# CO2 mediated optical investigation of pyridine transformation into 2,2′-bipyridine for nitrogen pollutant removal

## TL;DR

A CO2-assisted method converts pyridine pollutants into useful bipyridine, offering a sustainable solution for water purification.

## Contribution

A novel CO2-mediated process for pyridine removal and bipyridine production using optical monitoring.

## Key findings

- CO2 acts as an electron transfer mediator, accelerating pyridine conversion into bipyridine.
- UV-visible spectroscopy effectively tracks pyridine consumption and bipyridine formation.
- The process enables simultaneous water purification and production of an industrially valuable compound.

## Abstract

Nitrogen containing organic compounds such as pyridine are major industrial water pollutants that pose serious environmental and health risks. This study presents a sustainable, CO2 mediated process for removing dissolved pyridine from water through its conversion into 2,2′-bipyridine, an insoluble and recoverable compound of industrial value. The highly exothermic transformation was monitored by UV-visible spectroscopy to elucidate its kinetics and underlying mechanism. Characteristic bands at 255 nm and 282 nm were used to track the consumption of pyridine and the formation of bipyridine, respectively. The results show that CO2 acts as an electron transfer mediator, promoting dehydrogenative coupling of pyridine and accelerating its conversion into bipyridine. This process simultaneously enables the purification of pyridine contaminated water and the production of a valuable heterocyclic compound. Overall, these findings highlight a promising CO2 assisted pathway for the treatment of nitrogenous organic pollutants and demonstrate the utility of optical spectroscopy for monitoring green water purification reactions.