Rapid dehalogenation of pesticides and organics at the interface of reduced graphene oxide–silver nanocomposite

• Published in: Journal of hazardous materials 2016-05, Vol.308, p.192-198
• Main Authors: Koushik, Dibyashree, Sen Gupta, Soujit, Maliyekkal, Shihabudheen M., Pradeep, T.
• Format: Article
• Language: English
• Subjects: Adsorption; Degradation; Graphene; Mathematical analysis; Nanocomposites; Pesticide; Pesticides; Pollutants; Reduced graphene oxide–silver nanocomposite (RGO@Ag); Water purification
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.01.004

[Display omitted] •Preparation of reduced graphene oxide-silver nanocomposite (RGO@Ag).•Dehalogenation of various POPs at reduced graphene oxide–silver nanocomposite (RGO@Ag).•A two step mechanism involving degradation followed by the adsorption.•Adsorption kinetics followed a pseudo-second-order rate equation.•The material has high adsorption capacity and can be reused for multiple cycles. This paper reports dehalogenation of various organohalides, especially aliphatic halocarbons and pesticides at reduced graphene oxide–silver nanocomposite (RGO@Ag). Several pesticides as well as chlorinated and fluorinated alkyl halides were chosen for this purpose. The composite and the products of degradation were characterized thoroughly by means of various microscopic and spectroscopic techniques. A sequential two-step mechanism involving dehalogenation of the target pollutants by silver nanoparticles followed by adsorption of the degraded compounds onto RGO was revealed. The composite showed unusual adsorption capacity, as high as 1534mg/g, which facilitated the complete removal of the pollutants. Irrespective of the pollutants tested, a pseudo-second-order rate equation best described the adsorption kinetics. The affinity of the composite manifested chemical differences. The high adsorption capacity and re-usability makes the composite an excellent substrate for purification of water.