Search published articles


Showing 6 results for Fluoride
Servey  Impact of  Activated Alumina in Fluoride Concentration Peresent in Water and Appointment Adsorption Isotherm and Kinetics
M.t Samadi, R Nourozi, S Azizian, Y Dadban Shahamat, M Zarabi,
Volume 2, Issue 3 (11-2009)
Abstract

Backgrounds and Objectives: Determination of Fluoride in drinking water has received increasing interest, duo to its beneifical and detrimental effects on health. The aim of this research is investigation of Effect of  activated alumina in fluoride concentration reduction in drinking water.
Materials and Methods: Expriment in batch system and with change effective parameters such as pH(5, 7,9), equilibration time (30, 60, 90, 120 minute), initial fluoride concentration(1.4, 2, 2.4 mg/l) and activated Alumina dosage (0.1, 0.2, 0.3 gr/l) was investigated. Also found data of this research were fited with Langmuir and Freundlich models, kinetic data with pseudo- first order, pseudo- second order and modifited pseudo- first order  models.
Results: The results showed that with increasing of pH of solution, removal efficiency was decreased and optimum pH was found to be in the range of 5 to 7. Also removal efficiency of fluoride was increased with increasing of adsorbent dosage and decreasing of initial concentration of fluoride. Adsorption isotherm data show that the fluoride sorption followed the Langmuir model (r2=0.98). Kinetics of sorption of fluoride onto Activated alumina was well described by pseudo- second order model.
Conclusion: The concentration of Activated Alumina had significant effect on the reduction of fluoride ions concentration in water.The higher fluoride removals were observed for batch experiments at pH=5 because no free fluoride ion is present in the solutions, and it could be casued by electrostatic interactions between the surface of alumina and the dominant fluoride species in solution The kinetic model can adequately describe the removal behaviors of fluoride ion by alumina adsorption in the batch system.


Fluoride Removal from Water By Adsorption using Bagasse, Modified Bagasse and Chitosan
S Jorfi, R Rezaei Kalantary, A Mohseni Bandpi, N Jaafarzadeh Haghighifard, A Esrafili, L Alaei,
Volume 4, Issue 1 (5-2011)
Abstract

Background and Objectives: Fluoride is widely used in industries such as manufacture of semiconductors, power plants, glass production etc and release to the environment via their effluents. The purpose of this sturdy was to compare the efficiency of low price adsorbents in fluoride removal from water.
Materials and Methods: The optimum values of pH, contact time and adsorbent dosage were determined and different concentrations of fluoride were experimented in lab scale conditions for bagasse, modified bagasse and chitosan. Then Langmuir and Freundlich coefficient were determined based on optimum conditions.
Results: The pH value of 7, contact time of 60 min and adsorbent dosage of 2 g/L were determined as optimum conditions for all three adsorbents. The most fluoride removal efficiency of 91% was obtained for modified bagasse in optimum conditions.
Conclusion: Based on data obtained in this study, it can be concluded that adsorption by modified bagasse is an efficient and reliable method for fluoride removal from liquid solutions.


Determination of fluorosis prevalence in rural communities  of East Azerbaijan Province
Mohammad Ali Hosseinpour Feizi, Mohammad Mosaferi, Saeed Dastgiri, Maasumeh Mehdipour, Ahmad Kusha,
Volume 5, Issue 3 (10-2012)
Abstract
MicrosoftInternetExplorer4 Background and Objectives: Intake of high concentrations of fluoride in drinking water can cause dental fluorosis. In this study, the prevalence of dental fluorosis in rural communities of East Azerbaijan Province was studied.
Materials and Methods: 3 villages of Bashsizkooh, Bostanabad (fluoride concentration in drinking water = 0.12 mg/L), Nagharehkub,  Ahar (current water resource = 0.6 mg/L, old water resource = 1.1-1.2 mg/L), and Gharehbolaq, Jolfa (current water resource = 0.35 mg/L and old water resource = 2.4 mg/L old source) were selected as low, medium, and high exposure to fluoride respectively. All village residents above 6 years old were visited by physician. Quality of water resources was determined by referring to the records archived and through conducting new analysis.
Results: Dental fluorosis was observed in 62.7 % of the people visited. In 31.5% of participants, fluorosis Grade 1 in 22.4 % of participants, fluorosis grade 2 in 7.7 % of participants, fluorosis grade 3 and finally fluorosis grade 4 was observed in 4 patients. Different levels of fluorosis were observed in residents of the villages of Gharebolaq, Nagharehkub, and Bashsizkooh (83.3%, 70.5 %, and 32.5 % respectively). There was a significant difference in prevalence of fluorosis between villages (P < 0.001). Fluorosis was observed in both permanent and temporary teeth. Mean cumulative fluoride index (MCFI) in people with and without fluorosis was 22660.2 and 4743.2 mg, respectively. There was a correlation between this index and fluorosis (R =0.413).
Conclusion: In all three villages studied, even Bashsizkooh, different grades of fluorosis were endemic. It is recommended that the responsible authorities take a  new measure and approach  for the intake of fluoride from drinking water.

!mso]> ject classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui>


Modeling adsorption on fluoride and application of Box–Behnken design and response surface methodology for arsenic(V) removal from aqueous solution using Nano-Scale Alumina on Multi Walled Carbon Nanotube
H Zarei, A.h Mahvi, S Nasseri, R Nabizadeh Noudehi, F Shemirani,
Volume 8, Issue 3 (12-2015)
Abstract

Objective and Background: Fluoride is an element widely found in the earth crust. Advantages and disadvantages of fluoride in the human body are depended on its concentration. Long-term consumption of drinking water contaminated with arsenic can cause adverse health effects such as skin lesions and cancer in humans. The aim of this study was to study efficiency of nano alumina on multi walled carbon nano tube  for removal As(V) and fluoride from aqueous solution.

Materials and Method: In this study, nano-scale crystalline alumina was synthesized on single walled carbon nanotube by sol-gel method for using as a sorbent for solid phase extraction of Fluorine ion and arsenic(V). Response surface methodology based on Box-Behnken was used to assess the effect of independent variables on the response function and prediction of the best response value. In this study, effect of different parameters, such as contact time (10 to 120 min), pH (3-9), adsorbent dosage (0.25-1.5 g/L) and initial concentration of fluoride (2-8 mg/L) on efficiency of process was investigated. The structure of nano-scale alumina on multi walled carbon nano tube was determined by XRD and SEM techniques. Moreover, Freundlich and Langmuir isotherm models were used to calculate equilibrium constant.

Results: It was found that by increasing contact time and adsorbent dosage the rate of fluoride removal increased. However, by increasing pH and initial concentration the efficiency of fluoride removal decreased. High value for R2 (0.94) shows that removal of arsenic(V) can be described by this model. The Freundlich isotherm was the best fitted graph for experimental data with R2 more than 0.997.

Conclusion: In this study, it was observed that efficiency of arsenic(V) and fluoride  removal was greatly increased by using nano-scale alumina on multi walled carbon nanotubes (MWCNTs).


Adsorption of Fluoride using Diatomite-Supported Ferric Oxide Nanoparticles: Determination of Optimum Condition, Kinetics, and Adsorption Isotherms
S Dehestaniathar, Sh Amini, A Maleki, B Shahmoradi, N Reshadmanesh, P Teymouri,
Volume 9, Issue 2 (9-2016)
Abstract

Background and Objectives: Fluoride has both beneficial and detrimental effects on health. Therefore, it is important to determine its concentration in drinking water. Dental fluorosis and skeletal fluorosis are health effects caused by long term exposure to high levels of fluoride in drinking water. The aim of this research was to investigate fluoride removal using modified diatomite-supported ferric oxide nanoparticles and to determine the adsorption kinetics and isotherm.

Materials and Methods: This fundamental and practical study was performed at laboratory scale. The effects of pH (3.5-9.5), contact time (20-100 min), adsorbent dosage (1-5 g/L), and initial concentrations of fluoride (5-25 mg/L) on the adsorption efficiency were evaluated. The properties of adsorbent were investigated using XRD, XRF, FTIR and FESEM. Finally, the suitability of pseudo first and second order kinetics, and Langmuir and Freundlich isotherms for the data were investigated.

Results: This study showed that the removal efficiency of F- increased with increase in contact time, decrease in pH, increase in adsorbent dose, and increase in initial fluoride concentration. The highest removal efficiency was observed at pH=3.5, 60 minutes contact time, and 3 g/L of adsorbent dose in the initial concentration of 5 mg/L F-. Pseudo first order and Freundlich were the best fitted kinetic and isotherm models, respectively, for describing F- adsorption process.

Conclusion: The present study indicates that the modified diatomite-supported ferric oxide nanoparticles can be used as an effective and environmentally friendly biosorbent for the removal of fluoride ions from aqueous solutions.


Effectiveness of chemical and electrical coagulation process in removing fluoride from the wastewater of the pre-painting unit of the automotive industry
Sakine Shekoohiyan, Mojtaba Pourakbar, Asghar Zohdi Shiran, Farshid Ghanbari, Mostafa Mahdavianpour, Ehsan Aghayani,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: The development of the automobile industry has caused various pollutants to enter the environment, one of which is fluoride. Therefore, this study aims to improve the fluoride removal from wastewater pre-paint units of the automotive industry to achieve discharge standards to surface waters.
Materials and Methods: The study is descriptive and on an applied scale, which has been carried out to compare the efficiency of the chemical coagulation process using lime and alum, as well as the electrocoagulation process using aluminum anodes in the presence of lime to remove fluoride.
Results: The results of real wastewater characteristics showed that the pH of wastewater is in the range of 6.1 to 6.3, and its fluoride concentration is in the range of 45 to 55 mg/L. The results of the experiments show that in the most optimal possible state in the chemical coagulation process, it is possible to achieve fluoride removal efficiency in the range of 76 to 81 percent. However, the removal efficiency in the electrocoagulation process using an aluminum anode at a concentration of 5 mol/L of calcium ions, and current density of 20 A/m2 after reaction time of min 20 to 99% can also be achieved.
Conclusion: Considering the high fluoride removal rate (more than 99%) in the electrocoagulation process in the presence of calcium ions, this process can be introduced as an efficient technology for fluoride removal.
 

Page 1 from 1     

© 2024 , Tehran University of Medical Sciences, CC BY-NC 4.0

Designed & Developed by: Yektaweb