[Characteristics of Ag+ biosorption by the waste biomass of Saccharomyces cerevisiae].
To understand the characteristics of Ag+ biosorption by the waste biomass of Saccharomyces cerevisiae, the effect of environmental factors on metal biosorption were studied, including sorption time, initial concentration of metal ions, temperature, initial pH value, ionic strength. The relevant kinetics, equilibrium and thermodynamics were discussed. The results showed that biosorption of Ag+ on the biomass were very rapid processes. Ag+ uptake quantity within 10 min arrived at 86% of that of the equilibrium uptake during 24 h uptake when initial concentration of Ag+ was 1 mmol x L(-1) and the biomass concentration was 2 g x L(-1) x Ag+ uptake process followed the pseudo-first and the pseudo-second order kinetics. The pseudo-second order kinetic gave better fitting results than the pseudo-first order kinetic. The equilibrium data could be fitted well with the Langmuir model, better than the Freundlich model. The maximum sorption capacity obtained from the Langmuir model was 0.385 mmol x g(-1) when initial Ag+ concentration was 0-8 mmol x L(-1) and the biomass concentration of 2 g x L(-1). The values of the thermodynamic constants of biosorption were calculated and demonstrated that the biosorption process of Ag+ was spontaneous and the entropy increased. The biosorption process by the waste yeast was favorable for the removal and recovery of Ag+ from wastewater.
Chen
Can
C
Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, China.
Wang
Jian-Long
JL
D000327:Adsorption; D001673:Biodegradation, Environmental; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D012834:Silver / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*
D014874:Water Pollutants, Chemical; D012834:Silver