Fluoride Removal Research Articles

Polyaniline grafting induces abundant active sites on red soil for fluoride removal from wastewater

Polyaniline grafting induces abundant active sites on red soil for fluoride removal from wastewater

Adsorption of titanium-aluminum layered hydroxides for removal of fluorine at low concentrations in water

Layered double hydroxides have good application prospects in the fields of water treatment and defluoridation. In this study, Ti-Al layered hydroxides (Ti-Al LDHs) were synthesized by the co-precipitation method at a Ti/Al molar ratio of 2/8 and a medium solution pH of 6.0. The SEM, XRD, and BET results showed that the Ti-Al LDHs showed a uniform stacking of lamellar structure and existed mainly in dispersed amorphous form, with a wide pore size and a larger specific surface area (108.34 m2/g). The results of adsorption experiments showed that the highest capacity could reach 116.2 mg/g, and the adsorption adsorption of Ti-Al LDHs on fluoride was more in line with the proposed second-order model, and the adsorption isotherm was more in line with the Langmuir model.In addition, Ti-Al LDHs can be applied in a wide pH range (4−10), have strong resistance to anionic competition, and have good regeneration performance after five adsorption-desorption cycles where the adsorption capacity is still equivalent to 73 % of the initial capacity. From the FTIR and XPS results, the adsorption process was mainly attributed to ion exchange, electrostatic attraction and surface complexation. Therefore, Ti-Al LDHs is a layered hydroxide fluoride removal adsorbent with good application prospects.

Cerium-based metal-organic-frameworks with ligand tuning of the microstructures for fluoride adsorption: linear and nonlinear kinetic and isotherm adsorption models.

We present the synthesis and characterisation of three Ce-based metal-organic frameworks (Ce-MOFs) using fumaric acid (Fu), terephthalic acid (BDC), and trimesic acid (H3BTC) as linkers. The use of different linkers influenced the size of the MOF particles, surface area, crystallinity, and microporous structure. The successful implementation of Ce-Fu, Ce-BDC, and Ce-H3BTC MOFs for fluoride ion removal from wastewater was carried out, in which Ce-Fu MOFs exhibited a maximum adsorption capacity (AC) of 64.2 mg g-1. The study also reveals that the use of ultrasound as a mediator for adsorption study over conventional method gives rapid adsorption rate, in which 85% of the fluoride uptake took place just in 10 min and achieved maximum AC in 30 min. The kinetics data were most accurately explained by the pseudo-second-order model (PSO). The existence of co-ions such as NO3-, Cl-, HCO3-, SO42-, Br-, CO32-, and PO43- has a substantial effect on fluoride removal. The mechanism between the fluoride ions and the MOF surface took place via the electrostatic force and the ion exchange process, confirmed using X-ray photoelectron spectroscopy (XPS) and delsa nano. The material is sustained its relatively higher F- ions removal efficiency up to the five cycles. This research might help in the development of novel microporous Ce-based MOFs since it possesses a highly stable crystalline structure in water, suggesting a promising role in aqueous applications.

ADVANCEMENTS IN DEFLUORIDATION TECHNOLOGIES FOR SAFE DRINKING WATER: A COMPREHENSIVE REVIEW

Higher fluoride concentrations in groundwater have been reported in more than 20 developed and developing countries.In the quest for ensuring safe drinking water, the removal of fluoride has emerged as a critical concern globally. This comprehensive review paper delves into the realm of defluoridation technologies, exploring a myriad of methods employed to mitigate excess fluoride levels in water sources. By meticulously examining traditional techniques alongside cutting-edge advancements, this paper provides a detailed analysis of the evolution of defluoridation technologies. From adsorption processes to membrane technologies and electrocoagulation methods, diverse array of approaches are scrutinized for their efficacy in addressing the pressing issue of fluorosis. Through a systematic evaluation of the strengths and limitations of each technology, this review aims to offer valuable insights into the current landscape of defluoridation methodologies. By synthesizing existing knowledge with recent innovations, this paper highlights the progress made in combating fluoride contamination and also underscores the ongoing need for continuous research and development in this crucial field. It has been concluded that the selection of treatment process should be site-specific as per local needs and prevailing conditions as each technology has some limitations and no one process can serve the purpose in diverse conditions.

Study on improving the fluorine removal performance of Chitosan-Al2(SO4)3 modified bauxite

To improve the fluoride removal performance of the bauxite, chitosan (CTS)-Al2(SO4)3 modified bauxite was prepared to remove F− from water. The fluoride removal rates of chitosan and unmodified bauxite were 16.36 % and 48.69 % respectively, and that of CTS-Al2(SO4)3 modified bauxite could reach 98.28 %. The effects of addition amount of Al2(SO4)3 and chitosan, bauxite calcination temperature, reaction time, adsorbent dose, initial F− concentration and co-existing anions were investigated. SEM, FTIR, 77K N2 adsorption-desorption isotherm and XRD were used to analyze the bauxite before and after modification. The results showed that chitosan successfully combined with bauxite, and the morphological changes before and after modification were relatively small. The pseudo second-order kinetic model was more suitable for F− adsorption process of on CTS-Al2(SO4)3 modified bauxite.

Kinetic Studies and Adsorption of Fluoride from Drinking Water using Tamarind Shell as Adsorbent

The excessive intake of fluoride in drinking water is a serious health concern in most of the states in India and in the world. The regular consumption of drinking water containing fluoride leads to a disease called as fluorosis. The Present work of this paper explores the removal of fluoride from synthesized aqueous solution of fluoride using Tamarind fruit shell powder. The Adsorption of fluoride by Tamarind fruit shell is cost effective method and gives high efficiency than other adsorbents. In the present study, The pretreatment for moisture removal from the tamarind shell powder given also we have shown the Kinetics and comparative study to find highest fluoride removal efficiency. In the Kinetic study, the the controlling parameters for adsorption like pH, Adsorbent concentration, Contact time relation on the removal efficiency is studied. The data obtained is fitted in the Langmuir and Freundlich Adsorption Isotherms. The work shows the selective adsorbing property of tamarind shell powder for fluoride removal. The comparison of removal efficiency of fluoride by using tamarind shell powder with wheat straw is done

A Review of Fluoride Removal from Phosphorous Gypsum: A Quantitative Analysis via a Machine Learning Approach.

This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and defluorination techniques. It initially outlines the elemental composition of phosphogypsum prevalent in major production regions and infers the presence of fluorine compounds based on these constituents. The study highlights X-ray photoelectron spectroscopy (XPS) as a pivotal method for characterizing fluorine compounds, emphasizing its capability to determine precise binding energies essential for identifying various fluorine species. Additionally, the first-principle density functional theory (DFT) is employed to estimate binding energies of different fluorine-containing compounds. Significant correlations are observed between the total atomic energy of binary fluorides (e.g., of alkali metals, earth metals, and boron group metals) and XPS binding energies. However, for complex compounds like calcium fluorophosphate, correlations with the calculated average atomic total energy are less direct. The review categorizes defluorination methods applied to phosphogypsum as physical, chemical, thermal, and thermal-combined processes, respectively. It introduces neural network machine learning (ML) technology to quantitatively analyze and optimize reported defluorination strategies. Simulation results indicate potential optimizations based on quantitative analyses of process conditions reported in the literature. This review provides a systematic approach to understanding the phosphogypsum composition, fluorine speciation, analytical methodologies, and effective defluorination strategies. The attempts of adopting DFT simulation and quantitative analysis using ML in optimization underscore its potential and feasibility in advancing the industrial phosphogypsum defluorination process.

Enhanced Fluoride Removal in Wastewater Using Modified Activated Carbon in FCDI Systems

Enhanced Fluoride Removal in Wastewater Using Modified Activated Carbon in FCDI Systems

Experimental and DFT calculation study on the efficient removal of high fluoride wastewater from metallurgical wastewater by kaolinite

Fluoride pollution and water scarcity are urgent issues. Reducing fluoride concentration in water is crucial. Kaolinite has been used to study adsorption and fluoride removal in water and to characterize material properties. The experimental results showed that the adsorption capacity of kaolinite decreased with increasing pH. The highest adsorption of fluoride occurred at pH 2, with a capacity of 11.1 mg/g. The fluoride removal efficiency remained high after four regeneration cycles. The fitting results with the Freundlich isotherm model and the external diffusion model showed that the non-homogeneous adsorption of kaolinite fit the adsorption behavior better. Finally, the adsorption mechanism was analyzed by FT-IR and XPS. The binding energies of various adsorption sites and the chemical adsorption properties of atomic states were discussed in relation to DFT calculations. The results showed that Al and H sites were the main binding sites, and the bonding stability for different forms of fluoride varies, with the size of Al–F (−7.498 eV) > H–F (−6.04 eV) > H–HF (−3.439 eV) > Al–HF (−3.283 eV). Furthermore, the density of states and Mulliken charge distribution revealed that the 2p orbital of F was found to be active in the adsorption process and was the main orbital for charge transfer.

Continuous Electrocoagulation for a Sustainable Water Treatment: Effects of Electrode Configuration, Electrical Connection Mode, and Polarity Reversal on Fluoride Removal

Water pollution in southern Tunisia, particularly in the mining basin of Gafsa, is primarily due to elevated levels of fluoride ions. This study focuses on removing fluoride from Metlaoui’s tap water through a continuous electrocoagulation (EC) treatment. With a fluoride concentration of 3.5 mg·L−1, this water exhibits the highest fluoride levels in Gafsa’s mining basin. The study investigates the impact of electrode configuration on fluoride removal from tap water through continuous electrocoagulation treatment. Configuring the electrodes perpendicular to the water flow improves the aluminum dissolution by electrocoagulation and the fluoride removal efficiency. Additionally, the study explores the effect of electrical connection modes on electrode performance, showing consistent fluoride removal yield under identical current densities and electrochemical cell numbers. Furthermore, the study examines cathodic deposit removal through polarity reversal, demonstrating its effectiveness in eliminating deposits and achieving high fluoride removal yields, especially with polarity reversal every minute. This method proves to be an efficient approach for a more sustainable fluorinated water treatment, eliminating cathodic deposits without the need for chemical or mechanical interventions, and without producing additional effluents or waste. The optimization of these parameters not only enhances fluoride removal efficiency, but also reduces energy consumption and operational costs, thereby promoting the sustainable management of energy and water resources.

Enhanced fluoride removal from water using acid-modified red clay soil from the Loess Plateau of China

ABSTRACT The discharge of fluoride-containing wastewater poses a severe threat to global water resources, ecosystems, and human health. Urgently needed are economically feasible and environmentally sustainable solutions for worldwide fluoride contamination. This study explores utilizing unmodified and modified red clay soils from China's Loess Plateau as adsorbents for fluoride mitigation. Sulfuric acid-modified red clay soil showed higher fluoride removal than unmodified, NaOH-modified, and thermally modified soils. Fluoride adsorption decreased with rising pH from 2.0 to 10.0 for unmodified (67.67–3.91%) and acid-modified red clay soil (90.44–32.06%). The Langmuir model better described the data (R2 = 0.9821, 0.9901 for unmodified, acid-modified soil), improving maximum adsorption capacity by 252%. Pseudo-second-order kinetics (R2 = 0.9925, 0.9954 for unmodified, acid-modified soil) accurately described the kinetic data. Acid modification improved reaction rates, shortening the breakpoint from 6.694 to 2.318 min1/2. Over time, the process transitioned from intraparticle diffusion to external mass transfer and intraparticle diffusion. FTIR analysis showed that acid modification strengthened ligand exchange and provided ion exchange opportunities. This study advances fluoride adsorption through innovative clay soil utilization, offering economical, viable, and environmentally friendly solutions.

Defluoridation of drinking water by using low cost point of use treatment technologies: A review

Fluoride is an anionic pollutant found in surface or ground water in large quantities due to various human activities, for examples, disposal of industrial wastewater or geochemical reactions. The presence of fluoride in drinking water above certain limits has intense effects on human health. It strengthens the tooth enamel to a small level (1.0-1.5 mg/L). In drinking water, the presence of fluoride in the range of 1.5 to 4.0 mg/L may give rise to dental fluorosis at initial the stage, while the continuous exposure to high fluoride concentrations (4.0-10.0 mg/L) leads to skeletal fluorosis. In many countries of the world, including Pakistan, fluoride exists in ground water in high concentration, reaching above 30.0 mg/L on a large scale. The objective of writing this article is to offer accurate information on the efforts of a number of scholars who worked on fluoride removal from drinking water. The fluoride removal techniques have been categorized into two parts dealing with coagulation/precipitation and adsorption. Lime and alum (Nalgonda technique) and chitin have been discussed under coagulation technologies, while adsorption deals with a number of adsorbents, i.e., activated carbon, activated alumina, saw dust, bone char, rice husk ash, bauxite, tea-ash, and kaolin. Each technique discussed can remove fluoride under certain conditions. Each treatment technology has its limitations, and since there is no technology that can achieve its purpose in diverse conditions, the choice of fluoride removal techniques should be according to a specific site, depending on fundamental conditions and the needs of the local area.

Performance evaluation and mechanism of Al2O3/TiO2 sorbents for fluoride remediation in groundwater

Excessive fluoride levels in drinking water are problematic in several countries, particularly those which are relatively poor. Thus, there is a need to create cost effective sorbents which can easily be applied to make the water safe to use. Therefore, this study focussed on Al2O3/TiO2 sorbents which appear to address issues with commercially available alumina such as aluminium dissolution. Adjusting the alumina/titania ratio significantly influenced not only the fluoride uptake capacity but also the uptake of a wide range of contaminants found in groundwater. The exchange kinetics were relatively fast regardless of mixed oxide composition with equilibrium obtained within 6 h. Equilibrium isotherms were unfavourable for fluoride removal where titania compositions were dominant. In contrast, favourable isotherms were noted when alumina was the dominant oxide present. Barium, calcium, strontium, boron, iron, manganese, zinc, potassium, lithium, and silica were all substantially removed by varying the alumina/silica ratio in the sorbent. This behaviour may be valuable for broader remediation of dissolved species in groundwater (not just fluoride). Based upon the tests data a 70% Al2O3 – 30% TiO2 material was recommended to be the preferred composition for comprehensive treatment of groundwater. The sorbents appeared to comprise of alumina and titania with surface areas between 129 and 255 m2/g. There was no evidence for new oxide phases nor for a relationship between surface area and performance. Mechanistically both ion exchange and surface complexation may occur when treating groundwater.

Comprehensive batch studies on removal of fluoride from aqueous solution by acid and alkali-activated adsorbents prepared from Dal lake weeds: Mechanism, Kinetics and Thermodynamics

An efficient and economical way of eliminating fluoride from water is being investigated by employing the buoyant aquatic plant (Dal weed). Two post-pyrolysis chemical activation alteration techniques were implemented: acidic activation by employing sulfuric acid (H-activation) and alkaline activation using sodium hydroxide (OH-activation). The batch kinetic studies have been carried out considering varying starting fluoride levels such as 2–10 mg/L. The impact of diverse procedural factors, including dosage of Dal weed, starting fluoride level, pH and contact duration was observed to determine their influence on fluoride adsorption kinetics. Based on analyzed exploratory results, removal efficacy of 63% for the OH-activated carbon and 83% for H-activated carbon was achieved at commencing fluoride level of 10 mg/L, adsorbent dosage of 0.8 g, at 25 °C after 120 min. The maximal fluoride uptake capacity for H-activated carbon was observed to be 78.158 mg/g. Kinetic investigations showed that the Freundlich isotherm model provided a satisfactory match with an R2 value of 0.99. The reaction order nature adhered to kinetics resembling pseudo second order. Thermodynamic investigation revealed endothermic sorption, with negative ΔG indicating spontaneous fluoride uptake. In comparison, the positive number for ΔS suggested random behavior at the contact involving the adsorbent and adsorbate. The investigations into the regeneration capabilities of the adsorbent material revealed that even after undergoing for five consecutive cycles of adsorption and regeneration, the adsorbent exhibited an uptake potential of 45%. The presence of competing ions in the solution negatively impacted defluoridation efficacy, with the influence following the order of HCO3−< NO3−< Cl−< SO42−< PO43−.

Efficient fluoride removal in hybrid capacitive deionization enabled by Ce-Zn-MOF-derived CeO2@C and birnessite electrodes

Fluorine pollution has become a public health issue of global concern. Capacitive deionization (CDI) presents the benefits of simple operation, high energy efficiency, and good sustainability. The development of high adsorption performance, economical and environmentally friendly defluorination electrodes is the key direction of capacitive deionization. Here, a spherical metal–organic framework (MOF) Ce/Zn-BTC was prepared by solvothermal method utilizing benzene-tricarboxylic (BTC) acid as solvent, and then it was transformed into CeO2@C composites through pyrolysis. The spherical structure of the original MOFs is preserved by CeO2@C, leading to significant enhancements in specific surface area (275.48 m2/g), pore volume (0.3359 cm3/g), and electrochemical performance. In this work, the anode material CeO2@C was employed for the first time, while birnessite-type MnO2 (δ-MnO2) was utilized as a cathode material for the fabrication of a hybrid CDI (HCDI) device for the treatment of fluorinated wastewater. The CeO2@C/δ-MnO2 cell shows excellent fluoride removal performance with a removal capacity of 22.03 mg/g for 50 mg/L fluoride solutions under a 1.2 V applied voltage, which is better than most carbon-based materials. Importantly, the CeO2@C/δ-MnO2 cell has favorable fluoride selectivity and regeneration performance (>75 %) even after undergoing ten cycles. Fluoride is mainly removed by intercalation into the carbon skeleton, coordination with Ce, and electrostatic interaction. This study shows that the CeO2@C/δ-MnO2 cell has excellent fluoride removal performance and practical application prospects.

HZrO2@PPy nanocomposite for effective fluoride removal from environmental water

Fluoride contamination has become a worldwide concern since it can cause serious environmental problems. Zirconium-based adsorbents exhibit satisfactory fluoride removal capabilities. However, their narrow pH applicability, tendency to aggregate, and difficulty in separation hinder practical applications. Herein, a high efficiency hydrous ZrO2 polypyrrole nanocomposite (HZrO2@PPy) was prepared by in-situ oxidative polymerization. The results indicate that HZrO2@PPy exhibit optimal fluoride (F−) removal efficiency in a wide pH range (3−10), with good anti-interference performance to coexisting anions (Cl−, HSO4− and SO42–). The adsorption kinetics conformed to the quasi-second-order model and the adsorption process could reach equilibrium within 10 min. The adsorption isotherms are in good agreement with the Langmuir model, and the maximum adsorption capacity of F− at neutral pH could be 63.61 mg/g. Thermodynamic analysis shows that the adsorption defluorination of HZrO2@PPy is a spontaneous, endothermic, entropy-reducing reaction. In addition, the adsorption mechanism was investigated based on XPS and FTIR analyses. The results demonstrate that the electrostatic attraction, complexation effect and ion exchange are the main mechanisms for the adsorption of F− on HZrO2@PPy. The results presented in this work indicate the potential of the developed nanocomposite as a defluoridation material for environmental water.

Simple and modified chitosan gel beads from a natural source as a bio-sorbent for water defluoridation: Experimental and computational perspectives

Water contaminated with fluoride (F -) is widely acknowledged as a major global issue that poses serious health and environmental risks. Adsorption is one of the many fluoride removal treatment methods that has been widely and successfully investigated. In this work, we describe a simple process for making both cross-linked and uncross-linked chitosan gel beads from shrimp waste. SEM, FTIR, XRD and TGA analysis confirmed the successful synthesis of the non-cross-linked chitosan gel beads (Cs beads) and cross-linked chitosan gel (Cs-Ech beads) whose swelling behavior, stability and fluoride removal efficiency were studied. The adsorption conditions were also optimised. An adsorption capacity of 16.59 mg/g was achieved after just 30 min and at pH = 6.8, 10 mg/L and T = 25 °C. It was shown that chitosan gel beads cross-linked with epichlorohydrin removed more fluoride than non-cross-linked chitosan gel beads. The rate of adsorption of fluoride ions is determined by the pseudo-first order kinetic equation. On the other hand, equilibrium data was best described by Langmuir adsorption isotherms. Density functional theory calculations (DFT) based on quantitative analyses were used to explore the interfacial interaction mechanisms, offering valuable perspectives on the inter- and intra-molecular interactions. Further studies on weak interaction were conducted, focusing on the binding contribution of electrostatic interaction and vdW potential. DFT results confirmed the strong adsorption capacity and coordination behavior of F - ions on the cross-linked Cs-Ech, suggesting that the Ech group offers preferred adsorption sites.

Aluminum-Crosslinked Nanocellulose Scaffolds for Fluoride Removal.

Anionic carboxylated cellulose nanofibers (CNF) are effective media to remove cationic contaminants from water. In this study, sustainable cationic CNF-based adsorbents capable of removing anionic contaminants were demonstrated using a simple approach. Specifically, the zero-waste nitro-oxidization process was used to produce carboxylated CNF (NOCNF), which was subsequently converted into a cationic scaffold by crosslinking with aluminum ions. The system, termed Al-CNF, is found to be effective for the removal of fluoride ions from water. Using the Langmuir isotherm model, the fluoride adsorption study indicates that Al-CNF has a maximum adsorption capacity of 43.3 mg/g, which is significantly higher than that of alumina-based adsorbents such as activated alumina (16.3 mg/g). The selectivity of fluoride adsorption in the presence of other anionic species (nitrate or sulfate) by Al-CNF at different pH values was also evaluated. The results indicate that Al-CNF can maintain a relatively high selectivity towards the adsorption of fluoride. Finally, the sequential applicability of using spent Al-CNF after the fluoride adsorption to further remove cationic contaminant such as Basic Red 2 dye was demonstrated. The low cost and relatively high adsorption capacity of Al-CNF make it suitable for practical applications in fluoride removal from water.

Efficient removal of phosphate and fluoride from phosphogypsum leachate by lanthanum-modified zeolite: Synchronous adsorption behavior and mechanism

Phosphogypsum is a common large-tonnage by–product in phosphorous chemicals industry, its stacking not only causes severe environmental problems, but also leads to a serious waste of phosphate and fluoride resources. The objective of this study was to tackle the recycling treatment of phosphogypsum leachate by using a highly efficient adsorbent lanthanum hydroxide-modified zeolite (LMZ). The adsorption behaviors of phosphate and fluoride by LMZ in the coexisting system under static and dynamic conditions were studied. And further, the competitive adsorption mechanism involved was analyzed. The results showed that LMZ possessed excellent adsorption performance toward both phosphate and fluoride in the single system, but the fluoride adsorption capacity decreased by 57.9 % in the coexisting system, with no change in phosphate adsorption. In the competitive adsorption process, ligand exchange interaction on La active sites contributed most to phosphate adsorption, while fluoride could be adsorbed onto LMZ via electrostatic attraction, surface precipitation with Al sites, and hydrogen bonds with hydroxyl groups in La−OH and P−OH. In actual phosphogypsum leachate, the removal of phosphate had priority over the removal of fluorine. Under continuous adsorption condition, the concentration of phosphorus and fluoride could be decreased to below 0.5 and 1.0 mg/L, respectively, meeting the safe concentration in drinking water. This study promotes the application of La–based adsorbents in the treatment of phosphogypsum leachate, and provides a green and sustainable strategy toward practical phosphorus and fluorine recovery.

Enhanced fluoride removal using montmorillonite clay modified with CoFe2O4 and metal-organic frameworks

The use of modified clays can play an effective role as an effective adsorbent in removing fluoride (Flu) ions from water and aqueous solutions. In the present research, montmorillonite clay (MMt) was modified using CoFe2O4 magnetic particles and Al–Fe fumarate metal-organic framework (Al–Fe Fum) and was utilized as an efficient adsorbent for removing Flu from aqueous solution. The properties of MMt and MMt/CoFe2O4/Al–Fe Fum samples were investigated using different techniques. The results showed that with the modification of MMt using CoFe2O4 magnetic particles and the metal-organic framework of Al–Fe Fum, the BET surface has increased notably from 13.217 to 365.80 m2/g. To investigate the effect of independent variables and their interaction on the efficiency of the Flu adsorption, response surface method-central compound design (RSM-CCD) was served. Based on the results of ANOVA, the F-value and p-value parameters for the desired model were determined to be 783.09 and < 0.0001, respectively, which confirms the success and high ability of the model. The number of R2, adjusted R2, and Predicted R2 for adsorption of Flu ion was determined to be 0.998, 0.997, and 0.995, respectively, which shows that the proposed regression model can describe the process of adsorption and interaction between variables well. Compared to other kinetic models, the pseudo 2nd order kinetic model has a greater ability to describe the Flu adsorption behavior. The R2 parameter value determined that the Freundlich isotherm model has a suitable ability to investigate the isotherm behavior and confirms the effect of heterogeneous surfaces in the process. Generally, the outcomes signified that the MMt and MMt/CoFe2O4/Al–Fe Fum samples can be reused several times in the process of Flu adsorption, while the efficiency is more than 90%.