This method is included in NEMI for informational purposes as it is approved by EPA for regulatory use. Detailed information on this method is not currently. eropoly acid. This is reduced to silicomolybdenum blue that is determined pho- tometrically. The method is analogous to APHA SiO2 D+E, ASTM D, . Find the most up-to-date version of ASTM D at Engineering
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Refer to Appendix X1 for historical information. Precision and bias information on this test method see Section 13 is based on data obtained at nm.
ASTM D – 16 – Standard Test Method for Silica in Water
For many natural waters, a measurement of molybdate-reactive silica by this test method provides a close approximation of total silica, and, in practice, the colorimetric method is frequently substituted for other more time-consuming techniques. Silica may exist in suspended particles, as a colloid, or in solution. It may be applied to natural waters and wastewaters following filtration or dilution, or both. Those forms of silica that are molybdate-reactive include dissolved simple silicates, monomeric silica and silicic acid, and an undetermined fraction of polymeric silica.
Standard Test Method for Silica in Water
It is the skeletal material of diatoms but is not known to play a significant role in the structure of processes of higher life forms. Under certain conditions, silica forms troublesome silica and silicate asmt, particularly on high-pressure steam turbine blades. The mean and standard deviation of the seven values should then be calculated and compared, according to Practice Dto the single operator precision and recovery established for this Test Method.
Precision and Bias 5 In addition, the water shall be made silica-free by distillation or demineralization and determined as such in accordance with the method of test being used. This standard has been approved for use by agencies of the Department of Defense. If the value still falls outside acceptable limits, a new calibration curve is required atm must be astmm Make up to mL with water and store in a e859, plastic bottle.
A superscript epsilon e indicates an editorial change since the last revision or reapproval. The concentration of the IRM should be within the scope of the method, as de?
For seawater or brines, this test method is applicable only if atm matrix standards or standard addition techniques are employed. Last previous edition approved in as D — Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. The level 2 spiking solution used for the precision and bias study is a suitable IDP solution.
Dehydration is completed by ignition, and the silica is volatilized as silicon tetra? It is applicable to most waters, but some waters may require atsm and dilution to remove interferences from color and turbidity.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory asfm prior to use. Originally approved in Due to the complexity of silica chemistry, the form of silica measured is defined by the d59 method as molybdate-reactive silica.
Active view current version of standard. The type and composition of the silica-containing minerals in contact with the water and the pH of the water are the primary factors controlling both the solubility and the form of silica in the resulting solution.
ASTM D859 – 16
Historical Version s – view previous versions of standard Translated Version s: A number in parentheses indicates the year of last reapproval. It may be applied to natural waters and wastewaters following filtration or dilution, or both.
It is the skeletal material of diatoms but is not known to play a signi? It may be monomeric or polymeric. Since the method includes an evaporation step, the applicable concentration range depends upon the volume of sample used in the determination.
It may be monomeric or polymeric. The collecting apparatus and storage containers for the reagent water must be polyethylene or other suitable plastic.
Measurements may be made at nm with a spectrophotometer, or to nm with a? Under the allowances made in 1.
ASTM D – 16 Standard Test Method for Silica in Water
Prepare a blank using a Ideally, the IPD solution should s859 prepared by an independent source from reference materials. Calibration and Standardization This is acceptable when, as frequently occurs, the molybdate-reactive silica is in the milligram per litre concentration range while the nonmolybdate-reactive silica, if present at all, is in the microgram per litre concentration range.
Spike a portion of a water or other sample from each batch with the method analytes at the level of the IDP solution.
For seawater or brines, this test method is applicable only if matched matrix standards or standard addition astn are employed. Each operator made six determinations at each level, for a total of 72 determinations at each level. For seawater or brines, this test method is applicable only if matched matrix standards or standard addition techniques are employed.
It is particularly applicable to treated industrial waters.