微生物燃料电池电活化过硫酸盐降解甲基橙偶氮染料

为研究MFC（微生物燃料电池）产生电能活化PDS（过硫酸盐）对偶氮染料的降解能力，以MO（甲基橙）为目标污染物，探讨pH、c（PDS）、初始c（MO）、无机阴离子等对MO降解的影响及降解机理.结果表明:①当pH为3~5时，MO降解率随pH降低而升高；当pH低于3时，MO降解率随pH的降低而降低；MO降解率随初始c（MO）的增大而降低.当c（PDS）为1~2 mmol/L时，MO降解率随c（PDS）增加而增大；当c（PDS）超过2 mmol/L后呈减小趋势.②最佳反应条件pH为3、初始c（MO）为0.10 mmol/L、c（PDS）为2 mmol/L]下，反应4 h后MO降解率可达86.5%.③无机阴离子HCO₃-、NO₃-、CO₃2-对MO降解存在抑制作用，当阴离子投加量为10 mmol/L时，降解率分别为64.2%、68.8%、76.1%，而Cl-对MO降解无显著影响.④淬灭试验表明，体系的主要活性物质为SO₄-·及少量·OH.⑤通过紫外-可见光谱扫描，依据MO结构与特征吸收峰的关系，推测MO降解途径，即MO发色基团偶氮双键断裂，生成含苯环类中间产物，最终矿化为CO₂和H₂O.研究显示，MFC能有效活化PDS产生SO₄-·，对偶氮染料有较好的降解和矿化效果. 

Microbial Fuel Cell Electro-Activated Persulfate to Degrade Methyl Orange Azo Dye

In order to study the degradation of azo dyes by bio-activated persulfate (PDS) produced by the microbial fuel cell (MFC), methyl orange (MO) was selected as the target pollutant. The effects of pH, PDS concentration, initial MO concentration, and inorganic anions on the degradation of MO were investigated. The results showed that when the initial pH was in the range of 5 to 3, the removal rate of MO increased with the decreasing pH. When the initial pH was lower than 3, the removal rate decreased with the decreasing pH. The removal rate of MO decreased with the increasing initial concentration of MO. When the dosage of PDS was 1-2 mmol/L, the MO removal rate increased with the increasing PDS dosage. When PDS dosage exceeded 2 mmol/L, the removal rate decreased with the increasing PDS dosage. The optimal reaction conditions were as follows:initial pH=3, initial concentration of MO=0.10 mmol/L, dosage of PDS=2 mmol/L. MO removal efficiency reached 86.5% after 4 h. The inorganic anions had inhibitory effect on the removal of MO. When the dosage of each inorganic anion (HCO₃^-, NO₃^-, CO₃^2-) was 10 mmol/L, the removal rates of MO were 64.2%, 68.8% and 76.1%, respectively. But the removal of MO was not significantly affected by Cl^-. Quenching experiments showed that the main free radicals in the system were SO₄^-·and a small amount of·OH. According to the relationship between MO structure and characteristic absorption peaks obtained with UV-Vis spectroscopy, the pathway of MO degradation was inferred. The azo double bond structure of MO chromophore was broken. Then intermediates containing benzene rings were formed, and finally they were mineralized to form CO₂ and H₂O. These results showed that MFC could effectively activate persulfate to produce sulfate radicals. They had better removal and mineralization effects on azo dyes.