This document summarizes an experiment on desalination using coconut shell charcoal. The experimental setup involved preparing charcoal from coconut shells and passing salty water through a column of this charcoal. Samples were analyzed after 3 and 6 days. Results showed reductions of around 40-45% in chloride, sodium, total dissolved solids and salinity after treatment. Combining charcoal with Mauritius grass further reduced chloride by around 90%. The method provides an eco-friendly and cost-effective approach to desalination utilizing local resources. Future work aims to improve adsorption properties and find optimal natural additives.

1. Desalination by coconut shell charcoal
Deepak Malani
Gurav Bhimashankar S
NIT CALICUT
January 2006
Contact: malani.deepak@gmail.com

2. Contents
 Existing Techniques
 Idea
 Experimental setup
 Results & Discussion
 Conclusion

3. Existing Techniques
 MSF/Reverse Osmosis
 Solar Stills
 Electrodialysis
 Micro and nano-filtration
 ADIRA (MEDRC)

4. Our Idea
 Inspiration from available natural
resources & processes
 Use of wood charcoal for water purification
 Characteristics of coconut shell charcoal :
 100% organic
 Renewable resource
 Higher calorific heat value
 Environmental friendly
 Ready availability especially in coastal areas

5. Experimental Setup
 Preparation of coconut-shell charcoal
 Earth kiln
 Limited supply of air
 60-70 whole shells 2.5 kg of charcoal
 Sieve size : 2mm-20mm
 Thorough washing; drying

6. Contd.
 Preparation of salty water samples:
 Typical concentration of NaCl ~ 35gm/l
 Samples made in lab, conc. = 30gm/l
 Column setup (fig. 1)

7. Contd.
Fig 1. Apparatus for charcoal-based desalination

8. Observations
30000
25000
20000
15000 Sodium (mg/l)
Chloride (mg/l)
10000
TDS (mg/l)
5000
0
Original After 3 After 6
Sample days days
Reduction in dissolved ion concentration after charcoal treatment
Sample Analysis done at CWRDM, Calicut

9. 30
25
20
15
Salinity (ppt)
10
5
0
Original After 3 After 6
sample days days
 Reduction in salinity after charcoal content

10. Results
 Reduction in chloride ion concentration : 40.9%
 Reduction in sodium ion concentration : 42.0%
 Reduction in TDS (total dissolved salts) : 45.1%
 Reduction in salinity : 42.9%

11. Experimentation with mauritius grass
 Species : veteveria zizanioides (vetiver)
 Combination of charcoal and mauritius grass
 Reduction in chloride ion concentration : ~90%
 Reduction in sodium ion concentration : ~30%

12. Conclusion
Desalination Filtration
 Adsorption of dissolved  Removal of organic
salts contaminants &
 Attributed to the pathogenic micro-
surface characteristics organisms
of charcoal  Attributed to the macro-
pores in the charcoal
structure

13. Features
 Ease of manufacture
 Eco-friendly solution
 Safe disposal/reuse of charcoal
 Household utility (esp. coastal/rural areas)
 Cost effective solution
 Energy efficient

14. Future Work & Challenges
 Improvisation of adsorption characteristics of
charcoal by thermal treatment
 Finding natural resources like mauritius grass
with required desalination characteristics
 Effective design of the apparatus