Modification of Indophenol Reaction for Quantification of Reduction Activity of Nanoscale Zero Valent Iron

Hwang, Yuhoon; Lee, Wontae; Andersen, Henrik R.; Hwang, Yuhoon; Lee, Wontae; Andersen, Henrik R.

doi:2016.38.12.667

The Korean text of this paper can be translated into multiple languages on the website of http://jksee.or.kr through Google Translator.

J Korean Soc Environ Eng > Volume 38(12); 2016 > Article

Original Paper

J Korean Soc Environ Eng 2016;38(12): 667-675. doi: https://doi.org/10.4491/KSEE.2016.38.12.667

나노 영가철 환원 반응성의 정량 분석을 위한 수정된 인도페놀법 적용

황유훈¹, 이원태², Henrik R. Andersen³

¹서울과학기술대학교 환경공학과
²금오공과대학교 환경공학과
³덴마크공과대학 환경공학과

Modification of Indophenol Reaction for Quantification of Reduction Activity of Nanoscale Zero Valent Iron

Yuhoon Hwang¹, Wontae Lee², Henrik R. Andersen³

¹Department of Environmental Engineering, Seoul National University of Science and Technology
²Department of Environmental Engineering, Kumoh National Institute of Technology
³Department of Environmental Engineering, Technical University of Denmark

Corresponding author

Yuhoon Hwang ,Tel: 02-970-6626, Fax: 02-971-5776, Email: yhhwang@seoultech.ac.kr

Received: October 11, 2016; Revised: December 26, 2016; Accepted: December 28, 2016. Published online: December 31, 2016.

ABSTRACT

Nanoscale zero-valent iron (nZVI) has been effectively applied for environmental remediation due to its ability to reduce various toxic compounds. However, quantification of nZVI reactivity has not yet been standardized. Here, we adapted colorimetric assays for determining reductive activity of nZVIs. A modified indophenol method was suggested to determine reducing activity of nZVI. The method was originally developed to determine aqueous ammonia concentration, but it was further modified to quantify phenol and aniline. The assay focused on analysis of reduction products rather than its mother compounds, which gave more accurate quantification of reductive activity. The suggested color assay showed superior selectivity toward reduction products, phenol or aniline, in the presence of mother compounds, 4-chlorophenol or nitrobenzene. Reaction conditions, such as reagent concentration and reaction time, were optimized to maximize sensitivity. Additionally, pretreatment step using Na₂CO₃ was suggested to eliminate the interference of residual iron ions. Monometallic nZVI and bimetallic Ni/Fe were investigated with the reaction. The substrates showed graduated reactivity, and thus, reduction potency and kinetics of different materials and reaction mechanism was distinguished. The colorimetric assay based on modified indophenol reaction can be promises to be a useful and simple tool in various nZVI related research topics.

Key Words: Nanoscale Zero Valent Iron, Indophenol Reaction, Colorimetric Assay, Reducing Activity