scholarly journals Development of a novel Artemia eggshell-zirconium nanocomposite for efficient fluoride removal

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244711
Author(s):  
Wen Zhang ◽  
Yuqin Mao ◽  
Yin Lu
Keyword(s):  
Composite Material ◽  
Removal Efficiency ◽  
Treatment Time ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Pore Blockage ◽  
Pseudo Second Order ◽  
The Common ◽  
Kinetics Of ◽  
Better Than

Fluoride pollution in water has attracted widespread concern worldwide. In this study, an Artemia eggshell-zirconium (Aes-Z) nanocomposite has been used for fluoride removal. Material characterization results showed that nano-ZrO2 was immobilized on the inner surface of the Artemia eggshell, and there was no pore blockage on the composite material. Various parameters influencing on the fluoride removal, including treatment time, composite dosage, pH, initial fluoride concentration, and other anions, were analyzed. The removal efficiency of the composite material was better than that of the single zirconia material. The removal percentage of fluoride reached 93% in 30 min with an initial fluoride concentration of 10 mg/L and a nanocomposite dosage of 8.0 g/L. The composite material had a high removal efficiency for fluoride in the pH region 4.0–10.0. The adsorption of fluoride was not influenced by the common anions (e.g., Cl-, SO42-, and NO3-) in water. The regeneration revealed that the Aes-Z composite material could be reused and remove fluoride effectively in four cycles. The pseudo-second-order rate model adequately represented the adsorption kinetics of the Aes-Z composite material. A possible, defluoridation mechanism of the Aes-Z composite material was also proposed. This study demonstrates that Aes-Z is a promising adsorbent material for fluoride removal.

scholarly journals Eggshell-Derived Nanohydroxyapatite Adsorbent for Defluoridation of Drinking Water from Bofo of Ethiopia

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Kifle Workeneh ◽  
Enyew Amare Zereffa ◽  
Toshome Abdo Segne ◽  
Rajalakshmanan Eswaramoorthy
Keyword(s):  
Removal Efficiency ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Batch Adsorption ◽  
Alternative Source ◽  
Fluoride Adsorption ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Eggshell Waste

Fluoride has become a notable toxicological environmental hazard worldwide because it is often found in groundwater. In the present study, hydroxyapatite adsorbent was synthesized from eggshell waste to remove fluoride from aqueous solution. XRD, FT-IR, and TGA techniques were used to characterize the prepared adsorbent. Batch adsorption studies were performed to examine the adsorption capacity of hydroxyapatite such as the effect of the initial pH of the solution, contact time, adsorbent dose, and initial fluoride concentration. The fluoride ion-selective electrode was used to determine the fluoride removal efficiency. 98.8% of fluoride was removed at pH 3.0, but at pH ~7.0, 85% of fluoride was removed; it shows that the fluoride adsorption is pH dependent. The adsorption isotherm studies (Langmuir and Freundlich models) and the experimental results for the removal of fluoride showed that the Langmuir model was more favorable and the reaction followed pseudo-second-order kinetics. In real water samples, the prepared hydroxyapatite derived from eggshell exhibited 81% removal efficiency. Our results indicate that eggshell waste-derived hydroxyapatite may be an alternative source for defluoridation in developing countries.

scholarly journals REMOVAL OF FLUORIDE USING NEEM LEAVES BATCH REACTOR: KINETICS AND EQUILIBRIUM STUDIES

2018 ◽  
Vol 11 (3) ◽  
pp. 237
Author(s):  
Tej Pratap Singh ◽  
Majumder Cb
Keyword(s):  
Removal Efficiency ◽  
Batch Reactor ◽  
Low Cost ◽  
Fluoride Concentration ◽  
Second Order ◽  
Fluoride Removal ◽  
Equilibrium Studies ◽  
Neem Leaves ◽  
Pseudo Second Order ◽  
Adsorbent Dose

 Objective: The aim of this paper is to study the fluoride removal efficiency of the neem leaves low-cost biosorbent for defluoridation of sewage wastewater.Methods: For finding the best operating condition for maximum removal of fluoride, batchwise experiments were performed at different contact times and keeping other parameters to be constant such as pH, initial fluoride concentration, and adsorbent dose. Various kinetic models such as intraparticle diffusion model, Bangham’s model, and Elovich model had been investigated for determining the suitable adsorption mechanism. The rate of adsorption of fluoride on neem leaves has been determined by pseudo-first-order and pseudo-second-order rate models.Results: The adsorption kinetics rate and mechanism was best described by the pseudo-second-order model and Bangham’s model, respectively. The optimum pH, initial concentration, adsorbent dose, and contact time were found to be 7, 20 mg/L, 10 g/L, and 40 min, respectively, for which there was maximum fluoride removal.Conclusion: The result obtained from the experiments show that the neem leaves have been proved to be a low-cost biosorbent for the defluoridation of the sewage wastewater and have high fluoride removal efficiency.

Effects of operational parameters on defluoridation efficiency using electrocoagulation process

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Behbahani ◽  
M.R. Alavi Moghaddam ◽  
M. Arami
Keyword(s):  
Reaction Time ◽  
Anode Material ◽  
Removal Efficiency ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Operational Parameters ◽  
Applied Current ◽  
Initial Ph ◽  
Electrocoagulation Process ◽  
Electrode Connection

The aim of this study is to examine the effect of operational parameters on fluoride removal using electrocoagulation method. For this purpose, various operational parameters including initial pH, initial fluoride concentration, applied current, reaction time, electrode connection mode, anode material, electrolyte salt, electrolyte concentration, number of electrodes and interelectrode distance were investigated. The highest defluoridation efficiency achieved at initial pH 6. In the case of initial fluoride concentration, maximum removal efficiency (98.5%) obtained at concentration of 25mg/l. The increase of applied current and reaction time improved defluoridation efficiency up to 99%. The difference of fluoride removal efficiencies between monopolar and bipolar series and monopolar parallel were significant, especially at reaction time of 5 min. When aluminum used as anode material, higher removal efficiency (98.5%) achieved compared to that of iron anode (67.7%). The best electrolyte salt was NaCl with the maximum defluoridation efficiency of 98.5% compared to KNO3 and Na2SO4. The increase of NaCl had no effect on defluoridation efficiency. Number of electrodes had little effect on the amounts of Al3+ ions released in the solution and as a result defluoridation efficiency. Almost the same fluoride removal efficiency obtained for different interelectrode distances.

scholarly journals Fluoride removal efficiencies of Al-EC and Fe-EC reactors: process optimization using Box–Behnken design of the surface response methodology

2020 ◽  
Vol 10 (9) ◽  
Author(s):  
Magori J. Nyangi ◽  
Yonas Chebude ◽  
Kessy F. Kilulya
Keyword(s):  
Treatment Time ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Reactor Model ◽  
Optimal Operating ◽  
Surface Response Methodology ◽  
Box Behnken Design ◽  
Surface Response ◽  
Independent Variables ◽  
Initial Ph

Abstract In this study, surface response methodology was employed to investigate the effect of different interacting factors on the removal of fluoride from synthetic water using aluminum electrocoagulation (Al-EC) and iron electrocoagulation (Fe-EC) in different reactors. Box–Behnken design of a Design Expert version 11 was used for the optimization and evaluation of the process independent variables: applied electric density, initial pH, initial fluoride concentration and treatment time on the efficiency of fluoride removal as a response. Results showed that the effect of current density and initial fluoride concentration was significant model terms for fluoride reduction in Fe-EC and Al-EC reactors, respectively. The Al-EC reactor model presented the R2 value of 79.2% while Fe-EC presented R2 value of 75.8%, showing that both models can predict the response well. The reduction by 94% (initial concentration of 16 mgF/L) was established at optimal operating parameters of 18.5 mAcm−2, pH 6.80 in 50 min using Al-EC. On the other hand, 16 mgF/L was reduced by 92% to 1.28 mgF/L in Fe-EC reactor at optimal condition of 6.5 mAcm−2, pH 6.50 in 50 min. Experimental results correlated well to the model predicted results that were 95 and 94% for Al-EC and Fe-EC, respectively. Both reactors manage to reduce fluoride to a level recommended by WHO (≤ 1.5 mg/L) for drinking purpose.

scholarly journals An Experimental Study of Fluoride Removal from Wastewater by Mn-Ti Modified Zeolite

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3343
Author(s):  
Bo Yang ◽  
Guirong Sun ◽  
Bingxu Quan ◽  
Jiawei Tang ◽  
Chunhui Zhang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Removal Efficiency ◽  
Natural Zeolite ◽  
Fluoride Concentration ◽  
Current Work ◽  
Fluoride Removal ◽  
Metal Fluoride ◽  
Modified Zeolite ◽  
X Ray ◽  
Independent Variables

The emerging interest in fluoride-removal from wastewater has attracted attention to zeolite since it has been considered as a natural adsorbent. However, the fluoride-removal efficiency of natural zeolite is generally low. As part of the effort to improve the zeolite adsorption efficiency, we have produced and tested the Mn-Ti modified zeolite. In the current work, the material preparation is discussed, and prepared materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy, and Fourier transform infrared (FTIR) spectra. Both static and dynamic experiments were conducted to examine the effects of independent variables. In the static adsorption section, sensitivity analysis experiments were conducted for independent variables, such as adsorbent dosage, pH, temperature, and competitive ions. The maximum adsorption capacity is 2.175 mg/g, which was obtained at PH = 7, temperature = 25 °C, and initial fluoride concentration = 10 mg/L. For adsorption kinetics, both Lagergren and Pseudo-second order models predict the experiments very well, which probably demonstrates that the current process is a combination of physical sorption and chemisorption. For adsorption isotherms, the Freundlich model performs better than the Langmuir model since it is usually applied to illustrate adsorption on inhomogeneous surfaces. In the dynamic adsorption section, sensitivity analysis experiments were also conducted for independent variables, such as adsorbent thickness, flow velocity, initial fluoride concentration, and PH. Additionally, the adsorption mechanism is also discussed. The main reason is the hydrated metal fluoride precipitate formation. As we know, the current work provides the first quantified comparison of the natural zeolite and the Mn-Ti modified zeolite regarding fluoride-removal efficiency.

The Optimal Experimental Research on the Fluoride Removal from Efficient-Whirling Clarifier

2011 ◽  
Vol 374-377 ◽  
pp. 887-890
Author(s):  
Feng Ping Hu ◽  
Lin Yuan Wang ◽  
Jian Wen Luo
Keyword(s):  
Rotational Speed ◽  
Fluoride Concentration ◽  
Engineering Application ◽  
Fluoride Removal ◽  
Potassium Alum ◽  
Second Stage ◽  
Drinking Water Standard ◽  
Optimum Parameters ◽  
Polyaluminium Chloride ◽  
Better Than

In this paper the experiment research of fluoride removal was based on coagulating sedimentation method, and the defluorination effect of coagulant’s kinds and dosage、parameters of rotational speed and coagulant aid’s dosage was studied and optimized, which could provide crafts parameters of efficient-whirling clarifier for engineering application . In this experiment, five coagulants was compared, which including aluminum sulfate (Al2(SO4)3)、potassium alum(KAl(SO4)2)、ferric sulphate（Fe2(SO4)3）、ferric chloride（FeCl3）and polyaluminium chloride（PAC）. Parameters of rotational speed applied in this experiment were simulated from the G state of efficient-whirling clarifier, while polyacrylamide was employed as the coagulant aid. The experiment results showed that: First, the defluorination effect of polyaluminium chloride was better than that of other coagulants. Second, the optimum parameters of rotational speed was that mixing at the speed of 400 r/min for 60 seconds，the first stage of coagulation at the speed of 160r/min for 7minutes、the second stage of coagulation at the speed of 90r/min for 8 minutes and sedimentation for 15minutes. Third, PAM was helpful for the defluorination effect of PAC. The fourth, when fluoride concentration in raw water respectively were 2.0mg/L、5.0mg/L、10mg/L, the dosages of PAC respectively were 400 mg/L、500mg/L、1300mg/L and the dosage of PAM respectively were that of PAM was 0.09mg/L、0.12mg/L、0.09mg/L, which could make the outlet of fluoride concentration achieved the national drinking water standard (GB5749-2006).

scholarly journals Kinetics and equilibrium studies for removal of fluoride from underground water using cryptocrystalline magnesite

2015 ◽  
Vol 5 (3) ◽  
pp. 282-292 ◽  
Author(s):  
Vhahangwele Masindi ◽  
Wilson Mugera Gitari ◽  
Tholiso Ngulube
Keyword(s):  
Rural Areas ◽  
Fluoride Concentration ◽  
Underground Water ◽  
Fluoride Removal ◽  
Equilibrium Studies ◽  
Adsorption Mechanisms ◽  
Quality Guidelines ◽  
Monolayer Adsorption ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order

In the present study, the defluoridation capabilities and adsorption mechanisms of cryptocrystalline magnesite were evaluated. All experiments were done by batch procedure. Conditions assessed include time, dosage, concentration, pH and the effects of competing ions. Optimum defluoridation conditions were observed to be 20 g/L magnesite, 2:100 solid:liquid ratio, 20 min of agitation and 60 mg/L fluoride concentration. Adsorption of fluoride by magnesite was observed to be independent of pH. Cryptocrystalline magnesite showed >99% efficiency for fluoride removal. Adsorption kinetics fitted better to a pseudo-second order than a pseudo-first order thus confirming chemisorption. Adsorption data fitted better to a Langmuir than a Freundlich adsorption isotherm thus confirming monolayer adsorption. Cryptocrystalline magnesite successfully removed excess fluoride from aqueous solution to below Department of Water Affairs and Forestry water quality guidelines. As such, this material can be used for a point source defluoridation technique in rural areas and households in South Africa and other developing countries. Based on comparison studies, cryptocrystalline magnesite proved to have high adsorption capacity for fluoride removal and can be used as a substitute for conventional treatment methods.

scholarly journals Evaluation of bentonite clay in modified and unmodified forms to remove fluoride from water

2021 ◽  
Author(s):  
Adane Woldemedhin Kalsido ◽  
Arun Kumar ◽  
Beteley Tekola ◽  
Beshah Mogessie ◽  
Esayas Alemayehu
Keyword(s):  
Aluminum Oxide ◽  
Removal Efficiency ◽  
Fluoride Concentration ◽  
Bentonite Clay ◽  
Physicochemical Characteristics ◽  
Exchange Capacity ◽  
Point Of Zero Charge ◽  
Fluoride Removal ◽  
Modified Bentonite ◽  
Silica Alumina

Abstract The feasibility of fluoride adsorption from aqueous solutions using naturally available bentonite clay in both modified and unmodified forms is investigated in this report. SEM, EDX, XRD, and FT-IR analysis are applied to describe the structure and nature of unmodified and modified bentonite clay. The physicochemical characteristics of the adsorbent were also investigated by its moisture content, pH, apparent density, specific surface area, cation exchange capacity and its point of -zero charge determination. SEM image reveals particles are dispersed homogeneously and are irregular in shape. XRD and EDX analyses reveal that the bentonite is composed of seven materials: Calcite, Silica, Alumina, Hematite, bornite and Green cinnabar, and Chloride are considered as impurity. Raw bentonite (RB) clays have shown very low fluoride removal efficiency (47.19%). Modification of the clay surface with HCl (ATB) and aluminum oxide (AOMB), on the other hand, increased fluoride removal efficiency to 79.77% and 94.38%, respectively. At 5 mg/L initial fluoride concentration, 10 cm bed depth packed dose of adsorbent, and 180 min breakthrough time, a 2.88 mg/g of fluoride removal capacity was observed. As the result, aluminum oxide modified bentonite clay was chosen for further investigation and its result is not presented here.

scholarly journals Adsorption Efficiency of Cement Impregnated Magnesium Oxide on the Removal of Fluoride

2020 ◽  
Vol 5 (2) ◽  
pp. 109-117
Author(s):  
Iohborlang M. Umlong ◽  
Bodhaditya Das ◽  
Rashmi Rekha Devi
Keyword(s):  
Drinking Water ◽  
Magnesium Oxide ◽  
Fluoride Concentration ◽  
Sorption Process ◽  
Fluoride Removal ◽  
Cement Slurry ◽  
Freundlich Isotherms ◽  
Removal Capacity ◽  
Complex Process ◽  
Pseudo Second Order

Presence of fluoride in drinking water above the prescribed limit may lead to a severe health complication. We present in this paper the fluoride removal capacity of cement impregnated MgO (MgO-cement) from drinking water. MgO-cement was prepared by adding magnesium oxide (MgO) into the cement slurry solution in the ratio of 1:10. Batch experiments were performed as a function of adsorbent dose, contact time, effect of pH and effect of co-ions. The percentage removal decreases with increasing initial fluoride concentration. Co-ions effect revealed that hydroxide ion was found to interfere more with fluoride removal followed by bicarbonate and least effect with sulphate. Reaction mechanism follows Freundlich isotherms. From the kinetic study we observed that uptake of fluoride ion is fast in the first sixty minutes and equilibrium time found to be independent of the initial fluoride concentration. Adsorption kinetics followed the pseudo second order model showing that the sorption of fluoride is a complex process. Surface as well as intraparticle diffusion contribute in the sorption process. No leaching of magnesium in the treated water was detected.

scholarly journals An Experimental Study on Biosorption of Fluoride from Water Using LocallyObtained Moringa Oleifera Seeds

2021 ◽  
Vol 19 (1) ◽  
pp. 35-39
Author(s):  
Faheem Akhter ◽  
Arsalan A. Jokhio ◽  
Javed A. Noonari
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Contact Time ◽  
Moringa Oleifera ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Engineering Science ◽  
Environment Friendly ◽  
Experimental Facilities ◽  
Adsorbent Dose

Moringa Oleifera is considered to be a natural bio-adsorbent. Unlike chemical coagulants, Moringa Oleifera seeds are environment friendly with various other advantages. The present study investigated the fluoride removal efficiency of Moringa Oleifera from water. Influence of adsorbent dose (1, 2, 4 g/L), contact time (20, 40 and 60 min) and initial fluoride concentration (2 and 5 mg/L) over removal efficiency were determined and optimized. It was found that increased adsorbent dose and contact time enhanced the removal efficiency which is in agreement with the previous studies. The highest removal of 88.1% was achieved when the adsorbent dose and contact time were optimized to 4 g/L and 60 minutes with an initial fluoride concentration of 2 mg/L. The results showed that Moringa Oleifera can be used as an environment friendly, cheap and effective bio-adsorbent for fluoride removal from aqueous solution. All the experimental facilities were provided by Bio-Fuel Lab, Energy & Environment Department, Quaid-e-Awam University of Engineering, Science and Technology, Nawabshah, Pakistan. The samples were analyzed at the Pakistan Council of Research in Water Resources (PCRWR), Tando Jam, Pakistan.

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