title: Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste.
abstract: Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO3 as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions.
authors.affiliation: LSRE-Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. vilar@fe.up.pt
authors.forename: Vítor J P
authors.initials: VJ
authors.lastname: Vilar
authors.forename: José M
authors.initials: JM
authors.lastname: Loureiro
authors.forename: Cidália M S
authors.initials: CM
authors.lastname: Botelho
authors.forename: Rui A R
authors.initials: RA
authors.lastname: Boaventura
mesh_terms: D000327:Adsorption; D000362:Agar; D002104:Cadmium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D008956:Models, Chemical; D000461:Rhodophyta / Q000737:chemistry*; D014866:Waste Products; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014866:Waste Products; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead; D003300:Copper; D000362:Agar