Degradation mechanism and pathway of 2,4-dichlorophenol via heterogeneous activation of persulfate by using Fe-Cu-MOF@C nanocatalyst

Abstract

Bimetallic metal-organic framework (MOF) have shown stronger catalytic activity compared with monometallic MOF. Herein, we carbonized the iron and copper bimetallic MOF to prepare the Fe-Cu-MOF@C nanocatalyst for the first time. The prepared materials were characterized by SEM, TEM, TG, VSM, XRD, and BET. Then, Fe-Cu-MOF@C was used for the degradation of 2,4-dichlorophenol (2,4-DCP) via the heterogeneous activation of persulfate (PS). The Fe-Cu-MOF@C/PS system exhibited a high catalytic activity and excellent stability. Strikingly, we found that over 99.4 % of the 2,4-DCP removal rate within 60 min and 83.4 % of the COD removal rate within 180 min in the Fe-Cu-MOF@C/PS system. The scavenger experiments and electron paramagnetic resonance (EPR) analysis revealed that SO4-•, •OH, •O2− and 1O2 were the main reactive oxygen species (ROS) for the degradation of 2,4-DCP. Finally, the possible degradation mechanism and pathway of 2,4-DCP were given via High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The enhanced catalytic performance of Fe-Cu-MOF@C/PS system could be due to the porous core-shell structure and the synergistic effect of iron and copper active species in the internal bimetallic Fe-Cu-MOF@C, which indicated the Fe-Cu-MOF@C nanocatalyst could be potentially applied in the persulfate-mediated environmental remediation.