纳米磁铁矿/生物质炭催化对Fenton氧化降解苯酚的增强机理

摘要

以生物质炭负载纳米磁铁矿(nMBC)作为催化剂,采用非均相Fenton反应体系对模拟苯酚废水进行氧化降解处理研究,确定nMBC—Fenton法处理苯酚废水的最佳工艺条件,并揭示其强化机理.实验结果表明:对于质量浓度为50 mg/L的苯酚废水,其最佳降解条件为温度为45℃,pH为3.0,H2O2浓度为5 mmol/L,nMBC用量为2.0 g/L.反应进行20 min后,苯酚去除率可达约100％.nMBC剂量、废水初始pH和温度等因素均对处理效果有较大影响,其中pH决定苯酚去除率,而nMBC剂量是影响降解速率的主要因素.此外,nMBC—Fenton法催化氧化降解苯酚过程符合准一级动力学反应(R2 ＞0.97).%The phenol in a simulant wastewater was treated via oxidative degradation in a heterogeneous Fenton reaction system with the biochar supported nano-zero valent iron material (nMBC) as the catalyst,in oder to determine the optimal process conditions.The experimental results showed that for the phenol wastewater with the concentration of 50 mg/L,the optimum condition for the phenol degradation(i.e.,100％ removed after 20 min)was temperature 45 ℃,pH =3.0,H2O2 =5 mmol/ L,and nMBC dosage =2.0 g/L.Moreover,nMBC-Fenton method could remove phenol in a relatively short period of reaction time.Apparently,factors such as nMBC dosage,initial pH value and temperature had greater effect on the reaction.Among them,pH value determined the phenol removal rate,while nMBC dosage as one dominant factor,affecting the degradation rate.Under the abovementioned condition,the relevant phenol degradation followed the pseudo-first-order kinetics (R2 ＞ 0.97) in the heterogeneous Fenton system with the presence of nanomagnetite/biochar composites.