Chitosan crosslinked with polyamine-co-melamine for adsorption of Hg2+: Application in purification of polluted water

A batch experiment was carried out in order to remove Hg2+ from the aqueous solution as well as the polluted water using modified chitosan (CS) with polyamine compounds (triethylenetetramine (TETA), tetraethylenepentamine (TEPA)), and melamine. The obtained polyamine-co-melamine crosslinked CS derivatives (MCS-4N and MCS-5N) were characterized and used as adsorbents. In comparison to the raw CS, the modification significantly promoted the adsorption of Hg(2+ )ions. The results of the pseudo-second-order kinetic model revealed that pH-dependent derivatives adsorbents achieved the equilibrium state within 12 h. The Langmuir model was best fitted with the Hg2+ adsorption isotherm and showed the highest adsorption capacities of 1403 and 109.7 mg/g for MCS-4N and MCS-5N, respectively. A slight decrease in the adsorption efficiency of Hg 2 divided by was noticed with the increment of the ionic strength of the solution. However, the studied adsorbents were easily regenerated and presented adequate reusability. The Hg2+ adsorption was regulated by the combined process of coordination reaction and electrostatic attraction as well. The as-prepared polyamine-co-melamine crosslinked CS derivatives were found potential adsorbents for the adsorptive capture of H ions from aqueous solutions and polluted waters. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The modified chitosan with polyamine compounds and melamine derivatives showed enhanced adsorption capacity for Hg2+ ions, reaching equilibrium within 12 hours. The Langmuir model fitted best for the adsorption isotherm, with high adsorption capacities of 1403 and 109.7 mg/g for MCS-4N and MCS-5N, respectively, indicating potential for practical applications in removing Hg ions from aqueous solutions and polluted waters.