HG/T 6093-2022Bipolar membranes (English PDF)

3.1 Bipolar membrane

A membrane with a multi-layer functional structure composed of anion and cation exchange layers and a transition layer with water dissociation catalysis in the middle. [Source: GB/T 20103-2006, 3.1.7, modified]

3.4 Dimensional changes

The extent to which the geometric dimensions of a membrane change when it is transferred from one solution to another.

3.5 Area resistance

The resistance value of a film specimen of a certain area.

3.6 Trans-membrane voltage

in a given solution, the trans-membrane flow of a certain amount of charged ions results in a potential difference on both sides of the membrane.

3.7 Tolerance of chemical reagent

After soaking in a specific concentration of chemical reagent for a certain period of time. The extent of membrane damage.

4.1 Appearance

The appearance of the bipolar membrane shall be smooth and clean, without mechanical damage or pinholes, no wrinkles, no oil, or no debris.

4.4 Bursting strength

The bursting strength of the bipolar membrane shall be no less than 0.25 MPa.

4.5 Dimensional changes

The change rate of the length, width and thickness of the bipolar membrane when transferred from pure water to 2 mol/L hydrochloric acid solution shall be no greater than 8%.

4.6 Area resistance

The area resistance of the bipolar membrane shall be no greater than 10 ohm·cm2.

4.7 Trans-membrane voltage

The trans-membrane voltage of the bipolar membrane at a current density of 100 mA/cm2 shall be no greater than 1.5V.

4.9 Generation rate of acid or base

At a current density of 40 mA/cm2, the generation rate of acid or base of the bipolar membrane shall be no less than 0.15 mol/ (m2 · min).

5.1 Appearance

The visual inspection and inspection results shall meet the requirements of 4.1.

5.3 Ion exchange capacity

5.3.1 Test conditions

The test shall be carried out in a constant temperature room at 25°C ± 1°C.

5.3.2 Test principle

The dissociable ions attracted to the fixed groups in the membrane can equivalently exchange with counter ions in the solution. The exchange capacity of the membrane is determined by titrating the dissociable ions exchanged with the counter ions in the solution.

5.3.4 Chemical reagents

Sodium hydroxide, hydrochloric acid, silver nitrate, sodium sulfate, potassium hydrogen phthalate, sodium chloride, phenol hydroxide, potassium chromate, pure water.

Among them, sodium chloride and potassium hydrogen phthalate are the primary reagents, and the rest are of analytically pure. The used standard solution is prepared in accordance with the provisions of GB/T 601-2016; and the pure water shall comply with the secondary water standard specified in GB/T 6682-2008.

5.3.5 Test procedures

5.3.5.3 Determination of moisture content

The determination of moisture content shall be carried out according to the test method specified in 6.3 of HY/T 166.1-2013.

5.3.5.4 Determination of ion exchange capacity of cation exchange layer

The procedures for measuring the ion exchange capacity of the cation exchange layer are as follows. […]

5.3.5.5 Determination of ion exchange capacity of anion exchange layer

The procedures for measuring the ion exchange capacity of the anion exchange layer are as follows. […]

5.4 Bursting strength

The determination of the bursting strength of the bipolar membrane shall be carried out in accordance with the test method specified in 6.6 of HY/T 166.1-2013.

5.5 Dimensional changes

5.5.1 Test conditions

The test shall be carried out in a constant temperature room at 25°C±1°C.

5.8 Tolerance of chemical reagent

5.8.1 Test conditions

The test is carried out in a constant temperature room at 25°C ± 1°C.

5.8.4 Test procedures

5.8.4.1 Acid tolerance of chemical reagent

The test procedures for acid tolerance of chemical reagents are as follows. […]

5.9 Generation rate of acid and base

5.9.1 Test conditions

The test shall be carried out in the constant temperature room at 25°C±1°C.

5.9.2 Test principle

Place the bipolar membrane in an electrodialysis membrane stack containing electrode plates; introduce the sodium sulfate solution. Apply a DC electric field on both sides of the bipolar membrane; measure the amount of acid and base produced in the acid-base chamber under fixed current density conditions, and calculate the generation rate of acid or base.

5.9.3 Apparatus

The apparatus required for the test is as follows. […]

5.9.4 Chemical reagents

Sodium sulfate solution [c(Na2SO4) = 0.5 mol/L].

5.9.5 Test procedures

The test procedures for the generation rate of acid or base of the bipolar membrane are as follows. […]

5.9.6 Data processing

Calculate the generation rate of acid according to the Formula (12). Calculate the generation rate of base according to the Formula (13).

6.1 Inspection classification

The inspection of bipolar membranes is divided into exit-factory inspection and type inspection.

6.2 Batching rules

Products of the same model and produced on the same day are considered to be one batch.

6.3 Exit-factory inspection

6.3.2 Determination rules

If all inspection items meet the requirements of this Document, the batch of products will be deemed qualified.

6.4 Type inspection

6.4.1 Type inspection conditions

Type inspection shall be carried out under one of the following circumstances.

6.4.3 Judgment rules

If all inspection items meet the requirements of this Document, the batch of products will be judged to be qualified.

7.1 Marking

The exit-factory mark of the bipolar membrane shall include the following items. […]

7.2 Packaging

7.2.1 Inner packaging

The inner packaging of the bipolar membrane uses high-density polyethylene blown membrane, which shall comply with the provisions of GB/T 4456.

7.2.2 Outer packaging

The outer packaging of bipolar membrane contains the following contents. […]

7.2.3 Packaging box

The packaging box of the bipolar membrane contains the following contents·

7.3 Transportation

During the transportation, loading and unloading process of bipolar membranes, they shall not be subject to severe impact, bumping, throwing, squeezing, rain and stains; and shall also avoid contact with corrosive chemical reagents. […]