A novel nano-scale ferrite (MgFe2O4) was employed for hexachlorobenzene (HCB) removal in soil with microwave (MW) treatment. MW-generated hole (h(+))/electron pair could activate water and oxygen adsorbed on the surface of MgFe2O4 to produce (OH)-O-center dot and O-center dot(2)-. Radical scavenging tests confirmed it was (OH)-O-center dot but not h(+). and O-center dot(2)- that directly oxidized HCB. was a responsible oxidant of intermediates decomposition. Thus the co-existing of water and molecular oxygen had significant enhancement on HCB catalytic oxidation, showing high degradation (80%) and dechloriantion (93%) after 20 min of MW radiation. Electron spin resonance analysis demonstrated that O-center dot(2)- and (OH)-O-center dot radicals were aroused from MW-induced If/electron activation of molecule oxygen and water, but not from the lattice oxygen and -OH groups in the structure of ferrites. Thermal desorption of HCB occurred at the wide temperature of the surface soil at the range of 90-500 degrees C, and obviously catalytic oxidation happed at a temperature range of 90-620 degrees C in the water/oxygen-contained system. Complicated pyrolytic reactions happed at 90-670 degrees C in the absence of water and oxygen. The addition of MgFe2O4 with MW radiation elevated soil temperature, leading to HCB pyrolysis that fitted well with the first order kinetics model. When soil was vitrified at >670 degrees C, with the process of thermal fixation, changes of the soil structure took place. (C) 2016 Elsevier B.V. All rights reserved.