Fluoride Removal Research Articles

Enhancing fluoride removal in nanofiltration: a Box–Behnken design approach

Enhancing fluoride removal in nanofiltration: a Box–Behnken design approach

Electrospun nanofibers membranes of La(OH)3/PAN as a versatile adsorbent for fluoride remediation: Performance and mechanisms

Abstract Excessive existence of fluoride in water resources can lead to harmful impacts on ecosystems and organisms. Electrospun polyacrylonitrile (PAN) nanofiber membranes loaded with La(OH)3 nanorods composites (La(OH)3/PAN electrospun nanofiber membranes [ENFMs]) are fabricated and used as an efficient fluoride scavenger. Adsorbent fabricate protocols, pH, initial F− concentration, adsorbent dosage, and adsorption time, in addition to coexisting anions, were systematically evaluated. The investigation unveils that a pH of 3.0 is optimal for F− remediation. The adsorption kinetics and isotherm of La(OH)3/PAN ENFMs are well described by the pseudo-second-order model (R 2 > 0.997) with characteristics of chemisorption and Langmuir isotherm (R 2 > 0.999) with the feature of single-layer coverage. The existence of Cl−, SO4 2−, NO3 −, and CO3 2− does not significantly hinder fluoride removal by La(OH)3/PAN ENFMs with the exception of PO4 3−. Calculations of ΔH, ΔG, and ΔS reveal that the nature of F− adsorption onto La(OH)3/PAN ENFMs is endothermic and favorable at a higher temperature.

Synthesis of bagasse-derived magnetic biochar for the removal of fluoride from water solution

ABSTRACT Fluoride levels in drinking water pose a significant environmental threat, and adsorption is a common technique. However, many adsorbent materials have drawbacks such as poor adsorption capabilities, extended contact times, high pH levels, and large dosages. A biochar-based magnetic composite adsorbent has been developed for water defluoridation using a chemical co-precipitation process to immobilize iron particles on the biochar surface. X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy were used to analyse the composite. The central composite design was used to design laboratory tests, which included four input variables: solution pH, dosage, contact time, and initial concentration. The adsorbent dosage was 5.92 g/L, the aqueous pH was 5.79, the contact time was 66.48 min, and the initial fluoride concentration was 12.38 mg/L. The removal efficiency was predicted to be 98.61%, with a 98.55% removal efficiency at optimum conditions. The study concluded that the composite adsorbent can be a reliable and sustainable solution for fluoride removal from water.

Fluoride removal using membrane capacitive deionization: The role of pH-dependent dissolved inorganic carbon

Defluorination technology is crucial for ensuring safe and accessible water. The application of capacitive deionization (CDI) technology faces challenges due to competitive adsorption of fluoride ions within complex natural fluoride-rich brackish water matrices, which often contain high levels of dissolved inorganic carbon (DIC) species (mainly HCO3– and CO32–). These DIC species are pH-dependent, playing a significant role in the selective removal of fluoride by the CDI process. Thus, there is a knowledge gap in understanding the effects of membranes in membrane capacitive deionization (MCDI) on fluoride removal. In this study, we examined the key operating parameters in CDI and MCDI, including applied constant voltages and different types of anion-exchange membranes (AEMs), on the desalination performance in F- and dissolved inorganic carbon water matrices. The application of AEMs significantly improved the salt adsorption capacity (SAC) for both F- and DIC species, and reduced energy consumption. However, it simultaneously resulted in a notable decrease in F- selectivity as membranes control mass transfer. Higher applied voltages enhance the SAC performance for F- and DIC species, but also induce more severe Faradaic reactions, leading to increased energy consumption and lower energy efficiency. Additionally, ion species and pH changes during CDI and MCDI processes are interrelated, indicating that stability tests of CDI electrodes in batch mode are not reliable when using the same testing solution repeatedly. The diverse valence states of ions in the solution impact pH variations under different voltages in the CDI/MCDI process. These findings provide valuable insights into the development of water purification and desalination technology, particularly for the application and further advancement of selective fluoride removal by the CDI process.

Synthesize and Applications of Green Custard Apples leaves biosorbents for adsorptions of Sulphates and Fluorides from water

Industrial and domestic waste water release sulphur and fluoride metals into the water, thereby polluting the environment and affecting the humans and animals health. There are various techniques are available for eliminating sulphates and fluorides found in the water. Among these techniques, biosorption is a simple, cost-effective and environmentally friendly approach for removing the sulphates and fluorides from water. Biosorption is a physiochemical process that physically produces in specific biomass, enabling it to passively concentrate and bind sulphates and fluorides to its cellular structure. The custard apple leaf biosorbents are among the most effective biosorbents for the removal of fluorides and sulphates from water. In the experimental work observed that the using of 5.6g dosage of custard apple leaf biosorbents, successfully removed the sulphates and fluorides from water and a stable condition was reached. The optimal sorption of sulphur and fluoride over custard apple leaves biosorbents was achieved at a basic pH of 4-8, a concentration of 4.3g, contact time of 60minutes, temperature of 25°C, and an agitation speed of 100rpm. The particles present in custard apple leaves biosorbents have a size of 3.26µm and crystallite size 3.02nm. The surface area, pore volume and pore size of 43.68m2/g, 0.428cm3/g, and 38.64Å respectively. The adsorption of sulphates and fluorides on regenerated custard apple leaves biosorbents remained consistent for up to three cycles, but then decreased by 82.36% in the fourth cycle. The regeneration of custard apple leaf biosorbents was also calibrated, and it was observed that the custard apple leaves do not exhibit any high concentrations of changes in their performances, even after being reused for the removals of sulphates and fluorides from water. The adsorption rate move to equilibrium was due to the accessibility of lower amount of existing opening sites on the custard apple leaves biosorbents surface and also due to the binding forces between the custard apple leaves biosorbents and fluorides and sulfates molecules in the aqueous solution.

Facile preparation of zirconium(IV) immobilized carboxymethyl cellulose/multiwalled carbon nanotubes gels by radiation technique and its selective fluoride removal

Removal of excessive fluorine in the waterbody environment and the Zn hydrometallurgical system is an urgent problem. In this paper, zirconium oxychloride immobilized carboxymethyl cellulose/carboxymethyl multiwalled carbon nanotube (CMC+MWCCNT-ZrOCl2) gels are facilely prepared by radiation technique. The addition of MWCCNT endows the CMC-ZrOCl2 gel a typical nanotubes/fiber structure, also increase the gel fraction of the gel. The selective adsorption of fluoride from single or co-existed anions was investigated. The adsorption isotherms can be well fitted by both the Langmuir and Freundlich model. The calculated maximum adsorption capacity was 36.657 mg/g. The selectivity coefficients of CMC+MWCCNT-ZrOCl2 for fluoride versus NO3−, PO43−, and SO42− are 140.34, 10.953, and 72.572, respectively. Also, CMC+MWCCNT-ZrOCl2 can be used as a potential adsorbent for selective removing F− from high concentration SO42− solution. The adsorption mechanism was investigated by XPS analyses.

Optimizing solvothermal synthesis of aluminum-loaded pomelo peel for enhanced fluoride adsorption using response surface methodology

Addressing fluoride contamination in water remains a critical challenge, particularly when seeking cost-effective solutions. In this study, we present a novel aluminum-loaded pomelo peel adsorbent (PPA-Al), synthesized via a one-step solvothermal method, with parameters optimized through response surface methodology. The ideal conditions were established at 2.96 g of pomelo peel, 2 g of NaAlO₂, a reaction temperature of 168.62 °C, and a duration of 140.78 minutes. Characterization of PPA-Al revealed an abundance of hydroxyl and carbon functional groups, enhancing its reactivity with coordination unsaturated aluminum sites. Adsorption isotherms conformed to both Langmuir and Freundlich models, achieving a maximum adsorption capacity of 88.81 mg·g⁻¹, outperforming many existing biomass-based adsorbents. Kinetic analysis indicated that fluoride adsorption followed a pseudo-second-order model, with thermodynamic evaluations suggesting that this process is a spontaneous endothermic reaction. Characterization techniques, including Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), confirmed interactions between fluoride ions and -OH and -CH groups, as well as the formation of Al-F bonds. Notably, the use of PPA-Al reduces groundwater treatment costs by approximately 74.33∼83.24 % compared to activated alumina, and it can be reused multiple times without reagent regeneration. These findings highlight PPA-Al as a promising, efficient material for fluoride removal, while also demonstrating innovative applications for agricultural waste.

Adsorption Isotherm, Kinetic and Thermodynamic Studies for Removal of Fluoride Ions from Drinking Water Using Modified Natural Pumice

This study aimed to modify pumice using aluminum chloride as an adsorbent for defluoridation. Batch and column experiments were carried out to evaluate the effects of pH, initial fluoride concentration, contact time, dose, and temperatur. The modified pumice adsorbent showed good fluoride removal in both batch and column studies. Fluoride up-take was observed to be effective >7%, at pH 6.5-7.5, and adsorption equilibrium time was observed at 60 min. the adsorption results were modelled using kinetic and isotherm models. Experimental data indicated that fluoride adsorption follows the second pseudo-order kinetics model (R2 > 0.99) and fits well with both the Freundlich and Langmuir isotherm models, which showed favorability for the adsorption of fluoride with a maximum capacity of 0.083 mg/g. The negative values of ∆Ho and ∆Go indicate that the adsorption process was feasible, exothermic, and spontaneous. The column performance showed the best fluoride uptake efficiency, with a breakthrough capacity of 0.48 mg/g. The %R was approximately %100 using0.1M NaOH. Fluoride levels in real wells water decreased dramatically (e.g. 4.1-0.88, 7.1-1.54, and 6.2-1.46 mg/L). The results revealed that modified pumice has the potential for fluoride removal from drinking water.

Treatment of fluoride-contaminated water in a prototype adsorption unit using zirconium-activated carbon nanocomposites

ABSTRACT Zirconium-activated carbon nanocomposites (ZANC) are found to have high fluoride removal capacity and thus used as an adsorbent to perform column studies. The adsorbent was characterised using SEM-EDS and FTIR before and after the adsorption of fluoride. A packed bed adsorber prototype of 1 m length was fabricated to carry out defluoridation studies. The effect of varying initial fluoride concentration (2.5–10 ppm) and bed height (6–14 cm) was studied. The maximum fluoride removal was found to be 29.4% and uptake capacity was 4.72 mg/g at an initial fluoride concentration of 10 ppm, flow rate of 2 LPM, and bed height of 14 cm for synthetic samples. The Thomas, Yoon–Nelson and Bed Depth Service Time (BDST) models were employed and their results confirmed the experimental findings. The maximum fluoride adsorption capacities obtained from the Thomas model are 1.9 mg/g and from the BDST model, the N value was 20.979 mg/cm3. Regeneration studies were performed and found that the adsorbent can be regenerated for three cycles. Column studies were also performed using real-field groundwater samples collected from Pavagada of Tumakuru district. All the tested parameters of the treated water were found to be within the permissible limit.

Development of modified MgO/biochar composite for chemical adsorption enhancement to cleanup fluoride-contaminated groundwater

Fluoride contamination in groundwater has become a global environmental issue. Magnesium oxide (MgO) has demonstrated effectiveness as an adsorbent in treating fluoride pollution in groundwater. However, its use in powder and fine granular form often results in losses during the adsorption process, posing challenges for post-treatment recovery and potentially causing secondary environmental pollution. In this study, two novel fluoride adsorbents [rice husk (RH) and spent coffee grounds (SCG)-based magnesium oxide (MgO) biochar composites (MgO/RH and MgO/SCG)] were developed to cleanup fluoride-polluted groundwater. During the adsorbent synthesis process, RH and SCG biochar were pyrolyzed at 500 °C and modified by calcination using MgO. Both MgO/RH and MgO/SCG surfaces exhibited abundant pore structures and formed MgO crystal phases. Batch experiments results show that when the MgO/RH and MgO/SCG material dosages were 1 g/L, fluoride removal rates reached 80% and 86% respectively. The isotherms and kinetics of fluoride adsorption with MgO/RH and MgO/SCG followed the Langmuir isotherm equation and pseudo-second-order kinetic model. The maximum fluoride adsorption capacities of MgO/RH and MgO/SCG were 63.47 mg/g and 141.98 mg/g, respectively, indicating these materials used mono-layer adsorption mechanism for fluoride adsorption. The addition of MgO into the pores of porous adsorbent materials effectively increased their reactive sites and enhanced the adsorption performance of carbon materials. Particularly, SCG biochar had a richer pore structure than RH biochar, providing a larger contact surface area, facilitating the effective dispersion and doping of MgO into the pores. Therefore, MgO/SCG composite exhibited excellent fluoride adsorption properties in water, indicating the potential for developing a new type of MgO-modified SCG adsorbent material with green prospects. This composite effectively mitigated fluoride contamination, reducing the fluoride concentration in groundwater. Both RH and SCG are agricultural and food waste by-products, thus offering the opportunity to significantly reduce production, operation, and maintenance costs.

Evaluation of engineered binderless alumina – titania beads for fluoride removal from impaired water resources

Groundwater is often contaminated with various species, with fluoride concentrations being of particular concern. Numerous studies have used adsorbents for fluoride uptake, but most are tested only as powders and not commercially acceptable engineered shapes. Therefore, it was necessary to evaluate the performance of the newly developed Al2O3/TiO2 sorbents in their beaded form to assess their efficacy in comparison to activated alumina granules. Binderless sorbent beads were self-bound with the alumina and titania phases present. The fluoride exchange kinetics of Al2O3/TiO2 beads were comparable to the powdered form. Moreover, the Al2O3/TiO2 beads had higher fluoride loading than commercially available alumina (0.17 meq/g compared to 0.13 meq/g). The Al2O3/TiO2 beads also removed: barium, calcium, lithium, magnesium, manganese, potassium, silica, and strontium from groundwater. In fixed bed column tests, the beads-maintained fluoride within acceptable limits for 42 bed volumes, which substantially outperformed activated alumina (2.5 bed volumes). This study demonstrated that Al2O3/TiO2 beads outperformed commercially available activated alumina materials. Notably, transforming the materials into beaded forms significantly improved their suitability for fluoride removal in industrially relevant fixed-bed column environments. Future studies should focus on enhancing material binding properties to increase crush strength and attrition resistance. A deeper knowledge of regeneration strategies may also facilitate cost reduction.

Adsorption effect for removing fluoride with species of nitrogen by using La-BDC-NH2/C3N4: Experiments and mechanism

Fluoride contamination has emerged as a significant global environmental concern, with prolonged consumption of fluoride-rich groundwater being a primary contributor to fluorosis. Nitrogen sites play an important role in the process of fluoride removal, but the influence of different nitrogen species on fluoride adsorption has not been clearly clarified. In this study, a lanthanide organic framework adsorbent La-MOF-NH2 was prepared by solvothermal method, and a new adsorbent La-MOF-NH2@g-C3N4 was synthesized by adding g-C3N4 rich in various nitrogen sources. The effects of adsorbent dosage, pH, temperature and co-existing anions on the adsorption of fluorine were systematically studied. Optimal conditions were identified at a dosage of 2 g/L and a pH of 3, achieving theoretical maximum adsorption capacities of 219.4406 mg/g and 63.1401 mg/g, respectively. The results of five regeneration experiments shown that La-MOF-NH2 and La-MOF-NH2@g-C3N4 have strong recovery capacity. According to the adsorption isotherm and kinetic model, the adsorption mechanism of fluoride ions is mainly hydrogen bonding and chemisorption. In addition, through the experimental characterization and mechanism study, it was proved that amino group > pyridinic nitrogen > graphitic nitrogen. It provides a good guide for designing adsorbents containing nitrogen sites.

High-performance fluoride removal by Fe/N co-doped microporous carbon: Mechanism of capacitive deionization with FeNx sites

Fluoride pollution is becoming increasingly serious with industrial growth. Controlling fluoride pollution have become important environmental issues of global concern. Transition metal nitrides are excellent CDI electrode materials due to their excellent conductivity and electrochemical stability. In this study, FeNx/C was synthesized as an electrode material for using the capacitive deionization (CDI) technique to achieve the effective removal of fluoride ions from wastewater. Its high specific surface area (463.278 mg/g) and high capacitance (44.29 F/g) were demonstrated and it had a high adsorption capacity of 158.33 mg/g. FeN3 and FeN4 were used as the main sites as capacitive deionization for removing fluoride from the water by chemisorption and hydrogen bonding. The higher adsorption energy by density functional calculation also indicated that the existence of Fe-N coordination bond effectively improved its electrosorption capacity. This study is beneficial to provide references and research ideas for removing fluoride in the CDI field.

Sustainable fluoride removal with scrap aluminum: Co-producing cryolite and hydrogen

This study presents a novel continuous process for fluoride removal and re- source recovery as cryolite, using a scrap aluminum-packed column. Efficient aluminum dissolution in hydrofluoric acid (HF) generates hydrogen gas and provides cost-saving alkalinity. The process achieves high efficiency (Al/F molar ratio of 2/6) within short Empty Bed Contact Times (15 min) and at low HF concentrations (500 mg/L). Solution pH plays a crucial role, with Al/F ratios above 1 achievable at pH below 4. The exothermic reaction requires temperature control, with a strong correlation (R²=0.99) between HF concentration and heat generation. Hydrogen production matches theoretical predictions. Cryolite synthesis was confirmed at optimized pH (5–5.5) with a 1:1 bypass ratio, achieving 98 % fluoride removal. XRD and SEM- EDS analyses verified cryolite formation. This approach offers a promising solution for industrial fluoride management, resource recovery, and clean hydrogen production.

Hydroxyapatite‐spent cathode carbon block modified asphalt and molecular dynamics simulation study

AbstractThe highly toxic substances contained in spent cathode carbon blocks (SCCB) pose a serious threat to human health and the ecological environment, and are difficult to recycle. To address this issue, we utilize H2O2 to oxidize cyanides and grow hydroxyapatite (HAP) on spent cathode carbon blocks to adsorb fluoride ions, achieving controlled removal of cyanides and fluorides. Subsequently, the hydroxyapatite‐spent cathode carbon block composite material (H‐SCCB) is applied to modified asphalt, and simulations of the interaction between hydroxyapatite interfaces and asphalt components are conducted. The results indicate that the total cyanide and fluoride ion concentrations in the experimental wastewater meet the discharge standards for industrial wastewater in China. Hydroxyapatite successfully grows on SCCB, presenting a rich porous structure and significantly increased surface area. Mechanical testing shows that 4% H‐SCCB exhibits optimal performance, with a 23.28% increase in complex modulus (G*) compared to the matrix asphalt. Creep recovery capability (R) increases by 54.32% and 7%, respectively. Additionally, molecular dynamics simulations reveal that the interface adsorption between hydroxyapatite and asphalt binder is primarily influenced by electrostatic forces. Under the influence of hydroxyapatite, the diffusion abilities of asphalt four components are as follows: resin > aromatic > saturate > asphaltene.

Highly enhanced fluoride removal from aqueous systems via solvent extraction utilizing trialkyl phosphine oxide as an efficient extractant

Solvent extraction (SX) has been recognized as an efficient approach for the large-scale removal of impurities, demonstrating considerable potential for fluoride extraction in industrial applications. However, existing fluoride extraction methods typically require the incorporation of additives to form complexes with fluoride for its removal. Due to the excessive additive requirements for efficient fluoride removal, these methods inevitably result in secondary contamination of feed solution, necessitating additional purification efforts to remove them. In this study, four extractants (trioctyl amine, tributyl phosphate, trioctyl phosphate, and trialkyl phosphine oxide (TRPO)) were investigated for fluoride removal via hydrogen bonding with hydrofluoric acid (HF). Various parameters, including the concentrations of extractants and stripping agents, pH values, extraction time, and temperature were initially optimized. It was found that TRPO exhibits the highest extraction efficiency for HF, with a single-stage extraction rate exceeding 70 %. Complete fluoride removal (> 99.9 %) was achieved through a consecutive four-stage extraction process. Further experiments, including maximum loading and slope analysis, combined with FT-IR and 19F NMR characterization, and DFT calculations elucidate the mechanism of the extraction. The transfer of HF into the organic phase is accomplished by the formation of a 1:1 hydrogen-bonded complex with TRPO. The loaded fluoride in the organic phase can be easily stripped by a base to get a fluoride salt. This study paves the way for the construction of novel SX systems to remove fluoride as HF.

Extraction of bio-hydroxyapatite from devilfish (Loricariidae) for the fluoride and cadmium adsorption from water and its feasible photocatalytic properties

In this study, the adsorption capacity of bio-hydroxyapatite (Bio-HAp) from devilfish for the removal of F- and Cd(II) from aqueous solutions was investigated. This material was synthesized according to a 2FI factorial experimental design by varying the extraction conditions for Bio-HAp, including the type of pretreatment (alkaline and peroxide), the calcination temperature from 550 to 850 °C, and the sonication process. The maximum adsorption capacities were 8.48 and 83.56 mg g-1 for F- and Cd(II), respectively. Statistical analysis showed the importance of the type of pretreatment, temperature, and sonication for adsorption. The predicted optimal conditions were Bio-HAp extracted from bone with peroxide pretreatment, calcination at 550 °C and sonication. The surface of the Bio-HAp was found to be mesoporous and basic in character. TGA, FT-IR and SEM-EDS characterizations confirmed the presence of F- and Cd(II) on the Bio-HAp surface and confirmed the adsorption mechanisms by electrostatic forces, ion exchange, and chemisorption. The Praunitz-Rake model of adsorption isotherm showed better agreement with the equilibrium adsorption data of F- and Cd(II) at pH 7. Furthermore, photodegradation experiments showed 100% degradation methylene blue (MB) under natural sunlight. This study indicates an effective photodegradation process, suggesting high adsorption capacity of the samples. The use of devilfish as an adsorbent promises to be a viable and sustainable option for the removal of fluoride and cadmium from water, and for use in photodegradation experiments.

Synthesis and characterization of a crosslinked deacetylated chitin modified chicken bone waste-derived hydroxyapatite and TiO2 biocomposite for defluoridation of drinking water

This work represents an innovative approach to the synthesis and characterization of a chitosan-based biocomposite for fluoride adsorption. The work involved the development of a biocomposite based on modified chicken bone waste-derived hydroxyapatite and TiO2. The composite was characterized using scanning electron microscopy with Energy Dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD), Fourier-transform infrared analysis (FTIR), thermal-gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The optimum parameters for fluoride removal were determined, and the kinetic data was better fitted to the pseudo-first-order model. The Liu equations provided a better description of the experimental adsorption isotherm data. The adsorption mechanism and the interaction of the composite with fluoride were better understood using Density Functional Theory (DFT) calculations and Non-Covalent Interactions (NCI) analyses, paving the way for more effective and efficient defluoridation methods.

Synthesis of Copper-Doped Metal Nanoferrites for Efficient Removal of Pharmaceutical Wastewater Pollutants in Membrane Bioreactor System

Pharmaceuticals present in the aquatic environment can poison aquatic species and humans through drinking water and cause harmful bacteria to become resistant. The role of transition metal doped metal nanoferrites for the enhanced efficiency of degradation process is widely achieved. In this work, copper doped magnesium ferrite (Cu-MgFe2O4) and copper doped zinc ferrite (Cu-ZnFe2O4) nanoparticles were synthesized using a sol-gel method. X-ray diffraction (XRD) analysis confirmed the formation of the spinel structure for both samples, with crystal sizes of 16.72 nm and 59.05 nm, respectively. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM), which revealed that the addition of Cu2+ ions has a significant impact on the magnetic properties of the nanoparticles. The saturation magnetisation (Ms), retentivity (Mr) and coercivity value (Hc) for the Cu-MgFe2O4 sample were found to be 0.18453 emu, 39.584 × 10-3 emu and 139.61 Oe, respectively, while for the Cu-ZnFe2O4 sample, the values were 0.21271 emu, 71.022 × 10-3 emu and 285.91 Oe, respectively. The impact of copper doped nanoferrites on pollutant removal from pharmaceutical wastewater using the membrane Bioreactor (MBR) system has also been accomplished. The results demonstrated the effectiveness of ferrites in reducing concentrations of heavy metals, including lead and cadmium, within acceptable ranges for inland surface water and public sewers. Furthermore, the MBR system with ferrites exhibited efficient removal of fluoride, sulphide and radioactivity, ensuring compliance with the specified standards. Although the study exhibited the potential of ferrites in pollutants removal, further optimization is necessary to achieve complete compliance with water quality standards.

Effective removal of fluoride ions from contaminated water using electrochemical techniques: A critical review on recent developments and environmental perspective

Worldwide, water pollution poses significant threats to human health, with fluoride contamination emerging as a critical hazard. High fluoride concentrations in water cause severe health impacts, including dental and skeletal fluorosis, neurological damage, and harm to the parathyroid gland, cardiovascular, and reproductive systems. Electrochemical technique is one of the most widely used treatment technologies that has been extensively studied and provides a very effective, low-cost method of removing fluoride from contaminated water. The review reports the comprehensive electrochemical strategies for fluoride ions removal. The sources, toxicity, and impacts of fluoride pollution on health are discussed in this review. A comprehensive analysis of current electrochemical methods, including electrolysis, electrocoagulation, and the electro-fenton process, was provided in the context to facilitate the efficient removal of fluoride ions from wastewater. These methods exhibit high removal efficiencies, reaching up to 95 %, and offer scalability and operational flexibility, making them suitable for both centralized and decentralized water treatment systems. Furthermore, the recent advancements in the development of electrochemical technique for fluoride removal are critically reviewed. This study has prospected the recent developments, recommendations and future outlooks on electrochemical technique for fluoride removal.