Graphene oxide–aluminium oxyhydroxide interaction and its application for the effective adsorption of fluoride

Abstract

A novel aluminium oxy hydroxide [Al-O(OH)] modified graphene oxide was prepared by a chemical precipitation method wherein Al 3+ ions could interact effectively with the different functional groups of graphene oxide (GO). The prepared (GO-Al-O(OH) adsorbent was tested for the effective defluoridation of water. The Al 3+ modified graphene oxide adsorbent was characterized using FT-IR, FT-Raman, SEM-EDS, XRD and XPS studies. The thermodynamically feasible adsorption is supported by the pseudo second order kinetics and a high Langmuir maximum adsorption capacity (51.42 mg g À1 ) for the GO-Al-O(OH) adsorbent. Furthermore, we could treat 2.0 L of 5.0 mg L À1 fluoride ion solution to bring the level within the permissible limits and the regeneration of the adsorbent was done using ammonium hydroxide. Experimental details MaterialsGraphite with a mean particle size (<20 mm) was procured from Sigma Aldrich. Orthophosphoric acid (H 3 PO 4 , 85%), hydrogen peroxide (H 2 O 2 , 30%), potassium permanganate (KMnO 4 ), aluminum sulfate hydrate (Al 2 (SO 4 ) 3 $16H 2 O), sodium

Rapid and efficient removal of fluoride ions from aqueous solution using a polypyrrole coated hydrous tin oxide nanocomposite

“…However, still comparative evaluation of maximum adsorption capacity, working pH range and equilibrium time of adsorbents based on polypyrrole and tin oxide as well as some other adsorbents reported in the literature [32,52,53] for F À removal has been made to assess the efficiency of the PPy/HSnO adsorbent (Table 4). It can be clearly concluded, that PPy/HSnO NC 3 has significantly higher adsorption efficiency in comparison to other adsorbents [54,55] over a relatively wide pH range of 3.5-8.5, with a shorter equilibrium time.…”

Synthesis and characterization of reduced-graphene oxide/TiO2/Zeolite-4A: A bifunctional nanocomposite for abatement of methylene blue

“…Plethora of literature is available on GO exhibiting remarkable adsorption characteristics due to the presence of large amount of oxidized functional groups such as hydroxyl, aldehyde, carboxylic etc. [14][15][16][17][18][19]. One of the most popular methods of synthesizing GO from graphite is popularly known as modified Hummer's method.…”

A simple one-pot in-situ method for the synthesis of aluminum and lanthanum binary oxyhydroxides in chitosan template towards defluoridation of water

“…According to Pearson's principle, the strong electronegative anion, fluoride is considered as hard base and the chitosan containing amine, hydroxyl, aluminium and lanthanum groups as hard acid which attract effectively fluoride by hard base-hard acid interaction. As per Bharathi et al [14], the Al 3+ and La 3+ exists as cationic hydroxides form and these cationic hydroxide forms could attract fluoride ions by electrostatic interaction in the acidic pH. But in the case of neutral pH, the fluoride ion is tending to attack on hydroxide groups of aluminium and lanthanum by an ion-exchange mechanism.…”

“…Recently, Saha et al [13] examined aluminium oxyhydroxide synthesized in chitosan template and which has the defluoridation capacity (DC) of was 13.47 mg/g. Graphene -aluminium oxyhydroxide interaction and its fluoride uptake studies was clearly explained by Bharathi et al [14]. The Hence, the present investigation was to evaluate the synthesis of aluminium and lanthanum mixed oxyhydroxides by greener method and further these oxyhydroxide materials was developed onto chitosan biopolymer as oxygen rich template by in-situ method for the removal of fluoride from aqueous solution.…”

“…It is important to note that the binding energy of lanthanum and aluminium moves towards the positive side and hence it can be concluded that the two elements had strong interaction between the fluoride and lanthanum and also with aluminium. Furthermore, the binding energy of peaks of F1s were resolved into 688 and 686 eV for Al-F and La-F[14,29] respectively. Hence, the respective strong fluoride peaks of 689.19 and 30.2 eV were assigned to F1s and F2s photoelectrons, indicating fluoride distributed in the layer channel by ions exchange as well as surface adsorption onto CS@ALMOH adsorbent.…”