title: Biosorption of heavy metals onto nonliving Laminaria japonica.
abstract: In this paper, study of the biosorption of Cd(2+) and Pb(2+) by nonliving Laminaria japonica in a batch adsorption system is described. The content of acidic sites and the dissociation constant of carboxylic acid functional groups (metal-binding site) of L. japonica were experimentally determined by conductometric and potentiometric titrations and theoretically predicated by using monodentate and bidentate binding models. The models are based on the monodentate or bidentate binding reactions of bivalent metal ions to acidic sites. The acidic site content and carboxylic acid dissociation constants determined are 1.25 and 0.18 mmol L(-1), respectively. The results showed that the bidentate adsorption model fits well the biosorption of bivalent metal ions onto L. japonica with the bidentate binding constants for Cd(2+) and Pb(2+) being 5.72 × 10(3) and 6.24 × 10(4) L mol(-1), respectively. The adsorption process of L. japonica followed the pseudo-second-order kinetics.
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xiao
authors.forename: Miyamoto
authors.initials: M
authors.lastname: Chikanori
authors.forename: Ke-Feng
authors.initials: KF
authors.lastname: Yu
authors.forename: Seki
authors.initials: S
authors.lastname: Hideshi
authors.forename: Maruyama
authors.initials: M
authors.lastname: Hideo
authors.forename: Pei-Min
authors.initials: PM
authors.lastname: He
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000302:isolation & purification*; D003217:Conductometry; D007700:Kinetics; D007795:Laminaria / Q000737:chemistry*; D007854:Lead / Q000302:isolation & purification*; D011199:Potentiometry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead