TY - JOUR
T1 - Brönsted Catalyzed Hydrolysis of Microcystin-LR by Siderite
AU - Fang, Yanfen
AU - Zhou, Wei
AU - Tang, Changcun
AU - Huang, Yingping
AU - Johnson, David Mark
AU - Ren, Zhiyong Jason
AU - Ma, Wanhong
N1 - Funding Information:
This work is founded by the National Natural Science Foundation of China (21577078, 21677086, 21377067, and 21407092) and the Natural Science Foundation for Innovation Group of Hubei Province, China (2015CFA021). We thank Dr. Julien Allaz for the composition analysis of minerals from the Department of Geology, University of Colorado Boulder. We also thank Dr. Zhao Bo of the Department of Pharmacology, Medical Science College (CTGU, China) for his assistance in toxicity testing experiments.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/6/5
Y1 - 2018/6/5
N2 - Six naturally occurring minerals were employed to catalyze the hydrolysis of microcystin-LR (MC-LR) in water. After preliminary screening experiments, siderite stood out among these minerals due to its higher activity and selectivity. In comparison with kaolinite, which is known to act as a Lewis acid catalyst, siderite was found to act primarily as a Brönsted acid catalyst in the hydrolysis of MC-LR. More interestingly, we found that the presence of humic acid significantly inhibited catalytic efficiency of kaolinite, while the efficiency of siderite remained high (â¼98%). Reaction intermediates detected by LC-ESI/MS were used to indicate cleavage points in the macrocyclic ring of MC-LR, and XPS was used to characterize siderite interaction with MC-LR. Detailed analysis of the in situ ATR-FTIR absorption spectra of MC-LR indicated hydrogen bonding at the siderite-water-MC-LR interface. A metastable ring, involving hydrogen bonding, between surface bicarbonate of siderite and an amide of MC-LR was proposed to explain the higher activity and selectivity toward MC-LR. Furthermore, siderite was found to reduce the toxicity of MC-LR to mice by hydrolyzing MC-LR peptide bonds. The study demonstrates the potential of siderite, an earth-abundant and biocompatible mineral, for removing MC-LR from water.
AB - Six naturally occurring minerals were employed to catalyze the hydrolysis of microcystin-LR (MC-LR) in water. After preliminary screening experiments, siderite stood out among these minerals due to its higher activity and selectivity. In comparison with kaolinite, which is known to act as a Lewis acid catalyst, siderite was found to act primarily as a Brönsted acid catalyst in the hydrolysis of MC-LR. More interestingly, we found that the presence of humic acid significantly inhibited catalytic efficiency of kaolinite, while the efficiency of siderite remained high (â¼98%). Reaction intermediates detected by LC-ESI/MS were used to indicate cleavage points in the macrocyclic ring of MC-LR, and XPS was used to characterize siderite interaction with MC-LR. Detailed analysis of the in situ ATR-FTIR absorption spectra of MC-LR indicated hydrogen bonding at the siderite-water-MC-LR interface. A metastable ring, involving hydrogen bonding, between surface bicarbonate of siderite and an amide of MC-LR was proposed to explain the higher activity and selectivity toward MC-LR. Furthermore, siderite was found to reduce the toxicity of MC-LR to mice by hydrolyzing MC-LR peptide bonds. The study demonstrates the potential of siderite, an earth-abundant and biocompatible mineral, for removing MC-LR from water.
UR - http://www.scopus.com/inward/record.url?scp=85046546782&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85046546782&partnerID=8YFLogxK
U2 - 10.1021/acs.est.7b06096
DO - 10.1021/acs.est.7b06096
M3 - Article
C2 - 29697970
AN - SCOPUS:85046546782
SN - 0013-936X
VL - 52
SP - 6426
EP - 6437
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 11
ER -