Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
Pakistan Journal of Biological Sciences
Year: 1999  |  Volume: 2  |  Issue: 1  |  Page No.: 74 - 79

Cadmium Biosorption by Free and Immobilized Live Biomass of Rhizopus oligosporus

R. Aloysius, M.I.A. Karim and A.B. Ariff    

Abstract: Studies on the feasibility of using free and immobilized live cells of Rhizopus oligosporus as a biosorbent to remove cadmium from solution was carried out using shake flask experiments. The effect of various conditions such as pH, different initial cadmium concentrations, different biomass concentrations and initial cadmium concentration to biomass concentration ratio was investigated. The biosorption of Cd2+ was determined using several sorption isotherm models such as Langmuir and Scatchard plots. The Langmuir sorption model was found sufficient to describe the biosorption of cadmium by both immobilized and free cells, suggesting that the process was chemical, saturable and equilibrated mechanism similar to ion- exchange mechanism of metals adsorption. A curve of Scatchard transformation plot reflected the covalent nature of Cd2+ adsorption by live cells of Rhizopus oligosporus. Maximum uptake capacity for immobilized cells was about 2-fold higher (34.25 mg/g) than free cells. The immobilized cells projected a higher cadmium uptake capacity with increasing biomass concentration compared to free cells which reached optimum at 0.5 g/L. The initial cadmium concentration to biomass concentration ratio for immobilized cells was lower (33.3 mg/g) compared to free cells (200 mg/g) reflecting that effective removal of Cd2+ can be obtained with increasing immobilized biomass concentration. In bioreactor, the cadmium uptake capacity in comparison with shake flasks experiments for immobilized cells was not effected as observed for free cells. In fixed bed-column, packed-bed with immobilized cells permitted better process control with 2.5-fold higher (0.18 Lh–1) influent feeding rate achieved compared to packed-bed with free cells. About 99 per cent of cadmium removal was achieved for influent containing 5 mg/L and 20 mg/L of cadmium indicating strong affinity of free and immobilized live cells of Rhizopus oligosporus towards Cd2+.

Cited References   |    Fulltext    |   Related Articles   |   Back
 
 
   
 
 
 
  Related Articles

 
 
 
 
 
 
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility