Multifunctional diphenyl ether-based, cross-linked polyisocyanide for efficient iodine capture and NO2-/SO32- electrochemical probing

Compared with the extensively reported Schiff base-type polyimine (their backbones are connected by CN bond) porous organic polymers (POPs), there are rare reports regarding the exploration of polyisocyanide (PIC)-based, C1-type polyimine POPs. Herein, a kind of diphenyl ether-based, cross-linked PIC derivative (POBI) was successfully prepared. Fundamental properties of POBI as chemical structure, morphology, porosity, and thermal stability, were characterized. N, O-heteroatoms, aromatic motif and porous framework contained in the structure of POBI make it useful as a new type of iodine capture platform. Experimental results told that POBI can adsorb iodine in both vapor (under 75 °C and normal pressure) and solution (under 25 °C in cyclohexane) states. The maximum adsorption capacities in two states reached ~ 2.29 g g−1 and ~ 239 mg g−1, respectively. At the same time, the POBI-modified electrode (POBI/CS/GCE) illustrated stronger electrochemical response toward hazardous nitrite (NO2-) and sulfite (SO32-) anions relative to that of controlling electrodes (pristine glassy carbon electrode (GCE) and chitosan (CS)/GCE). The corresponding detection limits reached ~ 0.40 μmol L−1 (NO2-) and ~ 16.50 μmol L−1 (SO32-), respectively. We envisage that this work could play a positive role in further broadening the functional applications of polyisocyanide compounds.