Maximizing the zinc ions removal by organic ligand-stabilized conjugate polysterene macronet material

•Ligand-polymer system is stabilized by van der Waals and electrostatic forces.•Electrostatic interactions and chemical reactions promote the Zn2+ sorption.•The optimal pH for the Zn2+ sorption is found to be in the range of 6–10.•Sorption isotherm is better fitted by the Freundlich model than the Langmuir model.•PAD600-DEDTP exhibits higher sorption capacity than PAD600-MAB. Non-ionogenic cross-linked polystyrene-divinylbenzene resin (PAD-600) is modified with two different organic ligands: 2-amino-1-methylbenzimidazole (MAB) and diethyldithiophosphoric acid (DEDTP). The PAD600-MAB and PAD600-DEDTP have a porous microstructure, and the impregnated MAB and DEDTP molecules are homogenously distributed on the surface of PAD-600 via the hydrophobic part of organic ligands and van der Waals interactions. The sorption capacity and kinetics for Zn2+ removal are studied by a batch method. The Zn2+ sorption followed the Freundlich model (Kf = 1.11 for PAD600, Kf = 2.09 for PAD600-DEDTP, and Kf = 1.45 for PAD600-MAB) and pseudo-second order (k2 = 33.13 g∙mmol∙min–1 for PAD600, k2 = 0.35 g∙mmol∙min–1 for PAD600-DEDTP, and k2 = 3.45 g∙mmol∙min–1 for PAD600-MAB). The interaction of MAB and DEDTP with Zn2+ on the surface of PAD-600 can maximize the sorption of Zn2+ and change the morphology from homogenous porous to heterogeneous low-porous state. The FTIR spectra reveal the impregnation efficiency and the formation of zinc complexes after Zn2+ sorption. The equilibrium and maximum sorption are reached after 1 h at pH = 6. The effects of pH and temperature on Zn2+ sorption are also explored. PAD600-MAB exhibits a lower sorption capacity at higher temperature than PAD600-DEDTP due to the formation of stable zinc dialkyldithiophosphate on the surface. The computer modeling confirms the contribution of electrostatic and van der Waals forces to the solid stability for adsorption process, and the direct interactions of organic ligands with Zn2+ are highly dependent on complex formation. As inexpensive and green sorbents, the PAD600-MAB and PAD600-DiPDTP can be used for selective concentration and separation of various metal ions. [Display omitted]