Rapid removal of CH3Hg+by thioctic acid modified NH2-MIL-101 in water

CH3Hg+ in water is a neurotoxin that is difficult to eliminate and is readily absorbed by the human body through food chains. In this study, thioctic acid was grafted onto the surface of NH2-MIL-101 via an amidation reaction to prepare an adsorption material for the rapid and effective removal of CH3Hg+, which is designated as LA-MIL101.The synthesis of LA-MIL-101 was confirmed through analyses including FT-IR, XRD, SEM, TGA, and XPS. BET results indicate that the specific surface area of LA-MIL-101 is 464.92 m 2 & sdot; g- 1 . The ideal conditions for CH3Hg+ adsorption were explored by varying environmental factors such as pH, contact time, and temperature. Furthermore, the introduction of sulfur significantly enhanced the adsorption capacity for CH3Hg+. Batch adsorption experiments demonstrate that LA-MIL-101 exhibits an exceptionally rapid adsorption rate, achieving over 88.3 % of the total removal rate within just one minute. Additionally, LA-MIL-101 shows remarkable adsorption efficacy across a broad pH range. The adsorption behavior of LA-MIL-101 for CH3Hg+ aligns with the Elovich and Langmuir models, with a maximum adsorption capacity reaching 1391.77 mu g & sdot;g- 1 . LA-MIL-101 also displays a strong anti-interference capability in environments containing humic acid or Na+. Notably, it maintains high removal efficiency under conditions involving coexisting cations, as well as in simulated surface water, simulated groundwater, and natural seawater. Moreover, LA-MIL-101 demonstrates good stability and recyclability, retaining effective adsorption after five adsorption/desorption cycles. XPS results elucidate the adsorption mechanism of CH3Hg+, highlighting interactions with sulfur (S) and nitrogen (N) atoms. Overall, LA-MIL-101 exhibits high practicality and significant potential for application in the emergency treatment of CH3Hg+ in aquatic environments.