In order to remediate the very poor mineralization of paracetamol in water, even when well degraded by using a Non-Thermal Plasma (NTP) process at a very low dissipated power, a plasma-catalyst coupling process was tested and investigated. A homemade glass fiber supported Fe³⁺ catalyst was immersed in the liquid to be treated in a Dielectric Barrier Discharge plasma reactor. The plasma-catalysis process, at the same low dissipated power, achieved a mineralization rate of 54% with a full conversion rate of paracetamol at 25 mg L⁻¹ in initial concentration after 60 min treatment, thanks to Fenton-like effects. The synergetic effects of the plasma-catalysis coupling process also improved the Energy Yield by a factor of two. The catalyst before and after use for treatment was characterized by Brunauer-Emmett-Teller and Thermogravimetric analysis. High-Performance Liquid Chromatography was used to measure the concentration of treated solution and to investigate the intermediates. Two of them, namely 1,4-hydroquinone and 1,4-benzoquinone, were formally identified. Some intermediates are presented in this paper as a function of treatment time and their UV absorbance spectra. NTP processes with and without catalyst coupling were compared in terms of acidity, conductivity, and nitrate concentrations in the treated solution.

The treatment by adsorption on activated carbon, ozonation, and ozone/activated carbon coupling of a solution containing six pharmaceutical compounds (metoprolol, carbamazepine, terbutaline, fluoxetine, and sulfamethoxazole) chosen among different pharmaceutical classes has been investigated. The efficiency of the processes was estimated through the removal of each target pollutant and the evolution of both toxicity (inhibition of Vibrio fisheri bioluminescence) and the total organic carbon concentration. The influence of pH, ranging from 3 to 7, on the process efficiency was also studied. In each experimental condition, the fastest removal of the pharmaceutical compounds was achieved with ozone/activated carbon coupling. Nevertheless, this process (ozonation and ozone/activated carbon coupling) leads to the formation of toxic by-products that significantly increase the toxicity of the treated effluent. Their removal would require extending the treatment time or increasing the ozone concentration,...

Four activated carbons were employed to analyse the adsorption of different enantiomeric mixtures of the herbicide metolachlor in aqueous solution. The adsorption kinetics and isotherms were measured and fitted with different theoretical models to exhaustively analyse the adsorption mechanism. Different adsorption capacities were observed as a function of textural features of the adsorbents revealing an important effect of the presence of micro and mesoporous development on the adsorbent–adsorbate interactions. Additionally, enantioselective adsorption was detected for two of the activated carbons employed, rendering a greater adsorption of the S-metolachlor enantiomer compared to the racemic mixture. This fact was associated to the accessibility of certain conformers of the herbicide to the larger pores, facilitating the non-electrostatic adsorption.

The adsorption of diethyl phthalate (DEP) was studied on four activated carbons (ACs) with different chemical and microporous properties. The kinetic results showed that the non-linear form of the pseudo-second order kinetic model provided the best parameters. Results further showed that the DEP adsorption kinetics is favored by ACs which have a ratio of a specific microporous surface to a specific external surface that is relatively low. Besides, an increase in temperature induced an increase in the rate constant k ₂ , but the adsorption capacity is temperature independent. Two models, (Langmuir (linear and non-linear forms) and Dubinin-Radushkevich-Kaganer (DRK)), were tested from experimental data. While the Langmuir model provided the best correlation on all the ACs studied. The surface occupied, calculated with the Langmuir parameter obtained by the non-linear form, evidenced the importance of the external surface and the mean pore size. The results show that the non-electrostatic interactions are predominant in the DEP adsorption and are essentially due to dispersion and hydrophobic interactions (for L27 and X17). In the case of F22 and S21 the DEP adsorption is only due to dispersion interaction. A comparison of the thermogravimetric analysis of the ACs washed and saturated shows that the DEP is totally desorbed between 300 and 500°C with a characteristic peak.