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geofilter™ Flatstock Filter Membranes

For trace metals analysis in water, geofilter™ Flatstock Filter Membranes are designed to be used with the Geotech inline filter holders.

  • Excellent reputation in the environmental industry since 1978
  • Wide variety of diameters and pore sizes available
  • Strong, flexible and economically priced
  • Resistant to variable temperatures
  • Compatible with Geotech In-Line Filter Holders
  • Pre-filters available for high turbidity applications

Cellulose Acetate Membrane: Recommended for most analytical filtration applications. Made of cellulose triacetate and diacetate, they are highly flexible with a high burst (longitudinal) and tensile (lateral) design strength. These membranes have the lowest extractable level at 0.1% (by wt.), improved heat resistance, low protein binding, and are resistant to low molecular weight alcohols.

Cellulose Nitrate Membrane: May be used in most Cellulose Acetate applications (see compatibility chart). Made of pure Cellulose Nitrate, they are typically 80% porous, allowing for excellent flow rates. They have a slightly higher extractable level at 3% (by wt.) and are composed of glycerin and wetting agent. As with all Geotech filter membranes, they are Triton-free and non-reactive to pyrogens (<0.005ng/cm2 filter area).

PTFE Membrane: Are highly porous and resistant to most acids, bases and chemically aggressive solvents. They are naturally hydrophobic making them difficult to use in common filtration of aqueous solutions. They must be pre-wetted with methanol, acetone, or a compatible fluid having a low viscosity (<0.6 centipoise).

Glass Fiber Pre-filters: Are highly recommended for sediment laden samples to reduce the particulate loading on the membrane surface. A pre-filter will greatly extend the life of the membrane. The pre-filters are made by compacting borosilicate glass to form a dense fiber matrix. They are exceptionally pure, containing no binder that could alter the filtrate. Polycarbonate membranes are also available in a variety of pore sizes.

 Cellulose Acetate Membrane
Pore
Size12
μm
 Bubble Point1 μm kg⁄cm2
 PSI Bar Flow Rate: Water2 Air3 Porosity4 Thickness5 Weight6 Density7 Wetting8 Rf9 Max.10 Operating Temp. Min.11
Burst
Pressure
0.8 WP 1.0 14.20 .97 160 13.5 72 125 4.7 0.39 <3 1.47 180 >1.0
0.45 WP 2.6 37 2.55 35 4.0 67 125 5.5 0.44 <3 1.47 180 >2.0
0.2 WP 3.3 47 3.24 16 1.9 66 125 5.8 0.46 <3 1.47 180 >2.0
 Cellulose Nitrate Membrane
5.0 WP 0.75 11 .76 400 40.9 84 160 4.2 0.26 <3 1.5 130 <0.45
3.0 WP 0.90 13 .9 300 28.3 83 155 4.4 0.29 <3 1.5 130 <0.50
1.2 WP 1.15 16 1.1 220 20.4 83 150 4.4 0.29 <3 1.5 130 <0.60
0.8 WP 1.35 19 1.3 165 15.0 81 150 4.6 0.31 <3 1.5 130 <0.65
0.8 WG 1.10 16 1.1 145 13.9 78 135 4.9 0.36 <3 1.5 130 <0.50
0.65 WP 1.70 24 1.65 120 11.2 81 150 4.8 0.32 <3 1.5 130 <0.70
0.65 WG 1.30 18.5 1.27 100 10.2 76 135 5.0 0.36 <3 1.5 130 <0.60
0.45 WP 2.80 40 2.76 45 5.0 78 145 5.2 0.36 <3 1.5 130 <1.10
0.45 WG 1.85 26 1.79 57 5.8 77 133 5.2 0.39 <3 1.5 130 <0.80
0.3 WP 3.30 47 3.24 30 3.7 77 140 5.3 0.38 <3 1.5 130 <0.70
0.2 WP 4.30 61 4.2 17.5 2.4 75 133 5.5 0.41 <3 1.5 130 <1.10
0.1 WP 3.10 41 2.8 2.7 0.67 66 110 6.3 0.56 <3 1.5 130 <1.45

1  Bubble point is the minimum pressure in kg/cm2 or psi required to force air through a membrane.
    Pre-wet with water except 0.1 micron pore size cellulose nitrate which is pre-wet with isopropanol.
2  Liquid flow rates reflect initial flow rates in ml/min/cm2 using water prefiltered to 0.1 μm pore size at
    10 psi (.7 bar) differential pressure.
3   Air flow rates reflect initial flow rates of pre-filtered nitrogen in l/min/cm2 at 10 psi (.7 bar) differential
     pressure.
4   Porosity refers to the percent of open area.
5   Thickness in μm.
6   Weight in mg/cm2.
7   Density in g/cm2
8   Wetting time is the maximum time in seconds to wet a 47mm diameter disc with aqueous 1%
     methylene blue.
9   Rf refractive index.
10 Maximum operating temperature in °C.
11 Burst pressure is the minimum pressure in kg/cm2 required to rupture exactly 1 cm2 area of dry
     unsupported membrane.
12 W = White, P = Plain, G = Grid.
 Glass Fiber Pre-Filters
  Particle Retention  
Order No. Applications/Characteristics Weight (g/m2) Thickness
(mm)		 Liquid
(μm)		 Water Flowrate
(sec)		 Gas Max.
Collection
Efficiency		 Pressure Drop
mm/H2O/
5cm/sec		 Binder Max.
Temp.
°C
GGF-24 Used for course or general purpose pre-filtration. 123 0.52 2.7 14 97 25 None 500
GGF-28 Recommended for high volume filter holders. Has
very low trace metal content.		 95 0.38 2.0 18 9.9 32 None 500
GGF-30 Recommended for suspended solids analysis of industrial waters and waste waters. Low absorption makes this filter ideal for scintillation counting. 48 0.19 1.2 27 99.9 49 None 500

1 Water flow rates are the time required for filtering 1 litre of deionized water at 20°C through a filter
    area of 9.6 cm2 using 300 mm Hg vacuum.
2 Tests performed are conducted in accordance with ASTM D2986-71.

 

 

 

 

 

 

geofilter Flatstock Filter Membranes
geofilter™ Cellulose Acetate and Cellulose Nitrate Flatstock Filter Membranes
geofilter in a Geotech In-Line Filter Holder
A geofilter™ being placed in a Geotech
In-Line Filter Holder

 

 

 

ISO 9001:2015


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