电化学氧化降解磺胺嘧啶模拟废水的工艺优化

Optimization of Degradation of Sulfadiazine by Electrochemical Oxidation Process

摘要:

在无隔膜电解槽中，利用形稳阳极(DSA)产生的羟基自由基(•OH)和原位电生成的活性氯氧化降解磺胺嘧啶(Sulfadiazine，SD)模拟废水。通过高效液相色谱分析SD及其产物含量变化，水杨酸捕集羟基自由基法测定•OH的浓度，探讨工艺参数对•OH、氯离子、余氯、总氯和总有机碳(TOC)去除率的影响。结果表明：反应10 min 后SD去除率达100 %，反应4 h后溶液TOC明显下降；反应4 h后，pH为3、4、8、8.5、10和12的反应体系中TOC去除率分别为29%、46%、55%、61%、52%和47%，峰值出现在pH 8.5时；提高电流密度、电解质NaCl浓度及降低SD初始质量浓度可增大TOC去除率。本实验最优工艺条件为：pH 8.5，外加NaCl 0.025 mol/L，电流密度20 mA/cm2，初始质量浓度100 mg/L SD，经4 h的电化学氧化降解，TOC去除率达到66 %。

Abstract:

Artificial wastewater which contained sulfadiazine (SD) was electrochemically degraded by intermediate products (•OH and active chlorine) with metallic oxide coatings (DSA) as anode, and titanium plate as cathode in an undivided electric tank. The results indicated that: 1) The removal rate of SD was 100 % after 10 minutes treatment, and the TOC concentration significantly decreased after 4 hours; 2) After 4 h treatment, the removal rates of TOC at pH 3, 4, 8, 8.5, 10 and 12 were 29 %, 46 %, 55 %, 61 %, 52 % and 47 %, respectively, the peak of removal rate appeared at 8.5; 3) The removal rate of TOC could be enhanced through increasing the current density and the NaCl concentration, decreasing the initial SD mass concentration. The optimal treatment process was determined as follows: the pH value of 8.5; the NaCl concentration of 0.025 mol•L−1; the current density of 20 mA•cm−2; the initial SD mass concentration of 100 mg/L. The TOC removal rate could be 66% after 4 h treatment under this reaction conditions according to this research.