Defluoridation of Water Using Natural and Activated Coal

Abstract

High fluoride concentration is a worldwide problem in drinking water due its health effects. Batch mode investigation to remove fluoride from aqueous solution and real groundwater samples by natural coal and its modified forms was made. The physicochemical analysis of adsorbents and their activation was overseen to well understand the mechanism of sorption. Adsorption was found to be pH dependent with optimal removal efficiency at pH 2 for physically and chemically activated coal and at pH 4 for natural coal (NC). The experimental data was well fitted with Langmuir and Freundlich adsorption model providing maximum adsorption capacity of 5.9, 8.36 and 11.35 mg/g for natural, physical and chemical activated coal in their order written from Langmuir model. The Dubinin-Radushkevich isotherm (R 2 = 0.988) with mean free energy (E = 0.085 KJ/mol) for natural coal signify physiosorption should be mainly responsible for fluoride adsorption. The applicability of the adsorbents from fluoride contaminated groundwater indicated that natural coal (NC), physically activated coal (PAC) and chemically activated coal (CAC) can be used as an effective, low-cost adsorbent to remove fluoride from groundwater. The buffering capacity of adsorbents monitored during sorption induces a pH increase to nearly neutral, after sorption, which may be an important asset in real applications.

Green Synthesis of Hydroxyapatite Nanoparticles Using Monoon longifolium Leaf Extract for Removal of Fluoride from Aqueous Solution

“…Te increase in removal efciency with increase of adsorbent dose is due to the increase in the availability of binding sites. As a result, 0.75 g of adsorbent was discovered to be the best optimum dosage and this result has better matching with some of the previous research work [44,45].…”

Fe3O4@SiO2 magnetic nanocomposites as adsorbents for removal of diazinon from aqueous solution: isotherm and kinetic study

“…As 1/n value was in the range of 0-1 (1/n = 0.44) adsorption process is suitable (Abdoallahzadeh et al , 2016). As a result of the Dubinin–Radushkevich model analysis, where the determined E value was less than 8 kJ/mol (E = 4.45), it can be assumed that the adsorption process of diazinon onto the Fe 3 O 4 @SiO 2 is probably physical (Regassa et al , 2016).…”