Synthesis and characterization of aluminum-based adsorbent and application in fluoride removal from aqueous solution

Abstract

<jats:p>A novel adsorbent was obtained by a facile precipitation method and was used for fluoride removal from aqueous solution. Mineralogical and physicochemical characterization of the adsorbent was carried out by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Energy Dispersive X-Ray attached to Scanning Electron Microscopy (SEM-EDX), BET Specific Surface Area(SSAN2BET) analysis and Fourier-Transform Infrared Spectrometry (FTIR). The effect of various operational parameters such as contact time, initial fluoride concentration, (20-160 mg L-1) adsorbent dose (1-6 g L-1) and initial pH solution (3-11) was evaluated in batch procedures at room temperature (25±2°C). The results of the batch adsorption experiments proved that 24 h of contact time was sufficient for attaining equilibrium. The maximum wastewater defluoridation (84.91%) was obtained for 40 mg L-1 and 3 g L-1 of initial fluoride concentration and adsorbent dose, respectively. It appears that there was no significant effect on the F- removal over a wide range of pH 3-11. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second-order. The adsorption isotherm of fluoride sorption indicated that the maximum adsorption capacity was noted to be 43.29 mg g-1. Batch adsorption data was better described by Langmuir isotherm confirming monolayer adsorption with homogenous distribution of active sites and without interaction between adsorbed molecules. The obtained results indicated that the ion exchange is probably the main mechanism involved in the F- adsorption by the aluminium-based adsorbent.</jats:p>

Carbon-Enhanced Aluminum-Based Adsorbent for Highly Efficient Removal of Fluoride Contamination from Water

“…The experimental data indicated that the uoride removal was greater than 95% in the pH range of 3-12, except for pH 11, where the lowest value was 88.42%. Overall, the degree of uctuation in uoride removal e ciency was minimal, indicating that the pH dependence of uoride adsorption on CDAA was insigni cant (Assaoui, et al, 2020). It is noteworthy that the residual uoride concentration after de uoridation was consistently less than 0.3 mg/L at pH levels of 3-10 and 12, which was signi cantly lower than the WHO-speci ed drinking water uoride content of 0.7 mg/L.…”

“…An ion selective uoride electrode (PXSJ-216F, LEICI, China) was used for uoride determination. To avoid the in uence of other ions, the total ionic strength adjustment buffer (TISAB) is commonly mixed with the test solution prior to measurement (Assaoui, et al, 2020;De Silva, et al, 2020).…”

“…On the other hand, the increase in active sites with the increases in adsorbent dosage, results in higher uoride removal e ciency (Alemu, et al, 2014). In addition, the overlapping phenomenon of active sites at high adsorbent dosages can reduce the surface area available for adsorption, leading to a saturation trend in uoride removal e ciency (Assaoui, et al, 2020).…”

Bone char from an invasive aquatic species "devilfish" as a sustainable adsorbent for the removal of fluoride in water for human consumption

“…Various technologies are available for the removal of fluorides, including precipitation, coagulation, reverse osmosis, ion exchange, and adsorption. Of all methods, adsorption is highly effective and economical for the reduction of excess fluoride in water (Abeykoon et al 2020;Akafu et al 2019;Alkurdi et al 2019;Assaoui et al 2020;Emmanuel et al 2018;Fan et al 2019), and it uses a variety of adsorbent materials, including clay, soil, organic matter, alumina, zeolites, nanomaterials, activated carbon and bone char (Alkurdi et al 2019;Teusner et al 2016). Bone chars have been widely considered in fluoride removal and have gained considerable attention due to their cheapness, high availability, easy preparation and high adsorption capacity (Alkurdi et al 2019;Medellin-Castillo et al 2020).…”