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排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
Abstract: Fungal pellets (diameters ranging from 0.5 to 2 mm) were precultured in sugar-containing industrial sewage. They were packed into chromatography columns and then tested for biosorption of silver, copper and lead, using the downflow method. The physical parameters taken (differential pressure at the column, flow rate, bed height) showed rather good mechanical properties of the pellets. Charging the column with heavy metal solution (1 mM Ag+, Cu2+ or Pb2+ as nitrates in distilled water) resulted in very good biosorptive properties. Eluted solution contained less than or an equal amount of 1 gM heavy metal, demonstrating a removal of more than 99.9% of added metal. 相似文献
2.
Summary Accumulation of cobalt (60Co) by the estuarine microalgaChlorella salina has been characterized. At cobalt concentrations ranging over 3.125–100 M, a significant amount of cobalt was bound within 1 min. This was metabolism-independent and unaffected by incubation in light or dark conditions. This initial rapid phase of biosorption was followed by a slower phase of uptake which was apparently active and inhibited by incubation in the dark, or by the uncoupler dinitrophenol and the respiratory and photosynthetic inhibitor potassium cyanide in the light. For cells suspended in 10 mM Taps pH 8, cobalt biosorption followed a Freundlich adsorption isotherm. However, in the presence of 0.5 M NaCl, biosorption deviated from the Freundlich model because of competition by Na+. Cobalt biosorption was decreased by increasing concentrations of Na+, decreasing pH and the presence of Cs+, Li+, Rb+, Zn2+. Mn2+ and Sr2+ (added as chlorides). This was a result of competition between Co2+ and the other cations, including H+, for available binding sites on the cell wall and was confirmed by increased desorption of cobalt by solutions of low pH or high salinity. Increasing cell density resulted in increased removal of cobalt from solution but decreased the specific amount of cobalt taken up by the cells. 相似文献
3.
Godjevargova T. Mihova S. Gabrovska K. 《World journal of microbiology & biotechnology》2004,20(3):273-279
Dead cells of Saccharomyces cerevisiae 54 were immobilized by entrappment in polyacrylonitrile. The beads obtained were used to adsorb copper in an up-flow fixed-bed
column. The effect of polymer content and cell loading were studied to optimize the porosity and the efficiency in copper
removal of the biosorbent beads in a batch system. The optimal concentration of the polyacrylonitrile was assumed to be 12%(w/v)
and a concentration of 0.5 g cell dry weight in 1 g polymer was most effective in adsorption of Cu2+. The adsorption capacity of this biosorbent was 27 mg Cu2+/g dry biomass at 200 mg/l initial concentration of copper ions. Adsorption of Cu2+ in a batch system was studied using different initial concentrations of the solute. The optimal conditions in the up-flow
column of the following parameters were determined: flow rate, bed height, and initial concentration of Cu2+ of the solutions. Results of fixed-bed biosorption showed that breakthrough and saturation time appeared to increase with
the bed height, but decrease with the flow rate and the initial concentration. The linearized form of the Thomas equation
was used to describe dynamic adsorption of metal ions. As a result, the adsorption capacity of the batch system and the column
system was compared. Desorption of copper ions was achieved by washing the column biomass with 0.1 M HCl at an eluent flow
rate of 1 ml/min. The reusability of the immobilized biomass was tested in five consecutive adsorption-desorption cycles.
The regenerated beads retained over 45% of their original adsorption capacity after five A/D cycles.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Comparative studies on metal biosorption by two strains of Cladosporium cladosporioides 总被引:4,自引:0,他引:4
Two strains of a fungus, Cladosporium cladosporioides 1 and C. cladosporioides 2 showed different metal biosorption properties. Strain 1 showed preferential sorption of gold and silver, while strain 2 could bind metals such as copper and cadmium in addition to gold and silver. Strain 1 had a cell-wall hexosamine content of 0.1%. X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR) analyses indicated that nitrogen was not involved in metal biosorption by the strain. In strain 2 the cell-wall hexosamine content was 150 times that of strain 1. These results indicated that hexosamine was responsible for non-specific metal binding while cell-wall polymers other than hexosamines had a role in conferring selectivity in precious-metal binding. 相似文献
5.
Cadmium uptake by Spirulina maxima: toxicity and mechanism 总被引:4,自引:0,他引:4
Augusto da Costa A.C. de França F.P. 《World journal of microbiology & biotechnology》1998,14(4):579-581
Cadmium uptake by Spirulina maxima cells was more pronounced in living than in dead cells, with a maximum recovery of 47.63mg Cd/g cells for living cells and 37.00mg Cd/g cells for inactivated cells. When in the medium at 1.2mg/l, cadmium affected cell growth and diminished cell productivity. Cadmium was detected in the outer and inner faces of the external membrane, essentially in the lipid layer. 相似文献
6.
7.
The presence of toxic heavy metals in natural environments entails a potential health hazard for humans. Metal contaminants in these environments are usually tightly bound to colloidal particles and organic matter. On the other hand, the potential of these metals towards chelation by different chelating agents presents a good characteristic for their removal from the environment. On this basis, two chitosan/anionic surfactant complexes were prepared and evaluated for their ability to remove heavy metals from aqueous solutions. The experimental results of the uptake of metal ions including Cu2+, Sn2+, Co2+ and Ni2+ are reported in this study. The results show that modified chitosan with short‐spacer group cross‐linkers has a higher potential for heavy metal uptake than long‐chain cross‐linker‐modified chitosan. Also, increasing the electronegativity of the heavy metals increases their uptake from the medium. Increasing the time of exposure of the heavy metals to the modified polymer increases the efficiency of the metal uptake process. 相似文献
8.
Yeast-based biomass, immobilised in polyvinyl alcohol (PVA) cryogels, was used as a biosorbant material for the recovery of
platinum (PtCl62−) from aqueous solutions. The resulting biomass-Pt matrices were then employed directly as an electro-catalytic anode in a
fuel cell configuration to generate electrical energy from renewable sources such as glucose and ethanol. We suggest an integrated
strategy incorporating the derivation of a high-value product from a bioremediative process with a view towards producing
energy from renewable fuels such as glucose and ethanol. 相似文献
9.
Katarzyna Chojnacka 《World journal of microbiology & biotechnology》2007,23(8):1139-1147
The paper discusses biosorption of Cr(III), Cu(II), Mn(II), Zn(II) and Co(II) to the biomass of Chlorella vulgaris, to produce a biologically bound, concentrated form of microelements. The kinetics of biosorption was described with a pseudo-second
order equation and equilibrium with the Langmuir isotherm. The mechanism of biosorption was identified as cation-exchange
with alkaline metals. Cation-exchange capacity was evaluated as 4.07 meq g−1. The effect of operation conditions, pH and temperature, on biosorption performance was investigated and the best operation
conditions for biosorption were selected (pH 5, temperature 25 °C). The maximum sorption capacity of microelements was determined
in single-metal system at pH 5 and 25 °C: Zn(II) 3.30 meq g−1, Cu(II) 1.77 meq g−1, Co(II) 1.75 meq g−1, Cr(III) 1.74 meq g−1, Mn(II) 0.764 meq g−1. Biosorption experiments were also carried out in multi-metal system. The biomass of C. vulgaris enriched with microelements via the process of biosorption in both single- and multi-metal system was discussed in terms
of preparation of feed supplement for laying hens and piglets. The experiments showed that 1 kg of conventional feed for laying
hens can be supplemented with 0.20 g of the biomass enriched with microelements and for piglets with 0.15 g of the preparation. 相似文献
10.
Sorption of Co, Cu, Ni and Zn from industrial effluents by the submerged aquatic macrophyte Myriophyllum spicatum L. 总被引:1,自引:0,他引:1
E. Lesage C. Mundia D.P.L. Rousseau A.M.K. Van de Moortel G. Du Laing E. Meers F.M.G. Tack N. De Pauw M.G. Verloo 《Ecological Engineering》2007,30(4):320-325
The submerged aquatic plant Myriophyllum spicatum L. (Eurasian water milfoil) has been suggested as an efficient plant species for the treatment of metal-contaminated industrial wastewater. The process of metal removal by plants involves a combination of rapid sorption on the surface and slow accumulation and translocation in the biomass. This study focussed on the sorption/desorption characteristics of the surface of M. spicatum for Co, Cu, Ni and Zn. Batch sorption tests with mixed metal solutions covering a range of 0, 1, 5, 10, 50 and 100 mg l−1 of each metal, were performed. For Co, Ni and Zn, the sorption process was well described by the Langmuir model, whereas sorption of Cu was better described by the Freundlich model. The biomass showed the highest affinity for Cu and Zn. Langmuir sorption maxima of Co, Ni and Zn were 2.3, 3.0 and 6.8 mg g−1 DM, respectively. At the highest initial concentration of 100 mg l−1, a maximum of 29 mg g−1 DM of Cu was sorbed onto the surface of the biomass. Desorption by 0.1 M HCl did not fully recover the metals sorbed onto the surface and there was evidence of leaching from within the biomass. Recovery of heavy metals and regeneration of the biomass by washing with 0.1 M HCl was therefore not suggested as a viable strategy. 相似文献