Construction of Brönsted sites on pyrite surface via plasma technology for efficient hydrolysis of microcystins-LR

Enhancing the catalytic hydrolysis efficiency of microcystins (MCs) at ambient temperature has been a persistent challenge in water treatment. We employed N 2 /low-temperature plasma technology to modify the surface of natural pyrites (NP), and the resulting nitrogen-modified pyrites (NP N ) with a nanorod structure and new Fe-N x sites are more efficient for the hydrolysis of microcystins-LR (MC-LR). Kinetic experiments revealed that NP N exhibited significantly higher hydrolysis activity ( k obs = 0.1471 h −1 ) than NP (0.0914 h −1 ). Liquid chromatography-mass spectrometry (LC/MS) for the intermediates produced by hydrolyzing MC-LR, in situ attenuated total reflectance Fourier transform infrared spectroscopy (in situ ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis unfolded that the Fe and N atoms of Fe-N x sites on the surface act of NP N as Lewis acid and Brönsted basic respectively, selectively breaking amide bond on MC-LR molecule. This study demonstrates the effectiveness of plasma technology in modifying mineral materials to enhance their catalytic activity, providing a new method for eliminating MCs in practical water treatment.