纳米磁铁矿/生物质炭催化对Fenton氧化降解苯酚的增强机理

MECHANISM OF STRENGTHENING EFFECT OF BIOCHAR SUPPORTED NANO MAGNETITE IN PHENOL FENTON DEGRADATION

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n MBC—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,H_2O_2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(R^2>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（ n MBC） 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 n MBC dosage = 2. 0 g/L. Moreover,n MBC-Fenton method could remove phenol in a relatively short period of reaction time. Apparently,factors such as n MBC dosage,initial pH value and temperature had greater effect on the reaction. Among them,pH value determined the phenol removal rate,while n MBC dosage as one dominant factor,affecting the degradation rate. Under the abovementioned condition,the relevant phenol degradation followed the pseudo-first-order kinetics（ R^2〉0. 97） in the heterogeneous Fenton system with the presence of nanomagnetite/biochar composites.