Rapid preparation of adsorbent based on mussel inspired chemistry and simultaneous removal of heavy metal ions in water

In order to solve the problem of coexistence pollution of heavy metal ions in real water environment, a polydopamine (PDA) modified polypropylene non-woven adsorbent was rapidly prepared by one-step method based on mussel-inspired chemistry. The mussel inspired chemical reaction was accelerated by combining oxidants with diamine. The interaction between coexisting metal ions severely inhibits the removal of adsorbents with single active site, a multifunctional non-woven absorbent (PP/PDA/ASA) was synthesized through introducing salicylic acid groups at the end of PDA to increase the type of adsorption sites and address the issue of low removal efficiency caused by competitive effects in multicomponent system. The synthesized adsorbent was characterized by SEM, FTIR spectroscopy and XPS techniques. Meanwhile, the adsorption capacity of Cu(II), Cd(II) and Pb(II) on PP/PDA/ASA was systematically studied in single and multi-target systems under various conditions. The findings indicated that the PP/PDA/ASA could remove 90% of Cu(II) and Pb(II), and 80% of Cd(II) from 5 mg/L of Cu(II)/Cd(II)/Pb(II) mixed solution at the sorbent:solution mass ratio of 1:1000. Noticeably, the adsorption capacity and rate of the metal ions in the multi-component system were reduced, indicating the strong competitive adsorption in the multi-component system. XPS analysis showed that various functional groups (amino, hydroxyl and carboxyl groups) on the surface of PP/PDA/ASA were involved in the adsorption of heavy metal ions. The adsorption mechanism included coordination and ion exchange between metal ions and functional groups, while the adsorption mechanisms of Cu(II), Cd(II) and Pb(II) were different.