کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6306706 | 1618817 | 2016 | 8 صفحه PDF | دانلود رایگان |
- Salicylic, 4-aminosalicylic and 5-aminosalicylic acids treated in a BDD/air-diffusion cell.
- Faster pseudo-first-order decay for 4-aminosalicylic acid by AO-H2O2, EF and PEF.
- Quicker mineralization rate and current efficiency for salicylic acid in EF and PEF.
- More than 98% mineralization for all the drugs by the most powerful PEF treatment.
- Detection of oxalic acid as product of all the drugs and oxamic acid for both aminosalicylic acids.
Solutions of 100Â mL with 1.20Â mM of salicylic acid (SA), 4-aminosalicylic acid (4-ASA) or 5-aminosalicylic acid (5-ASA) have been comparatively degraded by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Trials were carried out with a stirred tank reactor with a BDD anode and an air-diffusion cathode for continuous H2O2 production. A marked influence of the functional groups of the drugs was observed in their decay kinetics, increasing in the order SA < 5-ASA < 4-ASA in AO-H2O2 and 5-ASAÂ <Â SA < 4-ASA in EF and PEF, due to the different attack of OH generated at the BDD surface and in the bulk from Fenton's reaction, respectively. This effect was clearly observed when varying the current density between 16.7 and 100Â mAÂ cmâ2. The relative mineralization power of the processes always followed the sequence: AO-H2O2 < EFÂ <Â PEF. The three drugs underwent analogous mineralization abatement up to 88% by AO-H2O2 at 100Â mAÂ cmâ2. The mineralization rate in EF and PEF grew in the order: 4-ASA < 5-ASAÂ <Â SA. The most powerful process was PEF, attaining >98% mineralization for all the drugs at 100Â mAÂ cmâ2. Oxalic and oxamic acids were detected as final short-linear aliphatic carboxylic acids by ion-exclusion HPLC, allowing the fast photolysis of their Fe(III) complexes by UVA light to justify the high power of PEF.
Journal: Chemosphere - Volume 154, July 2016, Pages 171-178