Efficient destruction of hexachlorobenzene by calcium carbide through mechanochemical reaction in a planetary ball mill

Mechanochemical destruction (MCD) is a good alternative to traditional incineration for the destruction of persistent organic pollutants (POPs), like hexachlorobenzene (HCB), and the key is to find an efficient co-milling reagent. Toward this aim, HCB was milled with various reagents in a planetary ball mill at room temperature, and CaC 2 was found to be the best one. HCB can be destroyed completely within 20 min at a mass ratio of CaC 2 /HCB = 0.9 and a rotation speed of 300 rpm. The ground samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy . The results show that the destruction products are nonhazardous CaCl 2 and carbon material with both crystalline and amorphous structures. On these bases, possible reaction pathways were proposed. Considering its excellent efficiency and safety, CaC 2 may be the most feasible co-milling regent for MCD treatment of HCB. Further, the results are instructive for the destruction of other POPs.