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.

Adsorption of Fluoride on Limestone-Derived Apatite

2012 ◽  
pp. 128-138
Author(s):  
Cyprian Murutu ◽  
Maurice S. Onyango ◽  
Aoyi Ochieng ◽  
Fred Otieno
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity ◽  
Dental And Skeletal Fluorosis ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Permissible Levels ◽  
Ph Range

Fluoride in drinking water above permissible levels is responsible for human dental and skeletal fluorosis. Adsorptive based defluoridation is the most popular technique with several end-user applications. Consequently, this paper describes the fluoride removal potential of a novel sorbent, limestone-derived apatite from drinking water. The adsorbent was prepared by calcining limestone followed by reacting with orthophosphoric acid. Batch sorption studies were performed as a function of contact time, pH, initial fluoride concentration, temperature and adsorbent dose. Sorption of fluoride was found to be pH dependent with a maximum occurring in the pH range of 5-9. The authors also observed that the material had a buffering effect on the same pH range. Meanwhile, the adsorption capacity was found to increase with temperature, depicting the endothermic nature of the adsorption process and decreases with adsorbent mass. The equilibrium data was well described by the conventional Langmuir isotherm, from which isotherm the maximum adsorption capacity was determined as 22.2 mg/g. From the kinetic perspective, the fluoride adsorptive reaction followed the pseudo-second order mechanism.

Adsorption of Fluoride on Limestone-Derived Apatite

2010 ◽  
Vol 1 (3) ◽  
pp. 13-22 ◽  
Author(s):  
Cyprian Murutu ◽  
Maurice S. Onyango ◽  
Aoyi Ochieng ◽  
Fred Otieno
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Maximum Adsorption Capacity ◽  
Dental And Skeletal Fluorosis ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Permissible Levels ◽  
Ph Range

Fluoride in drinking water above permissible levels is responsible for human dental and skeletal fluorosis. Adsorptive based defluoridation is the most popular technique with several end-user applications. Consequently, this paper describes the fluoride removal potential of a novel sorbent, limestone-derived apatite from drinking water. The adsorbent was prepared by calcining limestone followed by reacting with orthophosphoric acid. Batch sorption studies were performed as a function of contact time, pH, initial fluoride concentration, temperature and adsorbent dose. Sorption of fluoride was found to be pH dependent with a maximum occurring in the pH range of 5-9. The authors also observed that the material had a buffering effect on the same pH range. Meanwhile, the adsorption capacity was found to increase with temperature, depicting the endothermic nature of the adsorption process and decreases with adsorbent mass. The equilibrium data was well described by the conventional Langmuir isotherm, from which isotherm the maximum adsorption capacity was determined as 22.2 mg/g. From the kinetic perspective, the fluoride adsorptive reaction followed the pseudo-second order mechanism.

scholarly journals Fluoride Adsorption by Pumice from Aqueous Solutions

2012 ◽  
Vol 9 (4) ◽  
pp. 1843-1853 ◽  
Author(s):  
Amir Hossein Mahvi ◽  
Behzad Heibati ◽  
Alireza Mesdaghinia ◽  
Ahmad Reza Yari
Keyword(s):  
Drinking Water ◽  
Aqueous Solutions ◽  
Fluoride Concentration ◽  
Freundlich Isotherm ◽  
Fluoride Removal ◽  
Maximum Sorption Capacity ◽  
Fluoride Adsorption ◽  
Maximum Sorption ◽  
Pseudo Second Order ◽  
High Concentrations

Drinking water provides many vital elements for the human body, but the presence of some dissolved elements more than permissible concentration can endanger human health. Among the dissolved elements in drinking water, fluoride is noticeable, because both the very low or very high concentrations have adverse health impacts such as dental caries. Therefore, fluoride concentration should be kept in acceptable levels. In this study Pumice was used for fluoride removal. It was found that Fluoride sorption kinetic was fitted by pseudo-second-order model. The maximum sorption capacity of Pumice was found to be 13.51 mg/g at laboratory temperature (24°C). Maximum sorption study occurred at pH= 3. Results of Isotherm showed the fluoride sorption has been well fitted with Freundlich isotherm model. This study has demonstrated that Pumice can be used as effective adsorbents for fluoride removal from aqueous solutions. The adsorbent prepared in this study was cheap and efficient in removal of fluoride than other adsorbents.

Adsorption of fluoride from aqueous solution using low cost adsorbent

2013 ◽  
Vol 13 (2) ◽  
pp. 238-248 ◽  
Author(s):  
R. Buamah ◽  
R. Asare Mensah ◽  
A. Salifu
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Northern Ghana ◽  
Fluoride Removal ◽  
Order Kinetic ◽  
X Ray ◽  
Removal Capacity ◽  
Removal Technologies ◽  
High Aluminium ◽  
Model Water

High fluoride levels beyond the recommended value of 1.5 mg/L have been detected in several groundwater wells in Northern Ghana. This occurrence has led to the capping of many high yielding wells that hitherto have been major sources of drinking water for the populace in these arid areas. Most of the fluoride removal technologies applied in the area has not been versatile in effectively removing fluoride because of the varying water qualities. This study focused on screening adsorbents including high aluminium or iron containing bauxite ores, fabricated zeolite and activated Neem seeds for removal of fluoride from drinking water. The model water used was prepared by simulating the prevailing groundwater quality in Northern Ghana. The high aluminium bauxite ore (HABO) had the highest fluoride removal capacity. Within the pH range tested (5–7), the fluoride removal decreased with increasing pH. Occurrence of sulfate, chloride and nitrate in the model water reduced the fluoride removal capacity by 57, 24 and 38% respectively. The combined effect of these anions showed a 60% reduction in the fluoride removal capacity. The Freundlich and Langmuir isotherms gave an adsorption capacity (K) of 0.90 mg/g for the HABO. The adsorption kinetics fitted well the pseudo second-order kinetic model. The HABO is thermally stable and has kaolinite [Al2Si2O5(OH)5] and gibbsite [Al(OH)3] as its major components. X-ray fluorescence (XRF) and energy dispersive X-ray (EDX) results showed Al, Fe, Ti, O, C and Si as the predominant elements in the HABO.

Lab scale study on electrocoagulation defluoridation process optimization along with aluminium leaching in the process and comparison with full scale plant operation

2011 ◽  
Vol 63 (12) ◽  
pp. 2788-2795 ◽  
Author(s):  
Poonam Gwala ◽  
Subhash Andey ◽  
Vasant Mhaisalkar ◽  
Pawan Labhasetwar ◽  
Sarika Pimpalkar ◽  
...  
Keyword(s):  
Drinking Water ◽  
Process Optimization ◽  
Current Density ◽  
Fluoride Concentration ◽  
Full Scale ◽  
Experimental Results ◽  
Fluoride Removal ◽  
Electrode Polarization ◽  
Operational Conditions ◽  
Aluminium Leaching

An excess or lack of fluoride in drinking water is harmful to human health. Desirable and permissible standards of fluoride in drinking water are 1.0 and 1.5 mg/L, respectively, as per Indian drinking water quality standards i.e., BIS 10500, 1991. In this paper, the performance of an electro-coagulation defluoridation batch process with aluminium electrodes was investigated. Different operational conditions such as fluoride concentration in water, pH and current density were varied and performance of the process was examined. Influence of operational conditions on (i) electrode polarization phenomena, (ii) pH evolution during electrolysis and (iii) the amount of aluminium released (coagulant) was investigated. Removal by electrodes is primarily responsible for the high defluoridation efficiency and the adsorption by hydroxide aluminium floc provides secondary effect. Experimental data obtained at optimum conditions that favored simultaneous mixing and flotation confirmed that concentrations lower than 1 mg/L could be achieved when initial concentrations were between 2 and 20 mg/L. pH value was found to be an important parameter that affected fluoride removal significantly. The optimal initial pH range is between 6 and 7 at which effective defluoridation and removal efficiencies over 98% were achieved. Furthermore, experimental results prominently displayed that an increase in current density substantially reduces the treatment duration, but with increased residual aluminium level. The paper focuses on pilot scale defluoridation process optimization along with aluminium leaching and experimental results were compared with a full-scale plant having capacity of 600 liter per batch.

The sorption of lead, cadmium, copper and zinc ions from aqueous solutions on a raw diatomite from Algeria

2012 ◽  
Vol 65 (10) ◽  
pp. 1729-1737 ◽  
Author(s):  
Messaouda Safa ◽  
Mohammed Larouci ◽  
Boumediene Meddah ◽  
Pierre Valemens
Keyword(s):  
Metal Ions ◽  
Low Cost ◽  
Kinetic Equations ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Reaction Conditions ◽  
Freundlich Isotherms ◽  
Pseudo Second Order ◽  
Sorption Parameters

The adsorption of Cu2+, Zn2+, Cd2+ and Pb2+ ions from aqueous solution by Algerian raw diatomite was studied. The influences of different sorption parameters such as contact pH solution, contact time and initial metal ions concentration were studied to optimize the reaction conditions. The metals ions adsorption was strictly pH dependent. The maximum adsorption capacities towards Cu2+, Zn2+, Cd2+ and Pb2+ were 0.319, 0.311, 0.18 and 0.096 mmol g−1, respectively. The kinetic data were modelled using the pseudo-first-order and pseudo-second-order kinetic equations. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analysed using the Langmuir and the Freundlich isotherms; the results showed that the adsorption equilibrium was well described by both model isotherms. The negative value of free energy change ΔG indicates feasible and spontaneous adsorption of four metal ions on raw diatomite. According to these results, the high exchange capacities of different metal ions at high and low concentration levels, and given the low cost of the investigated adsorbent in this work, Algerian diatomite was considered to be an excellent adsorbent.

Fluoride removal from drinking water in Senegal: laboratory and pilot experimentation on bone char-based treatment

2011 ◽  
Vol 1 (4) ◽  
pp. 213-223 ◽  
Author(s):  
Sabrina Sorlini ◽  
Daniela Palazzini ◽  
Carlo Collivignarelli
Keyword(s):  
Drinking Water ◽  
Dental Fluorosis ◽  
Low Cost ◽  
Fluoride Concentration ◽  
Pilot Scale ◽  
Appropriate Technology ◽  
World Health ◽  
Fluoride Removal ◽  
Process Conditions ◽  
Bone Char

In Senegal there are four regions where fluoride concentration in drinking water exceeds the World Health Organization guide value of 1.5 mg/L. This generates permanent damages to the teeth (dental fluorosis) and to the skeleton (skeletal fluorosis). A safe, efficient, simple and low-cost effective defluoridation technique is not available yet and needs to be developed in order to prevent the occurrence of fluorosis. This experimental research was carried out in order to define an appropriate technology for fluoride removal from groundwater in Senegal. Batch tests and filtration tests at laboratory and pilot scale were carried out using animal bone char as adsorbent material for fluoride removal. Possible influencing parameters, such as specific ions in Senegalese drinking water, were investigated and the best process conditions were defined for the application in Senegal. The results attest to the efficacy of bone char in removing fluoride from Senegalese water: at pilot scale the mean specific adsorption was 2.7 mg F−/g of bone char, corresponding to a total treated volume of 4,000 L and a filter life of nearly three months.

scholarly journals Preparation of Nanochitosan as an Effective Adsorbent for Removal of Pb (II) From Aqueous Solution

2019 ◽  
Author(s):  
Camellia Zareie ◽  
Saeideh Kholghi Eshkalak ◽  
Ghasem Najafpour Darzi ◽  
Mazyar Sharifzadeh baei ◽  
Habibollah Younesi ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Ph Value ◽  
Sorption Process ◽  
Sorption Data ◽  
Kinetics Of Adsorption ◽  
Force Microscopy ◽  
Freundlich Isotherms ◽  
Atomic Force ◽  
Pseudo Second Order ◽  
Sorption Parameters

In this work, nanochitosan (NC) was prepared through ionic gelation using low-molecular-weight chitosan and maleic acid (MA). The synthesized NC was charac¬terized by means of Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). In the course of preparation, the particle size of the material was strongly depended on the parameters such as chitosan concentration and pH of the solution. By controlling the above parameters, NC with the size of smaller than 100 nm was prepared. The chitosan and prepared NC were used for the adsorption of Pb (II) from aqueous solutions in a batch system. Among the sorption parameters, pH showed the strongest effect on the sorption process and maximum Pb (II) removal was obtained at pH value of 6. The pseudo-first-order and pseudo-second-order were used to track the kinetics of adsorption process. Langmuir and Freundlich isotherms were subjected to sorption data to estimate the sorption capacity. NC proved to be an excellent adsorbent with remarkable capacity to remove Pb (II) ions from the aqueous solutions at various concentrations. The NC also showed incredible performance with a comparatively easier preparation process than other reported work.

scholarly journals Generation-3 Polyamidoamine Dendrimer-Silica Composite: Preparation and Cd(II) Removal Capacity

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Augustus N. Ebelegi ◽  
Nimibofa Ayawei ◽  
Azibaola K. Inengite ◽  
Donbebe Wankasi
Keyword(s):  
Freundlich Isotherm ◽  
Sorption Process ◽  
Pamam Dendrimer ◽  
Order Model ◽  
Diffusion Kinetic ◽  
Sorption Data ◽  
Removal Capacity ◽  
Pseudo Second Order ◽  
Film Layer ◽  
Solution Kinetic

Generation-3 polyamidoamine (PAMAM) dendrimer was implanted on silica to produce a very good adsorbent (G-3 PAMAM-SGA). The composite was characterized and used for the removal of Cd(II) ions from aqueous solution. Kinetic data fit the Lagergren pseudo-second-order model and also follow the intraparticle diffusion kinetic model to an extent, which is an indication that the sorption process is controlled by both mechanisms: intraparticle/film layer and adsorption inside the pores/crevices of the composite. Equilibrium sorption data of Cd(II) on G-3 PAMAM-SGA fit the Freundlich isotherm (R2 = 0.9993) which is indicative of multilayered adsorption that occurred on heterogeneous surfaces. The ΔG° values for all temperatures studied were negative, which indicated a spontaneous and feasible process. The result implies that G-3 PAMAM-SGA is a promising adsorbent for microscale scavenging of Cd(II) ions in aqueous solutions.

Preparation and Characterization of Biogenic Chitosan-Hydroxyapatite Composite: Application in Defluoridation

MRS Advances ◽  
2018 ◽  
Vol 3 (36) ◽  
pp. 2089-2098 ◽  
Author(s):  
Agatha W. Wagutu ◽  
Revocatus L. Machunda ◽  
Yusufu Abeid Chande Jande
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Fluoride Concentration ◽  
Health Concern ◽  
Coliform Bacteria ◽  
Fluoride Removal ◽  
Biomass Waste ◽  
Batch Mode ◽  
Treated Water ◽  
Hydroxyapatite Composite

ABSTRACTIn Northern Tanzania, high levels of fluoride in community drinking water supply is recognized as one of the major public health concern, the problem is further ameliorated by presence Escherichia coli and fecal coliform bacteria in surface water and shallow wells. Efforts to decontaminate the water involve mostly the use of low efficient bone char for fluoride removal without disinfecting the pathogens. To address this problem, a robust adsorbent which is capable of removing fluoride and microbes simultaneously with minimal diverse impact on the treated water is necessary. Here we highlight development of composite material developed from recycling of crustacean biomass waste from sea food industry. Chitosan polymer, isolated from prawns shell was composited with crab shell derived brushite (CaHPO4.2H2O) to form chitosan-hydroxyapatite composite. XRD and FT-IR analysis confirmed transformation of brushite phases into hydroxyapatite and formation hybrid composite. Fluoride adsorption tests were performed in batch mode to evaluate effectiveness. Defluoridation capacity of up to 6.4 mg/g in field water containing fluoride concentration of 5-70 mg/L was achieved. The best performance was observed with fluoride concentration of 10 mg/L and below. Apart from fluoride removal, the composite also reduced color tint and microbes from surface water samples. The pH of the treated water in most samples remained around 6.5-8.5, which is acceptable for drinking water.

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