caa a22 4500 378924907 CHVBK 20180305123614.0 cr unu---uuuuu 161128e20040601xx s 000 0 eng 10.1524/zpch.218.6.709.33451 doi (NATIONALLICENCE)gruyter-10.1524/zpch.218.6.709.33451 Effects of Polarization on the Extents and Kinetics of Adsorption of Ionic and Neutral Aromatic Heterocyclics Exhibiting Orientation Transitions at a Porous C Electrode [Elektronische Daten] [Brian E. Conway, Jianjun Niu] Comparative investigations of the adsorption and electrosorption of the heterocyclic compounds, pyridine, 1,4-pyrazine and 1-quinoline, and their orientation behaviours in an high specific-area C-cloth/H2O interphase, directly related to the replacement of preadsorbed and field-oriented solvent (H2O) molecules by oriented adsorbates themselves, have been carried out by means of in situ UV spectrophotometry conducted under positive or negative electric polarization at the C-cloth as an electrode. Surface charge, dipole moment of the adsorbate, polarization mode, acidity of the solution (leading to cation formation) and hydrophilic/hydrophobic properties of the adsorbed molecules in relation to the solvent (H2O vs. non-aqueous) are found to have important influences on these processes and hence govern the experimentally measurable extents and rates of their adsorption. The adsorption and orientation effects were indicated by evaluation of surface-dipole potential changes represented by Esin and Markov (EM)-type effects. Different adsorption and orientation processes amongst the three adsorbates, together with the possible rearrangement of the adsorbed molecules, were revealed by changes of the observed EM effects. The preferred adsorption/electrosorption behaviour arises by either "combined adsorption” (CAD) (i.e. combination of adsorption on open-circuit with electrosorption upon subsequent polarization) or by "alternate polarization electrosorption” (APE) (i.e. electrosorption by periodically reversed direction of polarization, between positive and negative, in one adsorption experiment). Negative-current polarization in a single transient also led to similar results for effective adsorptive removal of 1-quinoline from aqueous solution. Major differences of adsorption arise between neutral pyridine and its cation in acidic solution, including the effect of electrode polarization. © 2004 Oldenbourg Wissenschaftsverlag GmbH Thermodynamics & statistical physics nationallicence Laboratory techniques, experiments nationallicence Physical chemistry nationallicence Conway Brian E. aut Niu Jianjun aut Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/6/2004(2004-06-01), 709-740 0942-9352 218:6/2004<709 2004 218 zpch https://doi.org/10.1524/zpch.218.6.709.33451 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/zpch.218.6.709.33451 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Conway Brian E. aut NATIONALLICENCE 700 1- Niu Jianjun aut NATIONALLICENCE 773 0- Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics Oldenbourg Wissenschaftsverlag GmbH 218/6/2004(2004-06-01), 709-740 0942-9352 218:6/2004<709 2004 218 zpch CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter