EFFECTS OF SEVERAL METAL NITRATES AND OXIDES ON PCDD/Fs FORMATION FROM PENTACHLOROPHENOL

摘要

Chlorophenols (ClPhs) are considered to be important precursors of dioxins. The capacity of some metal nitrates (NaNO_3, Ca(NO_3)_2.4H_2O, Pb(NO_3)_2, AgNO_3, La(NO_3)_3. 6H_2O) and oxides (CaO, PbO, Ag_2O, La_2O_3) for suppressing of PCDD/Fs formation from the model precursor pentachlorophenol (PCP) was studied in a laboratory-scale reactor. It was found that although PbO and La_2O_3 have certain promoting effects on lower-chlorinated PCDD/Fs, which are more toxic than OCDDs. Most of the above compounds have obviously suppressing effects on the total amount of PCDD/Fs formation from PCP below 280℃. The interaction of basic metal oxides with the acid precursor PCP and the destruction of products from the decomposition of nitrates on PCDD/Fs were speculated to reduce their formation. The results of the present study may be taken into account to make measures to control and reduce PCDD/Fs emission from municipal solid waste incineration (MSWI) plants in the future.