title: Diclofenac removal from water with ozone and activated carbon.
abstract: Diclofenac (DCF) has been treated in water with ozone in the presence of various activated carbons. Activated carbon-free ozonation or single ozonation leads to a complete degradation of DCF in less than 15 min while in the presence of activated carbons higher degradation rates of TOC and DCF are noticeably achieved. Among the activated carbons used, P110 Hydraffin was found the most suitable for the catalytic ozonation of DCF. The influence of pH was also investigated. In the case of the single ozonation the increasing pH slightly increases the TOC removal rate. This effect, however, was not so clear in the presence of activated carbons where the influence of the adsorption process must be considered. Ecotoxicity experiments were performed, pointing out that single ozonation reduces the toxicity of the contaminated water but catalytic ozonation improved those results. As far as kinetics is concerned, DCF is removed with ozone in a fast kinetic regime and activated carbon merely acts as a simple adsorbent. However, for TOC removal the ozonation kinetic regime becomes slow. In the absence of the adsorbent, the apparent rate constant of the mineralization process was determined at different pH values. On the other hand, determination of the rate constant of the catalytic reaction over the activated carbon was not possible due to the effect of mass transfer resistances that controlled the process rate at the conditions investigated.
authors: Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, Avenida de Elvas S/N, 06071 Badajoz, Spain. fbeltran@unex.es
authors: Fernando J
authors: FJ
authors: Beltrán
authors: Pablo
authors: P
authors: Pocostales
authors: Pedro
authors: P
authors: Alvarez
authors: Ana
authors: A
authors: Oropesa
mesh_terms: D000327:Adsorption; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000302:isolation & purification; D002606:Charcoal; D016861:Cyclooxygenase Inhibitors / Q000302:isolation & purification; D004008:Diclofenac / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010126:Ozone; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D014874:Water Pollutants, Chemical; D004008:Diclofenac; D002606:Charcoal; D010126:Ozone