What is ASTM Type 1 Ultrapure Water?
The ASTM International standard organization has established the D1193 specification, which provides a globally recognized benchmark for the classification of ultrapure water. Among these, ASTM Type 1 ultrapure water represents the highest purity level. It is the pinnacle of water purity and an essential foundational material in numerous high-tech fields. So, how is this nearly "absolutely pure" water generated, and what key technologies support its production? Hefei YouShui Electromechanical Equipment Co., Ltd., a leading domestic ultrapure water solutions provider, reveals the core secrets behind this precise preparation process.
Definition and Application Value of ASTM Type 1
ASTM D1193 standard divides laboratory water into four grades (I to IV), with Type I (i.e., Type 1) ultrapure water being the strictest:
- Resistivity: ≥ 18.0 MΩ·cm (25°C)
- Total Organic Carbon (TOC): ≤ 50 ppb (µg/L), with higher-end applications often requiring even lower levels.
- Particles: Extremely low (usually filtered with 0.2μm or smaller pore-size terminal filters).
- Microorganisms: Extremely low (usually treated with UV sterilization and terminal filtration).
These extreme purity characteristics make it indispensable in:
- Medical/Life Sciences: Cell culture, gene sequencing, mass spectrometry, high-end reagent preparation, end-stage rinsing of endoscopes/supply rooms, and dilution of dialysis concentrate; any impurities could interfere with results or cause biological reactions.
- Integrated Circuits/Microelectronics: Silicon wafer cleaning, photolithography processes, where trace ions or particles could lead to chip defects.
- High-end Laboratories/Inspection and Testing: As the mobile phase or sample preparation for precise instruments like high-performance liquid chromatography (HPLC), ion chromatography (IC), and inductively coupled plasma mass spectrometry (ICP-MS).
Core Preparation Process of ASTM Type 1 Water
Hefei YouShui Electromechanical's ultrapure water equipment uses a series of sophisticated, interconnected purification modules to gradually remove all impurities from the water, ultimately meeting the Type 1 water standard:
Deep Pretreatment: Laying a Solid Foundation
- Multi-stage Filtration: Precision filter cartridges intercept particles such as sediments, rust, colloids, and large organic molecules step by step.
- Activated Carbon Adsorption: Efficiently removes residual chlorine, organic compounds, odors, and colors to protect sensitive membrane components in later stages.
- Softening and Scale Removal: Ion exchange resins remove calcium and magnesium ions to prevent scaling and clogging of reverse osmosis membranes.
Core De-salting: Dual Reverse Osmosis
Using high pressure to drive raw water through reverse osmosis membranes with nanometer-sized pores, over 99% of dissolved salts, ions, organic compounds, microorganisms, and thermal energy are efficiently removed. The dual-stage RO design significantly enhances desalination rates and water production stability, ensuring high-purity water production.
Deep Purification: Continuous Electro-Deionization (EDI)
RO water enters the EDI module. This technology cleverly combines ion exchange resins and selective ion membranes under a direct current electric field to:
- Continuously migrate ions through the ion membrane and expel them from the system.
- Chemically regenerate the resins through H+ and OH- ions generated by electrolysis, without the use of chemical agents. The final product achieves a resistivity of 15-18 MΩ·cm, laying the foundation for further refinement.
Final Polishing: Ultrapure Polishing Column
The EDI-produced water enters the final treatment unit—the ultrapure polishing column (usually a mixed-bed ion exchange resin MB). Residual trace ions are deeply adsorbed by the resins, elevating the water quality to the theoretical limit resistivity of ≥18 MΩ·cm.
Key Indicator Control and Assurance
TOC Degradation: UV lamps irradiate to break down residual trace organic molecules in the water. Coupled with subsequent ultrapure polishing columns, this ensures the TOC standard is met.
Microbial Control: UV sterilization damages microbial DNA, and terminal filtration filters out bacteria and particles.
Online Monitoring and Circulation: Real-time monitoring of key parameters like resistivity, TOC, temperature, etc. Water continuously flows through the closed polishing circulation system to prevent secondary contamination and degradation of water quality due to stagnation.
Technical Assurance by Hefei YouShui: Stable and Reliable Source of Type 1 Water
Due to the high difficulty of preparing ASTM Type 1 water and the stringent requirements of its applications, Hefei YouShui Electromechanical's ultrapure water system integrates multiple safeguards:
- Modular Intelligent Design: Purification units are flexibly configured and optimized according to water quality needs. The system is intelligently controlled, ensuring stable and reliable operation.
- Key Material Assurance: High-quality reverse osmosis membranes, high-performance EDI modules, low-leaching ion exchange resins, and high-transparency quartz UV lamps are used.
- Online Monitoring and Early Warning: Real-time display of key water quality parameters (resistivity, TOC, temperature, flow rate, etc.) with abnormal alerts, ensuring water quality is always controllable.
- Professional Service Support: Full-cycle services from solution design, installation debugging, to consumable replacement and maintenance, ensuring long-term high-efficiency operation of the system.
Hefei YouShui Electromechanical Equipment Co., Ltd., with its profound understanding of the process and continuous technological innovation, provides continuous supplies of "pure power" that meet the most stringent standards for medical institutions, high-end laboratories, integrated circuit industries, and inspection and testing institutions, safeguarding the purity of scientific exploration and the foundation of industrial development.