title: The efficiency of the red alga Mastocarpus stellatus for remediation of cadmium pollution.
abstract: This work reports the results of the study for cadmium binding by the dead red macroalga Mastocarpus stellatus. Kinetics sorption experiments demonstrated the high rate of metal biosorption: the system attained over 50% of the total biomass cadmium uptake within 2 min of contact and over 90% in the first 9 min. The kinetic data were successfully described by a pseudo-second order model with rate constants ranging from 1.06 to 10 gmmol(-1)min(-1), as a function of initial metal concentration and temperature. The equilibrium binding was accurately represented in terms of Langmuir and Langmuir-Freundlich models. The sorption isotherms at constant pH showed uptake values as 0.49 mmol g(-1) (at pH 2.4), 0.56 mmol g(-1) (at pH 4) and 0.59 mmol g(-1) (at pH 6), while the affinity constant values were between 0.6 and 5 mmol(-1) L (Langmuir fit). The acid-base properties of the alga were also studied, obtaining the total number of acid groups, 2.5 mmol g(-1), and their apparent pK value, 1.56, using the Katchalsky model. Desorption studies were conducted employing different HNO(3) concentrations and desorption times.
authors.affiliation: Departamento de Química Física e Ingeniería Química I, Universidad de A Coruña, Alejandro de la Sota 1, 15008 A Coruña, Spain. erob@udc.es
authors.forename: R
authors.initials: R
authors.lastname: Herrero
authors.forename: P
authors.initials: P
authors.lastname: Lodeiro
authors.forename: R
authors.initials: R
authors.lastname: Rojo
authors.forename: A
authors.initials: A
authors.lastname: Ciorba
authors.forename: P
authors.initials: P
authors.lastname: Rodríguez
authors.forename: Manuel E
authors.initials: ME
authors.lastname: Sastre de Vicente
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002104:Cadmium / Q000032:analysis*; D004787:Environmental Pollution; D007700:Kinetics; D008670:Metals / Q000032:analysis / Q000737:chemistry; D008956:Models, Chemical; D011199:Potentiometry; D000461:Rhodophyta / Q000378:metabolism*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D002104:Cadmium