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.

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 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 Aqueous Phase Adsorption of Pb (II) Ions onto Hymenoptera sphecidae (Mud-wasp) Nest

2020 ◽  
pp. 21-31
Author(s):  
Donald T. Kukwa ◽  
Peter A. Adie ◽  
Rose E. Kukwa ◽  
Paula D. Kungur
Keyword(s):  
Contact Time ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Batch Process ◽  
Second Order ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Best Fit ◽  
Adsorbent Dose

Removal of Pb (II) ion from aqueous solution using Hymenoptera sphecidae (mud-wasp) nest was investigated using a batch process. The effect of pH, contact time and adsorbent dose were also investigated. The result showed that the adsorption of Pb (II) ion onto mud-wasp nest was dependent on pH, contact time and adsorbent dose. Adsorption patterns were analysed in terms of three bi-parameter isotherms of Langmuir, Freundlich and Temkin. Freundlich isotherm gave the best fit to the adsorption data with a correlation coefficient of 0.992, while monolayer sorption capacity yielded 41.667 mg/g. Lagergren’s pseudo first-order and pseudo second-order kinetic models were used to test the adsorption kinetics. The kinetic data were well described by the pseudo second-order kinetic model, suggesting that the process was chemisorption type.  The results showed that mud-wasp nest can be used as a low-cost adsorbent for the removal of Pb (II) ion from aqueous solutions.

scholarly journals Influence of the Surface Properties of the Bois Carré Seeds Activated Carbon for the Removal of Lead From Aqueous Ssolutions

2012 ◽  
Vol 14 (3) ◽  
pp. 201 ◽  
Author(s):  
L. Largitte ◽  
S. Gervelas ◽  
T. Tant ◽  
P. Couespel Dumesnil ◽  
P. Lodewyckx
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Chemical Activation ◽  
Acid Sites ◽  
Second Order ◽  
Equilibrium Studies ◽  
Batch Mode ◽  
Initial Concentration ◽  
Pseudo Second Order ◽  
Adsorbent Dose

<p>An activated carbon from Bois carré (Citharexylum Fruticosum L.) seeds was prepared by chemical activation with phosphoric acid. The activated carbon obtained has a surface area of 594 m<sup>2</sup>/g and a high content of acid groups of 3.44 mmol.g<sup>-1</sup>. This carbon was studied for the removal of lead from water. Sorption studies were performed at 30 °C at different pH and adsorbent doses, in batch mode. Maximum adsorption occurred at pH 7 for an adsorbent dose of 1g/L. Kinetic studies, at the initial concentration of 150 mg/L of lead, pH 5 and an adsorbent dose of 1 g/L, yielded an equilibrium time of 30 h for this activated carbon. The kinetic data were modelled with the pseudo first order, the pseudo second order and the Bangham models. The pseudo second order model fitted the data well. The sorption rate constant (2.10<sup>-3</sup> mol<sup>-1</sup>.Kg.s<sup>-1</sup>) and the maximum amount of lead adsorbed are quite good (0.18 mol.kg<sup>-1</sup>) compared to the data found in literature. Sorption equilibrium studies were conducted in a concentration range of lead from 0 to 150 mg/L, at pH 5, adsorbent dose 1 g/L. In an aqueous lead solution with an initial concentration of 30 mg/L, activated Bois carré seed carbon removed (at equilibrium) 48% of the heavy metal. The equilibrium data were modelled with the Langmuir and Freundlich equations, of which the latter gave the best fit. The Freundlich constants n (3.76 L.mol<sup>-1</sup>) and Kf (1.06 mol.kg<sup>-1</sup>) are in good agreement with literature. The Bois carré seed activated carbon is a very efficient carbon in terms of the metal amount adsorbed per unit of surface area (0. 06 m<sup>2</sup>/g). This good result is due to the presence of many active acid sites on the surface of this activated carbon.</p>

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.

Equilibrium and Kinetic Modelling of Astrazon Yellow Adsorption by Sawdust: Effect of Important Parameters

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Naima Ouazene ◽  
Mohamed Nasser Sahmoune
Keyword(s):  
Particle Size ◽  
Contact Time ◽  
Low Cost ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Aleppo Pine ◽  
Pine Tree ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorbent Dose

This paper aims to investigate the sorption of Astrazon yellow (A.Y.) onto sawdust (Aleppo pine tree), a forest waste as that acts as a low-cost adsorbent. In our experiments, the batch sorption is studied with respect to solute concentration, contact time, adsorbent dose, particle size and pH. The adsorption process attains equilibrium within 300 minutes. The extent of dye removal decreased with increasing particle size and increased with increasing contact time, adsorbent dose and pH. The equilibrium data were analysed by the Langmuir and Freundlich isotherms. The characteristic parameters for each isotherm were determined. By considering the experimental results and adsorption models applied in this study, it can be concluded that equilibrium data were represented well by the Langmuir isotherm equation. Maximum adsorption capacity calculated at 293K was 81.8 mg/g. Five kinetic models (pseudo-first order, pseudo-second order, fractional power, Elovich and intraparticle diffusion kinetic equations) were used to predict the adsorption rate constants. The kinetics of adsorption of the basic dye followed both Elovich and pseudo-second order kinetics, and intraparticle diffusion was not the sole rate-controlling step. The effective diffusion of Astrazon yellow in sawdust according to Boyd Model was 24.22 .10-12 m2/S. In order to reveal the adsorption characteristic of sawdust samples, SEM and FTIR spectra analyses were carried out. The results show that sawdust (Aleppo pine tree) can be an alternative low-cost adsorbent for removing cationic dyes from wastewater.

Isotherm and Kinetics Modeling of Fluoride Removal from Industrial Effluent by Alumina

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Z. V. P. Murthy ◽  
Telu Prabhakar ◽  
Raj Kumar
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Kinetic Models ◽  
Fluoride Concentration ◽  
Industrial Effluent ◽  
Second Order ◽  
Fluoride Removal ◽  
Wide Range ◽  
Pseudo Second Order ◽  
High Level

Fluoride contamination occurs in a wide range of industrial wastewater that has to be regulated from time to time. In the present study, wastewater from a polybutadiene rubber plant of Indian Petrochemicals Corporation Limited, Vadodara, Gujarat, India with a higher temperature, acidic pH and high level of fluoride concentration is treated with alumina. The contact time between the adsorbent and the adsorbate should be sufficient for the adsorption to be effective. Though synthetic resins have good adsorption capacity for the wastewater, they have some disadvantages; therefore, alumina has been tried. Properties of alumina, such as pH, bulk density, surface area, pore specific volume, and bulk crushing strength, have been found. Adsorption by alumina is found to be favorable. Five equilibrium adsorption isotherms, viz. Freundlich, Langmuir, Temkin, Harkins-Jura and Halsey, have been tested. It is found that the Halsey and Freundlich adsorption isotherms are fitting the data well. Four kinetic models, viz. Lagergren, pseudo-first-order, second-order, pseudo-second-order and Elovich have been used to find the rate constants. Out of the four kinetic models tested, the pseudo-second-order model fitted the data well in the present case. It is found that when the pH of the wastewater is acidic the adsorption capacity is high. It is also seen that as the temperature of the wastewater increases, the capacity of adsorption also increases.

Performance and Mechanism for Fluoride Removal in Groundwater with Calcium Modified Biochar from Peanut Shell

2020 ◽  
Vol 12 (4) ◽  
pp. 492-501 ◽  
Author(s):  
Rui-Ling Zhang ◽  
Jing Xu ◽  
Lei Gao ◽  
Zhe Wang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Calcium Chloride ◽  
Functional Groups ◽  
Removal Efficiency ◽  
Low Cost ◽  
Calcium Content ◽  
Fluoride Removal ◽  
Peanut Shell ◽  
Modified Biochar ◽  
Pseudo Second Order ◽  
Safe Technique

Fluoride in groundwater poses a great risk to humans. Biochar is an effective and environmental-friendly adsorbent for fluoride removal. The objectives of this study were to develop a calcium modified biochar derived from peanut shell and to study its mechanism in the adsorptive removal of fluoride. For these purposes, biochar was prepared using three different techniques. No. 1 biochar was prepared by direct carbonization, No. 2 biochar was modifiied with 30% calcium chloride solution before carbonization, and No. 3 biochar was modified with 30% calcium chloride following carbonization. The No. 2 biochar clearly showed the highest percentage fluoride removal (92.1%) and the fluoride removal efficiency improved by 30%–60% compared with other techniques. The adsorption isotherms and kinetics of the biochar modified with calcium were best described by the Langmuir and pseudo-second-order model, respectively. Based on the calcium content from the energy spectrum, calcium was well loaded onto the biochar. Calcium detached experiments indicated the loaded calcium was the main method for fluoride removal of No. 2 biochar, the adsorption mechanism was clearly demonstrated through the changes of morphology and group during adsorption. Fourier transform infrared spectroscopic (FTIR) analyses indicated the highest fluoride removal efficiency of No. 2 biochar was due to cleavage and structural change in many functional groups. But only C–H was involved in No. 3 biochar fluoride removal process. The good performance of No. 2 biochar for de-fluoridation was due to the calcium stably loaded onto the biochar and many of the changed functional groups there. Biochar modified with calcium before carbonization is an efficient, low-cost, safe technique for de-fluoridation.

Removal of uranium ions from synthetic wastewater using ZnO/Na-clinoptilolite nanocomposites

2016 ◽  
Vol 104 (11) ◽  
Author(s):  
Azadeh Aghadavoud ◽  
Khadijeh Rezaee Ebrahim Saraee ◽  
Hamid Reza Shakur ◽  
Rasol Sayyari
Keyword(s):  
Removal Efficiency ◽  
Kinetic Data ◽  
Low Cost ◽  
Second Order ◽  
Synthetic Wastewater ◽  
Order Kinetic ◽  
Uranium Ions ◽  
Uranium Removal ◽  
Pseudo Second Order ◽  
Natural Clinoptilolite

AbstractUranium is one of the heavy metals that is found in industrial wastewater and is very toxic for human and environment. In this work, natural clinoptilolite is used as a low-cost adsorbent for uranium removal from aqueous solutions. The sodium form of clinoptilolite and ZnO/Na-clinoptilolite nanocomposite were prepared. The sample sorption capacities for uranium removal from simulated drinking water in the presence of other anions and cations were investigated. Natural zeolite and its modified forms were characterized by XRD, XRF, FTIR, TEM and BET. Batch experiments were used to determine the best adsorption conditions. The effects of various parameters such as contact time, pH, initial uranium concentration, temperature and mass sorbent on the removal efficiency of uranium ions were studied. The equilibration was attained after 2 and 6 h for the Na-clinoptilolite and ZnO/Na-clinoptilolite nanocomposite, respectively. Both adsorbents showed relatively fast adsorption. Effective removal of uranium was demonstrated at pH values of 4–8 for both forms of zeolite. Temperature had no significant effect on adsorption. The maximum removal efficiency of uranium by the ZnO/Na-clinoptilolite nanocomposite in pH=7.2 and room temperature was 98.55%. Langmuir, Freundlich and Sips models were used for describing the equilibrium isotherms for uranium uptake. The Sips model corresponded well with the experimental data. The thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, have been calculated and interpreted. The pseudo-first order and pseudo-second order models were applied to describe the kinetic data. The pseudo-second order kinetic model had excellent kinetic data fitting (R

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.

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