Cobalt molybdenum catalyst is a widely used catalyst in the production process of synthetic ammonia in recent years. Its service life is generally 3~. After failure, cobalt element in the catalyst belongs to the iron-based element and often exists in the human living environment in the form of divalent ions. Due to its inherent accumulation and non degradability, it can cause great harm to human health and the environment. Therefore, researching rapid detection methods for heavy metal element content is of great significance.

At present, the main analytical instruments and methods for determining heavy metal ions include atomic emission spectroscopyAtomic Fluorescence SpectrometerElectrochemical method, voltammetryAtomic absorption spectrometerAnd Coulomb counting method, etc. However, these instruments have relatively complex operating procedures and are relatively expensive, while spectrophotometry is used to determine the content of heavy metal ions. This method can effectively utilize masking agents to mask the influence of non target metal ions on the determination of target metal ions. It is simple, fast, easy to operate with detection instruments, high precision, and ideal recovery rate.

spectrophotometerWhen measuring samples, it is necessary to pre separate the interfering substances in the sample. The optimized experimental conditions for determining the cobalt content in waste cobalt molybdenum catalysts using spectrophotometry are:
Measure the wavelength at 530nm;
The mass concentration of sodium citrate solution is 250g/L;
The mass concentration of 3 sodium nitrite solution (oxidant) is 5g/L;
The dosage of 4 5g/L nitroso red salt solution (color reagent) is 5mL;
The dosage of 5 sulfuric acid (1+1) solution is 10mL.
There is a linear relationship between the mass of cobalt within 0.35mg and the absorbance. The detection limit of cobalt is 10 µ g/L, the average recovery rate is 98.9%, and the relative standard deviation of the measured value is 4.6%.