title: Influence of pH, soil humic/fulvic acid, ionic strength, foreign ions and addition sequences on adsorption of Pb(II) onto GMZ bentonite.
abstract: This work contributed to the adsorption of Pb(II) onto GMZ bentonite in the absence and presence of soil humic acid (HA)/fulvic acid (FA) using a batch technique. The influences of pH from 2 to 12, ionic strengths from 0.004M to 0.05M NaNO(3), soil HA/FA concentrations from 1.6 mg/L to 20mg/L, foreign cations (Li+, Na+, K+), anions (Cl(-), NO(3)(-)), and addition sequences on the adsorption of Pb(II) onto GMZ bentonite were tested. The adsorption isotherms of Pb(II) were determined at pH 3.6+/-0.1 and simulated with the Langmuir, Freundlich, and D-R adsorption models, respectively. The results demonstrated that the adsorption of Pb(II) onto GMZ bentonite increased with increasing pH from 2 to 6. HA was shown to enhance Pb(II) adsorption at low pH, but to reduce Pb(II) adsorption at high pH, whereas FA was shown to decrease Pb(II) adsorption at pH from 2 to 11. The results also demonstrated that the adsorption was strongly dependent on ionic strength and slightly dependent on the concentration of HA/FA. The adsorption of Pb(II) onto GMZ bentonite was dependent on foreign ions in solution. The addition sequences of bentonite/Pb(II)/HA had no effect on the adsorption of Pb(II).
authors.affiliation: School of Chemical Engineering, Shandong University of Technology, Zibo, PR China.
authors.forename: Suowei
authors.initials: S
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Jiaxing
authors.initials: J
authors.lastname: Li
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Dong
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D001578:Benzopyrans; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007854:Lead / Q000302:isolation & purification*; D009994:Osmolar Concentration; D012987:Soil; D012989:Soil Pollutants / Q000302:isolation & purification
chemical_list: D001578:Benzopyrans; D006812:Humic Substances; D007477:Ions; D012987:Soil; D012989:Soil Pollutants; D001546:Bentonite; D007854:Lead; C005023:fulvic acid