Removal of Nitrites from Waste Waters using Ashes of Some Herbal Plants as Bio-sorbents

M. Suneetha and K. Ravindhranath*

Department of Engg. Chemistry and Post Graduate Chemistry,

Bapatla Engineering College, BAPATLA-422101, Guntur Dt.,

Andhra Pradesh

ABSTRACT:

Ashes of leaves of Phyllanthus neruri, Azadiracta indica, Annona squamosa, Moringa tinctoria, Calotropis zygantia and Tridox procumbens have been probed for their sorption properties towards Nitrite ions. Batch methods of extractions have been adopted using simulated waters. Various physicochemical parameters such as pH, sorbent dosage and time of agitation have been optimized for the successful quantitative extraction of Nitrite. The methodologies are successfully applied to water samples collected from polluted lakes.

KEYWORDS:Nitrites; pollution control; bio-adsorbents

INTRODUCTION:

Nitrite is a toxic ion present in polluted waters due to the incomplete oxidation of nitrogenous organic matter in the waters. Vegetables, cured meat, fish and dairy products are the main sources of Nitrite^1-3. Meat products contain <0.2–6.4 mg of Nitrite per kilogram and dairy products contain <0.2–1.7 mg of Nitrite per kilogram^3b. Nitrite levels are more in vegetables that have been damaged, poorly stored, or stored for extended periods as well as pickled or fermented vegetables. In such circumstances, Nitrite levels of up to 400 mg/kg have been found³. Further, Nitrite is used as a preservative for meat and to import aesthetic dark red color to the meet and this practice became the important source of Nitrite contamination ^1-3.

Nitrite causes methemaglobinemia and subsequent cancer due to its ability to form Carcinogenic nitrosamine and N-nitroso compounds with blood cells. Nitrite reacts with nitrosatable compounds in the human stomach to form N-nitroso compounds. Many of these N-nitroso compounds have been found to be carcinogenic in humans and animals.

More than half of the Cancer deaths in developed countries are due to Nitrite^2-7. Nitrates and Nitrites are inter-convertible and anaerobic conditions reduce Nitrate to Nitrites^{3, 8}. In view of cancer prone epidemiological findings, many countries pass stringent laws to control the Nitrite prone cancer. The maximum permissible limits in waters are: EU: 0.5 ppm;USA: 1 ppm; China: 0.002 ppm in bottled waters. Thus removal of Nitrites from polluted waters assumes importance.

Some researchers developed methods for the removal of Nitrite from polluted waters^9-17. De. D. Kalu et al¹⁵ made kinetic studies of the electrochemical treatment of Nitrite and Nitrate ions on Iridium-modified Carbon Fiber Electrode. Saleem M et. Al¹⁷ studied electrochemical removal of Nitrite in simulated aquaculture. Katsuya Abe et al¹⁸ investigated the aerial microalgae Trentepohlia aurea in relation to the removal characteristics of Nitrites. Polatides et al¹⁹ studied the electro chemical removal of Nitrate and Nitrite ions from aqueous solutions by pulsing potential electrolysis. A patent product under the brand name ALGONE is available for removal of Nitrites in the marine aquarium.

The methodologies based on bio-sorbents derived from agricultural wastes for the removal of polluting ions offer a potential alternative to the existing methods of detoxification and recovery of toxic and valuable ions in polluted waters^20-29. In fact, these new novel biological approaches in the recent past have stimulated continuous and expanding research in developing eco-friendly procedures in the control of polluting ions^30-39.

This aspect of probing bio-sorbents is less trodden with respect to the control of Nitrites. Nes,e.Ozturk et al²⁰ investigated the removal of Nitrite from aqueous solution by adsorption using Sepiolite and powdered activated carbon.

In the present work different ashes derived from some herbal plants have been probed for their sorption abilities towards Nitrites from polluted waters.

METERIALS AND METHOD:

(A) CHEMICALS AND SOLUTIONS:

All Chemicals used were of analytical grade.

 Stock Solutions of Nitrite: 500 ppm stock was prepared using A.R. grade Sodium Nitrite and double distilled water and it is diluted as per the need.

 Sulphanilic acid reagent: 0.6 g of A.R. Sulphanilic acid was dissolved in 100 ml of 20% v/v hydrochloric acid.

 α-Napthylamine reagent: 0.48 g of A.R. α –naphthylamine was dissolved in 100 ml of 1.3 % v/v hydrochloric acid.

 Sodium acetate, 2 M: 16.4 g of anhydrous sodium acetate was dissolved in 100 ml of distilled water.

(B): ADSORBENTS:

Our pilot experiments revealed that ashes of leaves of Phyllanthus neruri, Azadiracta nndica, Annona squamosa, Moringa tinctoria, Calotropis zygantia and Tridox procumbens have been found to have affinity towards Nitrite ions. Phyllanthus Niruri is a herb belongs to Phyllanthaceae family and is found in Central and Southern India; it is found to have many therapeutic values in curing jaundice, diabetes, dyspepsia, ulcers, sores, swellings, ophthalmia and chronic dysentery. Azadirachta indica, or Neem Tree, is an evergreen tree native to Southeast Asia and it belongs to Meliaceae family. Annona squamosa is a small well-branched shrub that bears edible fruits called sugar-apple; belongs to Annonaceae family and grows well in lower altitudes. Morinda tinctoria, commonly known as Aal or Indian Mulberry is a species of flowering plant and belongs to Rubiaceae family and is native to South Asia. It is an evergreen shrub growing to 5-10 m tall. The plant is extensively cultivated in India and its leaves and roots are used traditional system of medicine, as astringent, deobstrent, emmengogue and to relive pain in the gout⁴¹. It is reported to have anticonvulsant activity⁴². Calotropis Zygantia is alarge shrub having traditional medicinal values, growing to 4 m tall and it belongs to Apocynaceae family and is widely grown in all types of soils.

Tridax procumbens is a species of flowering plant in the daisy family and is best known as a widespread weed and pest plant. It grows in tropical, subtropical and mild temperate regions worldwide. It possesses medicinal uses especially for diabetic treatment. The oral administration of leaf extracts at doses of 200 mg kg⁻¹ lead to a significant blood glucose reduction. This laid the foundation to study the active compounds of such anti-diabetic plants that are responsible for the hypoglycemic activities. It also proves the traditional claim of Mandesh region with regard to Tridax procumbens for its anti-diabetic activity⁴⁰.

Preparation of sorbents: The leaves of these plants were cut, washed with tap water followed by distilled water and then sun dried. Then these leaves were burnt to ashes and these ashes were used in this work.

(C): ADSORPTION EXPERIMENT:

The Batch system of extraction procedure was adopted^23,24,43. Carefully weighed quantities of adsorbents were taken into previously washed 1 lit/500 ml stopper bottles containing 500 ml /250 ml of Nitrite solutions of predetermined concentrations. The various initial pH values of the suspensions were adjusted with dil. HCl or dil. NaOH solution using pH meter. The samples were shaken in mechanical shakers for a desired period and after the equilibration period, an aliquot of the sample was taken, filtered and the Nitrite content in it is determined spectrophotometrically⁴⁴.

Estimation of Nitrites:

A measured quantity of the Nitrite sample was taken in to a 50 ml volumetric flask. To it 1 ml of Sulphanilic acid reagent solution was added, mixed well and was allowed to stand at least 3 min and not more than 10 min at room temp in diffused light. Then 1 ml of the α-Napthylamine solution and 1 ml of 2M-Sodium acetate solution to act as buffer (pH: 2.0-2.5) were added. The solution then diluted to 50 ml and mixed well. After 10 min, but not later than 30 min, the Optical Density of the reddish-purple color developed was measured at 520 nm against blank using U.V and visible spectrophotometer (Systronics make). Previously, a standard graph was constructed between O.D. and known concentrations of Nitrite, in conformation of Beer’s law adopting Least Square Method for linear graphs. The measured O.D. values for the unknown solutions were referred to standard graph to determine the concentrations of Nitrite in un-known samples.

(D): EFFECT OF INTERFERING IONS:

The interfering ions chosen for study are the common ions present in natural waters, viz., Phosphate, Sulphate, Fluoride, Chloride, Carbonate, Calcium, Magnesium, Iron, Nickel, Copper and Zinc. The synthetic mixtures of Nitrite and one of the interfering ions were so made that the concentration of the interfering ions maintained at tenfold excess than the Nitrate ion concentration.

500 ml of these solutions were taken in stopped bottles and then correctly weighed optimum quantities of the promising sorbents were added. Optimum pH was adjusted with dil. HCl or dil. NaOH using pH meter. The samples were shaken in shaking machines for desired optimum periods and then the samples were filtered and analyzed for Nitrites. % of extraction was calculated from the data obtained. The results are presented in the Table No. 1.

(E): APPLICATIONS OF THE DEVELOPED BIO-SORBENTS:

The workability of the developed bio-sorbents for removing Nitrite ion concentrations in naturally occurring polluted waters were tried. For this purpose, five samples were collected from five lakes polluted with Nitrite at different places in Bapatla Mandalam of Guntur Dt of Andhra Pradesh and the actual concentration of Nitrite present in them was analyzed. Then these samples were subjected to the extraction of Nitrites using the bio-sorbents developed in this work at optimum conditions of pH, equilibration time and sorbent concentration. The results obtained were presented in the Table 2.

RESULTS AND DISCUSSIONS:

The sorption characteristics of ashes of leaves of Phyllanthus niruri , Tridax procumbens, Morinda tinctoria, Azadirachta indica, Annona squamosa and Calotropis gigantean as bio-sorbents towards Nitrite have been investigated by varying the parameters such as pH of the equilibration system, time of agitation and adsorbent dosage. The results obtained are presented in the Graph No: A: 1-6; B: 1; C: 1 and Table No. 1 and 2.

The following observations are significant:

1. When percentage of extraction is studied with respect to varying agitation times at a fixed pH and sorbent dosage, the curves increase up to a certain interval and then onwards plateaus are obtained (vide Graph Nos.:A:1-5). This indicates that the extraction increases with time until a state of dynamic equilibrium is attained and from then onwards no further extraction is possible.

2. The extractions of Nitrites are found to be pH dependent. With the increase of pH of equilibrium system, the % of extractions of Nitrites decreases at a fixed equilibration time and sorbent concentration (Vide Graph Nos : A: 1-6; B: 1 ). As for example, in the case of leaves ash of Phyllanthus neruri, the maximum extractability is found to be :29.7% at pH:10; 42.8% at pH:8; 44.4% at pH:6; 79.5% at pH:4 and 100% at pH:2.

In the case of Azadiracta indica leaves ashes the maximum extractability is found to be 18.5% at pH:10; 39.9% at pH:8; 47.8% at pH:6; 79.8% at pH:4 and 100% at pH:2. In the case of Annona Squmosa leaves ashes, the maximum extractability is found to be : 24.2% at pH:10, 44.3% at pH:8; 64.5% at pH:6; 88.7% at pH:4and 97% at pH:2. With the ashes of leaves of Calotropis Zygantia , the maximum extractability is : 44.6% at pH:10; 59.2% at pH:8; 64.3% at pH:6; 68.7% at pH:4 and 88.0% at pH:2. With the leaves ashes of Moringa Tinctoria, the maximum extractability is found to be :15.8% at pH:10; 27.4% at pH:8; 44.8% at pH:6; 64.7% at pH:4 and 87.0% at pH:2. In the case of leaves ashes of Tridox Procumbens, the maximum extractability is found to be: 27.6% at pH: 10; 36.7% at pH: 8; 39.3% at pH: 6; 68.9% at pH: 4 and 85.0% at pH: 2.

3. It is evident that the ashes derived from different plants exhibits different sorption abilities towards Nitrite. Further, it is interesting to note that the optimum agitation time needed in all these ashes probed is :5 hrs. At pH 2 and agitation time of 5 hrs, the maximum extractability is found to be 100% with the leaves ashes Phyllanthus Neruri and Aazadiracta Indica; 97% with the leaves ashes of Annona Squamosa; 88% with the leaves ashes of Calotropis Zygantia; 87% with the leaves ashes of Moringa Tinctoria; and 85% with the leaves ashes of Tridox Procumbens.

4. When percentage removal is studied with respect to adsorbent dosage at fixed optimum pH: 2 and at optimum equilibration times, the graphs increase up to certain dosage and from then onwards plateaus are obtained.( Vide Graph No. C:1).

With ash of leaves, the optimum sorbent dosage is found to be 1.0g/lit for Phyllanthus Neruri and Azadiracta Indica; 1.5g/lit for Annona Squamosa; 2.0 g/lit for Moringa Tinctoria and Calotropis Zygantia; 4.0 g/lit for Tridox Procumbens (vide Graph No::C:1).

5. Interfering Ions: Cations, even in tenfold excess, are not interfering with the extraction of Nitrite ions at the optimum conditions of extractions as cited in the Table 1. The anions except Sulphate, have marginal interference. Sulphate interferes but the interesting point is that the % of extraction of Nitrite never comes down 77.5%.

TABLE: 1 Effect of Interfering Ions on the Extractability of Nitrite with Different Bio-sorbents

S. No	Adsorbent	Maximum extractability at optimu condition	% of Extraction of Nitrite in the presence of tenfold excess of interfering ions at optimum extraction conditions
			SO4^2-	NO3^-	Cl^-	PO4^2-	F^-	CO3^2-	Ca^2+	Mg^2+	Fe^2+	Cu^2+	Zn^2+	Ni^2+
1.	Ash of Leaves of Phyllanthus neruri	100.0%, pH:2, 5hrs 1.0gm/lit	78.3%	97.9%	98.2%	91.0%	94.5%	95.8%	95.5%	99.3%	97.3%	98.0%	96.8%	95.9%
2.	Ash of leaves of Azadiracta Indica	100.0%, pH:2, 5 hrs, 1.0gm/lit	77.5%	96.2%	94.0%	92.0%	96.0%	96.5%	94. 5 %	97.8%	96.8%	95.5%	97.0%	94.5%
3.	Ash of leaves of Annona Squmosa	97.0%, pH:2, 5 hrs, 1.5gm/lit	79.2%	950%	90.9%	93.0%	91.5%	92.0%	92.5%	93.6%	91.6%	92.5%	91.0%	90.7%
4.	Ash of leaves of Calotropis Zygantia	88.0% , pH:2 , 6 hrs, 2.0gm/lit	74.5%	84.0%	84.5%	85.0%	83.5%	82.5%	83.5%	83.4%	80.4%	82.5%	84/0%	83.3%
5.	Ash of leaves of Moringa Tinctoria leaves	87.0%, pH:2, 5 hrs, 2.0gm/lit	79.1%	83.0%	83.7%	83.0%	83.0%	81.5%	82.5%	81.5%	81.0%	81.4%	83.0%	81.5%
6.	Ash of leaves of Tridox Procumbens	85.0% , pH:2 , 5 hrs, 4.0 gm/lit	73.7%	80.0%	81.5%	82.0%	80.3%	80.5%	80.2%	80.5%	82.5%	80.5%	82.0%	80.5%

Table 2: Percentage of Extraction of Nitrites from Polluted Water Samples Using Bio-Sorbents Developed In This Work

S. No	Adsorbent	Conditions Of extraction	Different Samples (Actual Conc. Of Nitrite is shown in the parenthesis)
			Simulated Waters (50 ppm)	Sample :1 (5 ppm)	Sample 2 (7.5 ppm)	Sample:3 (9.0 ppm)	Sample:4 (10.0 ppm)	Sample:5 (11.5 ppm)
1.	Ash of Leaves of Phyllanthus neruri	pH:2, 5hrs 1.0gm/lit	100%	97..3%	92.9%	93.5%	94.5%	96.5%
2.	Ash of leaves of Azadiracta indica	pH:2, 5 hrs, 1.0gm/lit	100%	94.5%	93.2%	91.0%	92.0%	95.0%
3.	Ash of leaves of Annona squmosa	pH:2, 5 hrs, 1.5gm/lit	97.0%	90.0%	91.5%	92.5%	93.5%	94.0%
4.	Ash of leaves of Calotropis zygantia	pH:2 , 6 hrs, 2.0gm/lit	88.0%	84.5%	84.1%	83.4%	85.2%	81.5%
5.	Ash of leaves of Moringa tinctoria	pH:2, 5 hrs, 2.0gm/lit	87.0%	82.1%	83.4%	83.5%	82.3%	84.0%
6.	Ash of leaves of Tridox procumbens	pH:2 , 5 hrs, 4.0 gm/lit	85.0%	81.5%	80.5%	81.0%	82.5%	81.3%

DISCUSSIONS:

The affinity the sorbents towards Nitrite may be due to the naturally occurring surface functional groups like OH/COOH groups present in these lingo celluloses’ materials. The dissociation or association depends upon pH conditions. At high pH values, these groups dissociates as:

Adsorbent-OH = Adsorbent-O^-

Adsorbent-COOH = Adsorbent-COO^- + H⁺

and imparts surface negative charge and thereby a thrust for the oppositely charged ions viz., cation will prevail. At low pH values, the dissociation is less favored and protination may also occur:

Adsorbent-OH = Adsorbent-OH₂

resulting surface positive charge to surface and this causes an urge for negatively charged ions on the surface. This is reflected in sorption of Nitrite. Nitrite being an anion is held to the surface at low pH values and hence the high % of removal. At high pH values cation affinity persists and not anion and hence, Nitrite anion show low % of removal.

The decrease in the rate of sorption with the progress in the equilibration time may be due to the more availability of sorption sites initially and are progressively used up with time.

APPLICATIONS:

Sample waters at five lakes polluted with Nitrite ions have been collected and the successful sorbents developed in this work have been tried for the removal of Nitrite ions at optimum conditions of extraction. It is found that the sorbents developed in this work are successful in removing Nitrites considerably in these samples of water at optimum conditions of pH, equilibration time and sorbent dosage. % removal of Nitrite in these samples of water is found to be: 92.9 to 97.5% with Ash of Leaves of Phyllanthus neruri; 91.0 to 95.0% with Ashes of leaves of Azadiracta indica ; 90.0% to 94.0% with Ashes of leaves of Annona isqumosa; 81.5% to 84.5% with Ashes of leaves of Calotropis zygantia; 82.1% to 84.0% with Ashes of leaves of Moringa Tinctoria; 80.5% to 82.5% with Ashes of leaves of Tridox procumbens (vide Table 2).

CONCLUSIONS:

1. Ashes of leaves of Phyllanthus neruri, Azadiracta indica, Annona squamosa, Moringa tinctoria, Calotropis zygantia and Tridox procumbens have been probed for their sorption properties towards Nitrite ions.

2. At low pHs of equilibration, these ashes show affinity towards Nitrite ions.

3. Various physicochemical parameters such as pH, sorbent dosage and time of agitation have been optimized for the successful quantitative extraction of Nitrite.

4. We claim 100% removal with the ashes of leaves of Phyllanthus neruri and Aazadiracta indica; 97% with the leaves ashes of Annona squamosa; 88% with the leaves ashes of Calotropis zygantia; 87% with the leaves ashes of Moringa tinctoria; and 85% with the leaves ashes of Tridox procumbens from simulated waters.

5. Even tenfold excess of common cations and anions except Sulphate, normally present in waters have shown only marginal interference with the extraction of Nitrites from simulated synthetic waters at the optimum conditions of extraction as cited in the Table 2

6. The methodologies are successfully applied to water samples collected from polluted lakes.

ACKNOWLEDGEMENTS:

Authors thank UGC for granting the financial aid for conducting this research work.

REFERENCES:

1. 1. Ponde S.P., Hasan M.Z., Sexena K.L, J.I.W.W.A. XVIII (3) (1986) 145.

2. Poxton M. G, Allhouse S. B (1982)., Aquacult. Eng. 1 (1982) 153.

3.

a) APHAStandard Methods for the Examination of Water and Wastewater ,20 th ed.,. (1998) American Public Health Association: Washington, DC.

b) ECETOC (1988) Nitrate and drinking water. Brussels, European Chemical Industry Ecology and Toxicology Centre (Technical Report No. 27).

c) FAO/WHO (1995) Evaluation of certain food additives and contaminants. Geneva, World Health Organization, Joint FAO/WHO Expert Committee on Food Additives, pp. 29–35 (WHO Technical Report Series No. 859).

d) FAO/WHO (1996) Toxicological evaluation of certain food additives and contaminants. Prepared by the Forty-Fourth Meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA).Geneva, World Health Organization, International Programme on Chemical Safety (WHO Food Additives Series 35).

e) FAO/WHO (2002) Evaluation of certain food additives. Fifty-ninth report of the Joint FAO/WHO Expert Committee on Food Additives. Geneva, World Health Organization (WHOTechnical Report SeriesNo. 913; http://whqlibdoc.who.int/trs/WHO_TRS_913.pdf).

f) FAO/WHO (2003a) Nitrite (and potential endogenous formation of N-nitroso compounds). In: Safety evaluation of certain food additives and contaminants. Geneva, World Health Organization, Joint FAO/WHO Expert Committee on Food Additives (WHO Food Additives Series No. 50; http://www.inchem.org/documents/jecfa/jecmono/v50je05.htm).

g) FAO/WHO (2003b) Nitrate (and potential endogenous formation of N-nitroso compounds). In: Safetyevaluation of certain food additives and contaminants. Geneva, World Health Organization, Joint FAO/WHO Expert Committee on Food Additives (WHO Food Additives Series No. 50; http://www.inchem.org/documents/jecfa/jecmono/v50je06.htm).

4. Lin S., Wu C., Wat. Res. 30 (1996) 715.

5. Virkutyte J, Jegatheesan V., Bioresour. Technol. 100 (2009) 2189.

6. Virkutyte J., Rokhina E., Jegatheesan V., Bioresour. Technol. 101 (2010) 1440.

7. Foley J., Haas D., Yuan Z., Lant P. , Water Res. 44 (2010) 831.

8. Hu Q., Westerhoff P., Vermaas W., Appl. Environ. Microbiol. 66. (2000) 133.

9. Garbisu C., Hall D.O. , Serra J.L., J. Appl. Phycol. 4 (1992)139.

10. Emamjomeh M., Sivakumar M , J. Environ. Manage. 90 (2009) 663.

11. Reyter D., Bélanger D., Roué L., Water Res. 44 (2010) 1918.

12. Sun C.C.,, Chou T.C., (1999), Ind. Eng. Chem. Res. 38 (1999) 4545.

13. Sun C.C, Chou T.C., J. Mol. Catal. A: Chem. 151 (2000) 133.

14. Abuzaid N.S., Al-Hamouz Z., Bukhari A.A., Essa M.H., (1999. Water Air Soil Pollut. 109 (1999) 429.

15. De D., Kalu E.E., Tarjan P.P., Englehardt J.D., Chem. Eng. Technol. 2 (2004): 56.

16. Dı´az V., Ibanez R., Gomez P., Urtiaga A.M., Ortiz I., Water Res. 45 (2010) 125.

17. Saleem, M., Chakrabarti, M.H, Diya”uddeen Basheer Hasan, African J of Biotechnology 10 (73) (2011) 16566.

18. Katsuya Abe, Atsue Imamaki , Morio Hirano, J. of Applied Phycology 14(2) (2002) 129.

19. Polatides C., Dortsiou M., Kyriacow G.,(2005), Electrochimica Acta 50(25-26), (2005) 5237.

20. Nes¸e Öztürk, T., Ennil Köse, Desalination 223 (2008) 174.

21. Amir, Hossein Mahvi, Dariush, Naghipur, Forugh, Vaezi , Shahrokh, Nazamara., (2005), American Journal of Applied Sciences. 2(1) (2005) 372.

22. Orhan, Y and Buyukgungor , Water Sci. Technol. 28 (1993) 247.

23. Trivedy, R. K., Pollution Management in Industries, Environmental Publications, 2^nd Ed. (1995), Karad, India.

24. Gerard Kiely., Environmental Engineering, McGraw-hall International Editions (1998).

25. Baker, M.J., Blowes, D.W.,. Ptacek, C.J, Environ. Sci. Technol., 32 (1998) 2308.

26. Huang,.S.H., and Chiswell, B.(2000), Water Science and Technology, 42(2-3) (2000) 295.

27. Vaughan, T., C.W. Seo, W.E. Marshal, Bioresour. Technol. 78 (2001) 133.

28. Unnithan,M.R. Vinod, V.P., Anirudhan T.S., (2002), J. Appl. Polym. Sci. 84 (2002) 2541

29. Shukla A., Y.H. Zhang Y.H., Dubdey P.,. Margrave J.L., Sukla S.S., J. Hazard Materrials 95 (2002) 137.

30. Majeti N.V. and R. Kumar R., React. Funct. Polym. 46 (2000) 1

31. Tshabalaka M.A., Karthikeyan K.G., Wang D.,  J.Appl.Polym. Sci. 93 (2004) 1577

32. Dinesh Mohan and Charles U. Pittman Jr., J of Hazardous Materials 137(2) (2006) 762.

33. Boujelben N., Bouzid J., J. of Hazardous Materials 151(1) (2008) 103.

34. Han J.S., Hur N., Choi B., Min S.H., "Removal of phosphorous using chemically modified lignocelluloses materials" In: 6th Inter-regional Conference on Environmnent-Water,"Land and Water Use Planning and Management, Albacete, Spain (2003). 1.

35. Inglezakis V.J., Zorpas A., Loizidou M.D., Grigoropoulou H.P., Microprous and Mesoporous materials 61 (2003) 167.

36. Sandhya Babel and Tonni Agustions Kurniawan, J of Hazardous materials 97 (2003) 219.

37. LuzE. De-Bastan,Yoav Bashan., Water Research, 38 (2004), 4222 (a review article and other reference in it).

38. Khan, S.V , Moheman, A., Poll.Res., 25(1) (2006) 99.

39. Meera, D and Charan., Poll. Res. 25(1) (2006) 97.

40. Durgacharan A., Bhagwat Suresh G., Killedar, Rahul S Adnaik, (2008), International J of Green Pharmacy 2(2) (2008) 126.

41. Nadkarni A.K., Indian Matria Medica. Bombay: Popular Prakashan; (1998) 138.

42. Thirupathy Kumaresan P., Saravanan A., African Journal of Pharmacy and Pharmacology, 3(2) (2009) 63.

43. Metcalf and Eddy., Wastewater Engineering: Treatment of Reuse. 4th. Ed (2003) McGraw Hill Co., New York.

44. Vogel, Arthur I. "A Text Book of Quantitative Inorganic Analysis including Elementary Instrument Analysis", 3^rd Ed. (1961) ELBS.

Received on 03.06.2012

Modified on 12.06.2012

Accepted on 25.06.2012

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Research J. Science and Tech. 4(3): May-June 2012: 115-121