Unveiling the Functional Efficacy: A Guanidine-Based Organic Framework for Adsorption of Iodine, Organic Dyes, and Fabrication of a Heterogeneous Catalyst for Benzene Hydroxylation

Heteroatom-rich ionic porous organic polymers have emerged as fascinating materials for diverse applications. In the search for a single platform capable of performing multiple functions, we explored a guanidinium-based ionic porous organic polymer as a dynamic platform for adsorption of multiple toxic contaminants, metal ion impregnation, high-temperature carbonization, and consequent application in heterogeneous catalysis. The material showed a significant iodine uptake capacity of 3.28 g/g from the vapor phase and 1.7 g/g from the aqueous phase. The retention capacity and reusability of the polymer were remarkable. The material was also employed for the adsorptive removal of organic dyes like methyl orange (MO), crystal violet (CV), malachite green (MG), rhodamine B (RB), and eriochrome black T (EB) from water. The adsorption capacity was evaluated to be 1004, 400, 94, 120, and 110 mg/g for MO, CV, MG, RB, and EB, respectively. Taken together, these results showed that the polymer was highly efficient and reusable as a multitargeting adsorbent. Guanidinium-based ionic porous organic polymer was also employed as a precursor for the synthesis of a copper doped porous carbon catalyst [Cu-PCM]. The synthesized material was found to have a very high surface area of 1500 m²/g. The catalytic activity was tested for the hydroxylation of benzene. The effect of various reaction parameters such as temperature, time, concentration of substrate and oxidant, and amount of catalyst were carefully investigated. Under the optimized reaction conditions, a maximum benzene conversion of 86.9% was attained. This might be attributed to the activation of the redox cycle of Cu²⁺/Cu⁺ by the electrostatic interaction between Cu²⁺ and heteroatoms in the carbon skeleton of Cu-PCM. Thus, the porous carbon material is not only a catalyst support, but also a cocatalyst in this reaction, providing an ambient electronic arrangement for the redox cycle.