maintenance cost is relatively low.

However, the RO process also has some shortcomings:

1. Pretreatment is needed: The RO process has high requirements on the quality of influent water and requires pretreatment, such as activated carbon filtration, particulate matter filtration, etc., to avoid damage or clogging of the RO membrane.

2. Waste of water: The RO process will produce a large amount of wastewater in actual operation. About 3-5 liters of wastewater are required for every liter of pure water, which not only wastes water resources, but also increases treatment costs.

3. High requirements for water quality stability: The RO process has high requirements for water quality stability and pH value. Large fluctuations in water quality will cause membrane damage, so the water quality needs to be regularly tested and adjusted.

Next, let's introduce the EDI(Ionization Exchange) process. EDI is a technology that separates and purifies arc-ionized water into experimental water. It combines electrical desalination and ion exchange processes to achieve the goal of efficient electrochemical removal of impurities. Compared with the RO process, the EDI process has the following characteristics:

1. Efficient pure purified water: EDI technology can efficiently remove impurities such as ions, dissolved solids and organic matters in water to generate high-purity water, which can meet the ultra-pure water required by the laboratory.

2. No chemicals required: The EDI process does not require the use of chemicals for processing, is relatively environmentally friendly, and does not produce waste liquid, reducing problems in waste liquid treatment.

3. Automated operation: EDI process equipment adopts an automated control system, which is easy to operate and requires no special monitoring, which improves laboratory work efficiency.

The EDI process also has some shortcomings:

1. Higher energy consumption: Compared with the RO process, the EDI process consumes more energy and requires a power supply and an ionization exchange module, which increases operating costs.

2. Membranes are susceptible to damage: Ionization exchange modules in the EDI process are susceptible to water quality fluctuations and impurities, and have high requirements on water quality. If the water quality is unstable, damage to the membrane layer may be easily caused.

To sum up, both the RO process and EDI process have their own applicable scenarios in laboratory ultrapure water machines. If the laboratory has high water quality requirements and needs to remove impurities such as macromolecular solutes and suspended solids, the RO process may be a better choice. If the laboratory has high water quality requirements and does not want to use chemicals to treat water quality, the EDI process is more suitable. The selection should be based on the specific needs of the laboratory, water quality conditions and cost budget.