Highly selective heteroaromatic sulfur containing polyamides for Hg⁺² environmental remediation

Environmental remediation concerns about pollution and contamination removal from environmental media, such as soil, air, or surface water. Enormous efforts have been applied in metal removal from surface water. In this study, four novel heteroaromatic sulfur-containing polyamides 6 carry both types of aliphatic and aromatic species in their polymer backbones as selective adsorbents for Hg⁺² metal ion from aqueous solution have been synthesized in considerable amounts. The polycondensation method at low temperature is used as a simple and low coast polymerization technique. This occurred by the interaction of the thiophene-based monomer 5 with different diacid chlorides of both types. Beforehand the polymerization, the structures of monomer 5 were confirmed by spectral and elemental analyses. Also, the structures of the new polymers were investigated by both spectral and elemental analysis; besides their solubility, GPC data, XRD diffraction patterns, thermal analysis, and FE-SEM micrographs. The synthesized polymers were freely soluble in polar protic solvents due to the presence of heteroaromatic sulfur functional groups. Furthermore, the analytical competition of the new polymers has been tested using inductively coupled plasma-optical emission spectrometry (ICP-OES) for its selective extraction across different metal ions. Polymer 6 was the most selective toward Hg⁺² and considered as a highly selective adsorbent for Hg⁺² environmental remediation among all derivatives and its adsorption detection and efficiency were also investigated. Polymer 6c showed the most effective adsorption quantity on its surface at pH = 1. Moreover, the calculated adsorption isotherm showed a typical isotherm to the Langmuir adsorption type. This showed that the adsorption capacity of polymer 6 for Hg⁺² was 47.95 mg g^-1. These novel polymers are serving as simple and inexpensive heavy metal ions adsorbent materials from drinking water and wastewater.