Study On The Photochemical Degradation Of Phenol By Cation Doped Cryptomelane

With the acceleration of industrial development, large quantities of organic wastewater are discharged into rivers and lakes. This eventually leads to the shortage of water resources. So the treatment of phenol wastewater, which is one of the very toxic and having extensive sources organic wastewater is extremely urgent, Since Cryptomelane, a common manganese oxide, has adsorption, oxidation and catalysis performance, it can be used in organic wastewater treatment. Also, as a semiconductor, the photocatalysis properties research of Cryptomelane has been attracting more and more attention. However, the cation doping can in a certain extent change the structure and chemical properties of Cryptomelane, which may has great influence on its adsorption, oxidation and photocatalysis properties.This experiment firstly adopted reflux method for preparing Cryptomelane(Cry) and silver, cerium and cobalt doped Cryptomelane(M-Cry) with different concentration, and Secondly the crystal structure, specific surface area and chemical composition were characterized, and then with the the ultraviolet and illumination light conditions to study photochemical activity of cryptomelane degradation phenol, clear the photocatalytic activity of cryptomelane; Discuss the effect of different reaction conditions(pH, concentration of phenol initial and mineral) on Cryptomelane photochemical degradation of phenol; Thirdly, Studies the photochemical degradation of phenol by the three kinds of cationic doped Cryptomelane, Explore the different types of cationic introduced affect Cryptomelane photochemical activity, preliminary discussion of its photochemical reaction mechanism; Compared with photochemical reactivity of TiO2(P25) by the same reaction conditions at the same time, The main results are as follows:1) Cryptomelane can oxidative degradation of phenol under the Light, the degradation rate was 25.9% after 12 h; Light can significantly promote the degradation of phenol by Cryptomelane, After 12 h reaction, the degradation rate is 64.6%; The main mechanisms of manganese potash degradation of phenol oxidative degradation and light catalytic degradation.2) pH lower propitious to manganese potash to the degradation of phenol under the condition of lighting and unlighted; The concentration of phenol and mineral had a significant influence on the degradation of phenol with the condition of lighting; The best reaction condition of pH is 4.0, mineral concentration is 1.00 g/L, phenol concentration is 100 mg/L.3) The introduction of the cationic of Cryptomelane phenol degradation rate increase is not significant under the condition of lighting, but it can significantly improve the TOC removal rate. After 12 h, the reaction of phenol degradation rate by the three best doping ratio of potassium cation doped Cryptomelane(Ag-Cry-10、Co-Cry-15、Ce-Cry-15)were 78.8%, 84.5% and 81.4%, Compared with not doping increased by 17.4%, 25.9% and 25.9% respectively; And the TOC removal rate of 56.9%, 59.6% and 54.0% respectively, Compared with not doped increase 127.6%, 138.4% and 116.0% respectively. Under the condition of unlighted, The introduction of the cationic Lead to the phenol degradation rate of Cryptomelane increased by 21.9%, 35.6% and 35.6% respectively; And the TOC removal rate increased by 43.8%, 92.6% and 92.6% respectively. With the comparison of the light and unllighted conditions of phenol degradation rate and the TOC removal rate by cationic doped Cryptomelane show that the introduction of the cation can improve the oxidation of Cryptomelane properties and photocatalytic degradation activity, and the improvement of photocatalytic degradation activity is more significant.4) TiO2(P25) phenol degradation rate was 93.2% by the condition of the same reaction, and the TOC removal rate was 73.7%. It found that the photochemical degradation efficiency of the cationic doped Cryptomelane were very close to the TiO2 after comparison with Ti O2; Optimizing cost low potassium Co doped Cryptomelane after considering the economic applicability.