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Production of Biosorbents from Waste Olive Cake and Its Adsorption Characteristics for Zn2+ Ion
Grupo de Disciplinas de Ecologia da Hidrosfera/Unidade de Biotecnologia Ambiental, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal
Departamento de Engenharia Energética e Controle Ambiental, INETI, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, Portugal
* Author to whom correspondence should be addressed.
Received: 7 May 2009 / Accepted: 1 June 2009 / Published: 4 June 2009
Abstract: In this study, waste olive cake (OC) was utilized as the raw material for the production of biosorbents by chemical treatment and its adsorption capacity for zinc ion was evaluated. Tests were conducted with the total biomass (T) and with the fraction > 2.00 mm (P), in order to determinate the influence of this fractionation step on subsequent treatments. Two chemical agents were used: sulfuric acid and sodium hydroxide. The parameters studied include physical and chemical properties of materials, contact time, pH, adsorbent dose and initial concentrations. The kinetic data were best fitted to the pseudo-second order model. Zinc binding is strongly pH dependent, with more zinc ions bound at a higher pH (5-7 in a range of 3-7). Both Langmuir and Freundlich models are well suited to fit the data on sorption of zinc by OC. Data on sorption of zinc by waste olive cake treated with sulfuric acid (OC-H) was better described by the Freundlich model. Zinc sorption by waste olive cake treated with sodium hydroxide (OC-OH) was better described by the Langmuir model. Results show OC-OH is a biosorbent with a superior adsorption capacity for zinc than OC-H. The maximum adsorption capacity obtained from the Langmuir isotherms increases in the order (mg/g): OC-HT (14), OCT (22) and OC-OHT (27). Results also indicate that the previous fractionation step doesn´t produce a biosorbent with a superior adsorption capacity.
Keywords: biosorbents; chemical treatment; Zinc(II); olive cake; adsorption
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MDPI and ACS Style
Fernando, A.; Monteiro, S.; Pinto, F.; Mendes, B. Production of Biosorbents from Waste Olive Cake and Its Adsorption Characteristics for Zn2+ Ion. Sustainability 2009, 1, 277-297.
Fernando A, Monteiro S, Pinto F, Mendes B. Production of Biosorbents from Waste Olive Cake and Its Adsorption Characteristics for Zn2+ Ion. Sustainability. 2009; 1(2):277-297.
Fernando, Ana; Monteiro, Sofia; Pinto, Filomena; Mendes, Benilde. 2009. "Production of Biosorbents from Waste Olive Cake and Its Adsorption Characteristics for Zn2+ Ion." Sustainability 1, no. 2: 277-297.