Improved transformation of paracetamol with pulsed electron beam and UV treatment
摘要
The present study comparatively investigates the UV and e‑beam degradation of paracetamol to determine final residual products after its UV and pulsed e‑beam treatment. Using an experimental setup RSLS, paracetamol was irradiated by a vertical electron beam (a pulse duration of 2 ns, an average electron energy of 170 keV, a current density of 130 A/cm2, and a repetition rate of 1 Hz) from a RADAN-300 generator. Four methods, including UV-VUV photolysis (KrCl, Xe2, and UVB-04) and e‑beam radiolysis, were used to induce the paracetamol degradation from 1×10−4 to 4.6×10−7 mol×L−1 when the drug was dissolved in water or deposited to TLC plates in a solid state. A spectral-luminescent paracetamol transformation under UV and e‑beam irradiation was studied. New experimental data were obtained on the total phenol content (TPC) in a mixture of paracetamol transformation products in water under irradiation. Moreover, the lowest TPC value of 9.76 ± 0.82 mg GAE/g was observed in an aqueous solution of paracetamol irradiated with a Xe2 excilamp for 128 min. It was found that the conversion reached 92 and 93% after irradiation with e‑beams and the Xe2 excilamp, respectively. A solid-phase paracetamol transformation product, preserved after 128 min of UV irradiation, was detected using thin layer chromatography. The available results suggest that, apparently, after Xe2 excilamp (2.4 kGy) and e‑beam (1.47 kGy) treatment, paracetamol that may be present in the treated wastewater will be in the form of residual phenolic compounds.