Three series of Fe-containing BEA zeolites are prepared by two-step postsynthesis (PS), ion exchange (IE) and conventional wet impregnation (Imp) procedures with various Fe content (1.0-4.0 Fe wt.%). In these series of zeolites iron is mainly present as pseudo-tetrahedral Fe(III) as evidenced by combined used of DR UV-vis, Fe-57 Mossbauer and XPS investigations. Two kinds of pseudo-tetrahedral Fe(III) have been distinguished by Fe-57 Mossbauer spectroscopy in all Fe-containing BEA zeolites. As evidenced by TPD of NH3, the (Imp)-Fe(x)HAlBEA and (IE)-FeHAlBEA have a significantly higher acidity than (PS)-Fe(x)SiBEA. This is related to the presence in the former both pseudo-tetrahedral equivalent to Al(III)-O(H)-Si equivalent to and equivalent to Fe(III)-O(H)-Si equivalent to framework sites and in the latter only pseudo-tetrahedral equivalent to Fe(III)-O(H)-Si equivalent to. (PS)-Fe(x)SiBEA, (Imp)-Fe(x)HAlBEA and (IE)-FeHAlBEA are found to be active and selective catalysts of N2O decomposition, with 100% conversion in the temperature range of 750-800 K. Moreover, the samples are active in selective catalytic reduction of NO with ammonia, with selectivity toward N-2 exceeding 90% for NO conversions of 80-93% in the temperature range of 550-800K. Isolated pseudo-tetrahedral Fe(III), present in three series of Fe-containing BEA zeolites, seems to be involved in both N2O decomposition and SCR of NO processes. The higher activity of (Imp)-Fe(x)HAlBEA and (IE)-FeHAlBEA than (PS)-Fe(x)SiBEA in the SCR of NO process suggests that the acidic equivalent to Al(III)-O(H)-Si equivalent to framework sites present in the former catalysts play also a significant role in this process. (C) 2014 Elsevier B.V. All rights reserved.