| Summary: | 碩士 === 逢甲大學 === 化學工程研究所 === 83 === This research investigated the biosorption kinetics of lead,
copper, and cadmium ions on the biomass of Pseudomonas arginosa
PU21(Rip64). The effects of environmental factors (pH,
temperature) and growth conditions (growth phase, initial
mercury concentration for cultivation) on the biosorption were
also studied. The results showed that at pH 8.0, the resting
cells (O.D. 3.25) are able to uptake up to 108 mg Pb/g dry cell
, while the inactivated cells absorb 68 mg Pb/g dry cell.
Biomass of of Pseudomonas arginosa PU21 (Rip64) has lower
adsorption capacities for copper and cadmium ions than that for
lead ions. At pH 6.0, the resting cells have the maximum uptake
of 34 mg Cu/g dry cell (O.D. 2.0) for copper and 38 mg Cd/g dry
cell (O.D. 1.02) for cadmium. The saturation adsorption
capacities of inactivated cells (also pH 6.0) for copper and
cadmium are 31 mg Cu/g dry cell (O.D. 1.02) and 22 mg Cd/g dry
cell (O.D.1.02),respectively. The resting cells hold optimal Pb
capacity at the retardation phase, whereas for inactivated
cells , the effect of growth state on on Pb adsorption is
negligible. For the biosorption of Cd, the best uptake occurs
when the biosorbents (both resting cells and inactivated cells)
are prepared at the exponential growth phase. The growth phase
exhibits no effects on adsorption capacity of Cu, hower. By
applying high mercury concentrations (up to 50 mg Hg/L) for the
cell cultivation, the adsorption of Pb, Cu, and Cd are not
significantly improved, expcept a 27% increase in Cd uptake for
resting cells. This suggests that the induction of mer operon
by high mercury concentration did not affect the adsorption of
copper and lead, only slightly enhances the uptake of cadmium.
An increase in pH results in higher saturation adsorption
capacity and high metal-biomass affinity.
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