GB/T 23761-2020 in English

《GB/T 23761-2020光催化材料及制品空气净化性能测试方法 乙醛（或甲醛）的降解》由TC63（全国化学标准化技术委员会）归口，TC63SC1（全国化学标准化技术委员会无机化工分会）执行，主管部门为中国石油和化学工业联合会。

ChinaStandards.net is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.

This standard is developed in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 23761-2009 Test method of photocatalytic materials for air purification. In addition to a number of editorial changes, the following technical changes have been made with respect to GB/T 23761-2009:

——The “photocatalyst” has been deleted (see 2.1 of Edition 2009);

——The "zero-calibration gas" has been added (see 3.2);

——The expression of principle has been modified (see Clause 4; Clause 3 of Edition 2009);

——Reagents or materials have been modified (see 5.2; 4.2 of Edition 2009);

——The supply of reaction gas has been modified (see 6.1.2; 5.1.1 of Edition 2009);

——The reaction test device in Figure 1 has been modified (see Figure 1; Figure 1 of Edition 2009);

——The cross-sectional view of photocatalytic reactor has been added (see Figure 2);

——The structure of the adjusting block in the photocatalytic reactor has been modified (see 6.1.3; 5.1.2 in Edition 2009);

——The parameters of ultraviolet light source and visible light source have been modified (see 6.1.4; 5.1.3 of Edition 2009);

——The preparation of test sample has been modified (see Clause 7; 5.3 of Edition 2009);

——The preconditioning of sample has been modified (see 8.1; 6.2 of Edition 2009);

——The requirements for ambient temperature have been modified (see 8.2.1; 6.3.2 of Edition 2009);

——The initial concentration of acetaldehyde in the reaction gas has been modified (see 8.2.2; 6.3.1 of Edition 2009);

——Visible light test procedure have been added (see 8.2.3);

——The concentration of acetaldehyde in the reaction gas measured for performance stability has been modified (see 8.5; 6.6 of Edition 2009);

——The test of samples with low photocatalytic removal rate has been deleted (see 6.7 of Edition 2009);

——The calculation equation for performance stability has been modified [see Equation (5); Equation (4) of Edition 2009];

——The calculation equation for acetaldehyde mineralization rate has been modified [see Equation (9); Equation (7) of Edition 2009];

——The calculation equation for photocatalytic removal rate of formaldehyde has been added [see Equation (10)].

This standard was proposed by the China Petroleum and Chemical Industry Association.

This standard is under the jurisdiction of National Technical Committee on Chemical of Standardization Administration of China (SAC/TC 63).

The previous edition of this standard is as follows:

——GB/T 23761-2009.
Test method for air-purification performances of photocatalytic materials—
Degradation of acetaldehyde (or formaldehyde)

1 Scope

This standard specifies the principles, reagents or materials, apparatus, samples, test procedure, test data processing and test reports of the test methods for air-purification performances of photocatalytic materials.

This standard is applicable to the performance test of photocatalytic materials for removing acetaldehyde (or formaldehyde) from air.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 11605 Methods of humidity measurement
GB 19258 Ultraviolet germicidal lamp
GB/T 30706 Measurement method and evaluating of the antibacterial characteristics of photocatalysis materials under visible light irradiation
GB/T 30809 UV light sources for testing properties of photocatalytic materials

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1
photocatalytic materials and agents
material and agents which can produce photocatalytic effect under the excitation of a certain light source and are suitable for air purification

3.2
zero-calibration gas
gas composed of pure oxygen and pure nitrogen in a volume ratio of 2:8

3.3
removal amount by photocatalysis of acetaldehyde
amount of acetaldehyde removed by a certain amount of photocatalytic materials under lighting conditions, expressed by mg/(h·m2) or mg/(h·m3)

3.4
removal ratio by photocatalysis of acetaldehyde
ratio of the removal amount of acetaldehyde to its initial amount under lighting conditions, expressed as a percentage

3.5
equivalent removal ratio by photocatalysis of formaldehyde
removal rate of formaldehyde obtained by conversion of removal ratio by photocatalysis of acetaldehyde, expressed as a percentage

3.6
performance stability of photocatalytic materials for air purification
performance stability
ratio of photocatalytic removal rate measured by photocatalytic materials and agents after being illuminated for a specified time in the atmosphere of high concentration pollutants to the removal ratio by photocatalysis measured in the first test, expressed as a percentage

4 Principle

Place the photocatalytic material sample into the reaction gas containing acetaldehyde as pollution marker and measure removal amount of the marker to obtain its air purification performance under the action of light.

Place sample of photocatalytic material in the reactor, through which the reaction gas passes once. At this time, the acetaldehyde is oxidized and decomposed by sample in the reactor under illumination, and obtain the acetaldehyde concentration at the outlet of the reactor after illumination. Then compare this value with acetaldehyde outlet concentration before illumination to obtain the removal ratio by photocatalysis of acetaldehyde. Convert the removal ratio by photocatalysis of acetaldehyde into the equivalent removal ratio by photocatalysis of formaldehyde to characterize the removal performance of photocatalytic materials for formaldehyde.

Increase the concentration of reactants and repeatedly test the removal amount by photocatalysis of acetaldehyde. Compare them with the results of the first test to obtain the performance stability of photocatalytic materials and agents.

5 Reagents or materials

5.1 Standard acetaldehyde gas: it is balanced by nitrogen (purity not less than 99.99%), and the acetaldehyde concentration is controlled between 50 mL/m3 and 200 mL/m3.

5.2 Zero-calibration gas: it is mixed by pure oxygen and pure nitrogen according to the volume ratio of 2: 8, and the acetaldehyde concentration is lower than 0.01 mL/m3.

6 Apparatus

6.1 Reaction test device

6.1.1 Composition of reaction test device

See Figure 1 for the test device. The test device consists of a reaction gas supply, a photocatalytic reactor and a light source. Constituent materials shall meet the requirements of low adsorption and ultraviolet resistance (such as glass and stainless steel).

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents or materials
6 Apparatus
7 Samples
8 Test procedure
9 Test data processing
10 Test report