Cr(VI) and phenol simultaneous removal using attapulgite-supported nanoscale zero-valent iron in the presence of persulfate

In this paper, attapulgite (APT)-supported nanoscale zero-valent iron (nZVI) composites (nZVI/APT) were synthesized by chemical liquid phase reduction to remove Cr(VI) and phenol from aqueous solutions in the presence of persulfate (Ps). The structure of as-prepared nZVI/APT was characterized by various techniques. Various effects on the reduction of Cr(VI) and degradation of phenol were evaluated. Experimental results revealed that nZVI/APT composites at a relatively low Ps concentration can effectively remove Cr(VI) and phenol simultaneously, the removal efficiencies of Cr(VI) and phenol were 98.7% and 80.3% after 60 min, respectively. There was a good synergistic effect between nZVI/APT and persulfate for removal of Cr(VI) and phenol. APT as the supporter matrix could decrease the aggregation of nZVI and increase its reactivity. nZVI can not only act as a reductant for removal of Cr(VI) but also act as a catalyst to activate Ps and generate sulfate radicals for removal of phenol. The presence of persulfate has no obvious effect on the removal of Cr(VI), but has remarkably promoted phenol oxidation. This implies that the nZVI/APT nanocomposites can act as catalyst to activate persulfate for the simultaneous removal of heavy metal and organic pollutant for the actual wastewater treatment.