Azo-linked nanoporous organic polymer for efficient capture of cationic dyes and radioactive iodine

Water pollution from harmful dyes, global warming caused by greenhouse gases and radioactive iodine released from nuclear waste pose serious environmental and health risks, necessitating the development of an efficient multifunctional adsorbent material. A porous organic polymer having azo linkages named as TDMTA-AZO-POP has been developed here using copper-catalyzed homocoupling. 4,4’,4”-(1,3,5-triazine-2,4,6-triyl)tris(2,6-dimethylaniline) (TDMTA) having triazine substituted with three 3,5-dimethyl aniline rings has been utilized as a precursor. The introduction of methyl groups on the aniline ring of the triazine monomer assisted in stability and adsorption properties of TDMTA-AZO-POP. Comprehensive characterization is done through FTIR, NMR, P-XRD, TGA, BET, FE-SEM and HR-TEM. The nitrogen abundance and surface area analysis indicate the adsorptive nature of POP towards small organic molecules. BET surface area of TDMTA-AZO-POP for CO₂ adsorption is evaluated to be 78 m²/g at 298 K. The material has shown good adsorption capability for blue cationic dyes such as azur A (AA) and toluidine blue (TB) and radioactive pollutant, iodine in both aqueous and vapor phase. The prominent maximum adsorption capacity for TB, AA and iodine in aqueous medium are 255.75, 232.56 and 1900 mg/g respectively. Besides, the TDMTA-AZO-POP exhibits a high adsorption capacity for radioactive iodine in vapor phases 4341 mg/g. These findings express the potential of TDMTA-AZO-POP as multifunctional material for environmental remediation, particularly in wastewater treatment and radioactive iodine capture.