Theoretical investigation on the gas phase reaction mechanism of methanol with Sn and Pb in sludge incineration

Abstract

AbstractIn this work, using the M06‐2X method with Land2DZ for Sn and Pb atom and 6‐311++G(d,p) for the remaining atoms, the reaction mechanisms and products of Sn and Pb with methanol in sludge incineration were investigated. Result shows that Sn and Pb react with CH3OH via insertion mechanism into different chemical bond, that is, CH, CO, and OH bond. The order of stability of final products is CH3MOH > CH3OMH > HMCH2OH (M = Sn and Pb) from the most stable to the least stable. Moreover, the reactivity of Sn towards methanol is higher than that of Pb via the same insertion chemical bond. Kinetically, the order of barrier height via insertion into different chemical bond is CO > OH > CH bond from highest to lowest, which is contrast to the stability of products. Thermodynamics indicates that all products are spontaneous to be formed below 1500 K in incinerator. It is therefore Sn‐ and Pb‐contained organic compounds would be generated readily in incineration of sludge. The secondary treatment of bottom slag or fly ash is expected to reduce the pollution to environment after incineration of Sn‐ and Pb‐contained sludge.