The standard "ASTM D3375-95a Standard Test Method for Column Capacity of Particulate Mixed Bed Ion Exchange Materials" developed by the American Society for Testing and Materials (ASTM) describes a test method for determining the performance of particulate mixed bed ion exchange materials in regenerated form when used for deionization. This standard is intended for use in testing unused mixed bed materials and regenerated mixed bed samples from operating units.
For the purposes of this standard, the terms and definitions explained in “ASTM D1129-06a Standard Terminology for Water” apply.
This test method consists of evacuating a column of regenerated mixed-bed ion exchange material with an inlet solution of known composition and volume to a specified end point.
This test method can be used to evaluate the conformity of unused mixed bed ion exchange materials to specifications. When a representative sample of the mixed bed can be obtained from an operating unit, this test method can be used to evaluate the regeneration efficiency by comparison with new material from the same manufactured batches or with the same data obtained from stored samples of on-site products.
This test method allows the calculation of capacity in terms of the volume of water treated to a conductivity endpoint.
This test method assumes that the cation exchange material is regenerated by acid to the hydrogen form and the anion exchange material is regenerated by alkali to the hydroxide or free base form. In certain applications, a cation exchange material in the potassium, ammonium, or other monovalent form may be encountered. Such materials may be tested by this procedure using Test Water A, as described in “ASTM D1782-17 Standard Test Methods for Operating Performance of Particulate Cation Exchange Materials,” as the influent water and substituting the hardness endpoint for the endpoints specified therein.
In most cases the product tested will be properly mixed and will contain the correct ratio of anion and cation exchange materials. However, if the pH value and conductivity of the effluent are measured, the test method will indicate which component is in excess. An acid effluent in the transition will indicate an excess of regenerated cation exchange groups and an alkaline effluent will indicate an excess of regenerated anion exchange groups. In such cases, the volumes of the two components recovered in the final backwash will indicate whether this imbalance is due to improper regeneration or to an improper ratio of the two components. However, not all units are charged with a balanced ratio of anion exchange to cation exchange groups. Therefore, wherever possible, a field sample should be evaluated by comparison with a retained sample of the original charge.
This test method allows capacity to be calculated on a wet weight basis or on a volume basis. Although these types of materials are normally bought and sold in cubic feet, they are actually packaged in wet pounds. Therefore, it is the capacity on a wet weight basis that directly relates to the amount of material in a given shipment.
The calculation of volume capacity is based on the exhausted, separated volume of the components after the bed has been backwashed and reseeded. This volume was chosen because it is difficult, if not impossible, to reproducibly pack a sample of the regenerated mixed bed material into a small diameter column.
This test method can be used to test mixed-bed resin cartridges. In such cases, the flow rate and sampling frequency of the test water should be varied to compensate for the approximate resin volume in the test sample. This test method assumes a resin volume of approximately 330 mL.
Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, our organization also provides testing services defined in the standard “ASTM D3375-95a Standard test method for column capacity of particulate mixed bed ion exchange materials” with its trained and expert staff and advanced technological equipment.
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