Structure regulation induced by adding bismuth nitrate in the MIL-101(Fe) preparation and its effects on adsorption-photocatalytic performance for micro-organic contaminants

Herein, Bi(NO3)3 was innovatively introduced into the preparation process of MIL-101 (Fe), and the induced structural regulation and its impact on the adsorption-photocatalytic performance for micro-organic contaminants (MCs) were investigated systematically. The results show that, when FeCl3 was used as an iron source and Bi(NO3)3 mol percentage reached 45 %, BiOCl/MIL-88B(Fe) composite heterojunction was formed in situ, showing high adsorption (49.5 %) and removal rate (81.8 % and 91.2 %) after 180 min under visible light and UV irradiation for low concentration tetracycline (TC), respectively. The organics adsorbed on the composite surface could be further decomposed. When Fe(NO3)3 was used as the iron source, the introduction of a small amount of Bi(NO3)3 (5 %) contributed to the preparation of MIL-88B(Fe/Bi) in situ and the generation of more surface hydroxyl groups. The adsorption and removal rate of TC under visible light reached 68.9 % and 90.8 %, respectively and the generated by-products were also effectively degraded. The in-situ prepared BiOCl/MIL-88B(Fe) heterojunction could effectively promote the separation of photogenerated carriers and the dark generated ·OH and ·O2− could effectively accelerate the adsorption of pollutants. These results have opened up new ideas for the development of novel porous adsorption-photocatalysis materials with a simple preparation process, high efficiency, low cost, and the ability to effectively overcome the mass transfer resistance of MCs.