title: Removal of Phosphate from Aqueous Solution Using Alginate/Iron (III) Chloride Capsules: a Laboratory Study.
abstract: Binding phosphate at participation of alginate/FeCl3capsules was studied with laboratory experiments. The hydrogel microcapsules were obtained with the dropping-in method, by gelation of sodium alginate water solution by iron (III) chloride solution. Phosphate adsorption characteristics were studied in a static batch system with respect to changes in contact time, initial phosphates concentration, pH of solution, and temperature. After 24 h of the tests, average 87.5% of phosphate ions were removed from the natural water solutions; after 48 h, an equilibrium was reached. The adsorption data were well fit by the Freundlich isotherm model. Parameterkof the isotherms amounted from 43.4 to 104.7, whereas parameternamounted from 0.362 to 0.476. The course of processes of phosphate adsorption and iron desorption to aquatic phase, as well as changes in pH, suggests that phosphate adsorption is a major mechanism of phosphate removal, whereas simultaneously, but at a much lower degree, a process of precipitation of phosphate by iron (III) ions released from the capsules to the solution takes its place. Parameters calculated in the Freundlich isotherm equation show that by using several times smaller amounts of iron, it is possible to remove similar or bigger amounts of phosphorus than with other adsorbents containing iron. The alginate/FeCl3adsorbent removes phosphate in a wide pH spectrum-from 4 to 10. Results suggest that the proposed adsorbent has potential in remediation of contaminated waters by phosphate.
authors.affiliation: Department of General and Ecological Chemistry, West Pomeranian University of Technology, Szczecin, ul. J. Słowackiego 17, 71-434 Szczecin, Poland.
authors.forename: Hanna
authors.identifier: 0000-0003-2720-7047
authors.initials: H
authors.lastname: Siwek
authors.affiliation: Center of Bioimmobilisation and Innovative Packaging Materials, Faculty of Food Sciences and Fisheries, West Pomeranian University of Technology, Szczecin, ul. K. Janickiego 35, 71-270 Szczecin, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Bartkowiak
authors.affiliation: Department of General and Ecological Chemistry, West Pomeranian University of Technology, Szczecin, ul. J. Słowackiego 17, 71-434 Szczecin, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Włodarczyk
authors.affiliation: Center of Bioimmobilisation and Innovative Packaging Materials, Faculty of Food Sciences and Fisheries, West Pomeranian University of Technology, Szczecin, ul. K. Janickiego 35, 71-270 Szczecin, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Sobecka
keywords: Adsorption; Alginate; Iron (III) chloride; Phosphorus removal; Surface water