Hydrazide-linked perylene-based porous organic polymer: An innovative approach for removing organic dyes from aqueous solution

The presence of toxic pollutants in the aquatic environment is a significant environmental concern that requires the development of effective methods for their removal. This study focuses on applying perylene and triazine-based porous organic polymer (PT-POP) to effectively eliminate hazardous pollutants from industrial settings. Specifically, PT-POP was synthesized using two monomers, namely 3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA) and 2,4,6 tris(hydrazino)-s-triazine (THTZ). The resulting PT-POP has outstanding adsorption performance and high chemical and thermal stability, making it an attractive adsorbent material. Based on the thermogravimetric analysis, it has been confirmed that PT-POP is thermally stable. The presence of aromatic rings in PT-POP is responsible for the extraordinary stability of the polymer. Then, the performance of PT-POP in the adsorption of cationic Nile blue and anionic Direct Fast Scarlet 4BS (DFS-4BS) was studied. The optimization process involves adjusting several factors, including temperature, concentration, pH, time, and adsorbent dosage. The highest adsorption capacities (qM) for the Nile blue dye and the DFS-4BS dye were 280.16 mg. g−1 and 87.50 mg. g−1, respectively. The adsorption behavior best fits the pseudo-second-order kinetic model, and the Langmuir isotherm showed the most agreement with adsorption isotherms for both. The thermodynamic study shows that the adsorption process for both dyes is spontaneous and endothermic, as evidenced by the negative value of ΔG and the positive value of ΔH. The findings show that PT-POP is more inclined toward cationic dyes due to its negative surface charge.