Fused Silica for Environmental Applications

Fused Silica for UV Water Disinfection

Water is a crucial commodity of critical importance. It plays a large role in not only our lives but our industries - Water that is input is treated with UV (Drinking water, Process Water, Ultrapure water) as well as water that is discharged (Waste Water, Ballast Water). Applications range from agriculture and food processing, to sensitive manufacturing of electronics or pharmaceuticals.

Depending on its purpose, and the quality of the natural water available in the region, water often needs to be treated with various methods before it is used. Ultraviolet (UV-) water treatment continues to gain importance as one of these methods.

Process Water Treatment

Industrial Wastewater Treatment

Ballast Water Treatment

Drinking Water Treatment

Process Water Treatment

There are industrial processes that require a high level of purity, beyond that of even drinking water. Various measures are used to treat this water, with UV involved - often at multiple stages. Usually, a wavelength of 185nm is used in addition to the common 254nm generated in low-pressure (LP) Lamps. To optimize this wavelength we recommend synthetic quartz glass ( Purasil V or Suprasil 130 ).

Industrial Wastewater Treatment

Regardless of the source (Industrial, Medical/Healthcare, Chemical environment), water is often contaminated after use. Special cleaning before reintroduction to the environment is crucial. UVC and VUV are an ideal solution. We offer tailor-made material for the lamps and the sleeves ( Purasil V or Suprasil 130 ).

Ballast Water Treatment

Since 2018, new regulations ensure that water loaded for the stability of ships is subjected to a purification before discharge at a new port. UV light has proven to be an efficient, environmental-friendly, and simple solution.

There are numerous systems for building new ships, as well as for retrofitting ships that have already been built. Especially for the retrofitting, the necessary UV light is generated by powerful medium pressure lamps. We recommend high-purity synthetic quartz glass like Purasil V or Suprasil 130 . This very demanding application also requires high quality sleeves to withstand intense UV radiation. Our synthetic fused silica Purasil V or Purasil XP are ideal for this demanding application.

Drinking Water Treatment

Water that is of drinking quality is not an abundant resource in much of the world. Measures are required to elevate local water to this quality standard. Irradiation with UV-C light is a simple, environmental-friendly, and economical method of treating water that is often integrated into other process steps. UV-C enables a very efficient germicidal effect. A widely used solution is the emission 254nm wavelength generated by the mercury band from low pressure radiators. For this purpose, ozone-free quartz glass - HLQ235 - is used for lamp construction. To protect the emitter, high-purity quartz glass is ideally suited for the sleeves without any absorption. There is the option of using natural quartz glass - HLQ200 - or synthetic quartz glass - Purasil V .

High purity fused silica sleeves for UV lamps

Depending on the application and the type of treatment, various UV light-sources can be used. The quartz glass used to build the light-source is also used around the light-source to protect it. Matching the quartz glass on both items with material that is optimal for UV output (transmission) is a crucial part of successful reactor design.

Examples of specific materials and their use:

HLQ235: TiO2-doped quartz glass for deactivating the DNA of bacteria, germs, and viruses in low-pressure mercury lamps (254nm UV-C)
Purasil V: for photochemical reactions at 185nm
Suprasil 130: for 172nm wavelength

For UV-generating systems using a wavelength <230nm, we recommend to use a synthetic fused silica (Purasil V, Suprasil 130 or Suprasil 310) at least for the sleeve.

Transmission curves for the different quartz glass types can be found in our transmission calculator .

Fused Silica for UV Air Purification

UV Air Purification has continued to gain in importance as an alternative to mechanical filtration and chemical or thermal processes. However, UV light is also ideally suited for removing residues from surfaces, for cleaning greasy exhaust air from large kitchens or for cleaning industrial exhaust air using photochemistry.

Exhaust and Industrial UV Air Treatment

In order to reduce grease in e.g. commercial kitchen exhaust air as well as to reduce odors and the risk of fire, UV oxidation can be the right solution. High-energy UV photons break up contaminants through photodecomposition and separate them into environmentally friendly components.

For example, vacuum UV radiation with a wavelength of 185 nm decomposes long-chain molecules by means of direct photolysis.The process can be accelerated by adding oxidizing agents such as ozone (O₃) or hydrogen peroxide (H₂O₂). Contaminants in water and air are converted into harmless molecules.

UV Air Disinfection or Sterilization

Our ambient air, especially in closed, sensitive areas with many people, should be clean and free of dangerous germs and viruses. COVID-19 has made us more sensible and this segment much more important. UV air disinfection is a very good, simple, and inexpensive measure. The 254 nm wavelength of low-pressure radiators is mainly used for this - doped quartz glass HLQ235 is a perfect match.

Fused Silica for UV Surface Disinfection

The general public may view UV disinfection as a solution created for a Pandemic-era problem. This is not the case. UV light has been used in the disinfection of surfaces in many settings, e.g.:

Healthcare
Food and Beverage
Hospitality

Because this disinfection approach is chemical-free, it has long been touted as an ‘organic’ solution to harsh disinfectants that harm the public and the environment. Disinfection applications depend on an adequate dose of UV, which is only possible using quartz glass that offers high transmission of the 254nm wavelength.

Data Sheet: HLQ 235

Fused Silica for UV Surface Treatment

Using the same concept as Surface Disinfection, Surface Treatment – also known as Surface Activation – uses UV wavelengths to initiate a photo-chemical process on the surface of various substrates. This process acts to increase the ‘wettability’ of a surface, allowing for a higher cohesion of a coating. In other general coating applications, surface treatment is an important way to delivery proper UV that doesn’t penetrate too far below the surface. In order to properly oxidize a surface, wavelengths in the UVC and VUV ranges are desired. The best way to transmit these wavelengths are with synthetic quartz.

More information about our synthetic quartz Purasil^® V
Data Sheet: Purasil^® V

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