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CITRUS FRUIT WASTE-BASED ADSORPTION TECHNOLOGY FOR THE TREATMENT OF HEAVY METAL BEARING WASTEWATER. Asma Saeed and Muhammad Iqbal T.I Bioresource Utilization Group, Food and Biotechnology Research Centre PCSIR Laboratories Complex Lahore. What is Pollution?.
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CITRUS FRUIT WASTE-BASED ADSORPTION TECHNOLOGY FOR THE TREATMENT OF HEAVY METAL BEARING WASTEWATER Asma Saeed and Muhammad Iqbal T.I Bioresource Utilization Group, Food and Biotechnology Research Centre PCSIR Laboratories Complex Lahore
What is Pollution? Introduction of contaminants into natural environment that cause instability, disorder, harm or discomfort to the ecosystem. It may be in the form of chemical substances or energy like heat, light and noise. INORGANIC ORGANIC
ECOSYSTEM All organisms living in a particular area interacting with physical components like soil, water, air and sunlight
FOOD WEB Food cycle depicts who eats whom in an ecological community
SOURCES OF ENVIRONMENTAL CONTAMINATION • Air • Noise • Light • Water Water contamination is the most serious issue as it is vital for life
HEAVY METALS • Among various pollutants, heavy metals impart deleterious effect on the ecosystem due to their persistent and non-biodegrable nature that ultimately led them to enter into food chain • Dangerous Substances Directive by the European Union (76/464/EEC) Red ListGrey List 1. Hg 1. Zn 2. Cu 3. Ni 2. Cd4. Cr 5. Pb 6. As 7.Sb8. Mo 9. Ti 10.Sn11.Ba12. Be 13. B 14. U 15. V 16. Co 17. Ag 18.Tl 19. Se 20. Ti GREY LIST before 1997 Pb Cu Ni Cr Zn
HEAVY METAL CONTAMINATION OF FRESH WATER • Electroplating (Cu, Zn, Cr, Pb, Ni) • Metal finishing (Cd, Cr, Cu, Pb, Ni, Zn, Ag) • Petroleum (Pb and Organic compounds) • Steel works (Al, Co, Cu, Ce, Ti, Ni, Cr, Mo etc) • Vehicle and aircrafts (Oils, Emulsifiers, Al, Pb) • Storage batteries (Pb, Cu, Sb) • Mining (Zn, Pb) • Pulp and Paper (Cu) • Glass, ceramics and cement (Pb, W) • Textile and Leather (Dyes, Cr)
WATER TREATMENT TECHNOLOGIES Conventional technologies for heavy metal remediation include: • Chemical precipitation • Coagulation • Oxidation-reduction • Osmosis • Reverse osmosis • Evaporation • Ion Exchange
TECHNO-ECONOMICAL CONSTRAINTS • Expensive/costly • Inefficient/ineffective for the removal of heavy metals at low concentration • Hazardous/generate toxic sludge
BIOSORPTION-AN ALTERNATE TECHNOLOGY Biosorption is the passive accumulation of the adsorbate e.g. metal ions, organic molecules, colour ions etc., to biologically inactive material
ADVANTAGES OF BIOSORPTION Biosorption is a combination of several phenomena having several advantages: • Cost effective • Efficient • Reusability in repeated cycles • Low operational cost • Environment-friendly • Applicable over wide-range of physicochemical conditions • Non-selective work under multi-metal conditions
Biosorption as an Alternative Technique Biosorption Microbial Biomass Agro-waste Materials Bacteria, Algae, Fungi, Yeast Crop Residues, Grains/Fruit Wastes Purposefully Cultured Biomass Waste from Fermentation and Pharmaceutical Industry Food Industry Waste Plant Waste Biomass
Technical Limitations Towards Their Commercial Applications • Small particles • Very fragile/delicates • Low mechanical strength • Difficulty of separation • Process can not be scaled up
SOLUTION ? Immobilization/Entrapment A physical or chemical process used to fix micro-organisms on to a solid support or trap them in a solid matrix.
Biostructural Fibrous Network as an Alternative Immobilization Matrix Loofa Sponge Papaya Wood Palm Trunk Fibers
Biowastes used as Biosorbent Now I will discuss more about the application of citrus peel waste in the treatment of metal contaminated water Black gram husk Petiolar felt-sheet of Palm Papaya wood Orange peel
Citrus Peel as a Biosorbent wet wt dry wt Component (%) (%) ~ 6 25 - 35 sugars ~ 5 20 - 25 cellulose & hemicellulose ~ 4 15 - 25 soluble fiber (pectin) ~ 1 04 - 06 flavanones (hesperidin, naringin, etc) ~ 0.05 0.1 - 0.5 polymethoxylated flavones ~ 0.05 0.1 - 0.3 limonoids (limonin+glucosides) ~ 1 3 - 5 ash ~ 1 3 - 4 protein ~ 1 limonene/peel oil ~ 80 water
Citrus Peel as a Biosorbent Screening and Selection Effect of biomass quantity
Citrus Peel as a Biosorbent Effect of pH Effect of Time Time 60 min Optimum pH = 5.0
Citrus Peel as a Biosorbent Experimental Equilibrium Biosorption Langmuir and Freundlich Models Pb qeq = 99.05 mgg-1 Cdqeq= 68.92 mgg-1
FTIR Spectrum of CPW and Functional Moieties Pb-loaded CPW Cd-loaded CPW -OH stretch C=O stretch -CH stretch Native CPW
Biosorption and Ion-Exchange SEM-EDXIon Exchange Equation:M+n + BHn ↔ BM + nH+ SEM-EDX of Native CPW SEM-EDX of Pb-Loaded CPW
PROPOSED MECHANISM OF METAL BINDING Mn2+ Mn2+ II) Lignin moieties I) Cellulosic moieties Mn2+ III) Protein moieties
Citrus Peel as a Biosorbent a, Maximum acceptable concentration for health reasons b, Limits for aesthetic or consumer oriented reasons c, Provisional value for health reasons
Fixed Bed Column Bioreactor Studies Column Description Schematic diagram of fixed bed column bioreactor, packed with CPW designed to function as a continuous flow system for biosorption of heavy metals. • metal solution reservoir; • peristaltic pump; 3. flow control; 4. glass column reactor; 5. cpw biosorbent; 6. enlarged view of column packing; 7. extension for secondary column; and 8. effluent storage.
Thanks to: University of Alaska Fairbanks, USA University of Sheffield, UK Forschungszentrum Karlsruhe, Germany