biosorption of heavy metals
TRANSCRIPT
Presented by
Madiha Shehbaz2013-mscAZ-022
Presented by:
Biosorption of heavy metals
contentsBio sorption
Heavy Metals
Bio sorption of heavy Metal
Mechanism
Factors affecting
Bio sorbent
Advantage
Uses
BiosorptionThe biosorption process involves a solid phase (sorbent or biosorbent biological material) and a liquid phase (solvent, normally water) containing a dissolved species to be sorbet (sorbet, metal ions).
Due to higher affinity of the sorbent for the sorbet species, the latter is attracted and bound there by different mechanisms
Heavy metals• Heavy metals are chemical elements with a
specific gravity that is at least 5times the specific gravity of water
• Arsenic 5.7 %
•Cadmium 8.65 %
•Iron 7.9 %
•Lead 11.34 %
•Mercury 13.56 %
Heavy metals in periodic table
Source of heavy metals in the environment
Target organ toxicity of metals
Zinc in blood cause heme
toxicity
arsenic in liver cause hepatotoxicity
Mercury/lead in brain cause
neurotoxicity
Cadmium in kidney, lungs cause
nephrotoxicity
glycine & succinyl-CoA, with decarboxylation
d-aminolevulinic acid (ALA).
Pyridoxal phosphate (PLP) as coenzyme
d-Aminolevulinate Synthase
porphobilinogen (PBG)condensation of two (ALA)
Heme
Metals in aquatic environmentInsoluble metals deposited in
river sediments
More soluble at high temperature
Benthic organism accumulate the Benthic organism through food chain
soluble in acidic water
Aquatic organism breathing take up from water during respiration
Biomagnification
Biomagnification is the incremental
increase in a contaminant's
concentration at each level of the
food chain
Bioconcentration is defined as
occurring when uptake from the water is greater than excretion
it is the opposite of bio
magnification, thus a pollutant gets smaller in
concentration as it progresses up a
food web.
Bioconcentration Biodilution
Mechanism• The mechanism of biosorption is complex, mainly
ion exchange, chelation, adsorption by physical forces, entrapment in inter and intrafibrilliar capillaries and spaces of the structural polysaccharide network as a result of the concentration gradient and diffusion through cell walls and
Cont.…• According to the dependence on the cell's
metabolism, bio sorption mechanisms can be divided into:
Metabolism dependent
non-metabolism dependent/ physical adsorption
Conceptual model for the metal removal by ion
exchange.
M = Cu and Pb
Chelation• Chelation is the formation
of metal ion complex in which the metal ion is associated with a charged or uncharged electron donor referred to as ligand. A chelate is a cyclic complex formed between a metal and a compound that contains two or more ligands (binding site).
Chelating agent• An agent frequently used in chelation therapy is
dimercaprol oral chelating agent used alternative to BAL are 2,3demercaptosuccinic acid (DMSA)
• Dimercaptopropanesulfate(DMPS)• D-Penecillamine• Deferoxamine, is often used to chelate iron• EDTA also has an affinity for lead and was one of
the first chelator developed
• BENEFITS
Benefit against acute
poisoning
Form non toxic
complex
Removal metal from
tissue
DRAWBACKS
Redistribution of metals
Essential metal loss
No removal of metal from
intracellular space
Hepatotoxicity and
Neurotoxicity
Poor clinical recovery
Pro-oxidant effects(DTPA)
Increased blood pressure
Cont. …• According to the location where the metal
removed from solution is found, biosorption can be classified as
• Extra cellular accumulation• Cell surface sorption• Intracellular accumulation
Factors affecting Biosorption
Biomass concentrati
on
Temperature seems not to influence the bio sorption performances in the range
of 20-35 0C
pH
Bio remediation of metals by algae
• Cladophora: Spp are best indicator• Scenedesmus: Tolerant to the cu and Cr • Cell wall of brown algae contain fucoidin and
alginic acid
Biosorption by plants• Plants are unique ability to concentrate essential
and non essential elements from the soil, several substance such as
• Phytoextraction• Phytostabilization• Rhizofiltration• phytovolatilisation
Processes that takes place in the root zone
Biosorption of heavy metals
1. fungi• Saccharomyces• Filamentous fungi• Rhizopus Arrhizus2. Bacteria• Bacillus subtilus• B.licheniformes
Application Key feature of biosorption• Heavy metal selectivity• Coast effectiveness• Metal recovery• No sludge generation
suggestion
This process requires research and
investigation to modify and
effectiveness both in long term and short
term process biosorption has wide
industrial applications e.g. in
metal plating, mining processing
References• 1. G. Rich, K. Cherry, Hazardous Waste Treatment
Technologies, Pudvan Publishers, New york (1987)• 2. R.K. Trivedi, Pollution Management in
Industries, Environmental Publications, Karad (1989)
• 3. B. Volesky, Biosorbent Materials, BiotechnoI. Bioeng Symp., 16: 121-126 (1986)
• 5. N. Kuyucak and B. Volesky, Biosorbents for recovery of metals from industrial solutions. Biotechnol Left., 10 (2), 137-142 (1988)
References• 6. Z. Aksu et a!., The biosorption of copper (II) by
C. vulgaris and Zramigera. Environ Technol., 13: 579-586 (1992)
• 7. T.R. Muraleedharan and C. Venkobachar, Mechanism of biosorption of copper (II) by Ganoderma lucidum. Biotechnol. Bioeng., 35: 320-325 (1990)