| The treatment of organic wastewater with high toxicity and hard biodegradation were studied as the focus. Due to the benefits of high degradation efficiency and no second pollution, the method of electro-catalysis oxidation attracted people′s widespread attention. In the electrochemical oxidation process of organic pollutants, the choice of anodic materials was always the most crucial factor. In recent years, boron-doped diamond (BDD) film electrode had attracted an increasing attention due to its excellent physical and chemical capabilities. In this dissertation, the electrochemical capabilities of BDD film electrode were studied systematically, and the electrochemical behaviors of p-chlorophenol and degradation technology were investigated, the mechanism of degradation of p-chlorophenol was proposed.The results of cyclic voltammetry showed that the electrode had a very wide potential window and high potential of oxygen evolution, and in acidic, neutral, alkaline medium the potential windows were separately 3.3V, 3.8V, 2.7V, the potential of oxygen evolution were separately +2.3V, +2.1V, +1.0V; The oxygen evolution was a very complex electrochemical process, and the process was easy to produce hydroxyl radical and other strong oxidizing substances; in electrolyte including Ferri/Ferrocyanide, the electrode surface always kept good activity, and the electrochemical reaction was a diffusion-controlled process.The electrochemical oxidation behavior of p-chlorophenol on BDD film electrode had been studied by cyclic voltammetry,chronoamperomertry and AC Impedance. The results showed that a complex electrochemical reaction was occurred on BDD film electrode, In the low potential, p-chlorophenol occured direct electrochemical oxidation reaction on BDD film electrode that resulted in electrode fouling and deactivation due to the formation of organic film on its surface, while in the high potential, indirect electrochemical oxidation reaction and direct electrochemical oxidation reaction took place together, and electrogenerated active intermediates, probably·OH, could oxide the organic pollutants of the electrode surface during indirect electrochemical oxidation, so the electrode surface kept good activity during the electrochemical oxidation.We used a BDD film electrode as anode and a stainless steel (AISI304) as cathode to degrade p-chlorophenol in a no dissepimental electrobath, and the effects of anodic current density, the initial p-chlorophenol concentration, the initial pH value and the supporting electrolyte concentration were investigated in the process of degrading p-chlorophenol. Through the study of technological tests of electro-oxidation degradation of p-chlorophenol, the optimized technological parameters were obtained as following: anodic current density being 60mA·cm-2, the initial p-chlorophenol concentration being 10mmol·L-1, the initial pH value being 7, supporting electrolyte concentration being 10g·L-1. Under above optimized technological conditions, the removal of COD and the average current efficiency were obtained as 96.1% and 50.2%.The degradation of p-chlorophenol on BDD film electrode was better than the lead dioxide electrode. The mechanism of degradation of p-chlorophenol was proposed by the the results of high performance liquid chromatography and Mass spectra. The degradation of p-chlorophenol with lower concentration had been studied by the integration of the adsorption with AC and the electrolysis with BDD film electrode, and the effects of anodic current density, the supporting electrolyte concentration and the initial pH value were investigated. The results showed that compared with AC adsorption and electrolysis, the treatment efficiency was significantly promoted by the combined process integrated with electrolysis and AC adsorption. Under the optimal condition: the initial p-chlorophenol concentration being 200mg·L-1,the amount of AC being 2g·L-1,anodic current density being 15mA·cm-2,the supporting electrolyte concentration being 8g·L-1,the initial pH value being 7, the COD removal of COD was obtained as 98%, and AC kept good performance for five consecutive runs. So the reactor existed synergetic effects between the adsorption and electrolysis, the electrolysis efficiency was promoted by the adsorption of AC, and the regeneration of AC was obtained by the electrolysis of BDD film electrode, which enhanced the catalysis of AC and the removal of p-chlorophenol. And consecutive run of AC was obtained by the regeneration, which reduced the cost and the waste of the resource. |
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