Carboxylmethyl konjac glucomannan conjugated polydopamine composites for Pb(II) removal

Carboxylmethyl konjac glucomannan conjugated polydopamine (CMKGM-PDA) composite was successfully prepared using a cost-effective method. CMKGM-PDA exhibited excellent adsorption performance for the removal of Pb(II) and could be a convenient agent for recovery. The Langmuir linear model was suitable for describing the adsorption process of Pb(II). The maximum adsorption capacity was 95.24 mg g−1 at 298 K, showing a high absorption capacity in comparison to similar absorbents. The pseudo-second order equation and intra-particle diffusion model exhibited good correlation with the adsorption kinetic. The thermodynamic values (ΔH0 > 0, ΔS0 > 0, ΔG0 < 0) indicated that the adsorption process of Pb(II) was endothermic, feasible, and spontaneous in nature. The chelation and electrostatic attraction between Pb(II) and -OH (or -NH2) groups on the CMKGM-PDA formed a possible adsorption mechanism.