Metal–Organic Framework Based on Isonicotinate N‑Oxide for Fast and Highly Efficient Aqueous Phase Cr(VI) Adsorption

Synthesis of new porous materials has been developed for efficient capture of pollutants in environmental sciences. Here, the application of a new metal–organic framework (TMU-30) has been reported based on isonicotinate N-oxide as an adsorptive site for fast and highly efficient aqueous phase adsorption of Cr­(VI). The adsorption process showed no remarkable effect over a pH range of 2–9. The maximum capacity of the adsorption was reached in just less than 10 min and followed the pseudo-second-order kinetics. The maximum capacity of 2.86 mol mol–1 (145 mg/g) was obtained according to Langmuir model at 298 K. The spontaneous adsorption and an endothermic process were controlled by positive entropy changes. XPS analysis revealed electrostatic interactions between N-oxide groups of TMU-30 and Cr­(VI) species, which were responsible for the adsorption process.