Research On Removal Of Ibuprofen From Aqueous By Electrolysis-ozone Technology （E-O₃-CFA） Using Carbon Fiber Aerogel Cathode

Recently,organic pharmaceutical drugs（like IBP）have been detected in natural waters frequently,which are hard to be treated by traditional watertreatment techniques.They have caused the worse environmental impact and become the key point and difficulty of water pollution control gradually.Electrolysis-Ozone technology is a promising water treatment technology with the advantages of strong oxidation capacity,wide application range,low energy consumption,no secondary pollution,and so on.It is mainly dependent on the hydroxyl radical by cathode electric field to catalyze ozone,so the cathode material has great effect on the yield of hydroxyl radical.In this paper,carbon fiber aerogel material（CFA）was prepared by one-step direct pyrolysis using natural cotton fiber as a precursor.And The CFA cathode was used in the Electrolysis-Ozone technology（E-O₃-CFA）for the first time.The removal and reaction mechanism of IBP by E-O3-CFA process were systematically studied.The feasibility of using CFA cathode cathode for Electrolysis-Ozone technique was investigated.Firstly,the morphology,structure and surface chemical composition of CFA were investigated by SEM,XRD,XPS,BET and other analytical methods.The results showed that CFA had well-developed porous,interconnected three-dimensional network structure,large specific surface area,and high graphitization,meanwhile its surface was rich in functional groups,including C=C,C-O-C/C-OH,C=O,π-πand so on.Then,the removal of IBP by different cathode materials used in the Electrolysis-Ozone technique was compared and analyzed.The results showed that compared with activated carbon fiber（ACF）cathodes,graphite（GRA）cathodes and steel（STE）cathodes,the Electrolysis-Ozone technology using CFA cathode process significantly improved the removal rate and mineralization effect of IBP,significantly reduced the energy consumption of water treatment,and CFA had a good reuse performance in the E-O3-CFA process.Secondly,the effect of E-O₃-CFA process on the removal of IBP from aqueous was systematically investigated.Compared the removal of IBP by O₃,O₃-CFA,E-CFA,E-O₃-STE,and E-O₃-CFA process.The reaction of all processes followed the pseudo-first-order kinetic reaction model.The removal rate,mineralization rate and pseudo-first-order reaction kinetic constants of the E-O₃-CFA system were much higher than those of other systems and produced significant synergistic effects.The study of influencing factors showed that in the E-O₃-CFA process,the removal effect of IBP gradually increased with the carbon fiber aerogel filling amount and ozone concentration increased.But when they exceed a certain value,the improvement effect was not obvious.The removal effect of IBP increased with the current intensity and initial p H value increased gradually,but the removal effect was significantly suppressed when they over a certain value.The electrolyte concentration had no significant effect on the removal effect.The system was universal and had a good removal effect on IBP from surface water,groundwater,tap water and ultrapure water.Finally,the reaction mechanism was explored by free radical capture experiments.The linear sweep voltammetry results showed that the addition of carbon fiber aerogel promoted the reduction reaction of O₃ and O₂ at the cathode.E-O₃-CFA system would generate reactive oxygen species such as H₂O₂,·O₂^-,·OH,and ¹O₂.·O₂^-was a key intermediate to produce·OH.The E-O₃-CFA system significantly increased the yield of·OH.The IBP was mainly removed by the free radical oxidation pathway by·OH.The contribution of ¹O₂ indirect oxidation,electrochemical direct oxidation,ozone direct oxidation,and adsorption of activated carbon fibers to IBP removal was very low.