A novel CNTs-Fe3O4 synthetized via a ball-milling strategy as efficient fenton-like catalyst for degradation of sulfonamides

A novel composite (CNTs-Fe 3 O 4 ) was synthesized by a ball-milling strategy and characterized by BET, SEM, FTIR , XRD and VSM. The as-fabricated CNTs-Fe 3 O 4 was used to remove six sulfonamides by a Fenton degradation process, including sulfanilamide (SAM), sulfamerazine (SMR), sulfadimethoxine (SMX), sulfadiazine (SDZ), sulfamethazine (SMT) and sulfametoxydiazine (SMD). The degradation behaviors of six sulfonamides in CNTs-Fe 3 O 4 /H 2 O 2 system and the relationship between molecular structure of sulfonamides and their degradation behaviors were investigated systematically. Batch experimental results showed that the as-fabricated CNTs-Fe 3 O 4 had excellent Fenton catalytic activity for the degradation of sulfonamides due to its unique porous structure and the good combination mode of CNTs with Fe 3 O 4 particles. The first-order kinetic mode could better describe the degradation behaviors of six sulfonamides in CNTs-Fe 3 O 4 /H 2 O 2 system, and the degradation rate constant could be ordered as: SAM < SMT < SDZ < SMR < SMD < SMX. The quantitative relationship between the Mulliken charge of sulfonamides (x) and their degradation rate constant (y) in CNTs-Fe 3 O 4 /H 2 O 2 system could be described as: y =  - 28.719x + 15.67 (R 2  = 0.957). Finally, the possible synthesis mechanisms of CNTs-Fe 3 O 4 and the degradation mechanisms of sulfonamides in CNTs-Fe 3 O 4 /H 2 O 2 system was proposed.