A modified spectrophotometric method for the determination of ferrous ion during the Fenton process

ABSTRACT

Fe³⁺strongly interferes the determination of Fe²⁺ by spectrophotometric method during the Fenton process. This study evaluated a modified spectrophotometric method for the determination of Fe²⁺ at the presence of Fe³⁺ during the Fenton process. Based on the traditional o-phenanthroline method, the modified method used a masking agent, namely F^–, to form complex with Fe³⁺ to eliminate its interference. The optimal dosage of F^– was dependent on the concentration of Fe³⁺ and the best molar ratio of F^–:Fe³⁺ was 20:1. The optimal solution pH was found out to be around 3.0 for the modified method to get reliable results. The selected seven metal ions had negligible influence on the determination of Fe²⁺ by the modified method. The upper limit for the molar ratio of Fe³⁺:Fe²⁺ in the solution was 20:1 (95%), above which relatively high error could be reached. The average recovery rate of iron ion was determined to be 98.9%, which suggests that the modified o-phenanthroline method is ideal for the study of iron ion changing during the Fenton process.

KEYWORDS:

• Ferrous ion
• spectrophotometric method
• sodium fluoride
• Fenton process

Disclosure statement

We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work titled ‘A modified spectrophotometric method for the determination of ferrous ion during the Fenton process’.

Additional information

Funding

This study was financially supported by the Education Department of Hunan Province [Grant No. 18C0819] and the College of Food and Chemical Engineering, Shaoyang University, China.