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04/19/23 1
BIOSORPTION OF COBALT AND COPPER FROM HYDROMETALLURGICAL SOLUTIONS
MEDIATED BY Pseudomonas spp
PRESENTATION BY:
NONJABULO PRUDENCE DLAMINI
04/19/23 2
PRESENTATION LAYOUT
Introduction
Scope of the work
Experimental design
Results & discussions
Conclusions
04/19/23 3
INTRODUCTION
The use of micro-organisms in the dissolution of metals bearing minerals and the removal of some anions e.g. phosphates and ammonia is well known e.g. sulphur oxidisers Acidithiobacillus spp, Leptospirillum spp and Sulpholobus spp. (Acharya,1990) (Momba, 2005).
However, not much has been done on the use of microorganisms in the removal of leached metals from their aqueous solutions. E.g. Fixation of Ni and Fe by Pseudonomonas species through biosorption (Danalkova et al,2005).
In this study copper and cobalt are being removed from hydrometallurgical solutions using microorganisms
04/19/23 4
The use of biological methods for heavy metal recovery have gained considerable momentum due to their high efficiency, low operating costs and simplicity.
04/19/23 5
SCOPE OF THE WORK
This project was aimed at testing the viability of using bacteria as;
Alternatives to costly metal removal
techniques (water purification). Biosorbents to recover precious metals
from hydrometallurgical process solutions.
04/19/23 6
EXPERIMENTAL DESIGN
Sampling
•Soil & water samples were collected from water bodies around the small scale mines.
04/19/23 7
Sampled sites
•Acidic•Turbidity high•Conductivity high
04/19/23 8
CULTURING AND IDENTIFICATION
Soil samples were suspended in distilled water, vortexed (thoroughly mixed).
oBoth the water and soil samples supernatant were diluted in a sterile phosphate buffer and there after inoculated in Pseudomonas agar base.
oThe isolation of bacteria using Pseudomonas agar base yielded positive results meaning that there blue-green colonies of Pseudomonas spp were observed.
04/19/23 9
Synthetic solutions
Solutions of different concentrations (0.07M, 0.33M and 0.66M) were prepared using copper and cobalt sulphate.
Batch scale experiments to test the effects of
Contact time, concentration, pH, temperature, co-ions, biomass concentration were conducted.
04/19/23 10
Metal recovery
Bacteria : water (3:1) ratio Bacteria were inoculated into synthetic
solutions water samples and recovery was allowed to take place over a period of 24 h in a shaking incubator (150 rpm) at 36.5°C.
Metal concentrations were analysed using AAS and ICP.
Control experiments were conducted to monitor parameters like precipitation.
The same procedure was repeated for hydrometallurgical solutions which had lower metal concentrations.
04/19/23 11
Results & discussions
Contact time and temperature had an almost similar effect on the rate of biosorption. Increased up to a certain level then decreased.
04/19/23 12
pH
Maximum uptake of Cu and Co by Pseudomonas spp was attained at pH 6.5.
04/19/23 13
Biomass (bacterial concentration)
3 : 1
04/19/23 14
Co-ions
Mixing copper & cobalt enhanced removal of copper.
Ionic radii
04/19/23 15
Kinetic models
y = -1219.9x + 9.1768
R2 = 0.8615
0.55
0.75
0.95
1.15
1.35
1.55
1.75
1.95
2.15
2.35
2.55
0.0057 0.0059 0.0061 0.0063 0.0065 0.0067 0.0069 0.00711/C
1/(
x/m
)
Langmuir equation model
R2= 0.8615
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y = -6.3649x + 13.903R2 = 0.9622
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
2.14 2.16 2.18 2.2 2.22 2.24 2.26
Log C
Log
x/m
Freundlich equation model
The Freundlich equation gave a plot with higher correlation as compared to the Langmuir equation. The Freundlich gave an R2 value of 0.9622 whereas the Langmuir had an R2 value of 0.8615. Therefore the Fruendlich plot is favoured over the Langmuir.
R2=0.9622
04/19/23 17
Recovery from hydrometallurgical solutions
Sampled site
Copper Cobalt
% recovery % recovery
Nigel river 50 45Big dam 42 35HVH mine site A 37 65HVH mine site B 73 46HVH mine site C 61 11Shaft No 2 A 29 22Shaft No 2 B 24 40Shaft No 2 C 36 20
04/19/23 18
INTERACTION OF MICROBES WITH METALS (SEM)
SEM micrograph of the dried metal solution before interaction with Pseudomonas spp rods.
SEM micrograph showing the dried mixture of metal solution with Pseudomonas spp
04/19/23 19
TEM
metal bioaccumulation on the periplasmic wall of the Pseudomonas spp rods.
04/19/23 20
Conclusions
Pseudomonas spp reclaim both copper and cobalt from their sulphate synthetic solutions .
It tends to remove or extract more metal ions at low concentrations and the ratio of bacteria population to solution volume being 3:1 works best.
The maximum uptake of both copper and cobalt occurred at a pH of 6.5 beyond which the adsorption rates decreased.
The bacteria have successfully removed up to 45 % of copper from 0.07M and up 40 % from 0.07M cobalt from cobalt sulphate solutions and 73 % and 65 % of copper and cobalt respectively from mine water samples.
04/19/23 21
ACKNOWLEDGEMENTS
Nigel town municipality and small scale miners.
National research foundation and the University of Johannesburg for financial assistance.
Mr E. Fosso-Kankeu
04/19/23 22
….THANK YOU…
…….THANK YOU……
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