title: A fixed-bed column for phosphate removal from aqueous solutions using an andosol-bagasse mixture.
abstract: It is difficult to eliminate phosphate from large volumes of water in batch mode using an adsorbent such as andosol. In a fixed-bed column, andosol has a very low permeability. In this study, andosol was mixed with bagasse to increase permeability. The mixture was then applied for the adsorption of phosphate in a fixed-bed column. Optimum and stable permeability was obtained with a 50/50 mixture of andosol and bagasse. The maximum adsorption capacity obtained was 4.18 mg/g for a column with a bed depth of 1.8 cm and a flow rate of 4 mL/min. The experimental data fit best to Thomas and Adam-Bohart models. These experimental results were applied in the treatment of natural phosphate-containing water from Yaoundé Municipal Lake in Cameroon. Column performance increased by 60% due to the presence of Ca(2+) and Mg(2+) in the natural water. These cations form complexes with phosphate at the andosol surface. The standard enthalpy 15.964 kj/mol indicated that phosphate adsorption on andosol-bagasse mixture was an endothermic process. Kinetic experiments demonstrated that phosphate adsorption fitted better with a pseudo-second-order model.
authors.affiliation: Laboratoire de Physico-chimie des Matériaux Minéraux, Département de Chimie Inorganique, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon. Electronic address: edjoufac2000@yahoo.fr.
authors.forename: Emmanuel Djoufac
authors.initials: ED
authors.lastname: Woumfo
authors.affiliation: Laboratoire de Physico-chimie des Matériaux Minéraux, Département de Chimie Inorganique, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon.
authors.forename: Jean Mermoz
authors.initials: JM
authors.lastname: Siéwé
authors.affiliation: Laboratoire de Physico-chimie des Matériaux Minéraux, Département de Chimie Inorganique, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroon.
authors.forename: Daniel
authors.initials: D
authors.lastname: Njopwouo
mesh_terms: D000327:Adsorption; D002482:Cellulose; D007700:Kinetics; D010710:Phosphates / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D014867:Water; D002482:Cellulose; C027433:bagasse
keywords: Adsorption; Andosol; Breakthrough; Fixed-bed; Phosphate