Self-assembly regulation of montmorillonite nanosheet for Pb(II) removal from aqueous solution

L-cysteine (Lcys) induced the self-assembly of montmorillonite nanosheets (MMTNS), creating a threedimensional structured adsorbent with high adsorption capacity for Pb(II). Lcys was grafted onto the edge of MMTNS by hydrogen-bonding and then formed disulfide bonds (-S-S-) under the oxidation of H2O2 to form MMTNS-Lcys adsorbent. This technique maintains the exposed adsorption sites of MMTNS and resolves the challenge of nanosheet separation from water. MMTNS-Lcys possessed a large specific surface area (73.95 m2 g-1) and pore volume (0.1124 cm3 g-1), exhibiting outstanding adsorption performance for Pb(II), The adsorption process is consistent with the Pseudo-first-order kinetic and Langmuir isotherm models, indicating the monolayer adsorption of Pb(II) on the homogeneous surface of the MMTNS-Lcys adsorbent, with a maximum adsorption capacity of 46.92 mg/g (C0 = 80 mg/L, M = 0.5 g/L, T = 25 degrees C, pH = 6). These findings offer valuable insights for the design and development of future adsorbent materials.