Degradation of anatoxin-a by UV-C LED and UV-C LED/H2O2 advanced oxidation processes

Shilpi Verma, Mika Sillanpää

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)


In the present study UV-C LED photolysis and UV-C LED/H2O2 treatment processes were investigated for the degradation of anatoxin-a. The initial anatoxin-a concentration in the aqueous solution was kept at 1μM. During the treatment by UV-C LED, 50% degradation of anatoxin-a was achieved at UV fluence 4032J/m2. The optimum reaction conditions were: λ=260nm, initial pH=6.4, temperature=24°C and distance from water surface=5mm. The degradation of anatoxin-a followed the pseudo first order kinetics (k=2×10-4m2/J). The degradation of anatoxin-a was reduced to 28% in presence of carbonate ions (50mg/L) and at higher concentrations of carbonate ions the degradation was completely inhibited. The concentration of anatoxin-a was significantly reduced (62%) in the presence of dissolved organic matter (DOC) depicting the photosensitization effect of humic acid on the direct photolysis of anatoxin-a. The pseudo first order kinetic constant k at 0.03mg/L concentration of DOC was found to be 3×10-4m2/J. It was also observed that UV-C/H2O2 process enhanced the oxidation rate of anatoxin-a by 4.5 times in comparison to direct photolysis by UV-C LED leading to 97% degradation of anatoxin-a. In Pitkäjäärvi lake water, 96% removal of anatoxin-a was achieved by photolysis using UV-C LED and 79% removal was achieved with UV-C/H2O2 process. The acute toxicity tests were conducted using Vibrio fischeri. The results indicated a decrease in the acute toxicity of the treated samples, both after the UV-C LED photolysis and UV-C/H2O2 process.

Original languageEnglish
Pages (from-to)274-281
Number of pages8
JournalChemical Engineering Journal
Publication statusPublished - 5 Aug 2015
Externally publishedYes


  • Anatoxin-a
  • HO
  • Humic acid
  • Photolysis
  • Toxicity
  • UV-C LED

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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