Mechanochemical degradation of hexachlorobenzene using Mg/Al2O3 as additive

In the present work, we investigate the destruction efficiency of hexachlorobenzene (HCB) by milling with various reagents in a planetary ball mill under different milling conditions. Under the same conditions of mill rotary rate and charge ratio, the mixture of magnesium powder and aluminum oxide (Mg/Al2O3) was found best in promoting the destruction of HCB, which can be completed destroyed after 90 min grinding at a charge ratio of 20:1 (reagent/HCB, m/m), a ball mass/reagent mass ration of 30:1 and a mill rotation speed of 550 rpm. The ground samples were characterized and analyzed by X-ray fluorescence, gas chromatography (GC), X-ray diffraction and ion chromatography. The intermediate products, such as pentachlorobenzene, tetrachlorobenzene, trichlorobenzene isomers, dichlorobenzene and monochlorobenzene were detected by GC. Then the main dechlorination path way for HCB was proposed. With a series of verification experiments, the final degradation products of HCB were amorphous carbon and inorganic chlorine. Based on this study, Mg/Al2O3 has the potential to complete the innocuous treatment of chlorinated compounds.