Journal of Indian Association of Public Health Dentistry

: 2017  |  Volume : 15  |  Issue : 1  |  Page : 94--96

Efficacy of Indigenous, Unconventional Biosorbents in Defluoridation of Standard Water − An In Vitro Study

Priyanka Sontakke1, Prateek Jain1, Pramod Yadav2, Vivek Kumar Sharma3, Ramesh D Sontakke4, Veena Sontakke5,  
1 Public Health Dentistry, Department of Periodontics and Community Dentistry, Dr Z A Dental College AMU Aligarh, India
2 Assistant Professor, Department of Periodontics and Community Dentistry, Dr Z A Dental College AMU Aligarh, India
3 Associate Professor, Department of Periodontics and Community Dentistry, Dr Z A dental college AMU Aligarh, India
4 Assistant Professor, Department of Physics, Jankidevi Bajaj Science College, Wardha, Maharashtra, India
5 Microbiologist, Department of Microbiology, Jawaharlal Nehru medical college, DMIMS, Wardha, Maharashtra, India

Correspondence Address:
Priyanka Sontakke
c/o Dr. Ramesh Sontakke, Dr. Pisey’s Layout, Hindnagar, Sawangi (Meghe), Wardha, Maharashtra-442001


Introduction: Several adsorbents have been tried in the past to find a proficient and cost-effective defluoridating agent. Many of the methods have some precincts because of the low adsorption capacity, poor integrity and need for pre-treatment. Aim: To evaluate the efficacy of three natural, low-cost, household-level products to remove fluoride from standard water. Materials and Methods: In this in vitro study, a standard solution of fluoride and a known weight of tulsi leaves, drumstick leaves and tamarind seed powder was prepared and analysed for changes in fluoride level and pH level on treatment at baseline, after 6 h and after 24 h. Results: Amongst the three plants, Tamarindus indica was found to be more effective in defluoridation showing a reduction up to 0.18 parts per million. Conclusion: Amongst the aforementioned three plants, tamarind seed powder was the domestic material with the best defluoridation property.

How to cite this article:
Sontakke P, Jain P, Yadav P, Sharma VK, Sontakke RD, Sontakke V. Efficacy of Indigenous, Unconventional Biosorbents in Defluoridation of Standard Water − An In Vitro Study.J Indian Assoc Public Health Dent 2017;15:94-96

How to cite this URL:
Sontakke P, Jain P, Yadav P, Sharma VK, Sontakke RD, Sontakke V. Efficacy of Indigenous, Unconventional Biosorbents in Defluoridation of Standard Water − An In Vitro Study. J Indian Assoc Public Health Dent [serial online] 2017 [cited 2021 Jan 17 ];15:94-96
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In India, at the beginning of the twenty-first century, the rural drinking water supply programme provided a provisional report on groundwater. This report showed a decrease in incidence of water-borne diseases; however, the report also highlighted the diminution of drinking water sources and pathological pollution of the drinking water source. Fluoride is a regular component of natural water. In India, endemic fluorosis is a major problem in 18 of the 29 states, especially Rajasthan, Andhra Pradesh, Tamil Nadu, Gujarat and Uttar Pradesh, and its concentration varies depending on the water source.[1]

According to World Health Organization’s drinking water quality guideline, the accepted value for fluoride is 1.0 mg/l. Therefore, it is now essential to focus on the forthcoming impact of water resources. In recent years, there has been an increased interest in fluoride research because of its twin role on human health. The usual remedial measures are supplying water from a distant, safe source, using surface water after conventional treatment, household rainwater harvesting, community-based treatment unit and household treatment. Each of these solutions has situation-specific applicability. The first two alternatives are cost-intensive. Rainwater harvesting can only be a seasonal, supplementary source. Hence, the first choice has been to look for inspiration from small, dwelling-based and household-level treatment systems. At household-level treatment, methods for removal of fluoride are chemical addition/precipitation, adsorption/ion exchange and membrane-based technologies. Amongst all these methods, the adsorption method is more practicable.[2]

Most adsorbents and methods have some limitations such as low adsorption capacity, poor integrity and need for pre-treatment. Therefore, a suitable, low-cost, biologically friendly method is required for removal of fluoride in the drinking water. Drumstick seeds, vetiver grass roots, tamarind seeds, tea ash and egg shell powder are native materials available as effective fluorosis mitigation tools. Reports on fluoride removal using tulsi leaves, drumstick leaves and tamarind seed powders individually are available in recent literature; thus, an in vitro comparative study on these three biosorbents has been attempted. The purpose of this study was to evaluate the efficacy of three natural, low-cost, household-level products (Ocimum sanctum, Moringa oleifera and Tamarindus indica) to remove fluoride from standard water and to assess the best method of defluoridation amongst these materials.

 Materials and Methods

An in vitro study was conducted in B. Lal Institute of Biotechnology, Jaipur in the months of August–September 2015. Ethical clearance was obtained from the Ethical Committee of the institute.

Stock and test agents

O. sanctum leaf powder, M. oleifera leaf powder, T. indica seed powder, ammonium hydrogen difluoride, Alizarin red solution and zirconyl acid solution.

Study protocol

Step 1: Analysis of the fluoride content in water on treatment with different herbal plant samples (2% w/v) (baseline, 6 h and 24 h).

Preparation of reagent solution

Standard fluoride solution

1.5 g ammonium hydrogen difluoride (NH4F · HF) was weighed and dissolved in distilled water and diluted to 10 cm3. The solution contained 10,000 mg/l fluoride. A serial dilution of the stock solution was prepared in the range 10,000 mg/l.

Alizarin red solution

0.75 g Alizarin red was weighed and dissolved in distilled water and made to 1000 cm3 in a volumetric flask.

Zirconyl acid solution

0.345 g of zirconyl chloride was weighed and dissolved in about 800 cm3 distilled water; thereafter, 33.30 cm3 concentrated H2SO4 was slowly added and stirred, followed by the addition of 101 cm3 of Cl. The solution was stirred thoroughly and made up to 1000 cm3. The hue of the reagent turns from pink to yellow immediately, indicating that fluorides are present.


0.003 mg of fluorine.[3]

Spectrometric determination of fluoride

5.0 cm3 each of Alizarin red and zirconyl acid solutions were added to 10 cm3 of both standard and sample solutions. The solutions were mixed thoroughly and allowed to stand for 1 h for full colour development. Absorbance readings were taken at 520 nm.[4]

Fluoride was estimated after treatment of water with the following three different medicinal plants in 2% (w/v) solutions:

O. sanctum − 2 g/100 ml of distilled water.

M. oleifera − 2 g/100 ml of distilled water.

T. indica − 2 g/100 ml of distilled water.

Step 2: Analysis of pH variation in water after exposure to herbal plants at baseline, after 6 h and after 24 h.

The study results were based on the triple replication of test assessment of all the three herbal samples.


O. sanctum showed similar decrease in fluoride levels of 0.3 ppm at baseline, after 6 h and 24 h.

When compared with the reference point, M. oleifera presented with better results, lowering the fluoride concentration from 3 ppm to 0.015 ppm; however, after 6 h, fluoride concentration raised to 0.3 ppm and persisted as the same after 24 h [Table 1].{Table 1}

T. indica showed better decrease in fluoride concentration, viz. from 3 ppm to 0.18 ppm after 6 h with pH 5.30. After 24 h, treatment with O. sanctum resulted in the pH of water as 4.72 [Table 2].{Table 2}


This study presents a novel way of reducing fluoride content in water. Adsorption is the principle behind the mechanism of the defluoridation technique used in this study. Factors affecting adsorption methods are surface area, nature of the adsorbate, pH, temperature, presence of mixed solutes and nature of adsorbent.

In the study by Sudarshan et al.,[5] there was no appreciable decrease in fluoride concentration in the water samples on treating it with tulsi leaves, which is concurrent with this study. Santhi[6] showed significant change in the first time interval, and, thereafter, remains approximately similar after 24 h, which is similar to this study. Kumar et al.[7] demonstrated that the tamarind fruit cover in its natural and acid-treated forms could be used as a potential biosorbing agent for the removal of fluoride ions from an aqueous media. The maximum uptake of fluoride ions occurs at pH 6.0. This is in line with this study. Murugan et al.[8] showed the potential of tamarind seed powder as an efficient defluoridating agent for application in domestic and macro-level treatment systems, which is in concurrence with this study.

In this study, tamarind seed was found to be the most efficient amongst the medicinal plants in reducing fluoride concentration in water. It reduced the fluoride levels from 3 ppm to 0.18 ppm in 6 h by lowering the pH of water. This technique is easy to understand and can be adopted in rural as well as urban areas throughout the year, as these biosorbents are easily available in all seasons. Furthermore, in vivo studies need to be conducted to check its effect on the human body and especially on the teeth.

The Government of India has set up National Drinking Water Mission to provide safe drinking water to its people and to combat the fluorosis problem. The government should encourage this domestic method of defuoridation in fluorosis endemic areas and incorporate it into the daily routine in one way or another.


The sorption process of fluoride ion on tamarind seed is better compared to tulsi and drumstick leaves. This technique can be adopted in rural as well as urban areas.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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