Adsorbent For Fluoride Removal Research Articles

Adsorptive Removal of Fluoride by Micro-nanohierarchal Web of Activated Carbon Fibers

This study describes the development of aluminum impregnated hierarchal web of carbon fibers for the removal of dissolved fluoride in water. Micrometer-sized activated carbon fibers (ACF) were used as a substrate to grow carbon nanofibers (CNF) by chemical vapor deposition (CVD) using Ni as a catalyst. The hierarchal web of micro-nanocarbon fibers (ACF/CNF) thus prepared was impregnated with aluminum (in its metallic state) and then tested for the adsorption of fluoride ions over the concentration range of 1−50 ppm in water under both batch and flow conditions. The adsorbent web showed significant adsorption of fluoride ions. In addition, the total fluoride uptake was observed to be larger on aluminum impregnated ACF/CNF web than on its parent material, the ACF alone impregnated with Al. Various analytical techniques including the scanning electron microscopy (SEM), Raman spectroscopy, and the elemental analyzer were employed to characterize the Al-impregnated ACF/CNF. The SEM images showed a complex 3D network of nanofibers uniformly deposited with Al. This study is a step in developing a general platform suitable for producing potable water that also specifically addresses the problem of fluoride removal.

Defluoridation of Water Using Zirconium Impregnated Coconut Fiber Carbon

In this study the applicability of Zirconium ion impregnated coconut fiber carbon (ZICFC) as an adsorbent for fluoride removal from water was investigated. The dependence of fluoride adsorption on the physicochemical properties includes pH, agitation time, adsorbent dosage, temperature, and the initial concentration of the adsorbate. Maximum defluoridation was obtained at an original pH value of 4.0 with a rapid 93% adsorption being achieved within 10 min of contact with ZICFC. Adsorption data for fluoride onto ZICFC were better correlated to the Langmuir isotherm and pseudo-second order chemical reaction provided the best fit for the experimental data as obtained from kinetic studies. A combination of chemisorption and physisorption processes in hand with intraparticle diffusion, account for the high defluoridation ability of ZICFC, with the thermodynamic parameters indicating an endothermic phenomenon. The fluoride adsorption capacity of ZICFC when compared with those of other commonly used fluoride adsorbents highlights the substantial improvement in fluoride adsorption capacity of coconut fiber carbon on zirconium impregnation.

Cost Effective Natural Adsorbent for Fluoride Removal

In this study, the uptake of fluoride by raw diatomite and diatomite activated by heat treatment was investigated. Influential parameters such as contact time, pH and adsorption isotherm were also studied. The results showed that the diatomite heated to 500 oC performed better than other heat treatment products and the equilibration time needed for fluoride removal by the adsorbents was reached at 60 min. Results revealed that the capacity of the adsorbents for removing fluoride is independent of the pH when the pH is higher than 4. The adsorption isotherm of the 500 oC treated diatomite showed its Langmuir behavior. The maximum adsorption capacity of raw diatomite and 500 oC calcinated diatomite are 2.253 and 4.162 mg/g, respectively. Based on the results it can be concluded that the diatomite appears to be an economical and environmentally friendly material for defluoridation of water.

Adsorptive removal of fluoride from aqueous phase using waste fungus ( Pleurotus ostreatus 1804) biosorbent: Kinetics evaluation

This contribution presents results pertaining to the adsorptive studies carried out on fluoride removal using waste fungal biomass ( Pleurotus ostreatus 1804) derived from laccase fermentation process. Batch sorption studies were performed and the results revealed that biosorbent demonstrated the ability to adsorb fluoride from aqueous phase. The sorption interaction of fluoride onto non-viable fungal species obeyed the pseudo-first-order rate equation. Isothermal data fitted well with the Langmuir isotherm adsorption model. Fluoride sorption was found to be dependent on the aqueous phase pH and the fluoride uptake was observed to be greater at lower pH. The fluoride sorption phenomena on fungal biosorbent might be attributed to the chemical type of interaction. In order to gain the practical utility of the studied biosorbents, batch studies were performed to evaluate their viability for real field application using eight water samples collected from the fluorsis-affected area.

Study of a New Adsorbent for Fluoride Removal from Waters

Abstract A new adsorbent for fluoride removal is reported in this study. The process and mechanism of removing fluoride are also reported. The adsorbent was characterized as having high selectivity for fluoride, large adsorption capacity, applicability to neutral medium and much better adsorption at high temperature. The floride removal mechanism is a typical chemisorption which is different from the one used for activated alumina. Adsorption rate was considerably faster at the beginning of the adsorption process, followed by a much slower porous diffusion process. Results of field tests showed that the adsorbent was much more suitable for treating high temperature geothermal water with high fluoride content. It also had the advantages of reducing turbidity, decolorizing, dealkalizing, and removing iron from drinking water.

Fluoride removal from water by adsorption on china clay

China clay has been used as adsorbent for removal of fluoride from water at different concentrations, temperatures and pH. Kinetics of adsorption as well as adsorption isotherms at different temperatures for the present system have been investigated. Fluoride removal is favoured by low concentration, high temperature and acidic pH. The alumina constituent of china clay is responsible for maximum adsorption of fluoride in the pH range of interest.