Adsorption and Desorption of Pb(II) on l-Lysine Modified Montmorillonite and the simulation of Interlayer Structure

By Sidi Zhu, Mingzhu Xia, Yuting Chu, M. A. Khan, Wu Lei, Fengyun Wang, T. Muhmood, Along Wang. Applied Clay Science, 2019

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Abstract Herein, we reported the adsorption and desorption of Pb(II) on l -lysine modified montmorillonite (L-Mt) with molecular dynamics simulation. l -lysine (Lys) modified montmorillonite (L-Mt) was prepared, characterized by various analytical techniques, and the simulation studies were performed to evaluate the interlayer structure and interaction properties of l -lysine and L-Mt. The results of X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) spectrum suggested that Lys+ was intercalated into the interlayer of Na-montmorillonite (Na Mt) successfully. The batch adsorption experiments were implemented to study the adsorption capacity of Pb(II) on L-Mt in water. The maximum adsorption capacity of Pb(II) on the L-Mt (up to 43.3 mmol/100 g) were considerably higher than that on Na Mt (up to 15.3 mmol/100 g), at room temperature. The adsorption isotherms of both, L-Mt and Na Mt can fit the Langmuir isotherm. The adsorption experiments showed that Pb(II) removal efficiency of L-Mt is better than Na Mt in acidic solution. The simulation results revealed the micro-mechanism of Lys+ inserted into the interlayer gallery of Na Mt. It can be deduced that lysine interacted with montmorillonite surface mainly through the protonated side-chain amino group rather than through the protonated main-chain amino group or deprotonated carboxyl group. These consequences are expected to elucidate the adsorption mechanisms occurring at the water/clay minerals interface at atom level, providing significant insight into the adsorption and retention of Pb(II) on L-Mt composite, and lead to relevant engineering applications while treating heavy metals of wastewater.

Subfields: Biomaterials, Renewable Energy, Sustainability and the Environment, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/a4f4e629dda1e46560e5ea7fe2011b6163320998