响应面法对泡沫铜阴极电芬顿产H2O2与·OH性能优化

泡沫金属因其三维结构及优良导电性,使其作为电芬顿阴极开始引起学者关注。选择泡沫铜为阴极、石墨棒为阳极,搭建微孔曝气均匀的玻璃反应器,提高体系传质效率,并通过响应面探索体系产H2O2和·OH的机理。用响应面设计3因素(pH、电流、Fe2+初始浓度)3水平实验,得到体系产H2O2和·OH与3种因素之间的非线性回归方程,得到最优条件:当pH=2、电流0.25 A、Fe2+初始浓度为15 μmol·L-1时H2O2产量最大,为457.27 μmol·L-1；当pH=2、电流0.25 A、Fe2+初始浓度为20 μmol·L-1时·OH产量最多,可达18.56 μmol·L-1。根据方差分析,二次模型显著性很高(R2H2O2=0.977 8,R2·OH=0.964 2),能够很好地模拟实验结果。通过铜溶出实验分析得出铜溶出量在0.4~1.8 mg·L-1之间,符合现行污水排入城镇下水道水质标准(CJ 343-2010)。

Utilization of response surface modeling to optimize hydrogen peroxide and hydroxyl radicals generation by electro-Fenton with copper-foam as cathode

Foam-metal used as cathode in electro-Fenton (EF) has attracted attention recently due to it three-dimensional structure and good conductivity. In this study, copper-foam and graphite rod were used as cathode and anode, respectively. Moreover, micro-porous aeration glass reactor was designed, aiming for improving the low oxygen mass transfer rate in the EF configuration. The mechanism involved electro-generated active oxygen species (H2O2 and ·OH) was investigated by response surface modeling method. The effect of the different parameters affecting the performance of active oxygen species generation was investigated, including pH, current density and initial ferrous concentration. Response surface modeling method, more specifically, Box-Behnken design (BBD) was used to optimize the above-mentioned parameters for active oxygen species generation and then to put forward polynomial models between these parameters and active oxygen species. Results show that significant polynomial models were obtained (R2H2O2=0.977 8,R2·OH=0.964 2) and optimal conditions was obtained from BBD were shown as follows:pH=2, ferrous concentration=15 μmol·L-1 and current=0.25 A for H2O2 generation, while pH=2, ferrous concentration=20 μmol·L-1 and current=0.25 A for hydroxyl radicals generation. The copper concentration released from copper-foam cathode ranged from 0.4 to 1.8 mg·L-1, lowering than the standard concentration (CJ 343-2010).