Progressing adsorption

The catalytic surface being saturated to a large extent by N02 adsorbed species. NO and N02 are detected in the exhaust stream, The higher the reaction temperature, the more efficient the progressive adsorption of N02 and the oxidation of nitrites into nitrates. 

Figure 4.15. Schematic representation of the progressive adsorption of NO on a catalytic bed in a reactor flow [182].

Inset progressive adsorption (from a to h), zoomed in the v(OHhp) region. 

The difference between for the different solvent compositions at a given AG(r and the broken line in Fig. 18 may be used as an approximate measure of such resolvation. Inspection of Fig. 18 reveals that the behavior of the Zn(II)/Zn(Hg) system in H2O-DMF and H2O-DMSO mixtures is different from that described above. In this case there is no pure inhibition of the electrode reaction, since the decrease of the rate constant (Tfh) is accompanied by the change in AGtr- There occur progressive adsorption of the organic solvent (e.g., DMSO) on the electrode and in parallel the resolvation of Zn(II) ions. 

In Fig. 5 we report the advancing and receding contact angles of ionic-nonionic mixtures at supramicellar concentration. A similar behaviour is observed for monodisperse molecules such as CnDMPO and CiEj but not for Triton X-100. Again this can be related to the presence of smaller size molecules in this commercial surfactant. This progressive adsorption phenomenon is clearly evidenced by Fig. 6a and 6b where the variation of L-S area fraction, fl, at each cycle is reported for SDS, CTAB and their mixtures with non-ionic species. 

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