Piperazine-Linked Covalent Triazine Polymer as an Efficient Platform for the Removal of Toxic Mercury(II) Ions from Wastewater

Abstract

A piperazine-linked robust N-rich covalent organic polymer (COP), SMCOP-1, was synthesized by a catalyst-free method and characterized by Fourier transform infrared (FTIR), 13 C CP/MAS, X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (PXRD). This polymeric material can work as an efficient platform for removing toxic Hg 2+ from wastewater. This system showed >97% Hg 2+ removal, as confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES), with a maximum uptake capacity of 1329 mg g −1 . Hg 2+ incorporation inside SMCOP-1 was confirmed by XPS, energydispersive spectrometry (EDS), and elemental mapping of field emission scanning electron microscopy (FE-SEM). The high Hg 2+ removal capacity of SMCOP-1 can be attributed to the strong noncovalent interaction between the Hg 2+ ion and the binding sites of the covalent organic polymer, as suggested by density functional theory (DFT) calculations, noncovalent interaction (NCI) analysis, and the electrostatic potential (ESP) map. The material's recyclability was studied for up to four consecutive cycles, and it was observed that it retained a high removal capacity without any change in the structure and morphology, as confirmed by FTIR and FE-SEM.

Exploring multifunctional applications of a luminescent covalent triazine polymer in acid vapour sensing, CO2 capture, dye removal, and turn-off fluorescence sensing of dichromate ions

“…Characterization of SMCOP-2 SMCOP-2 was characterized by FT-IR, 13 C CP/MAS NMR, FE-SEM, PXRD, BET, and TGA. 13 C CP/MAS NMR (Fig.…”

“…Characterization of SMCOP-2 SMCOP-2 was characterized by FT-IR, 13 C CP/MAS NMR, FE-SEM, PXRD, BET, and TGA. 13 C CP/MAS NMR (Fig. 1(a)) shows a distinct peak at around 170 ppm corresponding to the triazine carbon.…”

“…7,8 Among all the materials, porous organic polymers (POPs) are extremely useful in solving environmental issues. [9][10][11][12][13][14] Since the last decade, overwhelming research activities have been carried out on POPs due to their robust nature, high porosity, tunable functionality, and significant host-guest interactions. [15][16][17][18][19][20] Porous organic polymers are accomplished to be an excellent choice for environmental remediation but these POPs can effectively resolve only a particular environmental issue.…”

Exploring a Redox-Active Ionic Porous Organic Polymer in Environmental Remediation and Electrochromic Application

“…The successful ion exchange was confirmed by 31 P CPMAS NMR, XPS, EDS, and elemental analysis. Multiplate at around −145 ppm in the 31 P CPMAS NMR spectra indicates the presence of PF 6 − ions in the material, where the multiplate originates from the 31 P− 19 F coupling (Figure S29). The complete absence of Br and clear presence of P and F in XPS, EDS, and elemental analysis data − ions with the cationic center in the polymer (Figure S31).…”

“…The fundamental understanding of the mechanism of the response of smart materials toward external stimuli is essential to design and fabricate such materials. − Extensive research on smart materials opens the opportunity to bring in newer technologies in the field of commercially and industrially relevant applications like smart windows, self-healing coatings, chemicals and gas separations, optical switches, artificial intelligence, electrochromic devices, etc. − Interestingly, examples of incorporation of such stimuli-responsive building blocks in the fabrication of covalent organic polymers (COPs) are relatively rare, although certain advantages of COPs are well known. Significant thermal, chemical, and tunable physicochemical stability along with pore size, large surface area, and low skeleton density remain very important among them. − In this particular work, we have utilized the advantage of incorporation of viologens, an N , N ′-disubstituted-4,4′-bipyridinium moiety, which is an electron-accepting dicationic organic structure with an excellent reversible redox property and fast electron transfer ability, to generate an ionic porous organic polymer (iPOP-Bpy). The polymer contains an electron-withdrawing triazine moiety in the core, which is a suitable electron acceptor with favorable electron-conducting properties. − The cationic nature of the polymer, nitrogen-rich structure, physicochemical stability, and presence of an aromatic skeleton make it a suitable candidate to explore its capacity for iodine adsorption.…”