Presentation on theme: "8/16/20151 BIOSORPTION OF COBALT AND COPPER FROM HYDROMETALLURGICAL SOLUTIONS MEDIATED BY Pseudomonas spp PRESENTATION BY: NONJABULO PRUDENCE DLAMINI."— Presentation transcript:
8/16/20151 BIOSORPTION OF COBALT AND COPPER FROM HYDROMETALLURGICAL SOLUTIONS MEDIATED BY Pseudomonas spp PRESENTATION BY: NONJABULO PRUDENCE DLAMINI
8/16/20152 PRESENTATION LAYOUT Introduction Scope of the work Experimental design Results & discussions Conclusions
8/16/20153 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
8/16/20154 The use of biological methods for heavy metal recovery have gained considerable momentum due to their high efficiency, low operating costs and simplicity.
8/16/20155 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.
8/16/20156 EXPERIMENTAL DESIGN Sampling Soil & water samples were collected from water bodies around the small scale mines.
8/16/20157 Sampled sites Acidic Turbidity high Conductivity high
8/16/20158 CULTURING AND IDENTIFICATION Soil samples were suspended in distilled water, vortexed (thoroughly mixed). o Both the water and soil samples supernatant were diluted in a sterile phosphate buffer and there after inoculated in Pseudomonas agar base. o The isolation of bacteria using Pseudomonas agar base yielded positive results meaning that there blue-green colonies of Pseudomonas spp were observed.
8/16/20159 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.
8/16/201510 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.
8/16/201511 Results & discussions Contact time and temperature had an almost similar effect on the rate of biosorption. Increased up to a certain level then decreased.
8/16/201512 pH Maximum uptake of Cu and Co by Pseudomonas spp was attained at pH 6.5.
8/16/201515 Kinetic models Langmuir equation model R 2 = 0.8615
8/16/201516 Freundlich equation model The Freundlich equation gave a plot with higher correlation as compared to the Langmuir equation. The Freundlich gave an R 2 value of 0.9622 whereas the Langmuir had an R 2 value of 0.8615. Therefore the Fruendlich plot is favoured over the Langmuir. R 2 =0.9622
8/16/201517 Recovery from hydrometallurgical solutions Sampled site CopperCobalt % recovery Nigel river 5045 Big dam 4235 HVH mine site A 3765 HVH mine site B 7346 HVH mine site C 6111 Shaft No 2 A 2922 Shaft No 2 B 2440 Shaft No 2 C 3620
8/16/201518 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
8/16/201519 TEM metal bioaccumulation on the periplasmic wall of the Pseudomonas spp rods.
8/16/201520 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.
8/16/201521 ACKNOWLEDGEMENTS Nigel town municipality and small scale miners. National research foundation and the University of Johannesburg for financial assistance. Mr E. Fosso-Kankeu