National Basic Research Program of China [2010CB732303]; National Natural Science Foundation of China [21173174, 20923004, 21033006, 21161130522]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036] ; Among several typical zeolites, H-ZSM-34 was found to be an efficient catalyst for the conversion of methyl chloride to lower olefins, i.e., ethylene, propylene, and butenes. Treatment of H-ZSM-34 with a Na(2)H(2)EDTA (EDTA = ethylenediaminetetraacetate) aqueous solution followed by ion exchange and calcination enhanced the catalytic performance significantly. The selectivity to lower olefins increased significantly for certain Na(2)H(2)EDTA aqueous solution concentrations; when the H-ZSM-34 catalyst was treated with a 0.1 mol/L Na(2)H(2)EDTA solution, the selectivity and yield of C-2-C-4 olefins reached 82% and 61%, respectively, at 673 K and a CH3Cl partial pressure of 9.2 kPa. The modification of H-ZSM-34 with Ce ions improved C-2-C-4 olefin selectivity and yield. Catalyst characterization suggests that treatment with Na(2)H(2)EDTA or modification by Ce decreases the acidity of H-ZSM-34. The weakened acidity of the treated or modified H-ZSM-34 may suppress the hydrogen transfer reaction and prevent lower olefins from further transformation to paraffins. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.