Photoelectrocatalytic Oxidation Of 2-nitrophenol By TiO 2 Nanotube Electrode

Environmental pollutants2-nitro phnol is widely used in industral production such asdynamite?pesticides?dye?rubber and so on. It has great toxicity and is difficult to degradatebecause of its special structure such as benzene ring and nitro. Photoelectrocatalysis has attractedmore and more concern and attention of people in waste water treatment for its high degradationefficiency?broad prospects and environmental-friendly. Therefore, I develop foundamentalresearch on photoelectrocatalysis for the organic waste water using2-nitro phnol.Electrodematerial and preparation is the core issue in photoelectrocatalysis, because it impacts thestructure of electrode, and then impacts photoelectrocatalysis activity and stability. With the riseand development of photoelectrocatalysis, people pay great attention to the study and research ofelectrode material which is new, clean and efficient.In this article, I investigate the preparation method of TiO₂nanotube, and discuss somefactors that impact the degredation efficiency of2-nitro phnol. I get the optimal degredationcondition and evaluate the electrode in waste water treatment. This fundamental work may helpthe electro-catalytic oxidation technology to be actually applied in waste water treatment.I prepare TiO₂nanotube with anodic oxidation?and optimize the preparation condations?oxidation solution, oxidation potential, oxidation time and temperature. Use the2-nitro phnol astarget pollution, test the electrode's degredation efficiency. The best condition is: solution0.15MNH₄F+0.5M H₃PO₄, H₂O:glycol=3:7?oxidation potential is20V, oxidation time is60min,oxidation temperature is28?, heat treatment rate is5?/min, maintaining3hours at500?. Ianalysis the growth process of TiO₂nanotube, it is initial oxide film, porous oxide film and itsgrowth. Using0.05mM2-nitro phnol and0.1M Na₂SO₄as solution, test electrode's efficiencywith cyclic voltammetry, potentiostatic chronoamperometry, AC impedance and UV-visiblespectrophotometry, discuss some factors that impact degradation efficiency: concentration of2-nitro phnol and Na₂SO₄,pH, potential and temperature. The result is: concentration of2-nitrophnol0.03mM>0.05mM>0.01mM>0.07mM>0.1mM, concentration of Na₂S_O40.05M>0.15M>0.08M>0.2M>0.1M, pH8>10>14>5>1, potential1V>0.8V>0.6V>0.4V>0.2V>0V, temperature28?>40?>13?>50?. So, when the concentration of2-nitrophnol is0.03mM, the concentration of Na2SO4is0.05M, pH=8, potential is0.6V, temperatureis28?, the degredation efficiency can be100%after90min. This proves TiO₂nanotube hasnice photoelectrocatalysis efficiency. In addition, cyclic voltammetry proves: the degredation of2-nitro phnol is irreversible reaction, Impedance spectroscopy is semicircle?shows that thereaction is controlled by charge and mass transfer process.At last, I discuss the reactionmechanism, the oxide of organics by TiO₂nanotube is by OH· radical.