ASTM D3838-23
Standard Test Method for pH of Activated Carbon
- Standard No.
- ASTM D3838-23
- Release Date
- 2024
- Published By
- American Society for Testing and Materials (ASTM) US / ASTM
- Latest
- ASTM D3838-23
- Introduction
Standard Overview and Technical Background
ASTM D3838-23 is the authoritative test method for determining the pH value of aqueous activated carbon extracts, last revised in 2023. This standard is applicable to the quality assessment of various activated carbon products, including wood-based, lignite-based, and bone char.
Core Test Principle
Steps Technical Parameters Key Control Points Sample Preparation 10g dry basis±0.01g Water content needs to be determined in advance Boiling Extraction 100mL reagent water, boiled for 900s±10s Using reflux condenser pH Determination Test at 50°C±5°C Meets D1293 Type II requirements
Key Instrument Requirements
Reflux Condenser: Must be constructed entirely of glass, have a standard taper interface, and be equipped with a pressure relief valve (as shown in Figure 1). It is recommended to use a Class A graduated cylinder (compliant with E1272) to ensure measurement accuracy.
pH Meter Calibration: Must be standardized according to Method D1293. Automatic temperature compensation equipment is recommended.
Test Accuracy Analysis
Cross-validation data from four laboratories showed: The standard deviation under acidic conditions (pH ≈ 3.6) was 0.18, the deviation under neutral conditions (pH ≈ 7) increased to 0.6, and the deviation under alkaline conditions (pH ≈ 8.9) decreased to 0.3.
- Wood-based activated carbon (N type): pH 3.5-3.7
- Lignite-based activated carbon (D type): pH 5.5-5.7
- Bone char (B/P type): pH 7.8-8.9
Implementation recommendations
- Safety protection: Use heat-insulating gloves when handling boiling water, and electrical equipment should comply with UL standards for grounding.
- Quality control: Record temperature, humidity and operator information for each batch of tests.
- Data comparability: It is recommended to establish an internal laboratory control sample database.
Standard evolution
Since its initial publication in 1980, major revisions have included updating safety specifications in 2017 and improving accuracy specifications in 2023. This standard complies with the requirements of the WTO/TBT Agreement on Technical Barriers to Trade and has international applicability.
ASTM D3838-23 Referenced Document
- ASTM D1193 Standard Specification for Reagent Water
- ASTM D1293 Standard Test Methods for pH of Water
- ASTM D2867 Standard Test Methods for Moisture in Activated Carbon
- ASTM D6851 Standard Test Method for Determination of Contact pH with Activated Carbon*， 2024-10-01 Update
- ASTM E1272 Standard Specification for Laboratory Glass Graduated Cylinders
- ASTM E300 Standard Practice for Sampling Industrial Chemicals
ASTM D3838-23 history
- 2024 ASTM D3838-23 Standard Test Method for pH of Activated Carbon
- 2017 ASTM D3838-05(2017) Standard Test Method for pH of Activated Carbon
- 2005 ASTM D3838-05(2011) Standard Test Method for pH of Activated Carbon
- 2005 ASTM D3838-05 Standard Test Method for pH of Activated Carbon
- 1980 ASTM D3838-80(1999) Standard Test Method for pH of Activated Carbon
