Strongly enhanced Fenton degradation of organic pollutants by cysteine: An aliphatic amino acid accelerator outweighs hydroquinone analogues

• Published in: Water research (Oxford) Vol. 105; pp. 479 - 486
• Main Authors: Li, Tuo, Zhao, Zhenwen, Wang, Quan, Xie, Pengfei, Ma, Jiahai
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.11.2016
• Subjects: Accelerators; Aliphatic compounds; Amino Acids; catalytic activity; Cysteine; Cystine; Degradation; Fenton; hydrogen peroxide; Hydrogen Peroxide - chemistry; Hydroquinone; Hydroquinones; iron; Iron - chemistry; Iron redox cycle; Oxidation-Reduction; Pollutants; Quinone–hydroquinone; Fenton; Cysteine; Iron redox cycle; Quinone–hydroquinone
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2016.09.019

Quinone–hydroquinone analogues have been proven to be efficient promoters of Fenton reactions by accelerating the Fe(III)/Fe(II) redox cycle along with self-destruction. However, so far there is little information on non-quinone–hydroquinone cocatalyst for Fenton reactions. This study found that cysteine, a common aliphatic amino acid, can strongly enhance Fenton degradation of organic pollutants by accelerating Fe(III)/Fe(II) redox cycle, as quinone–hydroquinone analogues do. Further, cysteine is superior to quinone–hydroquinone analogues in catalytic activity, H2O2 utilization and atmospheric limits. The cocatalysis mechanism based on the cycle of cysteine/cystine was proposed. [Display omitted] •Addition of cysteine strongly enhances the Fenton degradation of RhB.•The cysteine system has better H2O2 utilization and independence of dissolved oxygen.•The self-cycle mechanism of cysteine has been proposed and is distinct from that of hydroquinone/quinone.