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 1

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. ORGANIC INORGANIC 2

ECOSYSTEM All organisms living in a particular area interacting with physical components like soil, water, air and sunlight 3

FOOD WEB Food cycle depicts who eats whom in an ecological community 4

SOURCES OF ENVIRONMENTAL CONTAMINATION  Air  Noise  Light  Water Water contamination is the most serious issue as it is vital for life 5

ROUTES OF WATER CONTAMINATION 6

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 List Grey List 1. Hg1. Zn2. Cu3. Ni 2. Cd4. Cr5. Pb6. As 7. Sb8. Mo9. Ti 10. Sn11. Ba12. Be 13. B14. U15. V 16. Co17. Ag18. Tl 19. Se 20. Ti GREY LIST before 1997 Pb Cu Ni Cr Zn 7

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) 8

WATER TREATMENT TECHNOLOGIES Conventional technologies for heavy metal remediation include: 1.Chemical precipitation 2.Coagulation 3.Oxidation-reduction 4.Osmosis 5.Reverse osmosis 6.Evaporation 7.Ion Exchange 9

TECHNO-ECONOMICAL CONSTRAINTS  Expensive/costly  Inefficient/ineffective for the removal of heavy metals at low concentration  Hazardous/generate toxic sludge 10

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 11

ADVANTAGES OF BIOSORPTION Biosorption is a combination of several phenomena having several advantages: 1.Cost effective 2.Efficient 3.Reusability in repeated cycles 4.Low operational cost 5.Environment-friendly 6.Applicable over wide-range of physicochemical conditions 7.Non-selective work under multi-metal conditions 12

Biosorption as an Alternative Technique Biosorption Microbial Biomass Agro-waste Materials Bacteria, Algae, Fungi, Yeast Purposefully Cultured Biomass Waste from Fermentation and Pharmaceutical Industry Plant Waste Biomass Food Industry Waste Crop Residues, Grains/Fruit Wastes 13

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 Small particles  Very fragile/delicates  Low mechanical strength  Difficulty of separation  Process can not be scaled up Technical Limitations Towards Their Commercial Applications 15

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. 16

Biostructural Fibrous Network as an Alternative Immobilization Matrix Loofa SpongePapaya WoodPalm Trunk Fibers 17

Process for the Production of Loofa Sponge Disc Biosorbents 18

Scanning Electron Microscopy of Immobilization Process 19

Biowastes used as Biosorbent Petiolar felt-sheet of Palm Papaya wood Black gram husk Orange peel Now I will discuss more about the application of citrus peel waste in the treatment of metal contaminated water 20

Citrus Peel as a Biosorbent wet wt dry wtComponent (%) (%) ~ sugars ~ cellulose & hemicellulose ~ soluble fiber (pectin) ~ flavanones (hesperidin, naringin, etc) ~ polymethoxylated flavones ~ limonoids (limonin+glucosides) ~ ash ~ protein ~ 1limonene/peel oil ~ 80water 21

Citrus Peel as a Biosorbent Effect of biomass quantity Screening and Selection 22

Citrus Peel as a Biosorbent Effect of pH Effect of Time Optimum pH = 5.0 Time 60 min 23

Citrus Peel as a Biosorbent Experimental Equilibrium Biosorption Langmuir and Freundlich Models Pb q eq = mgg -1 Cd q eq = mgg -1 24

FTIR Spectrum of CPW and Functional Moieties Native CPW Cd-loaded CPW Pb-loaded CPW -OH stretch -CH stretch C=O stretch 25

Biosorption and Ion-Exchange SEM-EDX Ion Exchange Equation: M +n + BH n ↔ BM + nH + SEM-EDX of Native CPWSEM-EDX of Pb-Loaded CPW 26

PROPOSED MECHANISM OF METAL BINDING II) Lignin moieties I) Cellulosic moieties III) Protein moieties Mn 2+ 27

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 Metal ions Before biosorption (mg/L) After biosorption (mg/L) Limits recommended by WHO for drinking water (mg/L) NEQS maximum limits for effluent discharge (mg/L) Cd(II) Pb(II) Cu(II) Zn(II) Cr(III) Ni(II) ± ± ± ± ± ± a 0.01 a 1.00 a,b 0.1 a,b 0.05 c 0.07 a

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. 1.metal solution reservoir; 2.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. 29

Adsorption-Desorption Cycles 30

Thanks to: University of Alaska Fairbanks, USA University of Sheffield, UK Forschungszentrum Karlsruhe, Germany 31

THANK YOU 32

Kinetics of Cd 2+ and Pb 2+ Sorption 33