Adsorption kinetics of Pb and Cd by two plant growth promoting rhizobacteria.
A bench study was carried out to characterize the kinetics of two plant growth promoting rhizobacteria (PGPR) Azotobacter chroococcum and Bacillus megaterium to adsorb heavy metals from solution. Adsorption of Pb(2+) and Cd(2+) by bacterial cells was processed quickly with an equilibration achieved within 5 min. The adsorptions were fitted well with Freundlich and Langmuir isotherm models. The comparison of isotherm parameters indicated that A. chroococcum had a stronger capacity to bind metal ions than B. megaterium, with an average increase of 59.8% for Pb(2+) and 75.6% for Cd(2+), respectively. Both bacteria had a stronger affinity to Pb(2+) than Cd(2+) since Pb(2+) was more easily bound with the phosphoryl groups on the cell surface than Cd(2+). This demonstrated that the presence of bacteria in the rhizosphere may result in the reduction of mobile ions in soil solution.
Wu
S C
SC
Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Hong Kong, PR China.
Peng
X L
XL
Cheung
K C
KC
Liu
S L
SL
Wong
M H
MH
D000327:Adsorption; D001410:Bacillus megaterium / Q000166:cytology / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D007700:Kinetics; D007854:Lead / Q000378:metabolism*; D063245:Plant Development; D010944:Plants / Q000382:microbiology*; D012231:Rhizobium / Q000166:cytology / Q000378:metabolism*; D012996:Solutions; D013997:Time Factors
D012996:Solutions; D002104:Cadmium; D007854:Lead