A facile composite was fabricated via direct assembly of nitrogen and sulfur co-decorated carbon dots with abundant oxygen-containing functional groups on the surface of the positively charged layered double hydroxide (N,S-CDs-LDH). The novel N,S-CDs-LDH demonstrates highly selective bindings (M-S) and an extremely efficient removal capacity for soft metal ions such as Ag+ and He2+ ions. N,S-CDs-LDH displayed a selectivity order of Ag+ > Hg2+ > > Cu2+ > > > Pb2+ > Zn2+ > Cd2+ for their adsorption. The enormous capacities for Hg2+ (625.0 mg g(-1)) and Ag+ (714.3 mg g(-1)) and very high distribution coefficients (K-d) of 9.9 x 10(6) mL g(-1) (C-0 = 20 mg L-1) and 2.0 x 10(7) mL g(-1) (C-0 = 20 mg L-1) for He2+ and Ag+, respectively, place the N,S-CDs-LDH at the top of LDH based materials known for such removal. The adsorption kinetic curves for Hg2+ and Ag+ fitted well with the pseudo-second order model. For Hg2+ and Ag+, an exceptionally rapid capture with removal similar to 100% within 80 min was observed (C-ions = 30 mg L-1 and V/m ratio of 1000). The adsorption isotherms were well described using Langmuir isotherm. The N,S-CDs-LDH was successfully applied to highly efficient removal of He2+ and Ag+ from aqueous solutions.