Superior trichloroethylene removal from water by sulfide-modified nanoscale zero-valent iron/graphene aerogel composite

Abstract

Sulfide-modified nanoscale zero-valent iron (S-nZVI) is a promising material for removal of organic pollutants from water, but S-nZVI nanoparticles (NPs) easily agglomerate and have poor contact with organic contaminants. Herein, we propose a new S-nZVI/graphene aerogel (S-nZVI/GA) composite which exhibits superior removal capability for trichloroethylene (TCE) from water. Three-dimensional porous graphene aerogel (GA) can improve the efficiency of electron transport, enhance the adsorption of organic pollutants and restrain the agglomeration of the core-shell S-nZVI NPs. The TCE removal rates of FeS, nZVI, GA and S-nZVI were 27.8%, 42%, 63% and 75% in 2 hr, respectively. Furthermore, TCE was completely removed within 50 min by S-nZVI/GA. The TCE removal rate increased with increasing pH and temperature, and TCE removal followed the pseudo-first-order kinetic model. The results demonstrate the great potential of S-nZVI/GA composite as a low-cost, easily separated and superior monolithic adsorbent for removal of organic pollutants.

Keywords: Graphene aerogel; Nanocomposite; Organic pollutant removal; Sulfide-modified nanoscale zero-valent iron; Trichloroethylene (TCE).