Fe-PTFE-nano-PbO_2/Ti电极电催化氧化对硝基酚废水研究

研究了模拟废水对硝基酚(p-NP)的电化学降解情况,实验中以Fe-PTFE-nano-PbO2/Ti为阳极,石墨为阴极,讨论了电流密度、p-NP初始浓度、电解质(Na2SO4)浓度、溶液初始pH这些因素对p-NP降解的影响。实验表明,电流密度越大,生成的·OH更多,去除效果越好;p-NP初始浓度越小,电解速度高于扩散速度,反应速率越快,浓度越高,产生的更难降解的与p-NP竞争有机物中间产物越多,反应速率越低;Na2SO4浓度越大,SO42-产生的中间产物因具有氧化作用,在一定浓度范围内促进有机物的降解;溶液pH越小,析氧电位越低,越不容易发生析氧副反应,提高降解效率,有利于有机物降解。实验中电流密度20 mA/cm2,p-NP起始浓度100 mg/L,Na2SO4浓度0.02 mg/L,pH为5.1时条件最优,有机物降解效果较好,120 min时p-NP去除率99.23%,COD去除率77.38%,矿化率较高。

Electrochemical Degradation of P-nitrophenol on Fe-PTFE-nano-PbO2/Ti Electrode

Electrochemical degradation of p-nitrophenol was studied.Using Fe-PTFE-nano-PbO2/Ti as anode and graphite as cathode,influence factors of p-nitrophenol degradation such as current density,initial p-nitrophenol concentration,supporting electrolyte concentration,initial pH were investigated.It was found that when the current density was higher,more·OH was generated which could enhance the removal efficiency.When p-NP concentration was lower,electrochemical degradation speed was faster than diffusion which resulted in a faster degradation speed,while when the concentration was higher,more refractory intermediates were generated,which were hard to resolve than p-NP,the apparent rate constant was lower.When Na2SO4 concentration was higher,the intermediates generated from SO42-owned the oxidation ability which could enhance the removal efficiency.When pH was lower,the oxygen overpotential decreased,and it was hard to have side reaction which benefited p-NP removal.Under the conditions of current density 20 mA/cm2,initial p-nitrophenol concentration 100 mg/L,supporting electrolyte Na2SO4 concentration 0.02 mg/L,initial pH 5.1,p-NP and COD removal efficiency were 99.23% and 77.38% respectively,and mineralization rate was high.