Mechanistic insights into adsorptive and oxidative removal of monochlorobenzene in biochar-supported nanoscale zero-valent iron/persulfate system

•Adsorptive-catalytic capability of nZVI/biochar for MCB removal was demonstrated.•The activation of nZVI/RS500 outperformed other nZVI/biochar composites.•SO4•−, •OH and 1O2 were identified in the nZVI/biochar-PS system.•Both nZVI and biochar’s graphitic carbon structures were involved in PS activation.•Possible MCB degradation pathways in the nZVI/biochar-PS system was proposed.