Epoxidation of soybean oil catalyzed by peroxo phosphotungstic acid supported on modified halloysite nanotubes

► A natural halloysite nanotubes with end-opening acted as the support of catalysts. ► The mass transfer was enhanced by combination of mechanical and ultrasonic agitation. ► The catalyst can be recovered by centrifugation as deposit easily. ► The catalyst can be reused for three times with enough catalytic activity. ► The catalyst can be regenerated with the same catalytic activity by re-exchange of {PO4[W(O)(O2)2]4}3−.