title: Zinc and cadmium removal by biosorption on Undaria pinnatifida in batch and continuous processes.
abstract: Zn(II) and Cd(II) removal by biosorption using Undaria pinnatifida was studied in batch and dynamic systems. The kinetic uptake follows a pseudo second order rate equation indicating that the rate limiting step is a chemical reaction. The equilibrium data are described by the Langmuir isotherm in mono-component solutions. In binary solutions, the Jain and Snowyink model shows that most of the active sites are exclusively accessible to cadmium ions without competition with the zinc ions. The dynamic studies show that the biosorbent has higher retention and affinity for Cd(II) than for Zn(II) in both mono- and bi-component systems. SEM-EDX analysis indicates that the active sites are heterogeneously distributed on the cell wall surface. FT-IR spectrometry characterization shows that carboxylic groups and chemical groups containing N and S contribute to Zn(II) and Cd(II) uptake by U. pinnatifida. According to these results calcium-treated U. pinnatifida is a suitable adsorbent for Zn(II) and Cd(II) pollutants.
authors.affiliation: Centro de Investigación y Desarrollo en Fermentaciones Industriales, CINDEFI (CCT CONICET La Plata, UNLP), Facultad de Ciencias Exactas, 50 y 115, 1900 La Plata, Argentina.
authors.forename: J
authors.initials: J
authors.lastname: Plaza Cazón
authors.forename: M
authors.initials: M
authors.lastname: Viera
authors.forename: E
authors.initials: E
authors.lastname: Donati
authors.forename: E
authors.initials: E
authors.lastname: Guibal
mesh_terms: D000327:Adsorption; D001118:Argentina; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism*; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D044648:Undaria / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D015032:Zinc / Q000378:metabolism*
chemical_list: D002104:Cadmium; D015032:Zinc
keywords: Biosorption; Fixed bed column; Heavy metals; Undaria pinnatifida; Water treatment