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Evaluation of ultraviolet/peracetic acid to degrade M. aeruginosa and microcystins -LR and -RR
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2021-09-27 , DOI: 10.1016/j.jhazmat.2021.127357
Husein Almuhtaram 1 , Ron Hofmann 1
Affiliation  

The reactivity of peracetic acid (PAA) alone, and PAA exposed to ultraviolet radiation (UV), was investigated on Microcystis aeruginosa cells, and on microcystin-LR and -RR. Reaction rates between PAA and MC-LR (k = 3.46 M−1 s−1) and MC-RR (k = 2.67 M−1 s−1) were determined in an unbuffered acidic solution, and they are approximately 35–45 times lower than a previously reported reaction rate between MC-LR and chlorine at pH 6. Peracetic acid reacted with M. aeruginosa cells as a function of PAA and cell concentrations, with 10 mg/L PAA resulting in 1-log reduction of total MC-LR within 15 min. Advanced oxidation by UV/PAA readily degraded MC-LR and MC-RR, outperforming UV/H2O2 at pH 7.7 by > 50% on an equimolar basis. Indirect photolysis at this pH is due to OH and organic radicals, as determined by trials in the presence of excess tert-butanol to scavenge OH. The process is less effective when the pH departs from neutral conditions (5.9 or 10.6) due to the decreased effects of both radicals. These findings suggest that PAA alone might be a viable option for cyanobacteria and microcystins control in preoxidation applications and that UV/PAA is an effective process for degrading MC-LR and MC-RR at neutral pH.



中文翻译:

紫外线/过氧乙酸降解绿脓杆菌和微囊藻毒素-LR和-RR的评价

在铜绿微囊藻细胞和微囊藻毒素-LR 和-RR 上研究了单独的过乙酸 (PAA) 和暴露于紫外线辐射 (UV) 的 PAA 的反应性。PAA 和 MC-LR ( k  = 3.46 M -1 s -1 ) 和 MC-RR ( k  = 2.67 M -1 s -1 ) 之间的反应速率是在无缓冲的酸性溶液中测定的,它们约为 35-45 倍低于先前报道的 MC-LR 与氯在 pH 6 时的反应速率。过氧乙酸与绿脓杆菌反应细胞作为 PAA 和细胞浓度的函数,10 mg/L PAA 导致 15 分钟内总 MC-LR 减少 1-log。UV/PAA 的高级氧化很容易降解 MC-LR 和 MC-RR,在等摩尔基础上,在 pH 7.7 时优于 UV/H 2 O 2 > 50%。在此 pH 值下的间接光解是由于 OH 和有机自由基,正如在过量丁醇存在下进行试验所确定的那样哦。当 pH 值偏离中性条件(5.9 或 10.6)时,由于两种自由基的作用降低,该过程的效果较差。这些研究结果表明,单独使用 PAA 可能是在预氧化应用中控制蓝藻和微囊藻毒素的可行选择,并且 UV/PAA 是在中性 pH 条件下降解 MC-LR 和 MC-RR 的有效过程。

更新日期:2021-10-21
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