Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): Influence of variable amino acids on the degradation kinetics and reaction mechanisms

被引：81

作者：

He, Xuexiang ^{[1
,2
]}

de la Cruz, Armah A. ^{[3
]}

Hiskia, Anastasia ^{[4
]}

Kaloudis, Triantafyllos ^{[5
]}

O'Shea, Kevin ^{[6
]}

Dionysiou, Dionysios D. ^{[1
,2
]}

机构：

[1] Univ Cincinnati, Environm Engn & Sci Program, Cincinnati, OH 45221 USA

[2] Univ Cyprus, Nireas Int Water Res Ctr, CY-1678 Nicosia, Cyprus

[3] US EPA, Off Res & Dev, Cincinnati, OH 45268 USA

[4] Natl Ctr Sci Res Demokritos, Inst Adv Mat Physicochem Proc Nanotechnol & Micro, Athens 15310, Greece

[5] Athens Water Supply & Sewerage Co EYDAP SA, Water Qual Dept, Athens 11146, Greece

[6] Florida Int Univ, Dept Chem & Biochem, Miami, FL 33199 USA

来源：

WATER RESEARCH | 2015年 / 74卷

基金：

美国国家科学基金会;

关键词：

Microcystins; UV-254; nm; Hydrogen peroxide; Second-order rate constant; Mechanism; Variable amino acids; CYANOBACTERIAL TOXIN CYLINDROSPERMOPSIN; HYDROXYL RADICALS; AQUEOUS-SOLUTION; HYDROGEN-PEROXIDE; RATE CONSTANTS; POTASSIUM PEROXYMONOSULFATE; PHOTOCATALYTIC OXIDATION; UV/H2O2; TREATMENT; MAT COMMUNITIES; DRINKING-WATER;

D O I：

10.1016/j.watres.2015.02.011

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O82- and UV/HSO5-. Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O82- > UV/HSO5- > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms. (C) 2015 Elsevier Ltd. All rights reserved.

引用

页码：227 / 238

页数：12