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-BC900, 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(center dot-) and O-1(2) were the dominant active species in catalytic systems. Additionally, Fe@N-2-BC900 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.

Automated summary

The study investigated the application of N-doped biochar-loaded nanoscale zero-valent iron composites for persulfate activation, demonstrating excellent catalytic performance with strong synergistic effects for effective removal of organic pollutants. It provides a new approach for pollution control and deep exploration of reaction mechanisms.