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Titolo:
The effect of cationic surfactants on wetting, colloid stability and flotation of silica
Autore:
Koopal, LK; Goloub, T; de Keizer, A; Sidorova, MP;
Indirizzi:
WageningenrlandsAgr, Dept Phys & Colloid Chem, NL-6703 HB Wageningen, Nethe Wageningen Univ Agr Wageningen Netherlands NL-6703 HB Wageningen, Nethe St Petersburg State Univ, Dept Colloid Chem, St Petersburg 198904, Russia St Petersburg State Univ St Petersburg Russia 198904 burg 198904, Russia
Titolo Testata:
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
fascicolo: 1-2, volume: 151, anno: 1999,
pagine: 15 - 25
SICI:
0927-7757(19990615)151:1-2<15:TEOCSO>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
VARIABLE-CHARGE SURFACES; METAL-OXIDE SURFACES; IONIC SURFACTANTS; ANIONIC SURFACTANTS; ADSORBED LAYER; ADSORPTION; SUSPENSIONS; BROMIDE; MICA; (HYDR)OXIDES;
Keywords:
silica wetting; silica stability; silica flotation; surfactant adsorption; adsorbed surfactant orientation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Koopal, LK Wageningenageningen, Dept Phys & Colloid Chem, Dreijenplein 6, NL-6703 HB W Wageningen Univ Agr Dreijenplein 6 Wageningen Netherlands NL-6703 HB
Citazione:
L.K. Koopal et al., "The effect of cationic surfactants on wetting, colloid stability and flotation of silica", COLL SURF A, 151(1-2), 1999, pp. 15-25

Abstract

Contact angle, colloid stability and flotation measurements have been carried out for silica as a function of the concentration of cationic surfactants at different salt concentrations. The results are compared with surfactant adsorption and surface charge isotherms. The surfactants used are dodecyl and cetyl pyridinium chloride, and dodecyl trimethyl-ammonium bromide. Colloid instability, contact angles and flotation recovery all pass through amaximum at about the charge compensation point that corresponds for the present system to the iso-electric point and the (near) common intersection point of surfactant isotherms measured at a given pH and different ionic strength values. Before the charge compensation point the surfactant progressively neutralises the negative surface charge by head-on adsorption and simultaneously the surfactant tail causes an increase in hydrophobicity. Beyondthe charge compensation point admicelles are formed, leading to a net positive particle charge and an increase in hydrophilicity. In the charge compensation point the maximum of hydrophobicity occurs together with the minimal net particle charge. Therefore, the minimum in the stability and the maximum in the flotation recovery are related to both the low particle charge and the relatively large particle hydrophobicity around the charge compensation point. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 02:34:38