In this study, the degradation of β-N-methylamino -L-alanine (BMAA; a novel neurotoxin produced by cyanobacteria) in the UV₂₅₄/persulfate (PS) system was investigated. The degradation of BMAA satisfied the pseudo-first-order kinetic model. Moreover, the effects of reaction parameters (PS concentration, BMAA concentration, and pH) and water matrix (natural organic matter (NOM) and some anions) were evaluated. The second-order rate constants between BMAA and SO₄•^- or •OH at pH 7 were 4.75×10 ⁹ M ^-1·s ^-1 and 5.49×10 ⁹ M ^-1·s ^-1, respectively, as measured by a competition kinetics experiment. The results of the steady-state kinetics model and scavenging experiments indicated that SO₄^-• was the major radical contributing to BMAA degradation in the UV₂₅₄/PS system. Moreover, pH significantly affected the degradation rate of BMAA, and the highest rate was obtained at pH 8 with a pseudo-first-order rate constant (k_obs) of 1.039 min^-1. However, the degradation of BMAA was inhibited in aqueous solution due to the influence of the water matrix. The k_obs decreased in the presence of NOM and chloride ions (Cl^-) and increased in the presence of bicarbonate (HCO₃^-). Given that the degradation rate of total organic carbon (TOC) was lower than that of BMAA, the transformation products and a possible degradation pathway were investigated. The C-N bond on BMAA may be attacked by radicals, and BMAA may be transformed into 2,3-diaminopropionic acid or L-alanine. Moreover, BMAA could also be converted to 2-hydroxy-3-methylamino propanoic acid through hydroxylation. Three different BMAA transformants were further oxidized to generate pyruvic acid, after which decarboxylation leads to the formation of acetic acid from pyruvate.

在这项研究中，研究了β-N-甲基氨基-L-丙氨酸（BMAA；由蓝细菌产生的新型神经毒素）在UV ₂₅₄ /过硫酸盐（PS）系统中的降解。BMAA的降解满足伪一级动力学模型。此外，评估了反应参数（PS浓度，BMAA浓度和pH）和水基质（天然有机物（NOM）和一些阴离子）的影响。pH值为7时BMAA与SO ₄ • ^-或•OH之间的二级速率常数为4.75×10 ⁹ M ^-1 ·s ^-1和5.49×10 ⁹ M ^-1 ·s ^-1分别由竞争动力学实验测得。稳态动力学模型和清除实验的结果表明，SO ₄ ^- •是BMAA降解的主要贡献自由基在UV ₂₅₄ / PS体系。此外，pH值显着影响BMAA的降解速率，在pH值为8时以1.003 min ^-1的拟一级速率常数（k _obs）获得了最高速率。但是，由于水基质的影响，在水溶液中抑制了BMAA的降解。所述ķ _OBS在NOM和氯离子（CL的存在降低^- ）和碳酸氢盐的存在下增加（HCO ₃^-）。考虑到总有机碳（TOC）的降解率低于BMAA，研究了转化产物和可能的降解途径。BMAA上的CN键可能受到自由基的攻击，并且BMAA可能被转化为2,3-二氨基丙酸或L-丙氨酸。此外，BMAA还可以通过羟基化转化为2-羟基-3-甲基氨基丙酸。将三种不同的BMAA转化子进一步氧化生成丙酮酸，然后脱羧导致丙酮酸形成乙酸。