Adsorption of cadmium ions at the electrolyte/silica interface: I. Experimental study of surface properties

• Published in: Applied surface science Vol. 196; no. 1-4; pp. 322 - 330
• Main Authors: Prélot, B., Janusz, W., Thomas, F., Villiéras, F., Charmas, R., Piasecki, W., Rudzinski, W.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2002; Elsevier Science; Elsevier
• Subjects: Adsorption; Cadmium; Chemical Sciences; Chemistry; Continental interfaces, environment; Electrophoretic mobility; Environmental Sciences; Exact sciences and technology; General and physical chemistry; Global Changes; or physical chemistry; Potentiometric titration; Radiometry; Sciences of the Universe; Silica; Solid-liquid interface; Surface physical chemistry; Theoretical and; Cadmium; 68.45.D–82.65; Adsorption; Electrophoretic mobility; Radiometry; Silica; Potentiometric titration; Metallic adsorbate; Liquid solid interface; Liquid solid adsorption; Sodium perchlorates; Inorganic adsorbent; Potentiometry; Cadmium ion; Modeling; Heterogeneity; Precipitation; Silicon oxides; Surface properties
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(02)00070-3

Surface properties of the silica/NaClO4 interface were studied by potentiometric titration, Na adsorption versus pH, electrokinetic potential measurements, and adsorption of cadmium using the adsorption edge technique. The silica/NaClO4 interface is characterized by low negative charge, without clear intersection point on titration and electrokinetic potential curves at various ionic strengths, which tend towards zero charge for pH <4. Cadmium ions adsorption occurs through competition with sodium ions for the dissociated sites of silica. At the highest studied electrolyte concentration (10−1M) adsorption edges are dominated by precipitation of hydrolyzed cadmium. An effect of silica surface heterogeneity on cadmium adsorption was detected for low electrolyte concentration (10−3M). The data collected for this later electrolyte concentration are used for thermodynamic modeling of the cadmium adsorption at the silica/NaClO4 interface, performed in the second part of this paper.