Detection of iron content in activated carbon

1. Scope

This standard specifies the test method for the iron content of activated carbon.

This standard applies to wooden activated carbon.

2. Referenced standards

The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. At the time of publication of this standard, all versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards.

GB/T6682-1992 Specification and test methods for water used in analytical laboratories

GB/T9721-1988 Chemical reagents - General rules for molecular absorption spectrophotometry (UV and visible light parts)

3. Method 1: 1,10-Phenanthroline (o-Phenanthroline) spectrophotometric method

3.1 Method principle

Using hydroxylamine hydrochloride as a reducing agent and adjusting pH 4.5 with acetic acid sodium acetate buffer, ferrous (Fe2+) forms an orange red complex with 1,10 phenanthroline. The absorbance is measured at a wavelength of 510nm on a spectrophotometer.

3.2 Instruments

The spectrophotometer complies with the provisions of GB/T9721.

3.3 Reagents and Solutions

The water used in this method should comply with the third grade water specifications in GB/T6682, and all reagents used refer to analytical pure reagents.

3.3.1 Hydrochloric acid (GB/T622), "1+9" solution.

3.3.2 Acetic acid (GB/T676), sodium acetate (GB/T694), acetic acid sodium acetate buffer solution (pH=4.5)

Weigh 16.4g of anhydrous sodium acetate, add 8.4mL of glacial acetic acid, dissolve in water, and dilute to 100mL.

3.3.3 Hydroxylamine Hydrochloride (GB/T6685) Hydroxylamine Hydrochloride Solution

Weigh 1g of hydroxylamine hydrochloride and dissolve it in 100mL of water.

3.3.41, 10 phenanthroline solution (GB/T1293)

Weigh 0.50g of 1,10 phenanthroline and dissolve it in 10mL of ethanol. Mix with 90mL of water and store in a dark place. If the solution is colored, it should be prepared again.

3.3.5 Ferrous sulfate [FeSO4 (NH4) 2? SO4? 6H2O

0.01mg/mL iron standard solution: Weigh 0.702g of ammonium ferrous sulfate and dissolve it in a small amount of water containing 0.5mL of sulfuric acid. Transfer it to a 1000mL volumetric flask and dilute it to the mark. Take out 100mL and dilute it to 1000mL. This solution contains Fe2+0.01mg/mL.

3.4 Operation methods

3.4.1 Weighing and crushing to 71 μ A dry sample of 1.0g (accurately weighed to 10mg) is placed in a 100mL conical flask. 25mL of "1+9" hydrochloric acid solution is added and boiled gently for 5 minutes. It is then cooled and filtered into a 100mL volumetric flask, and the filter residue is washed in hot water in batches. The filter residue and washing solution are combined, cooled to room temperature, and diluted to the mark. Take 10mL of filtrate and transfer it to a 50mL volumetric flask. Add 5mL of acetic acid sodium acetate buffer solution (3.3.2) and 2.5mL of hydroxylamine hydrochloride solution (3.3.3), 1,10