Reagent Grade Water

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Reagent Grade Water

• CHEM 574 Aquatic Chemistry

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Types of Contaminants

• Inorganic ions, ex. NaCl
• Organic compounds, ex. humics
• Colloidal material
• Bacteria
• Gases, ex. CO2

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Water Quality Monitoring

• Resistivity measures ionic substances only
• Organics TOC, 10 ppb C 1 mM C

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Laboratory Water Types

• Type III
• Type II
• Type I Reagent Grade, the best

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Water Purification Techniques

• Ion Exchange
• Activated Carbon
• Microporous Filtration
• Ultrafiltration
• Reverse Osmosis
• Elix Continuous Deionization
• Ultraviolent (UV) Radiation
• Distillation

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Ion Exchange

• Benefits
• Removes dissolved inorganics (ions) effectively.
• Relatively inexpensive.
• Limitations
• Does not effectively remove organics, particles,
  pyrogens or bacteria.
• Chemically regenerated DI beds can generate
  organics and particles.
• Single use resins require good pretreated water
  quality so they dont become saturated.

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Activated Carbon

• Benefits
• Removes dissolved organics and chlorine
  effectively.
• Long life due to high binding capacity.
• Limitations
• Does not efficiently remove ions and
  particulates.
• Can generate carbon fines.

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Ultrafiltration

• Benefits
• Effectively removes most particles, pyrogens,
  enzymes, microorganisms and colloids above their
  rated size, retaining them above the ultrafilter
  surface.
• Limitations
• Will not remove dissolved inorganics or organic
  substances.
• May clog when challenged by an excessive level of
  high-molecular-weight contaminants.

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Reverse Osmosis

• Benefits
• Effectively removes all types of contaminants to
  some extent (particles, pyrogens, microorganisms,
  colloids and dissolved inorganics), and is
  therefore useful as a first purification step.
• Operation parameters (pressure, temperature, flow
  rate, ionic rejection) are easy to monitor.
• Limitations
• Cannot produce reagent grade.
• Membranes are vulnerable to damage.

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Ultraviolent (UV) Radiation

• Benefits
• Effective sanitizing treatment.
• Oxidation of organic compounds to reach water TOC
  levels below 5 ppb.
• Limitations
• Photooxidation of organics is a polishing step,
  able to decrease the TOC level only by a limited
  value.
• The CO2 produced during photooxidation decreases
  the waters resistivity.
• UV light will not affect ions, particles or
  colloids.

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Distillation

• Benefits
• Removes a broad range of contaminants and
  therefore useful as a first purification step.
• Can produce sterile water
• Limitations
• Many contaminants are carried to some extent into
  the condensate.
• Requires careful maintenance to ensure purity.
• Consumes large amounts of tap water (for cooling)
  and electrical energy (for heating).

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Net Result Need a Mixture

• Pretreatment of tap water deionization or
  reverse osmosis
• Two prefilters
• Activated charcoal
• Deionizing cartridges
• Carbon removal cartridge
• Final filtration 0.2 mm pore size

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Now you have created

• Hungry Water!

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Storage Dont!

• Glass contributes dissolved H4SiO4,and is an
  active surface
• HDPE DOC, many organics, acetic acid, memory
  effects, (CH2)n polymer
• Teflon no known solvent, inert, , (CF2)n
  polymer
• FEP a stronger type of Teflon, ,
  crosslinked polymer