Removal of Reactive Black 5 by UV-C assisted peroxydisulfate process: Effect of parameters, kinetic study, and phytotoxicity assessment

Omaç F., Karakurt H., KARTAL Ö. E.

International Journal of Environmental Analytical Chemistry, cilt.105, sa.10, ss.2432-2452, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 105 Sayı: 10
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1080/03067319.2024.2317424
  • Dergi Adı: International Journal of Environmental Analytical Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Chemical Abstracts Core, Chimica, Compendex, Environment Index, Food Science & Technology Abstracts, Pollution Abstracts, Veterinary Science Database
  • Sayfa Sayıları: ss.2432-2452
  • Anahtar Kelimeler: azo dye, decolourisation, electrical energy consumption, mineralisation, Peroxydisulfate, sulphate radical
  • İnönü Üniversitesi Adresli: Evet

Özet

Photochemical removal of Reactive Black 5 (RB5) was investigated by the UV-C assisted peroxydisulfate (UV-C/PDS) process. Parameters affecting the removal of RB5 were examined. Activation of PDS by UV-C light significantly improved the removal efficiency compared to direct photolysis or PDS alone. The removal of RB5 by UV-C/PDS process fitted well with the pseudo first-order kinetic model under all tested conditions. Almost complete removal of RB5 was achieved at the end of 120 min within the pH range of 3–7, whereas 90.7 and 89.4% removal efficiency values were observed at pH = 9 and 11, respectively. An increase in PDS dosage in the range of 0.25–1 mM led to a rise in removal from 48.5 to 97.3% after 120 min, and a complete removal was observed with a dosage higher than 2 mM. Pseudo firstorder rate constant (kobs) increased linearly with PDS dosage from 0.0058 to 0.0518 min−1 in the 0.25 mM − 2.3 mM concentration range. The removal efficiency decreased with an increase in the initial concentration of RB5 from 20 to 50 mg L−1 and an exponential correlation was observed between kobs and initial concentration of RB5. Scavenging experiments conducted using t-butyl alcohol and ethyl alcohol implied that both sulphate and hydroxyl radicals were involved in the removal of RB5. Adding HCO3− decreased the removal of RB5 within the range of 1–30 mM. The presence of CI− showed a negative impact on the removal at low concentrations (1–15 mM) and NO3− slightly inhibited the removal of RB5. With corresponding stoichiometric PDS dosage, almost a complete mineralisation was achieved for RB5 solution and simulated dyebath effluent after 720 min of reaction time. EE/O values were determined to be 91.0, 76.8, and 41.1 kWh m−3 order−1 for UV-C/H2O2, UV-C/PMS, and UV-C/PDS processes, respectively. The phytotoxicity tests indicated that the intermediates could be more toxic than the parent compound.