3D magnetic flower-spherical FeO-NiO derived from NiFe-layered double hydroxides for the efficient removal of Bensulfuron methyl: Morphological control and bimetallic synergy.

Three-dimensional (3D) magnetic flower-spherical FeO-NiO derived from NiFe-layered double hydroxides (NiFe-LDHs) was fabricated through urea hydrothermal and calcination methods. The as-prepared materials were applied to activate PMS to degrade one of herbicide named Bensulfuron methyl (BSM). FeO-NiO-1 demonstrated the highest catalytic activity and the lowest ions leaching by comparing the performance of LDHs and derivative bimetallic oxide synthesized by co-precipitation method, urea hydrothermal method and direct calcination method. Based on the results of SEM, BET and CV, the high catalytic activity of FeO-NiO-1 originated from 3D morphology, lager specific area and pore size and faster electron transfer capability. The factors influencing the degradation performance were investigated and 0.1 g·L FeO-NiO could effectively activate PMS (1 mmol·L) to completely remove 10 mg·L BSM within 30 min at pH 7.0. In FeO-NiO/PMS system, OH, SO and O were produced and contributed to the BSM removal according to the results of EPR and quenching experiments. In order to expand its application range, FeO-NiO/PMS system was used to degrade aniline (AN), sulfamethoxazole (SMZ), phenacetin (PNT), bisphenol A (BPA) and 2,4,6-triclofen (2,4,6-TCP) and the results showed the degradation efficiency could reach 90 % or more. Additionally, the application of catalysts in different actual water samples and the ability of reuse were tested. Based on the strategies of bimetallic synergy and morphology control, Fe-based bimetallic oxides with 3D morphology were developed in this study, which could effectively enhance the catalytic activity and inhibit the dissolution of metal ions, providing the design ideas for the construction of efficient catalysts and the removal of complex organic pollutants.