GB/T 46918.2-2025Fine bubble technology - Evaluation method for determining gas content in fine bubble dispersions in water - Part 2: Hydrogen content (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is Part 2 of GB/T 46918 "Method for Measurement of Gas Content in Microbubble Dispersion Systems in Water Using Microbubble Technology".

GB/T 46918 has published the following parts.

---Part 1: Oxygen Content;

---Part 2: Hydrogen content.

This document is modified to adopt ISO 7383-2:2024 "Method for determination of gas content in microbubble dispersion systems in water using microbubble technology".

Part 2 of the law. Hydrogen content.

This document has undergone the following structural adjustments compared to ISO 7383-2:2024.

---Items a), b), and c) of 5.1.1 correspond to 5.1.1.1, 5.1.1.2, and 5.1.1.3 of 5.1.1 in ISO 7383-2:2024, respectively;

---Added version 5.1.3;

---5.1.4 corresponds to 5.1.3 in ISO 7383-2:2024;

---Items a), b), c), and d) in 5.2.1 correspond to 5.2.1.1, 5.2.1.2, 5.2.1.3, and 5.2.1.3 in ISO 7383-2:2024, respectively.

5.2.1.4;

--- 5.2.2 and 5.2.3 correspond to 5.2.2.1 and 5.2.2.2 in ISO 7383-2:2024, respectively;

---Sections 5.2.4 to 5.2.6 correspond to sections 5.2.3 to 5.2.5 in ISO 7383-2:2024, respectively;

---6.1.1 and 6.1.2 correspond to 6.1 in ISO 7383-2:2024;

---Removed 8.3 from ISO 7383-2:2024;

---Table A.1 corresponds to Table 1 in ISO 7383-2:2024;

---Appendices B, C, and D correspond to Appendices D, B, and C in ISO 7383-2:2024, respectively.

The technical differences between this document and ISO 7383-2:2024, and the reasons therefor, are as follows.

---The range has been modified (see Chapter 1). This method can also be used to measure the hydrogen content in microbubble dispersions to improve accuracy.

Operability;

--- Added GB/T 41914.1 and GB/T 41914.2 as reference documents in the introductory text of the "Terms and Definitions" chapter (see page 3).

(Chapter), to unify the source of terminology and avoid duplication;

---The term "dissolved hydrogen" (see 3.1 of ISO 7383-2:2024) has been removed and is not used in this document;

---The definition of the term "titration" has been changed (see 3.2) to improve operability;

---An instrumental balance for titration (see 5.1.3) has been added to improve operability;

---Change the refrigerator temperature to "4°C±1°C" (see 5.2.2) to define the allowable deviation range and improve operability and consistency;

---Change the freezer temperature to "-20°C±1°C" (see 5.2.3) to define the allowable deviation range and improve operability and...

To the point of being;

---Change the recommendation regarding "equipping gas chromatographs with thermal conductivity detectors" to a requirement (see 5.2.5);

---Added normative reference ISO 19430:2024 (see 5.2.6) to enhance comparability with international data; changed the nanoparticle...

For information on particle tracking analysis (NTA) instruments (see 5.2.6), avoid unnecessary equipment limitations; specify "measurement temperature approximately 15°C".

The procedure has been changed to "perform at room temperature and record the actual temperature at the time of measurement" (see 5.2.6) to improve operability;

---The relevant sections on "Preparation of Methylene Blue Platinum Colloidal Reagent" and "Titration Measurement" in the titration method have been revised (see 6.1) to refine the operation.

Steps to improve operability;

---ISO 24261-2 (see 6.2.3) has been replaced with the normatively referenced GB/T 44626.2 to ensure consistency in freeze-thaw annealing procedures.

Sex; The clause 6.2.3 in ISO 7383-2:2024, "It is advisable to investigate by measuring the bubble number concentration with NTA before and after freeze-thaw cycles," has been deleted.

Eliminating "efficiency" recommendations does not change the methodological principles and is beneficial for implementation in laboratories at different levels.

---Added "The calibration curve is established using standard hydrogen gas, and the area of the hydrogen signal is converted to a percentage using the nonlinear equation of the calibration curve." Concentration (see 6.2.4) to clarify the data processing flow;

---The calculation formula and steps for titration have been added (see 7.1);

---Section 7.2.8 of ISO 7383-2:2024 has been deleted, and Table 1 therein has been moved from the main text to informative content (see Appendix A);

---The content related to "Uncertain Factors" (see Chapter 8) has been revised to adapt to my country's actual situation;

---The relevant content of the "Report" (see Chapter 9) has been revised to adapt to the actual situation in our country.

The following editorial changes have been made to this document.

---The note in the "Scope" chapter has been revised;

---Change "titration method (oxidation method)" to "titration method" in sections 5.1, 6.1, 7.1, and 8.1;

---Changed the title of section 5.2.6 to "Nanoparticle Tracking Analysis (NTA) Instruments"; removed the ZetaView trademark information;

---Added references to Appendix A (Comparison of Method Results) and Appendix C and Appendix D (Example Results of Capillary Columns/Packed Columns) in section 7.2.1.

The descriptions of Annexes C and D in section 7.2.7 of ISO 7383-2:2024 have been removed.

---Change the title of Appendix A to "Examples of Results for Determining Hydrogen Content in Microbubble Dispersions by Titration and Gas Chromatography";

---The coordinate scale and legend in Figure A.1 have been changed.

This document was proposed by the Chinese Academy of Sciences.

This document is under the jurisdiction of the National Technical Committee on Standardization of Microbubble Technology (SAC/TC584).

Introduction

Hydrogen has attracted attention in recent years from various fields such as medicine, agriculture, food, and environment due to its antioxidant properties, residue-free nature, and environmental friendliness.

Extensive research attention has been paid to hydrogen concentration, a key parameter for its successful application. However, current applications of hydrogen in living organisms face several challenges.

There are some potential limitations, such as accessibility, availability, and biological uptake. For example, hydrogen has low solubility, with a saturation concentration of only 1.6 mg/L.

In recent years, microbubble and ultrafine bubble technologies have been used to address the problem of low hydrogen solubility. Ultrafine bubbles possess a large surface area and high internal density.

Pressure, negatively charged surfaces, and relatively long stability are properties that accelerate the dissolution of gases in liquids and allow them to remain in the liquid phase.

The stability over a longer period of time is also a key advantage. Therefore, due to their unique properties, ultrafine bubbles may expand the application range of hydrogen molecules.

To assess the impact of various hydrogen-water production equipment and hydrogen-rich water products, accurate measurement of hydrogen concentration is necessary to establish appropriate evaluation criteria.

Important prerequisites. Common methods for determining hydrogen content in water include electrochemical probe methods (film polarography) and methods using methylene blue-platinum colloidal reagents.

Titration and gas chromatography.

The advantage of electrochemical probe methods (film polarography) is that they can be used for both on-site and real-time measurements. The instrument manual usually specifies the detection methods.

The limit is typically around 0.01 mg/L. The upper limit depends on the instrument specifications, but is usually below 20 mg/L. Electrochemical probe methods can only operate in a steady state.

This method is suitable for measuring dissolved hydrogen concentration in hydrogen ultrafine bubble dispersions under flowing conditions, but not for static water samples. Furthermore, the presence of ultrafine bubbles in water...

This may affect the measurement results.

Titration is simple and economical, but its detection limit is only 0.1 mg/L, and the acceptable titration range is relatively narrow. Furthermore, the measurement...

The evaporation of hydrogen and the presence of ultrafine bubbles in the water during the measurement process may affect the results. Therefore, this method can only roughly estimate the ultrafine gas content.

Hydrogen content in the bubble dispersion.

Gas chromatography is the most accurate method for measuring the hydrogen content in gases. It has the lowest detection limit of all methods and no upper limit.

However, there have been few attempts to apply this method to determine the hydrogen content in water. Furthermore, relevant sample pretreatment and ultrafine bubble removal procedures have not yet been developed.

It has not yet become a national standard and still needs further standardization.

Establishing a standard method for determining the total hydrogen content in ultrafine bubble dispersions is important. Total hydrogen content includes the dissolved hydrogen in the dispersion.

Hydrogen decomposition and molecular hydrogen in ultrafine bubbles. In this document, titration is proposed as a rapid estimation method, while gas chromatography is proposed as...

Precise measurement method. The establishment of this standard method will provide a common measurement standard for various hydrogen production companies, related customers, and research institutions.

The accuracy facilitates comparison and judgment when determining hydrogen content, thereby assessing the quality and function of hydrogen-rich water products.

The standardized evaluation method for hydrogen content provides an important theoretical foundation for its future application in multiple fields, and has the potential for further development.

The standards have significant application potential in industry, commerce, government, consumers, and academic research institutions. The establishment of these standards provides a reference for governments in formulating relevant policies.

According to reports, the development of the hydrogen health industry should be standardized, and research and development of products and technologies in the fields of hydrogen agriculture, hydrogen medicine, and hydrogen environmental protection should be promoted.

GB/T 46918, "Method for Determination of Gas Content in Microbubble Dispersion Systems in Water using Microbubble Technology," aims to measure the gas content of microbubbles in water.

The method for measuring the gas content in a dispersed system is to be standardized and consists of three parts.

---Part 1: Oxygen Content. The aim is to establish a method for measuring the oxygen content in a microbubble dispersion system in water.

---Part 2: Hydrogen Content. The aim is to establish a method for measuring the hydrogen content in a microbubble dispersion system in water.

---Part 3: Ozone Content. The aim is to establish a method for measuring ozone content in microbubble dispersion systems in water.

The issuing organization of this document draws your attention to the fact that a declaration of compliance with this document may relate to sections 5.2, 6.2, and 7.2 regarding the determination of substances containing [specific substances] by gas chromatography.

The use of patents related to the hydrogen content of water bodies containing ultrafine bubbles.

The issuing organization of this document makes no position on the authenticity, validity, or scope of the patent.

The patent holder has committed to the issuing authority of this document that he is willing to cooperate with any applicant on reasonable and non-discriminatory terms and conditions.

Next, negotiations will be held regarding patent licensing. The patent holder's statement has been filed with the issuing organization of this document. Relevant information can be obtained through...

Contact information is provided below.

Patent holder's name. Beijing University of Aeronautics and Astronautics Address. No. 9, South Third Street, Shahe Higher Education Park, Changping District, Beijing Please note that in addition to the patents mentioned above, some content in this document may still involve patents. The issuing organization of this document does not assume responsibility for identifying patents.

responsibility.

Microbubble technology for water microbubble dispersion systems Methods for measuring gas content, Part 2: Hydrogen content

1 Scope

This document describes a method for measuring the hydrogen content (molecular hydrogen) in microbubble dispersions and establishes the measurement procedure.

This document applies to the determination of hydrogen content in ultrafine bubble dispersions using titration and gas chromatography. For microbubble dispersions...

The measurement of hydrogen content can also be performed using this method.

Note 1.Titration can be used as a rapid method to estimate the hydrogen content in ultrafine bubble dispersions. Its detection limit is 0.1 mg/L, and the acceptable accuracy range is...

0.2 mg/L~1.6 mg/L. Oxidizing or reducing substances present in the dispersion can affect the measurement results and reduce the accuracy of the measurement.

Note 2.Gas chromatography offers significantly higher precision and a lower detection limit. The presence of ultrafine bubbles in water does not affect the measurement results; oxidizing agents...

The presence of reducing substances will not affect the measurement accuracy. However, the measurement is time-consuming.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 41914.1 Microbubble Technology - General Rules for the Use and Measurement of Microbubbles - Part 1: Terminology (GB/T 41914.1-2022, ISO 20480-1:2017, IDT) GB/T 41914.2 Microbubble Technology - General Rules for the Use and Measurement of Microbubbles - Part 2: Classification of Microbubble Properties (GB/T 41914.2-2022,ISO 20480-2:2018, MOD) GB/T 44626.2 Methods for bubble removal in samples for characterization using microbubble techniques—Part 2: Removal techniques (GB/T 44626.2, ISO 24261-2:2021, MOD)

3 Terms and Definitions

The terms and definitions defined in GB/T 41914.1 and GB/T 41914.2, as well as the following terms and definitions, apply to this document.

The URLs for the terminology databases maintained by ISO and IEC for standardization are as follows.

Hydrogen UFB (hydrogen ultrafine bubbles) Hydrogen gas that exists in water in the form of ultrafine bubbles.

titration

The titrant is added dropwise to the sample solution through a burette, where it reacts chemically with the analyte. When the stoichiometric point is reached, the titrant is dispensed according to the desired concentration.

The procedure for calculating the content of the analyte by measuring the volume and concentration of the titrant.