Photodegradation Behaviour of Nitrogen-Containing Graphene Derivatives Towards Pollutant Dyes and Real-TimeAssessment on Aquatic Weed

Abstract

Discharge of dyes in the aquatic system is ubiquitous environmental chaos, and combating this particular anthropogenic issue with graphene-based materials via photodegradation process has been a radiant approach in recent times. In this work, 3-aminophenol produced nanosheets of N-graphene (NG) in the presence of urea in a single step at a relatively low temperature of ~ 120 – 125°C in contrast to nitrogen-containing graphene oxide (NGO) produced in the absence of urea. The V- shape of urea facilitated the formation of a poly-hexagonal array of rings and prevented the attack of oxygen at normal atmospheric conditions. During the comparison of the photodegradation ability of both NG and NGO against MG, MB, and MO, the degradation efficiency was found to be 92 - 99%. Further LC-MS/MS studies proved that NGO was capable of mineralizing the complex structures of the dyes via the demethylation route initially followed by asymmetric cleaving at neutral pH. The in-vitro real-time application of an aquatic weed (Lemna minor) was also compared against the 1:1:1 ratio of MG, MB, MO, and NGO-treated dye water. No substantial growth of Lemna minor was found in the case of using the dye mixture even up to the 20th day, whereas rapid growth of this aquatic weed was observed within 15 days in the case of NGO treated dye mixture.