Enhancement of persulfate activation by Fe-biochar composites: Synergism of Fe and N-doped biochar

Persulfate-based (PS-based) advanced oxidation process is a promising technology for degradation of organic pollutants . PS activation needs efficient and economical catalysts and heterogeneous Fe-carbon composites are competitive. Herein, novel N-doped biochar-loaded nanoscale zero-valent iron (nZVI) composites (Fe@N-BC) were synthesized and evaluated for PS activation. Detailed characterization data indicated that graphitic and pyridine N structures were introduced by N-doping, which enhanced the anchoring, dispersion and loading of amorphous nZVI on biochar. Remarkably, the optimized Fe@N-BC material, Fe@N 2 -BC 900 , presented excellent catalytic performance for PS activation for lindane removal. The N-doped defects in biochar acted as reactive bridges and accelerated the electron transfer between nZVI and PS, showing strong synergistic effects toward nZVI. O 2 • −  and 1 O 2 were the dominant active species in catalytic systems. Additionally, Fe@N 2 -BC 900 catalyst showed effectiveness over a wide pH range for lindane removal. This work provides a new approach to the rational design and application of Fe@N-BC for persulfate activation in pollution control, which is certified by deep exploration of reaction mechanism.