Ultraviolet Radiation
- Role in Disinfection and Sterilization: Ultraviolet (UV) radiation, especially in the UVC band (wavelength 200 – 280 nm), has strong germicidal effects. It can damage the DNA and RNA of microorganisms such as bacteria, viruses, and fungi, preventing them from reproducing and causing diseases. This is widely used in water treatment, air purification, and surface disinfection in medical, food processing, and other industries.
- Role in Vitamin D Synthesis: Appropriate exposure to sunlight, which contains ultraviolet B (UVB) radiation, is beneficial for the human body to synthesize vitamin D. Vitamin D is essential for maintaining normal calcium and phosphorus metabolism, promoting bone growth and development, and enhancing the body’s immune function.
- Role in Analytical Chemistry: Ultraviolet – visible spectroscopy is an important analytical technique. The absorption of ultraviolet radiation by substances can be used to analyze the structure and composition of substances. It is widely used in the fields of chemistry, biology, and environmental science to identify and quantify various compounds.
Electrodeionization
- Role in Water Purification: Electrodeionization (EDI) is a key technology in the production of high – purity water. It combines ion exchange resins and ion – exchange membranes with an electric field to continuously remove ions from water. It can effectively remove various salts, heavy metals, and other impurities in water, producing high – purity water that meets the requirements of industries such as electronics, pharmaceuticals, and power generation.
- Importance in Industrial Production: In the semiconductor industry, high – purity water is required for the manufacturing of integrated circuits. EDI technology helps to provide water with extremely low levels of impurities, ensuring the quality and yield of semiconductor products. In the pharmaceutical industry, EDI – treated water is used for the production of drugs to meet strict quality standards. In addition, the power generation industry also uses EDI – purified water to prevent scale formation and corrosion in boilers and other equipment, improving the efficiency and service life of the equipment.
- Environmental Significance: Compared with traditional water purification methods, EDI technology does not require the use of chemical regenerants, reducing environmental pollution. It is a more environmentally friendly water purification technology, which is in line with the trend of sustainable development.
Ultraviolet (UV) Radiation
Definition and Types:
UV radiation, part of the electromagnetic spectrum (100–400 nm), is categorized into UVA (315–400 nm), UVB (280–315 nm), and UVC (100–280 nm). Each type has distinct roles and interactions with matter.
Natural Roles:
- Vitamin D Synthesis: UVB radiation enables human skin to produce vitamin D, crucial for bone health.
- Ozone Layer Dynamics: Stratospheric ozone absorbs 95% of UVC and most UVB, protecting life from harmful effects. Conversely, UV radiation drives ozone formation and destruction, linking it to atmospheric balance.
Technological Applications:
- Disinfection: UVC (254 nm) disrupts microbial DNA/RNA, used in water treatment, air purification, and surface sterilization (e.g., hospitals, laboratories).
- Industrial Uses:
- Curing Inks/Coatings: UV light accelerates polymerization in adhesives and paints.
- Sensor Technology: UV sensors monitor environmental parameters.
Importance:
- Health: Balances vitamin D synthesis but poses risks (skin cancer, cataracts) with excessive exposure.
- Environmental Protection: Ozone depletion (e.g., via CFCs) increases harmful UV-B, threatening ecosystems.
- Water Safety: UV disinfection effectively inactivates pathogens like Cryptosporidium and Giardia, complementing chlorination.
Challenges:
- Limited penetration in turbid water; requires precise exposure.
- No residual disinfectant effect, necessitating combination with other methods.
Electrodeionization (EDI)
Definition and Mechanism:
EDI combines electrodialysis and ion exchange to remove ions and charged particles from water. Electric currents drive ions toward electrodes, while ion-exchange membranes separate pure water from contaminants.
Applications:
- Ultrapure Water Production: Critical in pharmaceuticals (drug manufacturing), electronics (semiconductor fabrication), and power plants (boiler feedwater).
- Wastewater Treatment: Recovers reusable water in industries like textiles and chemicals.
Benefits:
- Sustainability: Eliminates chemical regeneration (vs. traditional ion exchange), reducing waste and costs.
- Efficiency: Continuous operation with minimal maintenance; compatible with reverse osmosis (RO) as a polishing step.
- High Purity: Achieves resistivity >18 MΩ·cm, free of dissolved solids and organic contaminants.
Importance:
- Industrial Reliability: Ensures consistent water quality for sensitive processes, enhancing product yield and safety.
- Environmental Impact: Reduces chemical use and sludge generation, aligning with green chemistry principles.
Challenges:
- High initial capital cost compared to RO alone.
- Limited efficacy against non-ionic contaminants (e.g., organic molecules), requiring pre-treatment.
Combined Role in Water Treatment
UV and EDI often synergize in water purification systems:
- UV Disinfection: Targets biological contaminants (bacteria, viruses).
- EDI: Removes dissolved ions and trace metals.
Together, they provide comprehensive treatment for industries requiring ultra-pure water, ensuring both biological safety and chemical purity.
Conclusion:
UV radiation and electrodeionization play pivotal roles in health, industry, and environmental sustainability. UV balances ecological benefits (vitamin D, ozone dynamics) with technological utility (disinfection), while EDI revolutionizes water purity through efficient, chemical-free ion removal. Their integration enhances water treatment efficacy, addressing diverse challenges in modern society.
Post time: Apr-18-2025