Mechanochemically Activated Aluminosilicate Clay Soils and their Application for Defluoridation and Pathogen Removal from Groundwater

Abstract

In this study, aluminosilicate rich clay soils were prepared through mechanochemical activation. The chemical and mineralogical properties were investigated using X-Ray Fluorescence (XRF) and X-ray diffraction (XRD). The functional groups, morphology and surface area were evaluated using Fourier Transform Infra-Red (FTIR), Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. Batch experiments were used to evaluate its defluoridation efficiency while antibacterial activities were assessed using well diffusion method. Maximum adsorption capacity was found to be 1.87 mg/g with 32% fluoride removal. Fluoride adsorption was found to reduce in the presence of Cl−, PO42− and CO32− while it increased in the presence of SO42− and NO3−. Adsorption data fitted well to Freundlich isotherms, hence, confirming heterogeneous multilayer adsorption. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second order model. The sorption of F− onto the clays’ surface followed intra-particle diffusion mode. High correlation coefficient indicates that the sorption process was greatly controlled by particle diffusion while it is minimal in pore diffusion model. Antibacterial studies revealed no zone of inhibition for all the activated clays, hence indicating that they are not active against the bacterial strains of Escherichia coli used in this study. The results showed activated clays’ potential for defluoridation. Its effectiveness in pathogen removal is limited. Hence further modifications of the clays’ surfaces are hereby recommended.

Volcanic Rock Materials for Defluoridation of Water in Fixed-Bed Column Systems

“…This type of observations were reported for the removal of pollutant in a previous study [ 6 ]. Furthermore, the elemental compositions of exchangeable cations also play a critical role in fluoride uptake during defluoridation [ 51 ]. There might be a slight increase in electro conductivities of the final solutions, which might not influence the adsorption process [ 52 ].…”

Glauconite clay-functionalized chitosan nanocomposites for efficient adsorptive removal of fluoride ions from polluted aqueous solutions

“…ion uptake throughout the de-uorination process such as Na + , K + , and Ca 2+ . 27 These results conrm the aluminosilicate structure of G clay that supports its application as a reliable sorbent for F À ion. Other physical features such as bulk density, specic surface area and moisture content were determined based on appropriate standards 28 and found to be 1.35 g cm À3 , 47.59 m 2 g À1 and 4.62%, respectively.…”

Development of Kaolin Clay as a Cost-Effective Technology for Defluoridation of Groundwater

“…However, the use of these techniques is limited by high operational cost and ineffective removal efficiency. Adsorption is predicted as the most effective, capable, and widely used crucial method in the water and wastewater treatment processes [26].…”