GB/T 12496.10-1999Test methods of wooden activated carbon--Determination of methylene blue adsorption (English PDF)

Foreword

The series of standards for wooden activated carbon test methods are the basis for testing the performance indicator of activated carbon. To formulate the quality standard of activated carbon, there must be corresponding test method standards. This series of standards is a revision of GB/T 12496.1~12496.22-1999 Test Methods of Wooden Activated Carbon .Compared with the original standard, this Standard has made major changes in the arrangement order and specific test methods, while some have only changed the words and sentences. In the terminology, change "ignition residue", "loss on drying" and "bulk density" into "ash content", "moisture content" and "apparent density", respectively. In the content, delete GB/T 12496.3-1990 Test Method of Wooden Activated Carbon - Adsorption of Acetic Acid , and GB/T 12496. 4-1990 Test Method of Wooden Activated Carbon - Adsorption of Zinc Acetate include in GB/T 13803.5-1999 Support Activated Carbon for Vinyl Acetate Synthesis . And add GB/T 12496.5-1999 Test Methods of Wooden Activated Carbon - Determination of Carbon Tetrachloride Activity , and GB/T 12496.17-1999 Test Methods of Wooden Activated Carbon - Determination of Sulphate . In addition, the omissions in the original standard were supplemented. This standard replaced GB/T 12496.1~12496.22-1990 from the date of implementation. This standard was proposed and under the jurisdiction of the State Forestry Administration. Drafting organization of this Standard: Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry. Chief drafting staff of this Standard: Shi Yinrui. This Standard was first-time published in 1990.

1 Scope

This Standard specifies the test methods for the methylene blue adsorption value of wooden activated carbon. This Standard applies to wooden activated carbon.

2 Normative References

The following standards contain provisions which, through reference in this Standard, constitute provisions of this Standard. At the time of publication, the editions indicated are valid. All standards are subject to revision. The parties who are using this Standard shall explore the possibility of using the latest version of the following standards. GB/T 6682-1992 Water for laboratory use - Specifications GB/T 9721-1988 Chemical reagent - General rules for the molecular absorption spectrophotometry (ultraviolet and visible)

3 Method Summary

The specimen is mixed with a certain amount (in milliliters) of methylene blue solution and then filtered. The absorbance of the filtrate is measured by a spectrophotometer. If the absorbance is lower than the absorbance of the standard solution at a specified concentration, the required number of milliliters of methylene blue is the methylene blue adsorption value of the activated carbon specimen.

4 Main Instruments

4.1 Electric oscillator (reciprocating), with frequency about 275 times/min.

4.2 Spectrophotometer (GB/T 9721).

5 Reagents and Solutions

The water used in this Standard shall comply with the Grade-3 water specifications in GB/T 6682. The listed reagents are analytically pure reagents unless otherwise specified.

5.1 Methylene blue, indicator.

5.2 Disodium hydrogen phosphate [Na2HPO4 -12H2O] (GB/T 1263).

5.3 Potassium dihydrogen phosphate (GB/T 1274).

5.4 Buffer solution: Weigh 3.6 g of potassium dihydrogen phosphate and 14.3 g of disodium hydrogen phosphate and dissolve them in 1,000 mL of water. The pH value of this buffer solution is about 7.

5.5 Methylene blue test solution (1.5 g/L)

5.5.1 Preparation Since the properties of methylene blue change during the drying process, it shall be used without drying. Therefore, it is necessary to measure its moisture content after drying at (105 ± 0.5) °C for 4 h. The amount of undried methylene blue to be used is calculated according to Formula (1): Where:

m1 - mass of undried methylene blue, in g

E - moisture content, in %

m - required amounts of dry products, in g

P - purity of methylene blue, in %. Calculate the amount of undried product equivalent to 1.5 g of dry methylene blue according to Formula (1). Dissolve the weighed methylene blue (accurate to 1 mg) in a buffer solution at a temperature of (60±10)°C. After it is completely dissolved, cool it to room temperature and filter it into a 1,000 mL volumetric flask. Wash the filter residue with buffer solution for several times and dilute it to the mark with buffer solution. Chinese Standards