Catalytic Degradation of Phenol and p-Nitrophenol Using Fe3O4/MWCNT Nanocomposites as Heterogeneous Fenton-Like Catalyst

Fe3O4 decorated multi-walled carbon nanotube (Fe3O4/MWCNT) nanocomposites were synthesized by co-precipitation process and used as heterogeneous Fenton catalyst for degradation of phenol and p-nitrophenol (p-NP). The Fe3O4 nanoparticles with size less than 20 nm were well-dispersedly coated on the surface of MWCNTs at relatively low loading. Some aggregations appear at high Fe3O4 content in composite. The Fe3O4/MWCNT with about 25 wt.% of Fe3O4 is the most cost-effective catalyst compared with others, whose phenol conversion and COD removal rates could, respectively, reach to 99.20 and 58.09%. And a high H2O2 utilization efficiency was achieved (about 132.41%) for this catalyst. For the p-NP degradation, the optimal reaction condition was that: 2.0 mg/L of catalyst dosage, 3 mmol/L of initial H2O2 concentration, 3 of pH value, and 40 degrees C of reaction temperature. At this condition, the removal rates of p-NP and COD in 120 min achieved 97.16 and 67.71%, respectively. And the Fe3O4/MWCNT nanocomposite also exhibits an acceptable stability and reusability.