Thiol-functionalized metal-organic framework for highly efficient removal of bromate from water

Metal-organic frameworks (MOFs) named HKUST-1 ([Cu-3(BTC)(2)(H2O)(3)](n), BTC= benzene-1,3,5-tricarboxylate) were functionalized by thiol groups through a facile coordination-based postsynthetic strategy (HKUST-1-SH). HKUST-1-SH was explored as a novel adsorbent for efficient removal of bromate. HKUST-1-SH showed a remarkable adsorption capacity of 59.6 mg g(-1), approximately 5-times higher than that of HKUST-1. The bromate adsorption process of isotherms, kinetics, the effects of pH value and co-existing ions were examined, and the adsorption mechanism was also studied. The results showed the adsorption process fits the Langmuir adsorption model, and the pseudo-second-order model described the kinetics well. HKUST-1-SH works effectively for removal of bromate in a wide pH range (3-10), and in the presence of other substances such as sulfate, bromide and nitrate. The production of bromide in solution and the detection of -SO3H groups from FT-IR spectra indicate that the main mechanism of HKUST-1-SH for bromate removal is redox reaction. The work opens up a new way for bromate removal in water.