Study On Impact Of Electrochemical Oxidation On Carbon Fibers As Functional Material

Carbon fiber without any modification can be hardly at its best due to the low surface energy, about 2.7×10-3 N/m, hydrophobic property and the lack of active functional groups. Chemically Modified Electrode(CME), which has got developed since the mid 70's, can fix useful molecules, ions, and polymers onto the surface of electrode by molecular design to remodel the micro-structure of electrode and electrolytic interface, so that the electrode can be of fabulous catalyst.. CME enriches electrodes and exploits a new way to realize water treatment through oxidation approach.Through experiment, this paper claims that the optimal method of improving carbon fiber is to oxidize it for 5min in 0.5/mol L-1 H3PO4 solution with 2.0A/g current intensity. After treatment, the contact angle degree degreases by about 16o,the surface energy increases by nearly 9 times, and the adhesion to epoxy-resin is enhanced by 33% and the electrochemical response has been greatly improved, which demonstrates that the surface of carbon fiber is modified by fixing abundance of active functional groups, mainly lactone, hydroxyl and carboxyl confirmed by FT-IR spectra. Besides, this paper has discussed the electrochemical properties of carbon fiber in the solution of acid, salt, alkali and points out that the most intense oxidation occurs in acid solution, followed by neutral solution (salt), and the oxidation in alkali solution is totally negligible. All these data fully prove that it's reasonable to use H3PO4 solution to oxidize carbon fiber electrochemically. The electrochemical properties of treated carbon fiber show that the 0.5V anodic peak has relation with bond breaking, active carbon atom increasing and functional groups oxidation, while 0.19V anodic peak demonstrates active carbon atoms react with adsorbent hydroxyls.In our experiment, the oxidized carbon fiber is found to be fine electrode for electrochemical analysis owing to its good response to K4Fe(CN)6 + KCl solution and FeSO4+HClO4 solution. Furthermore, it is noticed that both carbon fiber electrode and carbon nanotube electrode can be used to detect and oxidize aqueous phenol of low concentration (no more than 5m mol L-1) on a basis of low oxidation (1.0VvsSCE) that occurs continuously without electrode adsorption. The activity of Carbon fiber electrode can be kept for 1200s, during which phenol decreases dramatically, while that of carbon nanotube electrode is able to last 6000s, during which phenol is oxidized into CO2...