Fluoride Contamination In Water Research Articles

Mitigation of Fluoride Contamination from Drinking Water through Fluoride Removal Techniques: A Review

Water is the most vital natural resource for the survival of human being and environment on the earth surface. But Fluoride contamination of water has become a widespread and serious problem all over the world including India. Supplying the right amount of fluoride to drinking water protects the teeth from decay and reduces the risk of cavities. Exposure to fluoride beyond the recommended level for longer duration causes both dental and skeletal fluorosis. Health is the most important issue for the citizens of any country and consequently healthy citizens are the perfect and biggest assets for a nation. This paper reveals the techniques of Eradication of excessive fluoride from water. Various alleviation programmes and strategies to regulator the fluorosis and to eliminate the fluoride from water have been piloted all over the world using defluoridation. Nalgonda procedure is one of the well-known strategies generally utilized for defluoridation of water as a part of developing nations, for example, India, Kenya, Senegal and Tanzania. Among different techniques utilized for defluoridation of water, the adsorption procedure is broadly utilized.

IMPACT OF FLUORIDE TOXICITY- A WORLDWIDE THREAT

Fluoridation of water is a significant issue globally since millions of people utilise groundwater for drinking, causing health problems such dental and skeletal fluorosis as well as numerous other health hazards. Earlier studies were restricted to local or regional scales. The World Health Organization (WHO) states that 1.5 mg/l of fluoride is the safe limit for groundwater. Globally, Pakistan, China, and India are the most severely impacted nations. Fluoride pollution can induce osteosarcoma, dental fluorosis, and skeletal fluorosis, among other conditions. Since the issue has significant socioeconomic implications as well, there is a need for a serious concern in managing the fluoride level in ground water from a worldwide perspective. The investigation will assess more than a century's worth of studies conducted globally on the effects of fluoride pollution on human health. The researchers looked at the sources, mobilisation, association, and spread of fluoride contamination in water; these topics are covered here. Although research has been done all over the world, especially in developing nations like India, one area that is still urgently in need of attention is the cleanup of this contamination in ground water supplies.

Nanoarchitectonics and Kinetics Insights into Fluoride Removal from Drinking Water Using Magnetic Tea Biochar.

Fluoride contamination in water is a key problem facing the world, leading to health problems such as dental and skeletal fluorosis. So, we used low-cost multifunctional tea biochar (TBC) and magnetic tea biochar (MTBC) prepared by facile one-step pyrolysis of waste tea leaves. The TBC and MTBC were characterized by XRD, SEM, FTIR, and VSM. Both TBC and MTBC contain high carbon contents of 63.45 and 63.75%, respectively. The surface area of MTBC (115.65 m2/g) was higher than TBC (81.64 m2/g). The modified biochar MTBC was further used to remediate the fluoride-contaminated water. The fluoride adsorption testing was conducted using the batch method at 298, 308, and 318 K. The maximum fluoride removal efficiency (E%) using MTBC was 98% when the adsorbent dosage was 0.5 g/L and the fluoride concentration was 50 mg/L. The experiment data for fluoride adsorption on MTBC best fit the pseudo 2nd order, rather than the pseudo 1st order. In addition, the intraparticle diffusion model predicts the boundary diffusion. Langmuir, Freundlich, Temkin, and Dubnin–Radushkevich isotherm models were fitted to explain the fluoride adsorption on MTBC. The Langmuir adsorption capacity of MTBC = 18.78 mg/g was recorded at 298 K and decreased as the temperature increased. The MTBC biochar was reused in ten cycles, and the E% was still 85%. The obtained biochar with a large pore size and high removal efficiency may be an effective and low-cost adsorbent for treating fluoride-containing water.

Green nanomaterials for removal of arsenic and fluoride contamination from wastewater

Arsenic and fluoride contamination in water is one of the most serious issues prevailing currently. As arsenics and fluoride contains various harmful elements like carcinogenic and non-carcinogenic which causes adverse effects on human life. In this paper we have discussed why wastewater treatment is necessary, various contamination present in it and methods which are currently used to remove those contamination from water. Also, there are numerous ways in which the contaminated water will affect the living organisms on land and marine both. If this type of water is used for drinking purposes it will affect health and can cause various chronic diseases. The present paper also briefly covers the classification of various adsorbents used for the treatments. As the scopes in nanoparticles are increasing, we have mainly focused on nano-based adsorbent for the removal of arsenic and fluoride. Further, we have listed green nanomaterials for arsenic and fluoride removal in summaries and tabular form. In that we have mentioned the adsorbent used their capacity how was the testing procedure done and behavior in various pH range is mentioned both in summary and tabular form. Various challenges currently faced by society and by industry, along with future scopes in developing efficient methods and adsorbents which are environmentally suitable are briefly incorporated.

Spectroscopic Determination of Fluoride Using Eriochrome Black T (EBT) as a Spectrophotometric Reagent from Groundwater.

Fluoride health problem is a great concern worldwide, most often as a result of groundwater intake. Thus, determination of fluoride is vital to take appropriate measures upon fluoride contamination of water. Potentiometric method of analysis is reliable for the determination of fluoride in various samples. In addition, spectroscopic methods are found important to quantify fluoride levels from water; however, several factors hinder its easier determination. Among the bottlenecks, the use of toxic chemicals and tedious steps in preparing chemicals (e.g., SPADNS method) are to mention a few. In this study, a spectrophotometric method was developed for the determination of fluoride from groundwater using Eriochrome Black T (EBT) as a spectroscopic reagent. Experimental parameters that influence the determination of fluoride including ligand type, kinetics, pH, and ligand-to-metal ratio were assayed. Evaluation of fluoride levels showed that Beer–Lambert's law is obeyed in the range of 0.3–5.0 mg/L at 544 nm. The calibration curve, resulting in good linearity (R2 = 0.9997), was considered during quantitative analysis of the samples and in the spiking analysis. The limits of detection (LOD) and quantification (LOQ) of the method were found to be 0.19 and 0.64 mg/L, respectively. The precision studied in terms of intraday and interday at three concentration levels showed less than 5.4% RSD. Applicability of the method was investigated by analyzing groundwater samples spiked with fluoride standards, and satisfactory recoveries in the range of 98.18–111.4 were demonstrated. The developed spectrophotometric method has been successfully applied for fluoride determinations in groundwater samples. Thus, it could be used as an attractive alternative for the determination of fluoride from groundwater.

Photo-controllability of fluoride remediation by spiropyran-functionalized mesoporous silica powder

Fluoride contamination in water continues to be a great challenge to the sustainable development of global fluorine-containing industries. It is still a challenge to avoid the use of chemical desorbents induced secondary contamination in regenerating fluoride adsorbents. In this work, we aim to design a nanoadsorbent (SP@SiO2) specifically applicable for fluoride (F−) adsorption and desorption without using chemical desorbents, but via the approach of light-induction. The SP@SiO2 was fabricated by conjugating a rationally synthesised light-sensitive compound, spiropyran (SP), onto engineered mesoporous silica (SiO2) nanoparticles. Results showed that there was ∼0.14-0.15 mmol of SP conjugated onto per g of nanocomposite surface, forming a core-shell structure, which can realize conformational freedom of SP ↔ MC (merocyanine) transformation and corresponding adsorption and desorption fluoride under photo-controllable manner. Based on these, we intend to engineer a nanoadsorbent for F− remediation that may be potential guidance for those poisonous anions adsorption and light-induced desorption based on spiropyran-functionalized materials.

An artificial neural network-based non-destructive microwave technique for monitoring fluoride contamination in water

ABSTRACTThis article presents a novel non-destructive microwave technique for predicting fluoride contamination in pure water. The proposed microwave-based sensing technique uses an open-ended coaxial probe (OECP) microwave sensor for monitoring fluoride concentration in water. The sensor output is the input of Artificial Neural Network (ANN) for predicting the complex dielectric constant of contaminated water, which has direct correlation with fluoride contamination in water. The ANN is trained through analytically generated sensor output for various lossy liquid materials and tested for experimental data obtained through laboratory prepared samples. Hence, the proposed technique has the capability to compute the amount of fluoride contamination faster, when compared to analysis only method. The results shows that a well-trained ANN is computationally efficient and capable of predicting the amount of fluoride level in the pure water. The results also has good agreement with the data published in the literature at room temperature.

Fluorosis and cognitive development among children (6-14years of age) in the endemic areas of the world: a review and critical analysis.

The fluoride contamination in water is still a live discussion among the scientific community, because of its beneficial and injurious health effects inflicted on the human population. The magnitude of groundwater fluoride contamination is aggravated by increasing anthropogenic activities. Groundwater is supposedly the main source through which people are highly exposed to fluoride, compared with other sources of exposure. Among human populations, fluoride-related health issues span from mild effects on teeth and bones to severe kidney problems, neurotoxicity, and even cancer. Nowadays, fluoride toxicity is gaining much attention in the endemic areas due to its adverse impact on the children's cognitive function, since children are more susceptible to fluoride toxicity as compared to adults. The primary mechanism behind the neurotoxicity of fluoride is still not clearly understood. However, knowingly, fluoride disrupts the biochemical mechanism and thus alters the normal functioning of the brain. Several human studies are suggestive of lowering children's IQ who was exposed to fluoride during their childhood. The conclusive findings of past research suggest that the fluoride concentration in potable water tends to grossly affect the children's IQ level. However, the body of proof is limited, because most of the studies are concentrated in few countries, and have their own limitations and data gaps. The grave implications of fluoride toxicity, therefore, demand extensive and properly designed research to bridging the data gap in developing countries. Furthermore, spanning research work across all the endemic areas of the world could generate larger database, helping resolve the issue on a large scale.

Treatment of fluoride-contaminated water. A review

Delivering the right amount of fluoride to drinking water protects the teeth from decay and reduces the risk of cavities. Nonetheless, fluorosis has been diagnosed as the result of excessive exposure of fluoride, which induces brain impairment, muscle disorders and hyperactivity. Fluoride ingestion during the formation of the tooth enamel is the main reason for fluo-rosis, which is characterized by hypomineralization. Dissolution of fluoride-containing rock minerals contributes to naturally occurring fluoride contamination in water. The intentional addition of fluoride to water in dental care is alarming in growing countries such as India. This article reviews the origin of fluoride, the analysis of fluoride derivatives and the technologies to remove fluoride from water. The manuscript presents adsorption techniques for fluoride removal, using different types of adsorbents. The adsorption capacities of adsorbents under various conditions, such as contaminant concentration, adsorbent dosage, time, pH and temperature, are presented. Adsorbent types include alumina, zeolites, organic waste, shell-based and carbon-based including graphite and carbon nanotubes. Defluoridation of water using clays and muds, modified activated alumina, chitosan derivatives and composites are also discussed.

Studies on effects of sodium fluoride on seed germination and plant growth of Rauvolfia Tetraphylla L. a medicinally important plant

Plants are an indispensable source of various needs of human beings such as food, construction tools, flavoring agents, and medicine. Rauvolfia tetraphylla L. is endangered and is one of the important plants of Apocynaceae family being cultivated for its immense medicinal properties. The present studies on Fluoride contamination in water, soil and plants is a serious health problem throughout the world. We studied the effect of aqueous solutions of 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mM Sodium fluoride on seed germination and seedling growth of R. tetraphylla at the end of Two months of treatment. Significant reduction in root length, shoot length, Leaf legnth, fresh weight, % of germination were observed at increasing fluoride concentration. Decreasing trend in the growth of roots were observed with increasing Sodium Fluoride concentrations. The percentage of seedling growth decreased up to 62 percent with increasing Sodium fluoride treatment At 0.02 M Sodium Fluoride, significantly reduced growth in the root and shoot lengths occurred in all the seedlings, except the root lengths. In general, the shoot growth was more affected than the root growth at higher concentrations of Sodium Fluoride. The plants growth in soil supplemented with 400 mg NaF/kg soil shows maximum reduction in their growth parameters as compared to control plants.

Removal of fluoride from water through bacterial-surfactin mediated novel hydroxyapatite nanoparticle and its efficiency assessment: Adsorption isotherm, adsorption kinetic and adsorption Thermodynamics

Fluoride contamination in water due to natural and anthropogenic activities has been documented as serious problems worldwide commanding a major threat to the environment. Present study focuses to synthesis bacterial-surfactin (Bacillus subtilis) mediated nano-hydroxyapatite (HAp), novel adsorbents for defluoridation. HAp particle size and morphology were controlled by varying temperature of 90–150°C and pH of 7–11, respectively. The TEM and SEM micrographs reveal that the short-rod particle is observed 20–30nm at 90°C and pH 11. The ratio between the length (nm) and width (nm) of nanoparticle are decreased from 4.17 to 1.65 with increasing pH (7–11). The selected area diffraction (SAD) of particles are indicated uniform rod-like monocrystals. The XRD and FTIR observations were indicated the synthesized HAp nanoparticles were well-crystallized with purity phase and high quality. The study reflected that the fluoride removal from contaminated water by HAp was increased significantly (R2=99) with the increasing adsorbent concentration, temperature and time, with two-step adsorption process as the first portion a rapid adsorption occurs during first 90min after which equilibrium is slowly achieved. The adsorption process is closer to Freundlich isotherm (R2>98) than to Langmuir isotherm (R2≈92), indicating HAp as a good adsorbent (n>3). Above 97% of fluoride removal were noticed at a HAp dose of 0.06g/10mL. The adsorption kinetics more fit with pseudo-second-order (R2= 99) in compare to pseudo-first-order (R2≈91). The slope and intercept of Arrhenius equation indicated the activation/adsorption energy (Ea) of 3.199kJ/mol and frequency factor (A) of 1.78 1/s. Adsorption thermodynamic parameters (free energy (ΔG<0), enthalpy (ΔH>0) and entropy (ΔS>0)) indicates the spontaneous and endothermic reactions of the adsorption process. Thus, newly synthesized HAp nanoparticles exhibit as a good adsorbent for fluoride removal, theoretically and experimentally being applicable for environmental pollution control.

Occurrence and methods to remove arsenic and fluoride contamination in water

Groundwater contamination with arsenic and fluoride has affected over 300 million people worldwide. Ingestion of arsenic and fluoride for extended period of time or at high concentration causes severe health effects. Arsenic can cause thickening and discoloration of the skin, cardiovascular disorders, cancer and skin lesions. Excessive intake of fluoride leads to dental and skeletal fluorosis and bone deformities. This report reviews the distribution of arsenic and fluoride contamination, their sources, mobilization and associated health risks. Remediation technologies to remove arsenic and fluoride are presented.

Thermodynamics and kinetics study of defluoridation using Ca-SiO2-TiO2 as adsorbent: Column studies and statistical approach

Fluoride contamination of water is a potential health and environmental hazard worldwide. This study focuses on defluoridation efficiency in aqueous system by novel adsorbents, i.e., calcium impregnated silica (Ca-SiO2) and calcium impregnated silica combined with titanium dioxide (Ca-SiO2-TiO2). Comparative batch study was carried out using both adsorbents Ca-SiO2 and Ca-SiO2-TiO2 for fluoride removal efficiency in different experimental conditions where it was observed that chemically modified Ca-SiO2-TiO2 acted as a better adsorbent for defluoridation than Ca-SiO2. Thus, further batch isotherm and kinetics studies were performed using Ca-SiO2-TiO2. The phenomenon of fluoride ion uptake is realized by Langmuir and Freundlich isotherm model. Langmuir isotherm shows satisfactory fit to the experimental data. The rate of adsorption shows that the pseudo-second-order rate fitted the adsorption kinetics better than the pseudo-first-order rate equation. The mechanism of adsorption process was illustrated by calculating Gibbs free energy, enthalpy and entropy from thermodynamic studies. To further confirm the applicability of the adsorbent, a fixed bed study was carried out in column mode. Thomas and bed-depth-service-time (BDST) model were well-fitted to the experimental results. The optimal operating conditions of defluoridation were found by using response surface methodology (RSM) with the help of Design Expert Software. The maximum percentage of fluoride removal was 92.41% in case of calcium impregnated silica combined with titanium dioxide (Ca-SiO2-TiO2). Thus, it may be concluded that chemically synthesized Ca-SiO2-TiO2 could be used as an environmentally and economically safe adsorbent for defluoridation of waste water.

Worldwide contamination of water by fluoride

Fluoride contamination in water is a major problem across the globe, with health hazards such as dental and skeletal fluorosis. Most earlier studies are confined to local or regional scales. As the problem has serious socioeconomic implications, there is a need for a global perspective. Thus, here we review worldwide research for nearly a century on fluoride contamination in water. We investigated the distribution of fluoride contamination in water, its sources, mobilization and association. The major findings are: (1) Anomalous fluoride concentration in groundwater is mainly confined to arid and semiarid regions of Asia and North Africa. (2) The geogenic sources of fluoride in water are mainly fluorine-bearing minerals in rocks and sediments, whereas anthropogenic sources of fluoride in water are mainly pesticides and industrial waste. (3) Fluoride mobilization from geogenic sources is mainly controlled by alkalinity and temperature. (4) Fluoride occurrence in water is associated with ions such as sodium, arsenic chloride and bicarbonate. There are few associations of fluoride in water with calcium and magnesium.

Effect of Sodium Fluoride on Seed Germination, Seedling Growth and Biochemistry of Abelmoschus esculentus

Fluoride contamination in water, soil and plants is a serious health problem throughout the world. We studied the effect of aqueous solutions of 0, 10, 20, 30, 40 and 50 ppm sodium fluoride on seed germination, seedling growth and biochemical parameters of Abelmoschus esculentus. The experiment was conducted as factorial with completely randomized design with five replicates. The percentage of seed germination decreased up to 62 percent with increasing sodium fluoride treatment. The seedling growth parameters (root length, shoot length and vigor index) and biochemical parameters i.e., chlorophyll, nitrogen and protein content as well as the Fluoride uptake by the germinated seedlings were estimated after 20 days of treatment.

Removal of fluoride contamination in water by three aquatic plants

ABSTRACTPhytoremediation, popularly known as ‘green technology’ has been employed in the present investigation to examine the potential of fluoride removal from water by some aquatic plants. Fluoride contamination in drinking water is very much prevalent in different parts of the world including India. Batch studies were conducted using some aquatic plants e.g., Pistia stratiotes, Eichhornia crassipes, and Spirodela polyrhiza which profusely grow in natural water bodies. The experimental data exhibited that all the above three aquatic floating macrophytes could remove fluoride to some relative degree of efficiency corresponding to initial concentration of fluoride 3, 5, 10, 20 mg/l after 10 days exposure time. Result showed that at lower concentration level i.e., 3 mg/L removal efficiency of Pistia stratiotes (19.87%) and Spirodela polyrhiza (19.23%) was found to be better as compared to Eichhornia crassipes (12.71%). Some of the physiological stress induced parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, total protein, catalase, and peroxidase were also studied to explore relative damage within the cell. A marginal stress was imparted among all the plants for lower concentration values (3 mg/L), whereas at 20 mg/l, maximum damage was observed.

A Comprehensive Review Report on Assessment of Ground Water Quality in Jhunjhunu District of Rajasthan, India, Focus on Fluoride

Fluoride occurs naturally inside many types of rock that has health significance. However, unwarranted fluoride contamination in drinking water due to natural and caused by human activities has been reported as one of the major health related problems globally, with the developing world being no exemption. In view of this a comprehensive literature review was carried out to determine the present body of knowledge pertaining to fluoride related research work with focus on the environment and human health related aspects. The literature published in the standard journals was used for the purpose of this study and it (literature) was reviewed by following the principles of deductive reasoning. The literature shows that In India, several states are affected with excess fluoride in groundwater and cause a serious health threat to the people of these regions. Hence, it is important that specific region specific studies should be carried out to generate more and more data, which can help in delineating meaningful and efficient strategies for mitigating fluoride related problems. Also, the literature shows that there is scope for developing the region specific technologies for addressing the fluoride contamination in water in general and groundwater in particular.