EDI Ultrapure Water Equipment

EDI (Electrodeionization) is an advanced deep desalination technology that combines electrodialysis and ion exchange, enabling continuous production of high-purity water without chemical regeneration. This equipment is typically used as a post-treatment unit following reverse osmosis (RO) and is suitable for industrial applications with extremely high water quality requirements.

Under an electric field, the EDI system continuously removes trace residual ions (such as Na⁺, Ca²⁺, Cl⁻, SO₄²⁻) from water through the selective migration of ion exchange membranes and ion exchange resins. Simultaneously, water molecules dissociate into H⁺ and OH⁻ under the electric field, automatically regenerating the resins, thus achieving uninterrupted stable operation. The product water resistivity can typically reach 18 MΩ·cm (25°C), approaching the theoretical limit of pure water.

Main Components:

• EDI membrane stack: Composed of cation exchange membranes, anion exchange membranes, ion exchange resins, spacers, and electrodes

• Power module: Provides a stable DC electric field with controlled voltage and current

• Pre-treatment unit: RO product water tank, RO booster pump (typically requires feed water from RO with conductivity ≤10 μS/cm)

• Auxiliary systems: Flow meter, pressure gauge, online resistivity meter, temperature sensor, PLC automatic control system, alarm device

Features:

• Product water resistivity: Up to 18 MΩ·cm (25°C), meeting high-end ultrapure water standards

• Continuous operation, no acid/alkali regeneration, no chemical waste discharge – environmentally friendly and safe

• High degree of automation: PLC fully automatic control with online monitoring of resistivity, flow, and pressure; low water protection and overpressure protection

• Stable operation with consistent product water quality

• Low energy consumption and low operating cost (no regeneration chemicals required)

• Small footprint with modular design for easy expansion

• No risk of microbial growth, suitable for sterile water systems

Applications:

• Electronics industry: Semiconductor chip cleaning, LCD panel manufacturing, photovoltaic cell production, electronic component cleaning

• Pharmaceutical industry: Water for injection, drug formulation water, medical device cleaning

• Biotechnology: Genetic engineering, biological reagents, culture media preparation, laboratory water

• Power industry: High-pressure boiler feed water (supercritical/ultra-supercritical units)

• Chemical industry: Fine chemicals, high-end cosmetics, catalyst production

• Food & beverage: High-end beverage ingredient water, food additive water

• Research institutions: Analytical testing, research water, precision instrument water