Synthesis, Characterization and Heavy Metal Ion Adsorption Behavior of Imidazole-Based Novel Polyamides and Polyimides

Abstract

Imidazole-based polyamides (PA)s and polyimides (PI) s were prepared from condensation of a new aromatic heterocyclic diamine, 4,4›(4,4›-(2-(4-(triflouromethyl)phenyl)-1H-imidazole-4,5-dyl)bis(4,1-phenylen))bis(oxy)bis(3-(4,5-diphenyl-1H-imidazole-2-yl)aniline), with various diacids and dianhydrides, respectively. The structure of diamine, PAs and PIs were fully characterized by using elemental analysis, FT-IR, <sup>1</sup>H NMR and <sup>13</sup>C NMR techniques. Also, adsorption capability of these polymers for removal of heavy metal ions such as Co<sup>2+</sup>, Cr<sup>3+</sup>, Cd<sup>2+</sup>, Hg<sup>2+</sup> and Pb<sup>2+</sup> from aqueous solutions was also tested at pH 7-8. The PAs and PIs showed good solubility in aprotic polar organic solvents with high thermal stability exhibiting the glass transition temperatures (T<sub>g</sub>)s and 10% weight loss temperatures (T<sub>10</sub>%) in the range of 220-286 °C and 383-435 °C for PAs and 251-307 °C and 407-512 °C for PIs.

Efficient Removal of Lead(II), Cadmium(II) and Zinc(II) from Aqueous Solutions by Bis[2‐(1H‐benzimidazol‐2‐il)phenyl]disulfide, a Solid Chelating Agent

“…Metal salts Pb(NO 3 ) 2 , CdCl 2 , and ZnCl 2 were used as sources for lead(II), cadmium(II) and zinc(II), respectively. The bis[2-(1H-benzimidazol-2-yl)phenyl]disulfide material was prepared as described in literature, and it was identified by melting point, elemental analysis, and 1 H and 13 C NMR. The obtained data were consistent with literature.…”

“…Dujardin et al, [12] studied resins with thiol groups to remove the small quantities of mercury (10 ppm) contained in wastewater by ion exchange, obtaining a final concentration of 1 ppm. Soleimani et al, [13] investigated the heavy metal ion adsorption behavior of imidazole-based polyamides and polyimides, finding that adsorption of metal ions followed the sequence Cr 3 + > Co 2 + > Cd 2 + > Hg 2 + > Pb 2 + , which has a negative correlation with the radius of metal ions. Likewise, organic molecules with atoms capable of donating electron density, such as nitrogen, oxygen, and sulfur, among others, have been used to complex heavy metals.…”

Polyamidation of new diamine monomers containing bulky pendant groups based on imidazole ring and fabrication of polyamide/modified‐SiO2composite: Properties and applications

“…The outstanding features of imidazole rings include structure stiffness, high electron affinity, aromaticity, symmetry, and polarizability. Regarding prior reports, the introduction of this heterocyclic composition and its derivatives such as 2,4,5‐triphenylimidazole (lophine) into the polymers main chain can lead to improvement in their processing, chemical, mechanical, and thermal properties 24–27 . Moreover, the imidazole derivatives have powerful biological activities such as antibacterial, anti‐inflammatory, and antifungal activity 28–32 …”

“…Regarding prior reports, the introduction of this heterocyclic composition and its derivatives such as 2,4,5-triphenylimidazole (lophine) into the polymers main chain can lead to improvement in their processing, chemical, mechanical, and thermal properties. [24][25][26][27] Moreover, the imidazole derivatives have powerful biological activities such as antibacterial, anti-inflammatory, and antifungal activity. [28][29][30][31][32] Heavy metals, as toxic and non-biodegradable substances, can cause various problems in the environment.…”

High-performance polyimides based on pyridine and xanthene pendant groups; synthesis, characterization, photoactivity, thermal, antibacterial, and Cr(VI) ion adsorption properties

“…7,8 Therefore, many researches have been carried out to modify the chemical structure of PIs. 9 –15 The most general strategies to increase solubility and decrease T g of these polymers are the introduction of heterocyclic rings, 16 –18 flexible linkages, 19,20 or bulky pendant in the side or backbone chains of polymers, 21,22 and changing the symmetrical structure by using—meta or—ortho aromatic rings attachments. 23 The existence of bulky groups such as xanthene on the backbone affects polymer matrix orders, reduces the structural rigidity, and intermolecular hydrogen bonds.…”