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Abstract: Cu and Zn modified 13X zeolites prepared by ion exchange or impregnation and activated carbons (ACs) treated with KOH, NaOH or Na2CO3 solutions were studied as H2S sorbents for biogas purification for fuelling molten carbonate fuel cells. H2S sorption was studied in a new experimental set-up equipped with a high sensitivity potentiometric system for the analysis of H2S. Breakthrough curves were obtained at 40 °C with a fixed bed of 20 mg of the samples under a stream (6 L h−1) of 8 ppm H2S/He mixture. The adsorption properties of 13X zeolite improved with addition of Cu or Zn:Cu exchanged zeolite showed the best performances with a breakthrough time of 580 min at 0.5 ppm H2S, that is 12 times longer than the parent zeolite. In general, unmodified and modified ACs were more effective H2S sorbents than zeolites. Treating ACs with NaOH, KOH, or Na2CO3 solutions improved the H2S adsorption properties: AC treated with Na2CO3 was the most effective sorbent, showing a breakthrough time of 1222 min at 0.5 ppm, that is twice the time of the parent AC. [Copyright &y& Elsevier]

Abstract: Modified 13X zeolites and active carbons were studied for HCl adsorption from biogas employed as fuel of MCFCs. 13X zeolite was modified by addition of Cu or Zn by ion exchange or impregnation: commercial active carbon was modified by impregnation with KOH, NaOH or Na2CO3 solutions. The materials were tested for HCl adsorption in a laboratory apparatus designed to the scope. The tests were carried out under flow conditions with a 100 ppm HCl/N2 mixture at T = 40 °C and atmospheric pressure. Breakthrough curves were obtained from potentiometric analysis of HCl in the stream effluent from the adsorption cell. The zeolites modified by ion exchange were more effective for HCl adsorption than those modified by impregnation. The active carbon modified with Na2CO3 solution showed the highest adsorption capacity of 3.3 × 10−4 mol HCl g−1 at breakthrough concentration of 1 ppm. [Copyright &y& Elsevier]

Abstract: New nanodispersed Cu–ZrO2 systems (containing 0 and 8.3mol% Cu) were synthesized by sol–gel method. Homogeneous gels were prepared starting from Zr propoxide and Cu(NO3)2·2.5H2O. The materials were characterized by XRD, TG/DTA, N2 adsorption, TPR techniques and N2O surface oxidation. In the Cu-containing material part of Cu2+ ions were incorporated into the zirconia lattice and strongly influenced the crystallisation behaviour of zirconia matrix. After treatment at 450–600°C, the materials contained ZrO2 nanocrystals of the tetragonal polymorph. The samples heat treated up to 450°C showed high surface areas in the range 140–180m2/g. Copper oxide species with different reducibility were detected by TPR measurements. The H2 reduction treatments gave rise to metallic copper with very high dispersion. The catalysts showed high activity for the oxidative steam reforming of methanol. A noticeable activity was observed also with the not pre-reduced catalyst, although a previous reduction in H2 led to a higher selectivity and H2 production. [Copyright &y& Elsevier]