电晕放电等离子体与H_2O_2氧化降解甲基蓝的光谱行为比较

Comparison of Spectral Behavior of Methyl Blue Degraded by Corona Discharge Plasma and H_2O_2 Oxidation

采用紫外-可见光谱和FT-IR研究了电晕放电等离子体与H_2O_2氧化两种方法降解甲基蓝过程溶液的颜色变化和光谱行为差异。紫外-可见光谱结果表明,电晕放电等离子体降解甲基蓝过程溶液的颜色先加深再逐渐变浅,而H_2O_2氧化甲基蓝过程溶液的颜色一直变浅;H_2O_2氧化甲基蓝过程产生的中间物质在紫外-可见谱图中279 nm与372 nm处产生新吸收峰,而电晕放电等离子体降解甲基蓝过程的紫外-可见谱图中603 nm处甲基蓝发色基团吸收峰的强度先增强后减弱,并无新吸收峰出现。FT-IR分析结果表明,电晕放电等离子体技术破坏了甲基蓝结构中不稳定的环外C=C及C=N,在1 692.4 cm-1和1 400.4 cm-1处分别生成C=O和N=O的吸收峰;而H_2O_2氧化过程只破坏了C=N,在1 386.4 cm-1处产生N=O的吸收峰,表明这两种处理方法均对甲基蓝溶液有一定的降解能力。

Two kinds of treatment methods of corona discharge plasma and H_2O_2 oxidation were used to study the changes in color removal and spectral behavior of aqueous solution by UV-Vis and FT-IR. The UV-Vis spectrum results show that the color of the solution during corona discharge plasma degradation of methyl blue is first deepened and then gradually lightened,however,in H_2O_2 oxidation of methyl blue process,the color of the solution has been lightened. The new absorption peaks of the intermediate substances produced by the H_2O_2 oxidation of methyl blue were generated at 279 nm and 372 nm in the UVVis spectrum. However,the intensity of absorption peak of methyl blue chromophores at 603 nm in the UV-Vis spectrum during the degradation of methyl blue by corona discharge plasma first increased and then decreased,and no new absorption peak appeared. FT-IR results reveal that Corona discharge plasma technology destroys the unstable outer ring C = C and C = N in methyl blue structure,producing adsorp-tion peaks of C = O and N = O at 1 692. 4 cm^（-1） and 1 400. 4 cm^（-1）,respectively. The H_2O_2 oxidation process only destroys the C = N,generating the adsorption peak of N = O at 1 386. 4 cm^（-1）. Obviously,these two methods both have certain ability in the degradation of methyl blue.